<?php

namespace TypePhp\Backend;

use TypePhp\Platform\PlatformBase;
use TypePhp\Platform\Windows;
use TypePhp\Platform\Linux;
use TypePhp\Platform\Macos;

/**
 * 编译器工厂类
 * 根据平台自动创建合适的编译器后端
 */
class CompilerFactory
{
    /**
     * 创建默认编译器后端
     */
    public static function create(PlatformBase $platform): CompilerBackend
    {
        if ($platform instanceof Windows) {
            // Windows 默认使用 MSVC
            return new Msvc($platform, $platform->getDefaultCompiler());
        } elseif ($platform instanceof Linux) {
            // Linux 默认使用 GCC
            return new Gcc($platform, $platform->getDefaultCompiler());
        } elseif ($platform instanceof Macos) {
            // macOS 默认使用 Clang
            return new Clang($platform, $platform->getDefaultCompiler());
        } else {
            throw new \RuntimeException("Unsupported platform: " . $platform->getName());
        }
    }

    /**
     * 根据配置、环境变量和平台默认值解析编译器命令
     */
    public static function detectCompilerName(PlatformBase $platform, string $configuredCompiler = ''): string
    {
        if ($configuredCompiler !== '') {
            return $configuredCompiler;
        }

        $compilerEnv = getenv('PHPX_CC');
        if ($compilerEnv) {
            return $compilerEnv;
        }

        if (!$platform instanceof Windows) {
            $cxxEnv = getenv('CXX');
            if ($cxxEnv) {
                return $cxxEnv;
            }
        }

        return $platform->getDefaultCompiler();
    }

    /**
     * 创建指定类型的编译器后端
     */
    public static function createByName(string $compilerName, PlatformBase $platform): CompilerBackend
    {
        $normalized = self::normalizeCompilerName($compilerName);
        $lowerCommand = strtolower($compilerName);

        if (str_contains($normalized, 'clang') || str_contains($lowerCommand, 'clang')) {
            $linker = $platform instanceof Windows ? Clang::detectWindowsLinker() : null;
            return new Clang($platform, $compilerName, $linker);
        }

        if (
            $normalized === 'gcc' ||
            $normalized === 'g++' ||
            $normalized === 'c++' ||
            str_ends_with($normalized, '-gcc') ||
            str_ends_with($normalized, '-g++') ||
            str_contains($lowerCommand, 'g++') ||
            str_contains($lowerCommand, 'c++') ||
            str_contains($lowerCommand, 'gcc')
        ) {
            return new Gcc($platform, $compilerName);
        }

        if ($normalized === 'msvc' || $normalized === 'cl') {
            if (!$platform instanceof Windows) {
                throw new \RuntimeException("MSVC compiler is only supported on Windows");
            }
            return new Msvc($platform, $compilerName);
        }

        throw new \RuntimeException("Unsupported compiler: {$compilerName}");
    }

    /**
     * 自动检测并创建编译器和平台
     */
    public static function autoDetect(string $compilerName = '', ?PlatformBase $platform = null): array
    {
        // 创建平台
        $platform ??= \TypePhp\Platform\PlatformFactory::create();
        
        // 创建编译器
        $compilerName = self::detectCompilerName($platform, $compilerName);
        $compiler = self::createByName($compilerName, $platform);
        
        return [
            'platform' => $platform,
            'compiler' => $compiler,
        ];
    }

    public static function isCommandExecutable(string $command): bool
    {
        $program = self::getCommandProgram($command);
        if ($program === '') {
            return false;
        }

        if (self::isPathLikeCommand($program)) {
            return is_file($program) && is_executable($program);
        }

        $path = getenv('PATH');
        if ($path === false || $path === '') {
            return false;
        }

        $extensions = [''];
        if (DIRECTORY_SEPARATOR === '\\') {
            $pathext = getenv('PATHEXT') ?: '.COM;.EXE;.BAT;.CMD';
            $extensions = array_filter(array_map('strtolower', explode(';', $pathext)));
            if (preg_match('/\.[A-Za-z0-9]+$/', $program)) {
                array_unshift($extensions, '');
            }
        }

        foreach (explode(PATH_SEPARATOR, $path) as $dir) {
            if ($dir === '') {
                continue;
            }
            foreach ($extensions as $extension) {
                $candidate = rtrim($dir, DIRECTORY_SEPARATOR . '/\\') . DIRECTORY_SEPARATOR . $program . $extension;
                if (is_file($candidate) && is_executable($candidate)) {
                    return true;
                }
            }
        }

        return false;
    }

    public static function getCommandProgram(string $command): string
    {
        $command = trim($command);
        if ($command === '') {
            return '';
        }

        if ($command[0] === '"' || $command[0] === "'") {
            $quote = $command[0];
            $end = strpos($command, $quote, 1);
            if ($end !== false) {
                return substr($command, 1, $end - 1);
            }
        }

        $firstToken = strtok($command, " \t\r\n");
        return $firstToken === false ? '' : $firstToken;
    }

    private static function normalizeCompilerName(string $compilerName): string
    {
        $firstToken = self::getCommandProgram($compilerName);
        if ($firstToken === '') {
            return '';
        }

        $name = basename(str_replace('\\', '/', $firstToken));
        $name = strtolower($name);

        return preg_replace('/\.exe$/', '', $name);
    }

    private static function isPathLikeCommand(string $program): bool
    {
        return str_contains($program, '/')
            || str_contains($program, '\\')
            || preg_match('/^[A-Za-z]:[\/\\\\]/', $program) === 1;
    }
}