#!/bin/bash
# check-toolchain.sh - Verify clang installation and build requirements
# Checks for clang, required tools, and platform-specific dependencies

set -e

# =============================================================================
# Configuration
# =============================================================================

# Minimum required versions
MIN_CLANG_VERSION_MAJOR=6
MIN_CLANG_VERSION_MINOR=0

# Required tools
REQUIRED_TOOLS=(
    "clang++"
    "clang"
    "make"
    "bash"
)

# Platform-specific tools
REQUIRED_TOOLS_LINUX=(
    "pkg-config"
)

REQUIRED_TOOLS_MACOS=(
    "xcrun"
)

REQUIRED_TOOLS_WIN32=(
    "windres"  # For resource compilation
)

# =============================================================================
# Utility Functions
# =============================================================================

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

print_success() {
    echo -e "${GREEN}✓${NC} $1"
}

print_warning() {
    echo -e "${YELLOW}⚠${NC} $1"
}

print_error() {
    echo -e "${RED}✗${NC} $1"
}

print_info() {
    echo -e "ℹ $1"
}

# =============================================================================
# Version Checking
# =============================================================================

check_clang_version() {
    local clang_version
    local major minor
    
    if ! command -v clang++ &> /dev/null; then
        print_error "clang++ not found in PATH"
        return 1
    fi
    
    clang_version=$(clang++ --version | head -n1)
    print_info "Found: $clang_version"
    
    # Extract version numbers (handles various clang version formats)
    if [[ $clang_version =~ ([0-9]+)\.([0-9]+) ]]; then
        major=${BASH_REMATCH[1]}
        minor=${BASH_REMATCH[2]}
        
        if [[ $major -gt $MIN_CLANG_VERSION_MAJOR ]] || \
           [[ $major -eq $MIN_CLANG_VERSION_MAJOR && $minor -ge $MIN_CLANG_VERSION_MINOR ]]; then
            print_success "clang++ version $major.$minor meets minimum requirement ($MIN_CLANG_VERSION_MAJOR.$MIN_CLANG_VERSION_MINOR)"
            return 0
        else
            print_error "clang++ version $major.$minor is below minimum requirement ($MIN_CLANG_VERSION_MAJOR.$MIN_CLANG_VERSION_MINOR)"
            return 1
        fi
    else
        print_warning "Could not parse clang++ version, proceeding anyway"
        return 0
    fi
}

# =============================================================================
# Tool Checking
# =============================================================================

check_tool() {
    local tool=$1
    local required=${2:-true}
    
    if command -v "$tool" &> /dev/null; then
        local version_info
        case "$tool" in
            "clang++"|"clang")
                version_info=$(command "$tool" --version 2>/dev/null | head -n1 || echo "version unknown")
                ;;
            "make")
                version_info=$(command "$tool" --version 2>/dev/null | head -n1 || echo "version unknown")
                ;;
            "pkg-config")
                version_info=$(command "$tool" --version 2>/dev/null || echo "version unknown")
                ;;
            *)
                version_info="available"
                ;;
        esac
        print_success "$tool found ($version_info)"
        return 0
    else
        if [[ "$required" == "true" ]]; then
            print_error "$tool not found in PATH"
            return 1
        else
            print_warning "$tool not found (optional)"
            return 0
        fi
    fi
}

check_basic_tools() {
    local all_good=true
    
    print_info "Checking basic tools..."
    
    for tool in "${REQUIRED_TOOLS[@]}"; do
        if ! check_tool "$tool"; then
            all_good=false
        fi
    done
    
    if [[ "$all_good" == "true" ]]; then
        return 0
    else
        return 1
    fi
}

check_platform_tools() {
    local platform=$1
    local all_good=true
    local tools_var
    
    case "$platform" in
        "linux")
            tools_var="REQUIRED_TOOLS_LINUX[@]"
            ;;
        "macos")
            tools_var="REQUIRED_TOOLS_MACOS[@]"
            ;;
        "win32")
            tools_var="REQUIRED_TOOLS_WIN32[@]"
            ;;
        *)
            print_warning "Unknown platform '$platform', skipping platform-specific tool checks"
            return 0
            ;;
    esac
    
    print_info "Checking platform-specific tools for $platform..."
    
    # Use indirect reference to get the array
    local tools_array_name="$tools_var"
    if [[ -n "${!tools_array_name:-}" ]]; then
        local tools_array=("${!tools_array_name}")
        for tool in "${tools_array[@]}"; do
            if ! check_tool "$tool"; then
                all_good=false
            fi
        done
    fi
    
    if [[ "$all_good" == "true" ]]; then
        return 0
    else
        return 1
    fi
}

# =============================================================================
# Platform-Specific Checks
# =============================================================================

check_macos_requirements() {
    print_info "Checking macOS-specific requirements..."
    
    # Check for Xcode command line tools
    if ! xcode-select -p &> /dev/null; then
        print_error "Xcode command line tools not installed"
        print_info "Install with: xcode-select --install"
        return 1
    else
        print_success "Xcode command line tools installed"
    fi
    
    # Check for macOS SDK
    local sdk_path
    sdk_path=$(xcrun --show-sdk-path 2>/dev/null || echo "")
    if [[ -n "$sdk_path" && -d "$sdk_path" ]]; then
        print_success "macOS SDK found at $sdk_path"
    else
        print_warning "macOS SDK not found or not accessible"
    fi
    
    # Check for required frameworks (just check if headers exist)
    local frameworks=("Cocoa" "OpenGL" "Metal")
    for framework in "${frameworks[@]}"; do
        if [[ -d "$sdk_path/System/Library/Frameworks/$framework.framework" ]]; then
            print_success "$framework framework available"
        else
            print_warning "$framework framework not found"
        fi
    done
    
    return 0
}

check_linux_requirements() {
    print_info "Checking Linux-specific requirements..."
    
    # Check for development packages
    local packages=("libx11-dev" "libgl1-mesa-dev" "libfreetype6-dev" "libfontconfig1-dev")
    local missing_packages=()
    
    for package in "${packages[@]}"; do
        if dpkg -l | grep -q "$package" 2>/dev/null; then
            print_success "$package installed"
        elif rpm -q "$package" &>/dev/null; then
            print_success "$package installed"
        else
            print_warning "$package not found (may be required)"
            missing_packages+=("$package")
        fi
    done
    
    if [[ ${#missing_packages[@]} -gt 0 ]]; then
        print_info "Missing packages (Ubuntu/Debian): ${missing_packages[*]}"
        print_info "Install with: sudo apt-get install ${missing_packages[*]}"
    fi
    
    return 0
}

check_win32_requirements() {
    print_info "Checking Windows-specific requirements..."
    
    # Check for Windows SDK (approximate check)
    if [[ -n "${WINDOWSSDKDIR:-}" ]]; then
        print_success "Windows SDK environment detected"
    else
        print_warning "Windows SDK environment not detected"
        print_info "Make sure Visual Studio or Windows SDK is installed"
    fi
    
    return 0
}

# =============================================================================
# Library Checks
# =============================================================================

check_freetype_library() {
    local platform=$1
    local arch=$2
    
    print_info "Checking FreeType library availability..."
    
    case "$platform" in
        "macos")
            local freetype_lib="non-source/foreign/x64/libfreetype-mac.a"
            if [[ -f "$freetype_lib" ]]; then
                print_success "FreeType library found: $freetype_lib"
            else
                print_error "FreeType library not found: $freetype_lib"
                return 1
            fi
            ;;
        "linux")
            if pkg-config --exists freetype2; then
                local freetype_version
                freetype_version=$(pkg-config --modversion freetype2)
                print_success "FreeType2 found via pkg-config (version $freetype_version)"
            else
                print_warning "FreeType2 not found via pkg-config"
            fi
            ;;
        "win32")
            local freetype_lib="non-source/foreign/x64/freetype.lib"
            if [[ -f "$freetype_lib" ]]; then
                print_success "FreeType library found: $freetype_lib"
            else
                print_error "FreeType library not found: $freetype_lib"
                return 1
            fi
            ;;
    esac
    
    return 0
}

# =============================================================================
# Main Checking Function
# =============================================================================

check_build_environment() {
    local platform
    local arch
    local all_good=true
    
    echo "=== 4coder Build Environment Check ==="
    echo
    
    # Detect platform
    if command -v "$(dirname "$0")/detect-platform.sh" &> /dev/null; then
        platform=$($(dirname "$0")/detect-platform.sh detect)
        arch=$($(dirname "$0")/detect-platform.sh arch)
        print_info "Detected platform: $platform"
        print_info "Detected architecture: $arch"
    else
        print_warning "Platform detection script not found, assuming current platform"
        platform="unknown"
        arch="unknown"
    fi
    
    echo
    
    # Check clang version
    if ! check_clang_version; then
        all_good=false
    fi
    
    echo
    
    # Check basic tools
    if ! check_basic_tools; then
        all_good=false
    fi
    
    echo
    
    # Check platform-specific tools
    if ! check_platform_tools "$platform"; then
        all_good=false
    fi
    
    echo
    
    # Check platform-specific requirements
    case "$platform" in
        "macos")
            if ! check_macos_requirements; then
                all_good=false
            fi
            ;;
        "linux")
            if ! check_linux_requirements; then
                all_good=false
            fi
            ;;
        "win32")
            if ! check_win32_requirements; then
                all_good=false
            fi
            ;;
    esac
    
    echo
    
    # Check libraries
    if ! check_freetype_library "$platform" "$arch"; then
        all_good=false
    fi
    
    echo
    
    # Final result
    if [[ "$all_good" == "true" ]]; then
        print_success "Build environment check passed!"
        print_info "System is ready for 4coder compilation"
        return 0
    else
        print_error "Build environment check failed"
        print_info "Some requirements are missing. Please install missing components and try again."
        return 1
    fi
}

# =============================================================================
# Main execution
# =============================================================================

main() {
    local command="${1:-check}"
    
    case "$command" in
        "check")
            check_build_environment
            ;;
        "clang")
            check_clang_version
            ;;
        "tools")
            check_basic_tools
            ;;
        "help"|"-h"|"--help")
            echo "Usage: $0 [check|clang|tools|help]"
            echo ""
            echo "Commands:"
            echo "  check     - Run full build environment check (default)"
            echo "  clang     - Check clang version only"
            echo "  tools     - Check basic tools only"
            echo "  help      - Show this help message"
            ;;
        *)
            echo "Error: Unknown command '$command'" >&2
            echo "Run '$0 help' for usage information" >&2
            return 1
            ;;
    esac
}

# Only run main if script is executed directly (not sourced)
if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
    main "$@"
fi