/*
 * Miscellaneous helpers for common operations.
 */

// TOP

#define scope_attachment(app,S,I,T) ((T*)managed_scope_get_attachment((app), (S), (I), sizeof(T)))
#define set_custom_hook(app,ID,F) set_custom_hook((app),(ID),(Void_Func*)(F))

////////////////////////////////

function i32
get_command_id(Custom_Command_Function *func){
    i32 result = -1;
    for (i32 i = 0; i < ArrayCount(fcoder_metacmd_table); i += 1){
        if (func == fcoder_metacmd_table[i].proc){
            result = i;
            break;
        }
    }
    return(result);
}

function Command_Metadata*
get_command_metadata(Custom_Command_Function *func){
    Command_Metadata *result = 0;
    i32 id = get_command_id(func);
    if (id >= 0){
        result = &fcoder_metacmd_table[id];
    }
    return(result);
}

////////////////////////////////

internal Token_Array
get_token_array_from_buffer(Application_Links *app, Buffer_ID buffer){
    Token_Array result = {};
    Managed_Scope scope = buffer_get_managed_scope(app, buffer);
    Async_Task *lex_task_ptr = scope_attachment(app, scope, buffer_lex_task, Async_Task);
    if (lex_task_ptr != 0){
        async_task_wait(app, &global_async_system, *lex_task_ptr);
    }
    Token_Array *ptr = scope_attachment(app, scope, attachment_tokens, Token_Array);
    if (ptr != 0){
        result = *ptr;
    }
    return(result);
}

////////////////////////////////

internal Buffer_Seek
seek_location(ID_Line_Column_Jump_Location location){
    return(seek_line_col(location.line, location.column));
}

internal Buffer_Seek
seek_location(ID_Pos_Jump_Location location){
    return(seek_pos(location.pos));
}

internal Buffer_Seek
seek_location(Name_Line_Column_Location location){
    return(seek_line_col(location.line, location.column));
}

internal Buffer_Seek
seek_jump(Parsed_Jump jump){
    return(seek_location(jump.location));
}

////////////////////////////////

View_Context_Block::View_Context_Block(Application_Links *a, View_ID v,
                                       View_Context *ctx){
    this->app = a;
    this->view = v;
    view_push_context(a, v, ctx);
}

View_Context_Block::~View_Context_Block(){
    view_pop_context(this->app, this->view);
}

////////////////////////////////

internal Character_Predicate
character_predicate_from_function(Character_Predicate_Function *func){
    Character_Predicate predicate = {};
    i32 byte_index = 0;
    for (u32 i = 0; i <= 255;){
        b8 v[8];
        for (i32 bit_index = 0; bit_index < 8; i += 1, bit_index += 1){
            v[bit_index] = func((u8)i);
        }
        predicate.b[byte_index] = ((v[0] << 0) |
                                   (v[1] << 1) |
                                   (v[2] << 2) |
                                   (v[3] << 3) |
                                   (v[4] << 4) |
                                   (v[5] << 5) |
                                   (v[6] << 6) |
                                   (v[7] << 7));
        byte_index += 1;
    }
    return(predicate);
}

internal Character_Predicate
character_predicate_from_character(u8 character){
    Character_Predicate predicate = {};
    predicate.b[character/8] = (1 << (character%8));
    return(predicate);
}

#define character_predicate_check_character(p, c) (((p).b[(c)/8] & (1 << ((c)%8))) != 0)

internal Character_Predicate
character_predicate_or(Character_Predicate *a, Character_Predicate *b){
    Character_Predicate p = {};
    for (i32 i = 0; i < ArrayCount(p.b); i += 1){
        p.b[i] = a->b[i] | b->b[i];
    }
    return(p);
}

internal Character_Predicate
character_predicate_and(Character_Predicate *a, Character_Predicate *b){
    Character_Predicate p = {};
    for (i32 i = 0; i < ArrayCount(p.b); i += 1){
        p.b[i] = a->b[i] & b->b[i];
    }
    return(p);
}

internal Character_Predicate
character_predicate_not(Character_Predicate *a){
    Character_Predicate p = {};
    for (i32 i = 0; i < ArrayCount(p.b); i += 1){
        p.b[i] = ~(a->b[i]);
    }
    return(p);
}

internal i64
buffer_seek_character_class_change__inner(Application_Links *app, Buffer_ID buffer, Character_Predicate *positive, Character_Predicate *negative, Scan_Direction direction, i64 start_pos){
    i64 pos = start_pos;
    switch (direction){
        case Scan_Backward:
        {
            String_Match m1 = buffer_seek_character_class(app, buffer, negative, direction, pos);
            String_Match m2 = buffer_seek_character_class(app, buffer, positive, direction, m1.range.min);
            pos = m2.range.min;
            if (m1.buffer == buffer && m2.buffer == buffer){
                pos += 1;
            }
        }break;
        case Scan_Forward:
        {
            pos -= 1;
            String_Match m1 = buffer_seek_character_class(app, buffer, positive, direction, pos);
            String_Match m2 = buffer_seek_character_class(app, buffer, negative, direction, m1.range.min);
            pos = m2.range.min;
        }break;
    }
    return(pos);
}

internal i64
buffer_seek_character_class_change_1_0(Application_Links *app, Buffer_ID buffer, Character_Predicate *predicate, Scan_Direction direction, i64 start_pos){
    Character_Predicate negative = character_predicate_not(predicate);
    return(buffer_seek_character_class_change__inner(app, buffer, predicate, &negative, direction, start_pos));
}

internal i64
buffer_seek_character_class_change_0_1(Application_Links *app, Buffer_ID buffer, Character_Predicate *predicate, Scan_Direction direction, i64 start_pos){
    Character_Predicate negative = character_predicate_not(predicate);
    return(buffer_seek_character_class_change__inner(app, buffer, &negative, predicate, direction, start_pos));
}

////////////////////////////////

internal i64
view_pos_from_xy(Application_Links *app, View_ID view, Vec2_f32 p){
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    Rect_f32 region = view_get_buffer_region(app, view);
    f32 width = rect_width(region);
    Face_ID face_id = get_face_id(app, buffer);
    Buffer_Scroll scroll_vars = view_get_buffer_scroll(app, view);
    i64 line = scroll_vars.position.line_number;
    p = (p - region.p0) + scroll_vars.position.pixel_shift;
    return(buffer_pos_at_relative_xy(app, buffer, width, face_id, line, p));
}

internal Buffer_Point
view_move_buffer_point(Application_Links *app, View_ID view, Buffer_Point buffer_point, Vec2_f32 delta){
    delta += buffer_point.pixel_shift;
    Line_Shift_Vertical shift = view_line_shift_y(app, view, buffer_point.line_number, delta.y);
    buffer_point.line_number = shift.line;
    buffer_point.pixel_shift = V2f32(delta.x, delta.y - shift.y_delta);
    return(buffer_point);
}

internal void
view_zero_scroll(Application_Links *app, View_ID view){
    Buffer_Scroll scroll = {};
    view_set_buffer_scroll(app, view, scroll, SetBufferScroll_SnapCursorIntoView);
}

internal Vec2_f32
view_relative_xy_of_pos(Application_Links *app, View_ID view, i64 base_line, i64 pos){
    Rect_f32 rect = view_relative_box_of_pos(app, view, base_line, pos);
    return(rect_center(rect));
}

internal void
view_set_cursor_and_preferred_x(Application_Links *app, View_ID view, Buffer_Seek seek){
    view_set_cursor(app, view, seek);
    Buffer_Cursor cursor = view_compute_cursor(app, view, seek);
    Vec2_f32 p = view_relative_xy_of_pos(app, view, cursor.line, cursor.pos);
    view_set_preferred_x(app, view, p.x);
}

function i64
view_set_pos_by_character_delta(Application_Links *app, View_ID view, i64 pos, i64 character_delta){
    Buffer_Cursor cursor = view_compute_cursor(app, view, seek_pos(pos));
    i64 character = view_relative_character_from_pos(app, view, cursor.line, cursor.pos);
    i64 new_pos = view_pos_from_relative_character(app, view, cursor.line, character + character_delta);
    return(new_pos);
}

function i64
view_set_cursor_by_character_delta(Application_Links *app, View_ID view, i64 character_delta){
    i64 pos = view_get_cursor_pos(app, view);
    i64 new_pos = view_set_pos_by_character_delta(app, view, pos, character_delta);
    view_set_cursor_and_preferred_x(app, view, seek_pos(new_pos));
    return(new_pos);
}

function i64
view_correct_cursor(Application_Links *app, View_ID view){
    i64 pos = view_get_cursor_pos(app, view);
    i64 new_pos = view_set_pos_by_character_delta(app, view, pos, 0);
    view_set_cursor(app, view, seek_pos(new_pos));
    return(new_pos);
}

function i64
view_correct_mark(Application_Links *app, View_ID view){
    i64 pos = view_get_mark_pos(app, view);
    i64 new_pos = view_set_pos_by_character_delta(app, view, pos, 0);
    view_set_mark(app, view, seek_pos(new_pos));
    return(new_pos);
}

function Vec2_f32
buffer_point_difference(Application_Links *app, Buffer_ID buffer, f32 width, Face_ID face_id,
                        Buffer_Point a, Buffer_Point b){
    f32 y_difference = buffer_line_y_difference(app, buffer, width, face_id, a.line_number, b.line_number);
    Vec2_f32 result = a.pixel_shift - b.pixel_shift;
    result.y += y_difference;
    return(result);
}

function Vec2_f32
view_point_difference(Application_Links *app, View_ID view, Buffer_Point a, Buffer_Point b){
    f32 y_difference = view_line_y_difference(app, view, a.line_number, b.line_number);
    Vec2_f32 result = a.pixel_shift - b.pixel_shift;
    result.y += y_difference;
    return(result);
}

////////////////////////////////

internal Range_i64
buffer_range(Application_Links *app, Buffer_ID buffer){
    Range_i64 range = {};
    range.end = buffer_get_size(app, buffer);
    return(range);
}

internal i64
buffer_side(Application_Links *app, Buffer_ID buffer, Side side){
    return(range_side(buffer_range(app, buffer), side));
}

internal Range_i64
get_view_range(Application_Links *app, View_ID view){
    return(Ii64(view_get_cursor_pos(app, view), view_get_mark_pos(app, view)));
}

internal void
set_view_range(Application_Links *app, View_ID view, Range_i64 range){
    i64 c = view_get_cursor_pos(app, view);
    i64 m = view_get_mark_pos(app, view);
    if (c < m){
        view_set_cursor_and_preferred_x(app, view, seek_pos(range.min));
        view_set_mark(app, view, seek_pos(range.max));
    }
    else{
        view_set_mark(app, view, seek_pos(range.min));
        view_set_cursor_and_preferred_x(app, view, seek_pos(range.max));
    }
}

internal b32
is_valid_line(Application_Links *app, Buffer_ID buffer_id, i64 line){
    i64 max_line = buffer_get_line_count(app, buffer_id);
    return(1 <= line && line <= max_line);
}

internal b32
is_valid_line_range(Application_Links *app, Buffer_ID buffer_id, Range_i64 range){
    i64 max_line = buffer_get_line_count(app, buffer_id);
    return(1 <= range.first && range.first <= range.end && range.end <= max_line);
}

internal i64
get_line_number_from_pos(Application_Links *app, Buffer_ID buffer, i64 pos){
    Buffer_Cursor cursor = buffer_compute_cursor(app, buffer, seek_pos(pos));
    return(cursor.line);
}

internal i64
buffer_get_character_legal_pos_from_pos(Application_Links *app, Buffer_ID buffer, f32 width, Face_ID face, i64 pos){
    Buffer_Cursor cursor = buffer_compute_cursor(app, buffer, seek_pos(pos));
    i64 character = buffer_relative_character_from_pos(app, buffer, width, face, cursor.line, pos);
    return(buffer_pos_from_relative_character(app, buffer, width, face, cursor.line, character));
}

internal i64
view_get_character_legal_pos_from_pos(Application_Links *app, View_ID view, i64 pos){
    Buffer_Cursor cursor = view_compute_cursor(app, view, seek_pos(pos));
    i64 character = view_relative_character_from_pos(app, view, cursor.line, pos);
    return(view_pos_from_relative_character(app, view, cursor.line, character));
}

internal Buffer_Cursor
get_line_side(Application_Links *app, Buffer_ID buffer, i64 line_number, Side side){
    i64 character_index = (side == Side_Min)?(1):(-1);
    return(buffer_compute_cursor(app, buffer, seek_line_col(line_number, character_index)));
}
internal i64
get_line_side_pos(Application_Links *app, Buffer_ID buffer, i64 line_number, Side side){
    i64 pos = -1;
    Buffer_Cursor cursor = get_line_side(app, buffer, line_number, side);
    if (cursor.line != 0){
        pos = cursor.pos;
    }
    return(pos);
}

internal Buffer_Cursor
get_line_start(Application_Links *app, Buffer_ID buffer, i64 line_number){
    return(get_line_side(app, buffer, line_number, Side_Min));
}
internal i64
get_line_start_pos(Application_Links *app, Buffer_ID buffer, i64 line_number){
    return(get_line_side_pos(app, buffer, line_number, Side_Min));
}

// NOTE(allen): The position returned has the index of the terminating newline character,
// not one past the newline character.
internal Buffer_Cursor
get_line_end(Application_Links *app, Buffer_ID buffer, i64 line_number){
    return(get_line_side(app, buffer, line_number, Side_Max));
}
internal i64
get_line_end_pos(Application_Links *app, Buffer_ID buffer, i64 line_number){
    return(get_line_side_pos(app, buffer, line_number, Side_Max));
}

// NOTE(allen): The range returned does not include the terminating newline character
internal Range_Cursor
get_line_range(Application_Links *app, Buffer_ID buffer, i64 line_number){
    b32 success = false;
    Range_Cursor result = {};
    result.start = get_line_start(app, buffer, line_number);
    if (result.start.line != 0){
        result.end = get_line_end(app, buffer, line_number);
        if (result.end.line != 0){
            success = true;
        }
    }
    if (!success){
        block_zero_struct(&result);
    }
    return(result);
}

// NOTE(allen): The range returned does not include the terminating newline character
internal Range_i64
get_line_pos_range(Application_Links *app, Buffer_ID buffer, i64 line_number){
    Range_Cursor range = get_line_range(app, buffer, line_number);
    Range_i64 result = {};
    if (range.start.line != 0 && range.end.line != 0){
        result = Ii64(range.start.pos, range.end.pos);
    }
    return(result);
}

internal Range_i64
make_range_from_cursors(Range_Cursor range){
    return(Ii64(range.start.pos, range.end.pos));
}

internal i64
get_line_side_pos_from_pos(Application_Links *app, Buffer_ID buffer, i64 pos, Side side){
    i64 line_number = get_line_number_from_pos(app, buffer, pos);
    return(get_line_side_pos(app, buffer, line_number, side));
}
internal i64
get_line_start_pos_from_pos(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(get_line_side_pos_from_pos(app, buffer, pos, Side_Min));
}
internal i64
get_line_end_pos_from_pos(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(get_line_side_pos_from_pos(app, buffer, pos, Side_Max));
}

internal Token*
get_first_token_from_line(Application_Links *app, Buffer_ID buffer, Token_Array tokens, i64 line){
    i64 line_start = get_line_start_pos(app, buffer, line);
    return(token_from_pos(&tokens, line_start));
}

////////////////////////////////

internal i64
scan_any_boundary(Application_Links *app, Boundary_Function *func, Buffer_ID buffer, Scan_Direction direction, i64 pos){
    i64 a = func(app, buffer, Side_Min, direction, pos);
    i64 b = func(app, buffer, Side_Max, direction, pos);
    i64 result = 0;
    if (direction == Scan_Forward){
        result = Min(a, b);
    }
    else{
        result = Max(a, b);
    }
    return(result);
}

internal i64
scan(Application_Links *app, Boundary_Function *func, Buffer_ID buffer, Scan_Direction direction, i64 pos){
    Side side = (direction == Scan_Forward)?(Side_Max):(Side_Min);
    return(func(app, buffer, side, direction, pos));
}

internal i64
scan(Application_Links *app, Boundary_Function_List funcs, Buffer_ID buffer, Scan_Direction direction, i64 start_pos){
    i64 result = 0;
    if (direction == Scan_Forward){
        i64 size = buffer_get_size(app, buffer);
        result = size + 1;
        for (Boundary_Function_Node *node = funcs.first;
             node != 0;
             node = node->next){
            i64 pos = scan(app, node->func, buffer, direction, start_pos);
            result = Min(result, pos);
        }
    }
    else{
        result = -1;
        for (Boundary_Function_Node *node = funcs.first;
             node != 0;
             node = node->next){
            i64 pos = scan(app, node->func, buffer, direction, start_pos);
            result = Max(result, pos);
        }
    }
    return(result);
}

internal void
push_boundary(Arena *arena, Boundary_Function_List *list, Boundary_Function *func){
    Boundary_Function_Node *node = push_array(arena, Boundary_Function_Node, 1);
    sll_queue_push(list->first, list->last, node);
    list->count += 1;
    node->func = func;
}

internal Boundary_Function_List
push_boundary_list__innerv(Arena *arena, va_list args){
    Boundary_Function_List list = {};
    for (;;){
        Boundary_Function *func = va_arg(args, Boundary_Function*);
        if (func == 0){
            break;
        }
        push_boundary(arena, &list, func);
    }
    return(list);
}
internal Boundary_Function_List
push_boundary_list__inner(Arena *arena, ...){
    va_list args;
    va_start(args, arena);
    Boundary_Function_List result = push_boundary_list__innerv(arena, args);
    va_end(args);
    return(result);
}
#define push_boundary_list(a,...) push_boundary_list__inner((a), __VA_ARGS__, 0)

internal i64
boundary_predicate(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos, Character_Predicate *predicate){
    i64 result = 0;
    switch (side){
        case Side_Min:
        {
            result = buffer_seek_character_class_change_0_1(app, buffer, predicate, direction, pos);
        }break;
        case Side_Max:
        {
            result = buffer_seek_character_class_change_1_0(app, buffer, predicate, direction, pos);
        }break;
    }
    return(result);
}

internal i64
boundary_non_whitespace(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    return(boundary_predicate(app, buffer, side, direction, pos, &character_predicate_non_whitespace));
}

internal i64
boundary_base10(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    return(boundary_predicate(app, buffer, side, direction, pos, &character_predicate_base10));
}

internal i64
boundary_base10_colon(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    internal Character_Predicate predicate = {};
    internal b32 first_call = true;
    if (first_call){
        first_call = false;
        Character_Predicate colon = character_predicate_from_character((u8)':');
        predicate = character_predicate_or(&character_predicate_base10, &colon);
    }
    return(boundary_predicate(app, buffer, side, direction, pos, &predicate));
}

internal i64
boundary_base16(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    return(boundary_predicate(app, buffer, side, direction, pos, &character_predicate_base16));
}

internal i64
boundary_alpha_numeric(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    return(boundary_predicate(app, buffer, side, direction, pos, &character_predicate_alpha_numeric));
}

internal i64
boundary_alpha_numeric_unicode(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    return(boundary_predicate(app, buffer, side, direction, pos, &character_predicate_alpha_numeric_underscore_utf8));
}

internal i64
boundary_alpha_numeric_underscore(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    return(boundary_predicate(app, buffer, side, direction, pos, &character_predicate_alpha_numeric_underscore));
}

internal i64
boundary_alpha_numeric_underscore_utf8(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    return(boundary_predicate(app, buffer, side, direction, pos, &character_predicate_alpha_numeric_underscore_utf8));
}

internal i64
boundary_alpha_numeric_camel(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    i64 an_pos = boundary_alpha_numeric(app, buffer, side, direction, pos);
    String_Match m = buffer_seek_character_class(app, buffer, &character_predicate_uppercase, direction, pos);
    i64 cap_pos = m.range.min;
    if (side == Side_Max){
        i64 an_left_pos = boundary_alpha_numeric(app, buffer, flip_side(side), flip_direction(direction), an_pos);
        if (cap_pos == an_left_pos){
            m = buffer_seek_character_class(app, buffer, &character_predicate_uppercase, direction, cap_pos);
            cap_pos = m.range.min;
        }
    }
    i64 result = 0;
    if (direction == Scan_Backward){
        result = Max(an_pos, cap_pos);
    }
    else{
        result = Min(an_pos, cap_pos);
    }
    return(result);
}

internal i64
boundary_inside_quotes(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    internal Character_Predicate predicate = {};
    internal b32 first_call = true;
    if (first_call){
        first_call = false;
        predicate = character_predicate_from_character((u8)'"');
        predicate = character_predicate_not(&predicate);
    }
    return(boundary_predicate(app, buffer, side, direction, pos, &predicate));
}

internal i64
boundary_token(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    i64 result = boundary_non_whitespace(app, buffer, side, direction, pos);
    Token_Array tokens = get_token_array_from_buffer(app, buffer);
    if (tokens.tokens != 0){
        switch (direction){
            case Scan_Forward:
            {
                i64 buffer_size = buffer_get_size(app, buffer);
                result = buffer_size;
                if (tokens.count > 0){
                    Token_Iterator_Array it = token_iterator_pos(0, &tokens, pos);
                    Token *token = token_it_read(&it);
                    if (token->kind == TokenBaseKind_Whitespace){
                        token_it_inc_non_whitespace(&it);
                        token = token_it_read(&it);
                    }
                    if (token != 0){
                        if (side == Side_Max){
                            result = token->pos + token->size;
                        }
                        else{
                            if (token->pos <= pos){
                                token_it_inc_non_whitespace(&it);
                                token = token_it_read(&it);
                            }
                            if (token != 0){
                                result = token->pos;
                            }
                        }
                    }
                }
            }break;
            
            case Scan_Backward:
            {
                result = 0;
                if (tokens.count > 0){
                    Token_Iterator_Array it = token_iterator_pos(0, &tokens, pos);
                    Token *token = token_it_read(&it);
                    if (token->kind == TokenBaseKind_Whitespace){
                        token_it_dec_non_whitespace(&it);
                        token = token_it_read(&it);
                    }
                    if (token != 0){
                        if (side == Side_Min){
                            if (token->pos >= pos){
                                token_it_dec_non_whitespace(&it);
                                token = token_it_read(&it);
                            }
                            result = token->pos;
                        }
                        else{
                            if (token->pos + token->size >= pos){
                                token_it_dec_non_whitespace(&it);
                                token = token_it_read(&it);
                            }
                            result = token->pos + token->size;
                        }
                    }
                }
            }break;
        }
    }
    return(result);
}

internal i64
boundary_line(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    i64 line_number = get_line_number_from_pos(app, buffer, pos);
    i64 new_pos = get_line_side_pos(app, buffer, line_number, side);
    if (direction == Scan_Backward && new_pos >= pos){
        if (line_number > 1){
            new_pos = get_line_side_pos(app, buffer, line_number - 1, side);
        }
        else{
            new_pos = 0;
        }
    }
    else if (direction == Scan_Forward && new_pos <= pos){
        new_pos = get_line_side_pos(app, buffer, line_number + 1, side);
        if (new_pos <= pos){
            new_pos = (i32)buffer_get_size(app, buffer);
        }
    }
    return(new_pos);
}

////////////////////////////////

// TODO(allen): these need a little more rewrite
internal void
seek_string_forward(Application_Links *app, Buffer_ID buffer, i64 pos, i64 end, String_Const_u8 needle, i64 *result){
    if (end == 0){
        end = (i32)buffer_get_size(app, buffer);
    }
    String_Match match = {};
    match.range.first = pos;
    for (;;){
        match = buffer_seek_string(app, buffer, needle, Scan_Forward, (i32)match.range.first);
        if (HasFlag(match.flags, StringMatch_CaseSensitive) ||
            match.buffer != buffer || match.range.first >= end) break;
    }
    if (match.range.first < end && match.buffer == buffer){
        *result = match.range.first;
    }
    else{
        *result = buffer_get_size(app, buffer);
    }
}

internal void
seek_string_backward(Application_Links *app, Buffer_ID buffer, i64 pos, i64 min, String_Const_u8 needle, i64 *result){
    String_Match match = {};
    match.range.first = pos;
    for (;;){
        match = buffer_seek_string(app, buffer, needle, Scan_Backward, match.range.first);
        if (HasFlag(match.flags, StringMatch_CaseSensitive) ||
            match.buffer != buffer || match.range.first < min) break;
    }
    if (match.range.first >= min && match.buffer == buffer){
        *result = match.range.first;
    }
    else{
        *result = -1;
    }
}

internal void
seek_string_insensitive_forward(Application_Links *app, Buffer_ID buffer, i64 pos, i64 end, String_Const_u8 needle, i64 *result){
    if (end == 0){
        end = (i32)buffer_get_size(app, buffer);
    }
    String_Match match = buffer_seek_string(app, buffer, needle, Scan_Forward, pos);
    if (match.range.first < end && match.buffer == buffer){
        *result = match.range.first;
    }
    else{
        *result = buffer_get_size(app, buffer);
    }
}

internal void
seek_string_insensitive_backward(Application_Links *app, Buffer_ID buffer, i64 pos, i64 min, String_Const_u8 needle, i64 *result){
    String_Match match = buffer_seek_string(app, buffer, needle, Scan_Backward, pos);
    if (match.range.first >= min && match.buffer == buffer){
        *result = match.range.first;
    }
    else{
        *result = -1;
    }
}

internal void
seek_string(Application_Links *app, Buffer_ID buffer_id, i64 pos, i64 end, i64 min, String_Const_u8 str, i64 *result, Buffer_Seek_String_Flags flags){
    switch (flags & 3){
        case 0:
        {
            seek_string_forward(app, buffer_id, pos, end, str, result);
        }break;
        
        case BufferSeekString_Backward:
        {
            seek_string_backward(app, buffer_id, pos, min, str, result);
        }break;
        
        case BufferSeekString_CaseInsensitive:
        {
            seek_string_insensitive_forward(app, buffer_id, pos, end, str, result);
        }break;
        
        case BufferSeekString_Backward|BufferSeekString_CaseInsensitive:
        {
            seek_string_insensitive_backward(app, buffer_id, pos, min, str, result);
        }break;
    }
}

////////////////////////////////

internal Range_i64
get_line_range_from_pos_range(Application_Links *app, Buffer_ID buffer, Range_i64 pos_range){
    Range_i64 line_range = {};
    line_range.first = get_line_number_from_pos(app, buffer, pos_range.first);
    if (line_range.first != 0){
        line_range.end = get_line_number_from_pos(app, buffer, pos_range.one_past_last);
        if (line_range.end == 0){
            line_range.first = 0;
        }
    }
    return(line_range);
}

// NOTE(allen): The end of the returned range does not include the terminating newline character of
// the last line.
internal Range_i64
get_pos_range_from_line_range(Application_Links *app, Buffer_ID buffer, Range_i64 line_range){
    Range_i64 pos_range = {};
    if (is_valid_line_range(app, buffer, line_range)){
        pos_range.first = get_line_start_pos(app, buffer, line_range.first);
        pos_range.one_past_last = get_line_end_pos(app, buffer, line_range.end);
    }
    return(pos_range);
}

internal Range_i64
enclose_boundary(Application_Links *app, Buffer_ID buffer, Range_i64 range,
                 Boundary_Function *func){
    i64 new_min       = func(app, buffer, Side_Min, Scan_Backward, range.min + 1);
    i64 new_min_check = func(app, buffer, Side_Max, Scan_Backward, range.min + 1);
    if (new_min_check <= new_min && new_min < range.min){
        range.min = new_min;
    }
    i64 new_max       = func(app, buffer, Side_Max, Scan_Forward, range.max - 1);
    i64 new_max_check = func(app, buffer, Side_Min, Scan_Forward, range.max);
    if (new_max_check >= new_max && new_max > range.max){
        range.max = new_max;
    }
    return(range);
}

internal Range_i64
left_enclose_boundary(Application_Links *app, Buffer_ID buffer, Range_i64 range,
                      Boundary_Function *func){
    i64 new_min       = func(app, buffer, Side_Min, Scan_Backward, range.min + 1);
    i64 new_min_check = func(app, buffer, Side_Max, Scan_Backward, range.min + 1);
    if (new_min_check <= new_min && new_min < range.min){
        range.min = new_min;
    }
    return(range);
}

internal Range_i64
right_enclose_boundary(Application_Links *app, Buffer_ID buffer, Range_i64 range,
                       Boundary_Function *func){
    i64 new_max       = func(app, buffer, Side_Max, Scan_Forward, range.max - 1);
    i64 new_max_check = func(app, buffer, Side_Min, Scan_Forward, range.max - 1);
    if (new_max_check >= new_max && new_max > range.max){
        range.max = new_max;
    }
    return(range);
}

internal Range_i64
enclose_non_whitespace(Application_Links *app, Buffer_ID buffer, Range_i64 range){
    return(enclose_boundary(app, buffer, range, boundary_non_whitespace));
}
internal Range_i64
enclose_pos_non_whitespace(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(enclose_boundary(app, buffer, Ii64(pos), boundary_non_whitespace));
}

internal Range_i64
enclose_tokens(Application_Links *app, Buffer_ID buffer, Range_i64 range){
    return(enclose_boundary(app, buffer, range, boundary_token));
}
internal Range_i64
enclose_pos_tokens(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(enclose_boundary(app, buffer, Ii64(pos), boundary_token));
}

internal Range_i64
enclose_base10(Application_Links *app, Buffer_ID buffer, Range_i64 range){
    return(enclose_boundary(app, buffer, range, boundary_base10));
}
internal Range_i64
enclose_pos_base10(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(enclose_boundary(app, buffer, Ii64(pos), boundary_base10));
}

internal Range_i64
enclose_base16(Application_Links *app, Buffer_ID buffer, Range_i64 range){
    return(enclose_boundary(app, buffer, range, boundary_base16));
}
internal Range_i64
enclose_pos_base16(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(enclose_boundary(app, buffer, Ii64(pos), boundary_base16));
}

internal Range_i64
enclose_base10_colon(Application_Links *app, Buffer_ID buffer, Range_i64 range){
    return(enclose_boundary(app, buffer, range, boundary_base10_colon));
}
internal Range_i64
enclose_pos_base10_colon(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(enclose_boundary(app, buffer, Ii64(pos), boundary_base10_colon));
}

internal Range_i64
enclose_alpha_numeric(Application_Links *app, Buffer_ID buffer, Range_i64 range){
    return(enclose_boundary(app, buffer, range, boundary_alpha_numeric));
}
internal Range_i64
enclose_pos_alpha_numeric(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(enclose_boundary(app, buffer, Ii64(pos), boundary_alpha_numeric));
}

internal Range_i64
enclose_alpha_numeric_unicode(Application_Links *app, Buffer_ID buffer, Range_i64 range){
    return(enclose_boundary(app, buffer, range, boundary_alpha_numeric_unicode));
}
internal Range_i64
enclose_pos_alpha_numeric_unicode(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(enclose_boundary(app, buffer, Ii64(pos), boundary_alpha_numeric_unicode));
}

internal Range_i64
enclose_alpha_numeric_underscore(Application_Links *app, Buffer_ID buffer, Range_i64 range){
    return(enclose_boundary(app, buffer, range, boundary_alpha_numeric_underscore));
}
internal Range_i64
enclose_pos_alpha_numeric_underscore(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(enclose_boundary(app, buffer, Ii64(pos), boundary_alpha_numeric_underscore));
}
internal Range_i64
right_enclose_alpha_numeric_underscore(Application_Links *app, Buffer_ID buffer,
                                       Range_i64 range){
    return(right_enclose_boundary(app, buffer, range, boundary_alpha_numeric_underscore));
}

internal Range_i64
enclose_alpha_numeric_underscore_utf8(Application_Links *app, Buffer_ID buffer, Range_i64 range){
    return(enclose_boundary(app, buffer, range, boundary_alpha_numeric_underscore_utf8));
}
internal Range_i64
enclose_pos_alpha_numeric_underscore_utf8(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(enclose_boundary(app, buffer, Ii64(pos), boundary_alpha_numeric_underscore_utf8));
}
internal Range_i64
right_enclose_alpha_numeric_underscore_utf8(Application_Links *app, Buffer_ID buffer,
                                            Range_i64 range){
    return(right_enclose_boundary(app, buffer, range, boundary_alpha_numeric_underscore_utf8));
}


internal Range_i64
enclose_alpha_numeric_camel(Application_Links *app, Buffer_ID buffer, Range_i64 range){
    return(enclose_boundary(app, buffer, range, boundary_alpha_numeric_camel));
}
internal Range_i64
enclose_pos_alpha_numeric_camel(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(enclose_boundary(app, buffer, Ii64(pos), boundary_alpha_numeric_camel));
}

internal Range_i64
enclose_pos_inside_quotes(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(enclose_boundary(app, buffer, Ii64(pos), boundary_inside_quotes));
}

internal Range_i64
enclose_whole_lines(Application_Links *app, Buffer_ID buffer, Range_i64 range){
    return(enclose_boundary(app, buffer, range, boundary_line));
}
internal Range_i64
enclose_pos_whole_lines(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(enclose_boundary(app, buffer, Ii64(pos), boundary_line));
}

////////////////////////////////

internal Range_i64
get_snipe_range(Application_Links *app, Boundary_Function_List funcs, Buffer_ID buffer, i64 pos, Scan_Direction direction){
    Range_i64 result = {};
    i64 buffer_size = buffer_get_size(app, buffer);
    i64 pos0 = pos;
    i64 pos1 = scan(app, funcs, buffer, direction, pos0);
    if (0 <= pos1 && pos1 <= buffer_size){
        i64 pos2 = scan(app, funcs, buffer, flip_direction(direction), pos1);
        if (0 <= pos2 && pos2 <= buffer_size){
            if (direction == Scan_Backward){
                pos2 = clamp_bot(pos2, pos0);
            }
            else{
                pos2 = clamp_top(pos2, pos0);
            }
            result = Ii64(pos1, pos2);
        }
    }
    return(result);
}

internal Range_i64
get_snipe_range(Application_Links *app, Boundary_Function *func, Buffer_ID buffer, i64 pos, Scan_Direction direction){
    Scratch_Block scratch(app);
    return(get_snipe_range(app, push_boundary_list(scratch, func), buffer, pos, direction));
}

////////////////////////////////

internal String_Const_u8
push_buffer_range(Application_Links *app, Arena *arena, Buffer_ID buffer, Range_i64 range){
    String_Const_u8 result = {};
    i64 length = range_size(range);
    if (length > 0){
        Temp_Memory restore_point = begin_temp(arena);
        u8 *memory = push_array(arena, u8, length);
        if (buffer_read_range(app, buffer, range, memory)){
            result = SCu8(memory, length);
        }
        else{
            end_temp(restore_point);
        }
    }
    return(result);
}

internal String_Const_u8
push_token_lexeme(Application_Links *app, Arena *arena, Buffer_ID buffer, Token *token){
    return(push_buffer_range(app, arena, buffer, Ii64(token)));
}

internal String_Const_u8
push_buffer_line(Application_Links *app, Arena *arena, Buffer_ID buffer, i64 line_number){
    return(push_buffer_range(app, arena, buffer, get_line_pos_range(app, buffer, line_number)));
}

internal String_Const_u8
push_whole_buffer(Application_Links *app, Arena *arena, Buffer_ID buffer){
    return(push_buffer_range(app, arena, buffer, buffer_range(app, buffer)));
}

internal String_Const_u8
push_view_range_string(Application_Links *app, Arena *arena, View_ID view){
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    return(push_buffer_range(app, arena, buffer, get_view_range(app, view)));
}

internal String_Const_u8
push_view_range_string(Application_Links *app, Arena *arena){
    View_ID view = get_active_view(app, Access_Always);
    return(push_view_range_string(app, arena, view));
}

internal String_Const_u8
push_enclose_range_at_pos(Application_Links *app, Arena *arena, Buffer_ID buffer, i64 pos, Enclose_Function *enclose){
    Range_i64 range = enclose(app, buffer, Ii64(pos));
    return(push_buffer_range(app, arena, buffer, range));
}

////////////////////////////////

internal String_Const_u8
token_it_lexeme(Application_Links *app, Arena *arena, Token_Iterator_Array *it){
    String_Const_u8 result = {};
    Token *token = token_it_read(it);
    if (token != 0){
        result = push_token_lexeme(app, arena, (Buffer_ID)it->user_id, token);
    }
    return(result);
}

internal b32
token_it_check_and_get_lexeme(Application_Links *app, Arena *arena, Token_Iterator_Array *it, Token_Base_Kind kind, String_Const_u8 *lexeme_out){
    Token *token = token_it_read(it);
    b32 result = {};
    if (token != 0 && token->kind == kind){
        result = true;
        *lexeme_out = push_token_lexeme(app, arena, (Buffer_ID)it->user_id, token);
    }
    return(result);
}

internal String_Const_u8
token_it_lexeme(Application_Links *app, Arena *arena, Token_Iterator_List *it){
    String_Const_u8 result = {};
    Token *token = token_it_read(it);
    if (token != 0){
        result = push_token_lexeme(app, arena, (Buffer_ID)it->user_id, token);
    }
    return(result);
}

internal b32
token_it_check_and_get_lexeme(Application_Links *app, Arena *arena, Token_Iterator_List *it, Token_Base_Kind kind, String_Const_u8 *lexeme_out){
    Token *token = token_it_read(it);
    b32 result = {};
    if (token != 0 && token->kind == kind){
        result = true;
        *lexeme_out = push_token_lexeme(app, arena, (Buffer_ID)it->user_id, token);
    }
    return(result);
}

////////////////////////////////

internal b32
buffer_has_name_with_star(Application_Links *app, Buffer_ID buffer){
    Scratch_Block scratch(app);
    String_Const_u8 str = push_buffer_unique_name(app, scratch, buffer);
    return(str.size > 0 && str.str[0] == '*');
}

internal u8
buffer_get_char(Application_Links *app, Buffer_ID buffer_id, i64 pos){
    i64 buffer_size = buffer_get_size(app, buffer_id);
    u8 result = ' ';
    if (0 <= pos && pos < buffer_size){
        buffer_read_range(app, buffer_id, Ii64(pos, pos + 1), &result);
    }
    return(result);
}

internal b32
line_is_valid_and_blank(Application_Links *app, Buffer_ID buffer, i64 line_number){
    b32 result = false;
    if (is_valid_line(app, buffer, line_number)){
        Scratch_Block scratch(app);
        String_Const_u8 line = push_buffer_line(app, scratch, buffer, line_number);
        result = true;
        for (u64 i = 0; i < line.size; i += 1){
            if (!character_is_whitespace(line.str[i])){
                result = false;
                break;
            }
        }
    }
    return(result);
}

////////////////////////////////

internal i64
get_pos_past_lead_whitespace_from_line_number(Application_Links *app, Buffer_ID buffer, i64 line_number){
    Scratch_Block scratch(app);
    Range_i64 line_range = get_line_pos_range(app, buffer, line_number);
    String_Const_u8 line = push_buffer_range(app, scratch, buffer, line_range);
    i64 result = line_range.end;
    for (u64 i = 0; i < line.size; i += 1){
        if (!character_is_whitespace(line.str[i])){
            result = line_range.start + i;
            break;
        }
    }
    return(result);
}

internal i64
get_pos_past_lead_whitespace(Application_Links *app, Buffer_ID buffer, i64 pos){
    i64 line_number = get_line_number_from_pos(app, buffer, pos);
    i64 result = get_pos_past_lead_whitespace_from_line_number(app, buffer, line_number);
    result = clamp_bot(pos, result);
    return(result);
}

internal void
move_past_lead_whitespace(Application_Links *app, View_ID view, Buffer_ID buffer){
    i64 pos = view_get_cursor_pos(app, view);
    i64 new_pos = get_pos_past_lead_whitespace(app, buffer, pos);
    view_set_cursor_and_preferred_x(app, view, seek_pos(new_pos));
}

internal void
move_past_lead_whitespace(Application_Links *app, View_ID view){
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    move_past_lead_whitespace(app, view, buffer);
}

internal b32
line_is_blank(Application_Links *app, Buffer_ID buffer, i64 line_number){
    Scratch_Block scratch(app);
    String_Const_u8 line = push_buffer_line(app, scratch, buffer, line_number);
    b32 is_blank = true;
    for (u64 i = 0; i < line.size; i += 1){
        if (!character_is_whitespace(line.str[i])){
            is_blank = false;
            break;
        }
    }
    return(is_blank);
}

internal i64
get_line_number_of__whitespace_status_line(Application_Links *app, Buffer_ID buffer, Scan_Direction direction, i64 line_number_start, b32 get_blank_line){
    i64 line_count = buffer_get_line_count(app, buffer);
    i64 line_number = line_number_start + direction;
    for (;1 <= line_number && line_number <= line_count; line_number += direction){
        b32 is_blank = line_is_blank(app, buffer, line_number);
        if (is_blank == get_blank_line){
            break;
        }
    }
    line_number = clamp(1, line_number, line_count);
    return(line_number);
}

internal i64
get_line_number_of_non_blank_line(Application_Links *app, Buffer_ID buffer, Scan_Direction direction, i64 line_number_start){
    return(get_line_number_of__whitespace_status_line(app, buffer, direction, line_number_start, false));
}

internal i64
get_line_number_of_blank_line(Application_Links *app, Buffer_ID buffer, Scan_Direction direction, i64 line_number_start){
    return(get_line_number_of__whitespace_status_line(app, buffer, direction, line_number_start, true));
}

internal i64
get_pos_of_blank_line(Application_Links *app, Buffer_ID buffer, Scan_Direction direction, i64 pos_start){
    i64 line_number_start = get_line_number_from_pos(app, buffer, pos_start);
    i64 blank_line = get_line_number_of_blank_line(app, buffer, direction, line_number_start);
    i64 pos = get_line_start_pos(app, buffer, blank_line);
    return(pos);
}

internal i64
get_line_number_of_blank_line_grouped(Application_Links *app, Buffer_ID buffer, Scan_Direction direction, i64 line_number_start){
    i64 line_number = line_number_start;
    if (line_is_blank(app, buffer, line_number)){
        line_number = get_line_number_of_non_blank_line(app, buffer, direction, line_number);
    }
    line_number = get_line_number_of_blank_line(app, buffer, direction, line_number);
    return(line_number);
}

internal i64
get_pos_of_blank_line_grouped(Application_Links *app, Buffer_ID buffer, Scan_Direction direction, i64 pos_start){
    i64 line_number_start = get_line_number_from_pos(app, buffer, pos_start);
    i64 blank_line = get_line_number_of_blank_line_grouped(app, buffer, direction, line_number_start);
    i64 pos = get_line_start_pos(app, buffer, blank_line);
    return(pos);
}

internal Indent_Info
get_indent_info_range(Application_Links *app, Buffer_ID buffer, Range_i64 range, i32 tab_width){
    Scratch_Block scratch(app);
    String_Const_u8 s = push_buffer_range(app, scratch, buffer, range);
    
    Indent_Info info = {};
    info.first_char_pos = range.end;
    info.is_blank = true;
    info.all_space = true;
    
    for (u64 i = 0; i < s.size; i += 1){
        u8 c = s.str[i];
        if (!character_is_whitespace(c)){
            info.is_blank = false;
            info.all_space = false;
            info.first_char_pos = range.start + (i64)i;
            break;
        }
        if (c == ' '){
            info.indent_pos += 1;
        }
        else{
            info.all_space = false;
        }
        if (c == '\t'){
            info.indent_pos += tab_width;
        }
    }
    
    return(info);
}

internal Indent_Info
get_indent_info_line_number_and_start(Application_Links *app, Buffer_ID buffer, i64 line_number, i64 line_start, i32 tab_width){
    i64 end = get_line_side_pos(app, buffer, line_number, Side_Max);
    return(get_indent_info_range(app, buffer, Ii64(line_start, end), tab_width));
}

////////////////////////////////

internal History_Group
history_group_begin(Application_Links *app, Buffer_ID buffer){
    History_Group group = {};
    group.app = app;
    group.buffer = buffer;
    group.first = buffer_history_get_current_state_index(app, buffer);
    group.first += 1;
    return(group);
}

internal void
history_group_end(History_Group group){
    History_Record_Index last = buffer_history_get_current_state_index(group.app, group.buffer);
    if (group.first < last){
        buffer_history_merge_record_range(group.app, group.buffer, group.first, last, RecordMergeFlag_StateInRange_MoveStateForward);
    }
}

////////////////////////////////

internal void
replace_in_range(Application_Links *app, Buffer_ID buffer, Range_i64 range, String_Const_u8 needle, String_Const_u8 string){
    // TODO(allen): rewrite
    History_Group group = history_group_begin(app, buffer);
    i64 pos = range.min - 1;
    i64 new_pos = 0;
    seek_string_forward(app, buffer, pos, range.end, needle, &new_pos);
    i64 shift = replace_range_shift(needle.size, string.size);
    for (; new_pos + (i64)needle.size <= range.end;){
        Range_i64 needle_range = Ii64(new_pos, new_pos + (i32)needle.size);
        buffer_replace_range(app, buffer, needle_range, string);
        range.end += shift;
        pos = new_pos + (i32)string.size - 1;
        seek_string_forward(app, buffer, pos, range.end, needle, &new_pos);
    }
    history_group_end(group);
}

internal Range_i64
swap_lines(Application_Links *app, Buffer_ID buffer, i64 line_1, i64 line_2){
    Range_i64 result = {};
    i64 line_count = buffer_get_line_count(app, buffer);
    if (1 <= line_1 && line_2 <= line_count){
        Range_i64 range_1 = get_line_pos_range(app, buffer, line_1);
        Range_i64 range_2 = get_line_pos_range(app, buffer, line_2);
        
        Scratch_Block scratch(app);
        
        String_Const_u8 text_1 = push_buffer_range(app, scratch, buffer, range_1);
        String_Const_u8 text_2 = push_buffer_range(app, scratch, buffer, range_2);
        
        History_Group group = history_group_begin(app, buffer);
        buffer_replace_range(app, buffer, range_2, text_1);
        buffer_replace_range(app, buffer, range_1, text_2);
        history_group_end(group);
        
        i64 shift = replace_range_shift(range_1, text_2.size);
        result.min = range_1.min;
        result.max = range_2.min + shift;
    }
    return(result);
}

internal i64
move_line(Application_Links *app, Buffer_ID buffer, i64 line_number, Scan_Direction direction){
    i64 line_1 = 0;
    i64 line_2 = 0;
    if (direction == Scan_Forward){
        line_1 = line_number;
        line_2 = line_number + 1;
    }
    else{
        line_1 = line_number - 1;
        line_2 = line_number;
    }
    Range_i64 line_starts = swap_lines(app, buffer, line_1, line_2);
    i64 result = 0;
    if (line_starts.min < line_starts.max){
        if (direction == Scan_Forward){
            result = line_starts.max;
        }
        else{
            result = line_starts.min;
        }
    }
    else{
        result = get_line_side_pos(app, buffer, line_number, Side_Min);
    }
    return(result);
}

internal void
clear_buffer(Application_Links *app, Buffer_ID buffer){
    buffer_replace_range(app, buffer, buffer_range(app, buffer), string_u8_litexpr(""));
}

////////////////////////////////

internal String_Match_List
find_all_matches_all_buffers(Application_Links *app, Arena *arena, String_Const_u8_Array match_patterns, String_Match_Flag must_have_flags, String_Match_Flag must_not_have_flags){
    String_Match_List all_matches = {};
    for (Buffer_ID buffer = get_buffer_next(app, 0, Access_Always);
         buffer != 0;
         buffer = get_buffer_next(app, buffer, Access_Always)){
        String_Match_List buffer_matches = {};
        for (i32 i = 0; i < match_patterns.count; i += 1){
            Range_i64 range = buffer_range(app, buffer);
            String_Match_List pattern_matches = buffer_find_all_matches(app, arena, buffer, i, range, match_patterns.vals[i],
                                                                        &character_predicate_alpha_numeric_underscore_utf8, Scan_Forward);
            string_match_list_filter_flags(&pattern_matches, must_have_flags, must_not_have_flags);
            if (pattern_matches.count > 0){
                if (buffer_matches.count == 0){
                    buffer_matches = pattern_matches;
                }
                else{
                    buffer_matches = string_match_list_merge_front_to_back(&buffer_matches, &pattern_matches);
                }
            }
        }
        all_matches = string_match_list_join(&all_matches, &buffer_matches);
    }
    return(all_matches);
}

internal String_Match_List
find_all_matches_all_buffers(Application_Links *app, Arena *arena, String_Const_u8 pattern, String_Match_Flag must_have_flags, String_Match_Flag must_not_have_flags){
    String_Const_u8_Array array = {&pattern, 1};
    return(find_all_matches_all_buffers(app, arena, array, must_have_flags, must_not_have_flags));
}

////////////////////////////////

internal b32
is_modified(User_Input *input){
    return(is_modified(&input->event));
}

internal String_Const_u8
to_writable(User_Input *in){
    return(to_writable(&in->event));
}

internal b32
has_modifier(User_Input *in, Key_Code key_code){
    b32 result = false;
    Input_Modifier_Set *mods = get_modifiers(&in->event);
    if (mods != 0){
        result = has_modifier(mods, key_code);
    }
    return(result);
}

internal b32
match_key_code(User_Input *in, Key_Code key_code){
    return(match_key_code(&in->event, key_code));
}

internal b32
match_core_code(User_Input *in, Key_Code core_code){
    return(match_core_code(&in->event, core_code));
}

internal String_Const_u8
backspace_utf8(String_Const_u8 string){
    if (string.size > 0){
        u64 i = string.size - 1;
        for (; i > 0; --i){
            if (string.str[i] <= 0x7F || string.str[i] >= 0xC0){
                break;
            }
        }
        string.size = i;
    }
    return(string);
}

////////////////////////////////

function User_Input
get_next_input(Application_Links *app, Event_Property use_flags, Event_Property abort_flags){
    User_Input in = {};
    if (use_flags != 0){
        for (;;){
            in = get_next_input_raw(app);
            if (in.abort){
                break;
            }
            Event_Property event_flags = get_event_properties(&in.event);
            if ((event_flags & abort_flags) != 0){
                in.abort = true;
                break;
            }
            if ((event_flags & use_flags) != 0){
                break;
            }
        }
    }
    return(in);
}

////////////////////////////////

Query_Bar_Group::Query_Bar_Group(Application_Links *app){
    this->app = app;
    this->view = get_active_view(app, Access_Always);
}

Query_Bar_Group::Query_Bar_Group(Application_Links *app, View_ID view){
    this->app = app;
    this->view = view;
}

Query_Bar_Group::~Query_Bar_Group(){
    clear_all_query_bars(this->app, this->view);
}

internal b32
query_user_general(Application_Links *app, Query_Bar *bar, b32 force_number, String_Const_u8 init_string){
    if (start_query_bar(app, bar, 0) == 0){
        return(false);
    }
    
    if (init_string.size > 0){
        String_u8 string = Su8(bar->string.str, bar->string.size, bar->string_capacity);
        string_append(&string, init_string);
        bar->string.size = string.string.size;
    }
    
    b32 success = true;
    for (;;){
        User_Input in = get_next_input(app, EventPropertyGroup_Any,
                                       EventProperty_Escape|EventProperty_MouseButton);
        if (in.abort){
            success = false;
            break;
        }
        
        Scratch_Block scratch(app);
        b32 good_insert = false;
        String_Const_u8 insert_string = to_writable(&in);
        if (insert_string.str != 0 && insert_string.size > 0){
            insert_string = string_replace(scratch, insert_string,
                                           string_u8_litexpr("\n"),
                                           string_u8_litexpr(""));
            insert_string = string_replace(scratch, insert_string,
                                           string_u8_litexpr("\t"),
                                           string_u8_litexpr(""));
            if (force_number){
                if (string_is_integer(insert_string, 10)){
                    good_insert = true;
                }
            }
            else{
                good_insert = true;
            }
        }
        
        if (in.event.kind == InputEventKind_KeyStroke &&
            (in.event.key.code == KeyCode_Return || in.event.key.code == KeyCode_Tab)){
            break;
        }
        else if (in.event.kind == InputEventKind_KeyStroke &&
                 in.event.key.code == KeyCode_Backspace){
            bar->string = backspace_utf8(bar->string);
        }
        else if (good_insert){
            String_u8 string = Su8(bar->string.str, bar->string.size, bar->string_capacity);
            string_append(&string, insert_string);
            bar->string.size = string.string.size;
        }
        else{
            // NOTE(allen): is the user trying to execute another command?
            View_ID view = get_this_ctx_view(app, Access_Always);
            View_Context ctx = view_current_context(app, view);
            Mapping *mapping = ctx.mapping;
            Command_Map *map = mapping_get_map(mapping, ctx.map_id);
            Command_Binding binding = map_get_binding_recursive(mapping, map, &in.event);
            if (binding.custom != 0){
                Command_Metadata *metadata = get_command_metadata(binding.custom);
                if (metadata != 0){
                    if (metadata->is_ui){
                        view_enqueue_command_function(app, view, binding.custom);
                        break;
                    }
                }
                binding.custom(app);
            }
            else{
                leave_current_input_unhandled(app);
            }
        }
    }
    
    return(success);
}

internal b32
query_user_string(Application_Links *app, Query_Bar *bar){
    return(query_user_general(app, bar, false, string_u8_empty));
}

internal b32
query_user_number(Application_Links *app, Query_Bar *bar){
    return(query_user_general(app, bar, true, string_u8_empty));
}

internal b32
query_user_number(Application_Links *app, Query_Bar *bar, i32 x){
    Scratch_Block scratch(app);
    String_Const_u8 string = push_u8_stringf(scratch, "%d", x);
    return(query_user_general(app, bar, true, string));
}

////////////////////////////////

internal Buffer_Identifier
buffer_identifier(char *str, i32 len){
    Buffer_Identifier identifier;
    identifier.name = str;
    identifier.name_len = len;
    identifier.id = 0;
    return(identifier);
}

internal Buffer_Identifier
buffer_identifier(String_Const_u8 str){
    return(buffer_identifier((char*)str.str, (i32)str.size));
}

internal Buffer_Identifier
buffer_identifier(Buffer_ID id){
    Buffer_Identifier identifier;
    identifier.name = 0;
    identifier.name_len = 0;
    identifier.id = id;
    return(identifier);
}

internal Buffer_ID
buffer_identifier_to_id(Application_Links *app, Buffer_Identifier identifier){
    Buffer_ID id = 0;
    if (identifier.id != 0){
        id = identifier.id;
    }
    else{
        String_Const_u8 name = SCu8(identifier.name, identifier.name_len);
        id = get_buffer_by_name(app, name, Access_Always);
        if (id == 0){
            id = get_buffer_by_file_name(app, name, Access_Always);
        }
    }
    return(id);
}

internal Buffer_ID
buffer_identifier_to_id_create_out_buffer(Application_Links *app, Buffer_Identifier buffer_id){
    Buffer_ID result = 0;
    if (buffer_id.name != 0 && buffer_id.name_len > 0){
        String_Const_u8 buffer_name = SCu8(buffer_id.name, buffer_id.name_len);
        Buffer_ID buffer_attach_id = get_buffer_by_name(app, buffer_name, Access_Always);
        if (buffer_attach_id != 0){
            result = buffer_attach_id;
        }
        else{
            buffer_attach_id = create_buffer(app, buffer_name, BufferCreate_AlwaysNew|BufferCreate_NeverAttachToFile);
            if (buffer_attach_id != 0){
                buffer_set_setting(app, buffer_attach_id, BufferSetting_ReadOnly, true);
                buffer_set_setting(app, buffer_attach_id, BufferSetting_Unimportant, true);
                result = buffer_attach_id;
            }
        }
    }
    else{
        result = buffer_id.id;
    }
    return(result);
}

////////////////////////////////

function void
place_begin_and_end_on_own_lines(Application_Links *app, char *begin, char *end){
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    
    Range_i64 range = get_view_range(app, view);
    Range_i64 lines = get_line_range_from_pos_range(app, buffer, range);
    range = get_pos_range_from_line_range(app, buffer, lines);
    
    Scratch_Block scratch(app);
    
    b32 min_line_blank = line_is_valid_and_blank(app, buffer, lines.min);
    b32 max_line_blank = line_is_valid_and_blank(app, buffer, lines.max);
    
    if ((lines.min < lines.max) || (!min_line_blank)){
        String_Const_u8 begin_str = {};
        String_Const_u8 end_str = {};
        
        i64 min_adjustment = 0;
        i64 max_adjustment = 0;
        
        if (min_line_blank){
            begin_str = push_u8_stringf(scratch, "\n%s", begin);
            min_adjustment += 1;
        }
        else{
            begin_str = push_u8_stringf(scratch, "%s\n", begin);
        }
        if (max_line_blank){
            end_str = push_u8_stringf(scratch, "%s\n", end);
        }
        else{
            end_str = push_u8_stringf(scratch, "\n%s", end);
            max_adjustment += 1;
        }
        
        max_adjustment += begin_str.size;
        Range_i64 new_pos = Ii64(range.min + min_adjustment, range.max + max_adjustment);
        
        History_Group group = history_group_begin(app, buffer);
        buffer_replace_range(app, buffer, Ii64(range.min), begin_str);
        buffer_replace_range(app, buffer, Ii64(range.max + begin_str.size), end_str);
        history_group_end(group);
        
        set_view_range(app, view, new_pos);
    }
    else{
        String_Const_u8 str = push_u8_stringf(scratch, "%s\n\n%s", begin, end);
        buffer_replace_range(app, buffer, range, str);
        i64 center_pos = range.min + cstring_length(begin) + 1;
        view_set_cursor_and_preferred_x(app, view, seek_pos(center_pos));
        view_set_mark(app, view, seek_pos(center_pos));
    }
}

////////////////////////////////

function Face_ID
get_view_face_id(Application_Links *app, View_ID view){
    Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
    return(get_face_id(app, buffer));
}

function Face_Metrics
get_view_face_metrics(Application_Links *app, View_ID view){
    Face_ID face = get_view_face_id(app, view);
    return(get_face_metrics(app, face));
}

function f32
get_view_line_height(Application_Links *app, View_ID view){
    Face_Metrics metrics = get_view_face_metrics(app, view);
    return(metrics.line_height);
}

internal View_ID
open_view(Application_Links *app, View_ID view_location, View_Split_Position position){
    View_ID result = 0;
    if (view_location != 0 && view_exists(app, view_location)){
        Panel_ID panel_id = view_get_panel(app, view_location);
        if (panel_id != 0){
            Dimension split = (position == ViewSplit_Left ||
                               position == ViewSplit_Right)?Dimension_X:Dimension_Y;
            Side side = (position == ViewSplit_Left ||
                         position == ViewSplit_Top)?Side_Min:Side_Max;
            if (panel_split(app, panel_id, split)){
                Panel_ID new_panel_id = panel_get_child(app, panel_id, side);
                if (new_panel_id != 0){
                    View_ID new_view_id = panel_get_view(app, new_panel_id,
                                                         Access_Always);
                    if (new_view_id != 0){
                        result = new_view_id;
                    }
                }
            }
        }
    }
    return(result);
}

internal View_ID
get_first_view_with_buffer(Application_Links *app, Buffer_ID buffer_id){
    View_ID result = {};
    if (buffer_id != 0){
        for (View_ID test = get_view_next(app, 0, Access_Always);
             test != 0;
             test = get_view_next(app, test, Access_Always)){
            Buffer_ID test_buffer = view_get_buffer(app, test, Access_Always);
            if (test_buffer == buffer_id){
                result = test;
                break;
            }
        }
    }
    return(result);
}

internal b32
open_file(Application_Links *app, Buffer_ID *buffer_out, String_Const_u8 file_name, b32 background, b32 never_new){
    b32 result = false;
    Buffer_ID buffer = get_buffer_by_name(app, file_name, Access_ReadVisible);
    b32 exists = buffer_exists(app, buffer);
    if (!exists){
        Buffer_Create_Flag flags = 0;
        if (background){
            flags |= BufferCreate_Background;
        }
        if (never_new){
            flags |= BufferCreate_NeverNew;
        }
        buffer = create_buffer(app, file_name, flags);
        exists = buffer_exists(app, buffer);
    }
    if (exists){
        if (buffer_out != 0){
            *buffer_out = buffer;
        }
        result = true;
    }
    return(result);
}

internal b32
view_open_file(Application_Links *app, View_ID view, String_Const_u8 file_name, b32 never_new){
    b32 result = false;
    if (view != 0){
        Buffer_ID buffer = 0;
        if (open_file(app, &buffer, file_name, false, never_new)){
            view_set_buffer(app, view, buffer, 0);
            result = true;
        }
    }
    return(result);
}

internal void
view_disable_highlight_range(Application_Links *app, View_ID view){
    Managed_Scope scope = view_get_managed_scope(app, view);
    Managed_Object *highlight = scope_attachment(app, scope, view_highlight_range, Managed_Object);
    if (*highlight != 0){
        managed_object_free(app, *highlight);
    }
    managed_scope_attachment_erase(app, scope, view_highlight_range);
    managed_scope_attachment_erase(app, scope, view_highlight_buffer);
}

internal void
view_set_highlight_range(Application_Links *app, View_ID view, Range_i64 range){
    view_disable_highlight_range(app, view);
    
    Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
    Managed_Scope scope = view_get_managed_scope(app, view);
    Managed_Object *highlight = scope_attachment(app, scope, view_highlight_range, Managed_Object);
    *highlight = alloc_buffer_markers_on_buffer(app, buffer, 2, &scope);
    Marker markers[2] = {};
    markers[0].pos = range.min;
    markers[1].pos = range.max;
    managed_object_store_data(app, *highlight, 0, 2, markers);
    Buffer_ID *highlight_buffer = scope_attachment(app, scope, view_highlight_buffer, Buffer_ID);
    *highlight_buffer = buffer;
}

function void
view_look_at_region(Application_Links *app, View_ID view, i64 major_pos, i64 minor_pos){
    Range_i64 range = Ii64(major_pos, minor_pos);
    b32 bottom_major = false;
    if (major_pos == range.max){
        bottom_major = true;
    }
    
    Buffer_Cursor top = view_compute_cursor(app, view, seek_pos(range.min));
    if (top.line > 0){
        Buffer_Cursor bottom = view_compute_cursor(app, view, seek_pos(range.max));
        if (bottom.line > 0){
            Rect_f32 region = view_get_buffer_region(app, view);
            f32 view_height = rect_height(region);
            f32 skirt_height = view_height*.1f;
            Range_f32 acceptable_y = If32(skirt_height, view_height*.9f);
            
            f32 target_height = view_line_y_difference(app, view, bottom.line + 1, top.line);
            
            f32 line_height = get_view_line_height(app, view);
            if (target_height + 2*line_height > view_height){
                i64 major_line = bottom.line;
                if (range.min == major_pos){
                    major_line = top.line;
                }
                
                Buffer_Scroll scroll = view_get_buffer_scroll(app, view);
                scroll.target.line_number = major_line;
                scroll.target.pixel_shift.y = -skirt_height;
                view_set_buffer_scroll(app, view, scroll, SetBufferScroll_SnapCursorIntoView);
            }
            else{
                Buffer_Scroll scroll = view_get_buffer_scroll(app, view);
                Vec2_f32 top_p = view_relative_xy_of_pos(app, view, scroll.position.line_number, range.min);
                top_p -= scroll.position.pixel_shift;
                if (top_p.y < acceptable_y.min){
                    scroll.target.line_number = top.line;
                    scroll.target.pixel_shift.y = -skirt_height;
                    view_set_buffer_scroll(app, view, scroll, SetBufferScroll_NoCursorChange);
                }
                else{
                    Vec2_f32 bot_p = view_relative_xy_of_pos(app, view, scroll.position.line_number, range.max);
                    bot_p -= scroll.position.pixel_shift;
                    if (bot_p.y > acceptable_y.max){
                        scroll.target.line_number = bottom.line;
                        scroll.target.pixel_shift.y = skirt_height - view_height;
                        view_set_buffer_scroll(app, view, scroll, SetBufferScroll_NoCursorChange);
                    }
                }
            }
        }
    }
}

function void
view_look_at_region(Application_Links *app, View_ID view, Range_i64 range){
    view_look_at_region(app, view, range.min, range.max);
}

////////////////////////////////

function Buffer_ID
get_buffer_next_looped(Application_Links *app, Buffer_ID buffer, Access_Flag access){
    buffer = get_buffer_next(app, buffer, access);
    if (buffer == 0){
        buffer = get_buffer_next(app, 0, access);
    }
    return(buffer);
}

////////////////////////////////

internal View_ID
get_next_view_looped_all_panels(Application_Links *app, View_ID view_id, Access_Flag access){
    view_id = get_view_next(app, view_id, access);
    if (view_id == 0){
        view_id = get_view_next(app, 0, access);
    }
    return(view_id);
}

internal View_ID
get_prev_view_looped_all_panels(Application_Links *app, View_ID view_id, Access_Flag access){
    view_id = get_view_prev(app, view_id, access);
    if (view_id == 0){
        view_id = get_view_prev(app, 0, access);
    }
    return(view_id);
}

////////////////////////////////

internal Buffer_Kill_Result
try_buffer_kill(Application_Links *app, Buffer_ID buffer, View_ID gui_view_id, Buffer_Kill_Flag flags){
    Buffer_Kill_Result result = buffer_kill(app, buffer, flags);
    if (result == BufferKillResult_Dirty){
        if (do_buffer_kill_user_check(app, buffer, gui_view_id)){
            result = buffer_kill(app, buffer, BufferKill_AlwaysKill);
        }
    }
    return(result);
}

////////////////////////////////

internal String_Const_u8
get_query_string(Application_Links *app, char *query_str, u8 *string_space, i32 space_size){
    Query_Bar_Group group(app);
    Query_Bar bar = {};
    bar.prompt = SCu8((u8*)query_str);
    bar.string = SCu8(string_space, (u64)0);
    bar.string_capacity = space_size;
    if (!query_user_string(app, &bar)){
        bar.string.size = 0;
    }
    return(bar.string);
}

internal Token*
get_token_from_pos(Application_Links *app, Token_Array *array, u64 pos){
    Token *result = 0;
    if (array->count > 0){
        i64 index = token_index_from_pos(array, pos);
        result = array->tokens + index;
    }
    return(result);
}

internal Token*
get_token_from_pos(Application_Links *app, Buffer_ID buffer, u64 pos){
    Token_Array array = get_token_array_from_buffer(app, buffer);
    return(get_token_from_pos(app, &array, pos));
}

internal String_Const_u8
push_token_or_word_under_pos(Application_Links *app, Arena *arena, Buffer_ID buffer, u64 pos){
    String_Const_u8 result = {};
    Token *token = get_token_from_pos(app, buffer, pos);
    if (token != 0 && token->size > 0 && token->kind != TokenBaseKind_Whitespace){
        Range_i64 range = Ii64(token);
        result = push_buffer_range(app, arena, buffer, range);
    }
    return(result);
}

internal String_Const_u8
push_token_or_word_under_active_cursor(Application_Links *app, Arena *arena){
    View_ID view = get_active_view(app, Access_Always);
    Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
    i64 pos = view_get_cursor_pos(app, view);
    return(push_token_or_word_under_pos(app, arena, buffer, pos));
}

////////////////////////////////

internal b32
file_exists(Application_Links *app, String_Const_u8 file_name){
    Scratch_Block scratch(app);
    File_Attributes attributes = system_quick_file_attributes(scratch, file_name);
    return(attributes.last_write_time > 0);
}

internal b32
file_exists_and_is_file(Application_Links *app, String_Const_u8 file_name){
    Scratch_Block scratch(app);
    File_Attributes attributes = system_quick_file_attributes(scratch, file_name);
    return(attributes.last_write_time > 0 && !HasFlag(attributes.flags, FileAttribute_IsDirectory));
}

internal b32
file_exists_and_is_folder(Application_Links *app, String_Const_u8 file_name){
    Scratch_Block scratch(app);
    File_Attributes attributes = system_quick_file_attributes(scratch, file_name);
    return(attributes.last_write_time > 0 && HasFlag(attributes.flags, FileAttribute_IsDirectory));
}

internal Data
dump_file_handle(Arena *arena, FILE *file){
    Data result = {};
    if (file != 0){
        fseek(file, 0, SEEK_END);
        u64 size = ftell(file);
        char *mem = push_array(arena, char, size);
        if (mem != 0){
            fseek(file, 0, SEEK_SET);
            fread(mem, 1, (size_t)size, file);
            result = make_data(mem, size);
        }
    }
    return(result);
}

internal String_Const_u8
push_file_search_up_path(Application_Links *app, Arena *arena, String_Const_u8 start_path, String_Const_u8 file_name){
    String_Const_u8 result = {};
    String_Const_u8 path = start_path;
    for (;path.size > 0;){
        Temp_Memory temp = begin_temp(arena);
        if (character_is_slash(string_get_character(path, path.size - 1))){
            path = string_chop(path, 1);
        }
        String_Const_u8 full_path = push_u8_stringf(arena, "%.*s/%.*s",
                                                    string_expand(path),
                                                    string_expand(file_name));
        if (file_exists(app, full_path)){
            result = full_path;
            break;
        }
        path = string_remove_last_folder(path);
        end_temp(temp);
    }
    return(result);
}

internal FILE*
open_file_try_current_path_then_binary_path(Application_Links *app, char *file_name){
    FILE *file = fopen(file_name, "rb");
    if (file == 0){
        Scratch_Block scratch(app);
        List_String_Const_u8 list = {};
        string_list_push(scratch, &list, system_get_path(scratch, SystemPath_Binary));
        string_list_push_overlap(scratch, &list, '/', SCu8(file_name));
        String_Const_u8 str = string_list_flatten(scratch, list, StringFill_NullTerminate);
        file = fopen((char*)str.str, "rb");
    }
    return(file);
}

internal FILE*
open_file(Arena *scratch, String_Const_u8 name){
    Temp_Memory temp = begin_temp(scratch);
    String_Const_u8 name_copy = push_string_copy(scratch, name);
    FILE *file = fopen((char*)name_copy.str, "rb");
    end_temp(temp);
    return(file);
}

internal File_Name_Data
dump_file(Arena *arena, String_Const_u8 file_name){
    File_Name_Data result = {};
    FILE *file = open_file(arena, file_name);
    if (file != 0){
        result.file_name = file_name;
        result.data = dump_file_handle(arena, file);
        fclose(file);
    }
    return(result);
}

internal File_Name_Data
dump_file_search_up_path(Application_Links *app, Arena *arena, String_Const_u8 path, String_Const_u8 file_name){
    File_Name_Data result = {};
    String_Const_u8 full_path = push_file_search_up_path(app, arena, path, file_name);
    if (full_path.size > 0){
        result = dump_file(arena, full_path);
    }
    return(result);
}

internal void
sort_pairs_by_key__quick(Sort_Pair_i32 *pairs, i32 first, i32 one_past_last){
    i32 dif = one_past_last - first;
    if (dif >= 2){
        i32 pivot = one_past_last - 1;
        Sort_Pair_i32 pivot_pair = pairs[pivot];
        i32 j = first;
        b32 interleave = false;
        for (i32 i = first; i < pivot; i += 1){
            Sort_Pair_i32 pair = pairs[i];
            if (pair.key < pivot_pair.key){
                pairs[i] = pairs[j];
                pairs[j] = pair;
                j += 1;
            }
            else if (pair.key == pivot_pair.key){
                if (interleave){
                    pairs[i] = pairs[j];
                    pairs[j] = pair;
                    j += 1;
                }
                interleave = !interleave;
            }
        }
        pairs[pivot] = pairs[j];
        pairs[j] = pivot_pair;
        sort_pairs_by_key__quick(pairs, first, j);
        sort_pairs_by_key__quick(pairs, j + 1, one_past_last);
    }
}

internal void
sort_pairs_by_key(Sort_Pair_i32 *pairs, i32 count){
    sort_pairs_by_key__quick(pairs, 0, count);
}

internal Range_i32_Array
get_ranges_of_duplicate_keys(Arena *arena, i32 *keys, i32 stride, i32 count){
    Range_i32_Array result = {};
    result.ranges = push_array(arena, Range_i32, count);
    u8 *ptr = (u8*)keys;
    i32 start_i = 0;
    for (i32 i = 1; i <= count; i += 1){
        b32 is_end = false;
        if (i == count){
            is_end = true;
        }
        else if (*(i32*)(ptr + i*stride) != *(i32*)(ptr + start_i*stride)){
            is_end = true;
        }
        if (is_end){
            Range_i32 *new_range = &result.ranges[result.count++];
            new_range->first = start_i;
            new_range->one_past_last = i;
            start_i = i;
        }
    }
    pop_array(arena, Range_i32, count - result.count);
    return(result);
}

internal void
no_mark_snap_to_cursor(Application_Links *app, Managed_Scope view_scope){
    b32 *snap_to_cursor = scope_attachment(app, view_scope, view_snap_mark_to_cursor, b32);
    *snap_to_cursor = false;
}

internal void
no_mark_snap_to_cursor(Application_Links *app, View_ID view_id){
    Managed_Scope scope = view_get_managed_scope(app, view_id);
    no_mark_snap_to_cursor(app, scope);
}

internal void
no_mark_snap_to_cursor_if_shift(Application_Links *app, View_ID view_id){
    Scratch_Block scratch(app);
    Input_Modifier_Set mods = system_get_keyboard_modifiers(scratch);
    if (has_modifier(&mods, KeyCode_Shift)){
        no_mark_snap_to_cursor(app, view_id);
    }
}

internal b32
view_has_highlighted_range(Application_Links *app, View_ID view){
    b32 result = false;
    if (fcoder_mode == FCoderMode_NotepadLike){
        i64 pos = view_get_cursor_pos(app, view);
        i64 mark = view_get_mark_pos(app, view);
        result = (pos != mark);
    }
    return(result);
}

internal b32
if_view_has_highlighted_range_delete_range(Application_Links *app, View_ID view_id){
    b32 result = false;
    if (view_has_highlighted_range(app, view_id)){
        Range_i64 range = get_view_range(app, view_id);
        Buffer_ID buffer = view_get_buffer(app, view_id, Access_ReadWriteVisible);
        buffer_replace_range(app, buffer, range, string_u8_litexpr(""));
        result = true;
    }
    return(result);
}

internal void
begin_notepad_mode(Application_Links *app){
    fcoder_mode = FCoderMode_NotepadLike;
    for (View_ID view = get_view_next(app, 0, Access_Always);
         view != 0;
         view = get_view_next(app, view, Access_Always)){
        i64 pos = view_get_cursor_pos(app, view);
        view_set_mark(app, view, seek_pos(pos));
    }
}

////////////////////////////////

internal void
seek_pos_of_textual_line(Application_Links *app, Side side){
    View_ID view = get_active_view(app, Access_ReadVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    i64 pos = view_get_cursor_pos(app, view);
    i64 new_pos = get_line_side_pos_from_pos(app, buffer, pos, side);
    view_set_cursor_and_preferred_x(app, view, seek_pos(new_pos));
    no_mark_snap_to_cursor_if_shift(app, view);
}

internal void
seek_pos_of_visual_line(Application_Links *app, Side side){
    View_ID view = get_active_view(app, Access_ReadVisible);
    i64 pos = view_get_cursor_pos(app, view);
    Buffer_Cursor cursor = view_compute_cursor(app, view, seek_pos(pos));
    Vec2_f32 p = view_relative_xy_of_pos(app, view, cursor.line, pos);
    p.x = (side == Side_Min)?(0.f):(max_f32);
    i64 new_pos = view_pos_at_relative_xy(app, view, cursor.line, p);
    view_set_cursor_and_preferred_x(app, view, seek_pos(new_pos));
    no_mark_snap_to_cursor_if_shift(app, view);
}

CUSTOM_COMMAND_SIG(seek_beginning_of_textual_line)
CUSTOM_DOC("Seeks the cursor to the beginning of the line across all text.")
{
    seek_pos_of_textual_line(app, Side_Min);
}

CUSTOM_COMMAND_SIG(seek_end_of_textual_line)
CUSTOM_DOC("Seeks the cursor to the end of the line across all text.")
{
    seek_pos_of_textual_line(app, Side_Max);
}

CUSTOM_COMMAND_SIG(seek_beginning_of_line)
CUSTOM_DOC("Seeks the cursor to the beginning of the visual line.")
{
    seek_pos_of_visual_line(app, Side_Min);
}

CUSTOM_COMMAND_SIG(seek_end_of_line)
CUSTOM_DOC("Seeks the cursor to the end of the visual line.")
{
    seek_pos_of_visual_line(app, Side_Max);
}

CUSTOM_COMMAND_SIG(goto_beginning_of_file)
CUSTOM_DOC("Sets the cursor to the beginning of the file.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    view_set_cursor_and_preferred_x(app, view, seek_pos(0));
    no_mark_snap_to_cursor_if_shift(app, view);
}

CUSTOM_COMMAND_SIG(goto_end_of_file)
CUSTOM_DOC("Sets the cursor to the end of the file.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    Buffer_ID buffer_id = view_get_buffer(app, view, Access_ReadVisible);
    i32 size = (i32)buffer_get_size(app, buffer_id);
    view_set_cursor_and_preferred_x(app, view, seek_pos(size));
    no_mark_snap_to_cursor_if_shift(app, view);
}

////////////////////////////////

internal b32
view_set_split(Application_Links *app, View_ID view, View_Split_Kind kind, f32 t){
    b32 result = false;
    if (view != 0){
        Panel_ID panel_id = view_get_panel(app, view);
        if (panel_id != 0){
            Panel_ID parent_panel_id = panel_get_parent(app, panel_id);
            if (parent_panel_id != 0){
                Panel_ID min_child_id = panel_get_child(app, parent_panel_id, Side_Min);
                if (min_child_id != 0){
                    b32 panel_is_min = (min_child_id == panel_id);
                    Panel_Split_Kind panel_kind = ((kind == ViewSplitKind_Ratio)?
                                                   (panel_is_min?PanelSplitKind_Ratio_Min:PanelSplitKind_Ratio_Max):
                                                   (panel_is_min?PanelSplitKind_FixedPixels_Min:PanelSplitKind_FixedPixels_Max));
                    result = panel_set_split(app, parent_panel_id, panel_kind, t);
                }
            }
        }
    }
    return(result);
}

internal b32
view_set_split_proportion(Application_Links *app, View_ID view, f32 t){
    return(view_set_split(app, view, ViewSplitKind_Ratio, t));
}

internal b32
view_set_split_pixel_size(Application_Links *app, View_ID view, i32 t){
    return(view_set_split(app, view, ViewSplitKind_FixedPixels, (f32)t));
}

////////////////////////////////

internal Record_Info
get_single_record(Application_Links *app, Buffer_ID buffer_id, History_Record_Index index){
    Record_Info record = buffer_history_get_record_info(app, buffer_id, index);
    if (record.error == RecordError_NoError && record.kind == RecordKind_Group){
        record = buffer_history_get_group_sub_record(app, buffer_id, index, record.group_count - 1);
    }
    return(record);
}

////////////////////////////////

function Nest_Delimiter_Kind
get_nest_delimiter_kind(Token_Base_Kind kind, Find_Nest_Flag flags){
    Nest_Delimiter_Kind result = NestDelim_None;
    switch (kind){
        case TokenBaseKind_ScopeOpen:
        {
            if (HasFlag(flags, FindNest_Scope)){
                result = NestDelim_Open;
            }
        }break;
        case TokenBaseKind_ScopeClose:
        {
            if (HasFlag(flags, FindNest_Scope)){
                result = NestDelim_Close;
            }
        }break;
        case TokenBaseKind_ParentheticalOpen:
        {
            if (HasFlag(flags, FindNest_Paren)){
                result = NestDelim_Open;
            }
        }break;
        case TokenBaseKind_ParentheticalClose:
        {
            if (HasFlag(flags, FindNest_Paren)){
                result = NestDelim_Close;
            }
        }break;
    }
    return(result);
}

function b32
find_nest_side(Application_Links *app, Buffer_ID buffer, i64 pos,
               Find_Nest_Flag flags, Scan_Direction scan, Nest_Delimiter_Kind delim,
               Range_i64 *out){
    b32 result = false;
    
    b32 balanced = HasFlag(flags, FindNest_Balanced);
    if (balanced){
        if ((delim == NestDelim_Open && scan == Scan_Forward) ||
            (delim == NestDelim_Close && scan == Scan_Backward)){
            balanced = false;
        }
    }
    
    Managed_Scope scope = buffer_get_managed_scope(app, buffer);
    Token_Array *tokens = scope_attachment(app, scope, attachment_tokens, Token_Array);
    if (tokens != 0 && tokens->count > 0){
        Token_Iterator_Array it = token_iterator_pos(0, tokens, pos);
        i32 level = 0;
        for (;;){
            Token *token = token_it_read(&it);
            Nest_Delimiter_Kind token_delim = get_nest_delimiter_kind(token->kind, flags);
            
            if (level == 0 && token_delim == delim){
                *out = Ii64_size(token->pos, token->size);
                result = true;
                break;
            }
            
            if (balanced && token_delim != NestDelim_None){
                level += (token_delim == delim)?-1:1;
            }
            
            b32 good = false;
            if (scan == Scan_Forward){
                good = token_it_inc(&it);
            }
            else{
                good = token_it_dec(&it);
            }
            if (!good){
                break;
            }
        }
    }
    
    return(result);
}

function b32
find_nest_side(Application_Links *app, Buffer_ID buffer, i64 pos,
               Find_Nest_Flag flags, Scan_Direction scan, Nest_Delimiter_Kind delim,
               i64 *out){
    Range_i64 range = {};
    b32 result = find_nest_side(app, buffer, pos, flags, scan, delim, &range);
    if (result){
        if (HasFlag(flags, FindNest_EndOfToken)){
            *out = range.end;
        }
        else{
            *out = range.start;
        }
    }
    return(result);
}

function b32
find_surrounding_nest(Application_Links *app, Buffer_ID buffer, i64 pos,
                      Find_Nest_Flag flags, Range_i64 *out){
    b32 result = false;
    Range_i64 range = {};
    if (find_nest_side(app, buffer, pos - 1, flags|FindNest_Balanced,
                       Scan_Backward, NestDelim_Open, &range.start) &&
        find_nest_side(app, buffer, pos, flags|FindNest_Balanced|FindNest_EndOfToken,
                       Scan_Forward, NestDelim_Close, &range.end)){
        *out = range;
        result = true;
    }
    return(result);
}

function void
select_scope(Application_Links *app, View_ID view, Range_i64 range){
    view_set_cursor_and_preferred_x(app, view, seek_pos(range.first));
    view_set_mark(app, view, seek_pos(range.end));
    view_look_at_region(app, view, range.first, range.end);
    no_mark_snap_to_cursor(app, view);
}

////////////////////////////////

function Line_Ending_Kind
guess_line_ending_kind_from_buffer(Application_Links *app, Buffer_ID buffer){
    u64 size = buffer_get_size(app, buffer);
    size = clamp_top(size, KB(8));
    Scratch_Block scratch(app);
    String_Const_u8 string = push_buffer_range(app, scratch, buffer, Ii64(0, size));
    return(string_guess_line_ending_kind(string));
}

////////////////////////////////

// TODO(allen): REWRITE THIS EXACTLY HOW YOU WANT IT --- start ---

internal Child_Process_Set_Target_Flags
flags_system_command(Command_Line_Interface_Flag flags){
    Child_Process_Set_Target_Flags set_buffer_flags = 0;
    if (!HasFlag(flags, CLI_OverlapWithConflict)){
        set_buffer_flags |= ChildProcessSet_FailIfBufferAlreadyAttachedToAProcess;
    }
    if (HasFlag(flags, CLI_CursorAtEnd)){
        set_buffer_flags |= ChildProcessSet_CursorAtEnd;
    }
    return(set_buffer_flags);
}

internal b32
set_buffer_system_command(Application_Links *app, Child_Process_ID process, Buffer_ID buffer, Command_Line_Interface_Flag flags){
    b32 result = false;
    Child_Process_Set_Target_Flags set_buffer_flags = flags_system_command(flags);
    if (child_process_set_target_buffer(app, process, buffer, set_buffer_flags)){
        clear_buffer(app, buffer);
        if (HasFlag(flags, CLI_SendEndSignal)){
            buffer_send_end_signal(app, buffer);
            
            Buffer_Hook_Function *begin_buffer = (Buffer_Hook_Function*)get_custom_hook(app, HookID_BeginBuffer);
            if (begin_buffer != 0){
                begin_buffer(app, buffer);
            }
        }
        result = true;
    }
    return(result);
}

internal b32
exec_system_command(Application_Links *app, View_ID view, Buffer_Identifier buffer_id,
                    String_Const_u8 path, String_Const_u8 command, Command_Line_Interface_Flag flags){
    b32 result = false;
    Child_Process_ID child_process_id = create_child_process(app, path, command);
    if (child_process_id != 0){
        result = true;
        Buffer_ID buffer_attach_id = buffer_identifier_to_id_create_out_buffer(app, buffer_id);
        if (buffer_attach_id != 0){
            if (set_buffer_system_command(app, child_process_id, buffer_attach_id, flags)){
                if (view != 0){
                    view_set_buffer(app, view, buffer_attach_id, 0);
                    view_set_cursor(app, view, seek_pos(0));
                }
            }
        }
    }
    return(result);
}

// TODO(allen): --- end ---

////////////////////////////////

function f32
font_get_glyph_advance(Face_Advance_Map *map, Face_Metrics *metrics, u32 codepoint){
    return(font_get_glyph_advance(map, metrics, codepoint, (f32)global_config.default_tab_width));
}
function f32
font_get_max_glyph_advance_range(Face_Advance_Map *map, Face_Metrics *metrics,
                                 u32 codepoint_first, u32 codepoint_last){
    return(font_get_max_glyph_advance_range(map, metrics, codepoint_first, codepoint_last,
                                            (f32)global_config.default_tab_width));
}
function f32
font_get_average_glyph_advance_range(Face_Advance_Map *map, Face_Metrics *metrics,
                                     u32 codepoint_first, u32 codepoint_last){
    return(font_get_average_glyph_advance_range(map, metrics, codepoint_first, codepoint_last,
                                                (f32)global_config.default_tab_width));
}

// BOTTOM