<?php

namespace App\Http\Controllers;

use App\Jobs\GenerateAnalysisPdfJob;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Log;

class ExamAnalysisPdfController extends Controller
{
    private const ENQUEUE_LOCK_TTL_SECONDS = 120;

    public function show(Request $request)
    {
        $paperId = $request->query('paperId');
        $studentId = $request->query('studentId');
        $recordId = $request->query('recordId'); // 可选的OCR记录ID

        if (!$paperId || !$studentId) {
            return response()->json([
                'success' => false,
                'message' => 'paperId 和 studentId 不能为空',
            ], 400);
        }

        // 已生成则直接返回链接
        $existingPdfUrl = DB::connection('mysql')
            ->table('exam_analysis_results')
            ->where('paper_id', $paperId)
            ->where('student_id', $studentId)
            ->whereNotNull('analysis_pdf_url')
            ->where('analysis_pdf_url', '!=', '')
            ->orderByDesc('updated_at')
            ->value('analysis_pdf_url');

        if ($existingPdfUrl) {
            return response()->json([
                'success' => true,
                'message' => '学情报告已生成',
                'data' => [
                    'paper_id' => $paperId,
                    'student_id' => $studentId,
                    'record_id' => $recordId,
                    'status' => 'completed',
                    'pdf_url' => $existingPdfUrl,
                    'queued' => false,
                ],
            ]);
        }

        $lockKey = sprintf('analysis_pdf:enqueue:%s:%s', $paperId, $studentId);
        $acquired = Cache::add($lockKey, now()->timestamp, now()->addSeconds(self::ENQUEUE_LOCK_TTL_SECONDS));
        if (! $acquired) {
            return response()->json([
                'success' => true,
                'message' => '学情报告正在生成中，请稍后重试',
                'data' => [
                    'paper_id' => $paperId,
                    'student_id' => $studentId,
                    'record_id' => $recordId,
                    'status' => 'processing',
                    'pdf_url' => null,
                    'queued' => false,
                ],
            ], 202);
        }

        dispatch(new GenerateAnalysisPdfJob($paperId, $studentId, $recordId));
        Log::info('ExamAnalysisPdfController: 学情报告生成任务已入队', [
            'paper_id' => $paperId,
            'student_id' => $studentId,
            'record_id' => $recordId,
        ]);

        return response()->json([
            'success' => true,
            'message' => '学情报告任务已入队，正在后台生成',
            'data' => [
                'paper_id' => $paperId,
                'student_id' => $studentId,
                'record_id' => $recordId,
                'status' => 'processing',
                'pdf_url' => null,
                'queued' => true,
            ],
        ], 202);
    }
}