<?php

namespace App\Services;

use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Process;
use Illuminate\Support\Str;

/**
 * PDF合并工具类
 * 支持pdfunite（生产环境）和qpdf（本地开发）
 */
class PdfMerger
{
    private string $mergeTool;
    private bool $isProduction;

    public function __construct()
    {
        $this->isProduction = app()->environment('production');
        $this->mergeTool = $this->detectMergeTool();
    }

    /**
     * 检测系统中可用的PDF合并工具
     */
    private function detectMergeTool(): string
    {
        // 生产环境优先使用pdfunite
        if ($this->isProduction) {
            if ($this->commandExists('pdfunite')) {
                return 'pdfunite';
            }
        }

        // 本地开发环境使用qpdf
        if ($this->commandExists('qpdf')) {
            return 'qpdf';
        }

        // 备选：尝试pdfunite
        if ($this->commandExists('pdfunite')) {
            return 'pdfunite';
        }

        throw new \Exception('未找到可用的PDF合并工具（pdfunite或qpdf）');
    }

    /**
     * 检查命令是否存在
     */
    private function commandExists(string $command): bool
    {
        // 【修复】异步环境中PATH可能不完整，尝试绝对路径
        $fullPaths = [
            "/opt/homebrew/bin/{$command}",
            "/usr/bin/{$command}",
            "/usr/local/bin/{$command}",
        ];

        Log::debug("检查命令是否存在: {$command}", [
            'checking_absolute_paths' => $fullPaths
        ]);

        // 首先尝试绝对路径
        foreach ($fullPaths as $path) {
            if (file_exists($path) && is_executable($path)) {
                Log::debug("找到命令（绝对路径）: {$command} -> {$path}");
                return true;
            }
        }

        // 如果绝对路径都不行，再尝试which命令
        Log::debug("绝对路径未找到，尝试which命令: {$command}");
        $output = Process::run("which {$command}");
        $result = $output->successful();

        Log::debug("which命令结果", [
            'command' => $command,
            'successful' => $result,
            'output' => $output->output(),
            'error' => $output->errorOutput()
        ]);

        return $result;
    }

    /**
     * 合并多个PDF文件
     *
     * @param array $pdfPaths PDF文件路径数组
     * @param string $outputPath 输出文件路径
     * @return bool 合并是否成功
     * @throws \Exception
     */
    public function merge(array $pdfPaths, string $outputPath): bool
    {
        // 验证输入文件
        foreach ($pdfPaths as $path) {
            if (!file_exists($path)) {
                throw new \Exception("PDF文件不存在: {$path}");
            }
        }

        // 确保输出目录存在
        $outputDir = dirname($outputPath);
        if (!is_dir($outputDir)) {
            mkdir($outputDir, 0755, true);
        }

        Log::info('开始合并PDF', [
            'tool' => $this->mergeTool,
            'input_count' => count($pdfPaths),
            'output_path' => $outputPath
        ]);

        try {
            switch ($this->mergeTool) {
                case 'pdfunite':
                    return $this->mergeWithPdfunite($pdfPaths, $outputPath);
                case 'qpdf':
                    return $this->mergeWithQpdf($pdfPaths, $outputPath);
                default:
                    throw new \Exception("不支持的合并工具: {$this->mergeTool}");
            }
        } catch (\Exception $e) {
            Log::error('PDF合并失败', [
                'tool' => $this->mergeTool,
                'error' => $e->getMessage(),
                'trace' => $e->getTraceAsString()
            ]);
            throw $e;
        }
    }

    /**
     * 使用pdfunite合并PDF
     * pdfunite file1.pdf file2.pdf ... output.pdf
     */
    private function mergeWithPdfunite(array $pdfPaths, string $outputPath): bool
    {
        $command = 'pdfunite ' . implode(' ', array_map('escapeshellarg', $pdfPaths)) . ' ' . escapeshellarg($outputPath);

        Log::debug('执行pdfunite命令', ['command' => $command]);

        $output = Process::run($command);

        if ($output->successful()) {
            Log::info('pdfunite合并成功', ['output_path' => $outputPath]);
            return true;
        }

        Log::error('pdfunite合并失败', [
            'exit_code' => $output->exitCode(),
            'output' => $output->output(),
            'error' => $output->errorOutput()
        ]);

        return false;
    }

    /**
     * 使用qpdf合并PDF
     * qpdf --empty --pages file1.pdf file2.pdf -- -- output.pdf
     */
    private function mergeWithQpdf(array $pdfPaths, string $outputPath): bool
    {
        // 构建qpdf命令
        $pagesArg = implode(' ', array_map('escapeshellarg', $pdfPaths));
        $command = "qpdf --empty --pages {$pagesArg} -- -- " . escapeshellarg($outputPath);

        Log::debug('执行qpdf命令', ['command' => $command]);

        $output = Process::run($command);

        if ($output->successful()) {
            Log::info('qpdf合并成功', ['output_path' => $outputPath]);
            return true;
        }

        Log::error('qpdf合并失败', [
            'exit_code' => $output->exitCode(),
            'output' => $output->output(),
            'error' => $output->errorOutput()
        ]);

        return false;
    }

    /**
     * 获取当前使用的合并工具
     */
    public function getMergeTool(): string
    {
        return $this->mergeTool;
    }

    /**
     * 检查环境是否支持PDF合并
     */
    public function isSupported(): bool
    {
        return in_array($this->mergeTool, ['pdfunite', 'qpdf']);
    }
}