<?php

namespace App\Services;

use App\Models\Document;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Storage;
use Illuminate\Support\Str;
use Paperdoc\Support\DocumentManager;

/**
 * 文档转换服务
 * 使用 paperdoc-lib 将文档（DOCX/PPTX/XLSX/PDF）转换为 Markdown
 */
class DocumentConversionService
{
    protected int $previewLength;

    public function __construct()
    {
        $this->previewLength = config('documents.markdown.preview_length', 500);
    }

    /**
     * 将文档转换为 Markdown
     */
    public function convertToMarkdown(Document $document): array
    {
        $documentPath = Storage::disk('local')->path($document->file_path);

        if (!file_exists($documentPath)) {
            throw new \Exception("文档文件不存在: {$documentPath}");
        }

        $doc = DocumentManager::open($documentPath, ['ocr' => false]);
        $markdown = DocumentManager::renderAs($doc, 'md');

        if (empty(trim($markdown))) {
            throw new \Exception('文档转换后内容为空，可能是扫描件或不支持的内容格式');
        }

        return ['markdown' => $markdown];
    }

    /**
     * 将 Markdown 内容保存到存储
     */
    public function saveMarkdownToFile(Document $document, string $markdown): string
    {
        $path = $this->generateMarkdownPath($document);

        $saved = Storage::disk('markdown')->put($path, $markdown);
        if (!$saved) {
            throw new \Exception("无法保存 Markdown 文件");
        }

        return $path;
    }

    /**
     * 生成 Markdown 文件路径
     */
    protected function generateMarkdownPath(Document $document): string
    {
        $organizeByDate = config('documents.storage.organize_by_date', true);
        $uuid = Str::uuid()->toString();

        if ($organizeByDate) {
            $date = $document->created_at ?? now();
            $directory = $date->format('Y/m/d') . '/' . $uuid;
        } else {
            $directory = $uuid;
        }

        return "{$directory}/{$uuid}.md";
    }

    /**
     * 获取 Markdown 内容的预览（前 N 个字符）
     */
    public function getMarkdownPreview(string $markdown, ?int $length = null): string
    {
        $length = $length ?? $this->previewLength;
        $cleaned = preg_replace('/\s+/', ' ', $markdown);
        $cleaned = trim($cleaned);

        if (mb_strlen($cleaned) <= $length) {
            return $cleaned;
        }

        return mb_substr($cleaned, 0, $length) . '...';
    }

    /**
     * 更新文档的 Markdown 信息
     */
    public function updateDocumentMarkdown(Document $document, string $markdownPath): void
    {
        $markdown = Storage::disk('markdown')->get($markdownPath);

        if ($markdown === false) {
            Log::warning('无法读取 Markdown 文件以生成预览', [
                'document_id' => $document->id,
                'markdown_path' => $markdownPath,
            ]);
            $preview = '';
        } else {
            $preview = $this->getMarkdownPreview($markdown);
        }

        $document->update([
            'markdown_path' => $markdownPath,
            'conversion_status' => 'completed',
            'conversion_error' => null,
        ]);
    }

    /**
     * 处理转换失败
     */
    public function handleConversionFailure(Document $document, \Exception $exception): void
    {
        Log::error('文档转换失败', [
            'document_id' => $document->id,
            'document_title' => $document->title,
            'file_name' => $document->file_name,
            'error' => $exception->getMessage(),
            'trace' => $exception->getTraceAsString(),
        ]);

        $document->update([
            'conversion_status' => 'failed',
            'conversion_error' => $exception->getMessage(),
        ]);
    }

    /**
     * 将转换任务加入队列
     */
    public function queueConversion(Document $document): void
    {
        $document->update([
            'conversion_status' => 'processing',
            'conversion_error' => null,
        ]);

        $queue = config('documents.conversion.queue', 'documents');
        \App\Jobs\ConvertDocumentToMarkdown::dispatch($document)->onQueue($queue);
    }
}