<?php

namespace App\Services;

use App\DTO\ExamAnalysisDataDto;
use App\DTO\ReportPayloadDto;
use App\Models\Paper;
use App\Models\PaperQuestion;
use App\Models\Student;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\File;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Storage;
use Illuminate\Support\Facades\URL;
use Symfony\Component\Process\Exception\ProcessSignaledException;
use Symfony\Component\Process\Exception\ProcessTimedOutException;
use Symfony\Component\Process\Process;

/**
 * PDF导出服务（重构版）
 * 负责生成试卷PDF、判卷PDF和学情报告PDF
 */
class ExamPdfExportService
{
    public function __construct(
        private readonly LearningAnalyticsService $learningAnalyticsService,
        private readonly QuestionBankService $questionBankService,
        private readonly QuestionServiceApi $questionServiceApi,
        private readonly PdfStorageService $pdfStorageService
    ) {}

    /**
     * 生成试卷 PDF（不含答案）
     */
    public function generateExamPdf(string $paperId): ?string
    {
        $url = $this->renderAndStoreExamPdf($paperId, includeAnswer: false, suffix: 'exam');

        // 如果生成成功，将 URL 写入数据库
        if ($url) {
            $this->savePdfUrlToDatabase($paperId, 'exam_pdf_url', $url);
        }

        return $url;
    }

    /**
     * 生成判卷 PDF（含答案与解析）
     */
    public function generateGradingPdf(string $paperId): ?string
    {
        $url = $this->renderAndStoreExamPdf($paperId, includeAnswer: true, suffix: 'grading', useGradingView: true);

        // 如果生成成功，将 URL 写入数据库
        if ($url) {
            $this->savePdfUrlToDatabase($paperId, 'grading_pdf_url', $url);
        }

        return $url;
    }

    /**
     * 生成学情分析 PDF
     */
    public function generateAnalysisReportPdf(string $paperId, string $studentId, ?string $recordId = null): ?string
    {
        if (function_exists('set_time_limit')) {
            @set_time_limit(240);
        }

        try {
            // 构建分析数据
            $analysisData = $this->buildAnalysisData($paperId, $studentId);
            if (!$analysisData) {
                return null;
            }

            // 创建DTO
            $dto = ExamAnalysisDataDto::fromArray($analysisData);
            $payloadDto = ReportPayloadDto::fromExamAnalysisDataDto($dto);

            // 渲染HTML
            $html = view('exam-analysis.pdf-report', $payloadDto->toArray())->render();
            if (!$html) {
                Log::error('ExamPdfExportService: 渲染HTML为空', ['paper_id' => $paperId]);
                return null;
            }

            // 生成PDF
            $pdfBinary = $this->buildPdf($html);
            if (!$pdfBinary) {
                return null;
            }

            // 保存PDF
            $version = time();
            $path = "analysis_reports/{$paperId}_{$studentId}_{$version}.pdf";
            $url = $this->pdfStorageService->put($path, $pdfBinary);
            if (!$url) {
                Log::error('ExamPdfExportService: 保存学情PDF失败', ['path' => $path]);
                return null;
            }

            // 保存URL到数据库
            $this->saveAnalysisPdfUrl($paperId, $studentId, $recordId, $url);

            return $url;

        } catch (\Throwable $e) {
            Log::error('ExamPdfExportService: 生成学情分析PDF失败', [
                'paper_id' => $paperId,
                'student_id' => $studentId,
                'record_id' => $recordId,
                'error' => $e->getMessage(),
                'exception' => get_class($e),
                'trace' => $e->getTraceAsString(),
            ]);
            return null;
        }
    }

    /**
     * 渲染并存储试卷PDF
     */
    private function renderAndStoreExamPdf(
        string $paperId,
        bool $includeAnswer,
        string $suffix,
        bool $useGradingView = false
    ): ?string {
        // 放宽脚本执行时间
        if (function_exists('set_time_limit')) {
            @set_time_limit(240);
        }

        try {
            $html = $this->renderExamHtml($paperId, $includeAnswer, $useGradingView);
            if (!$html) {
                Log::error('ExamPdfExportService: 渲染HTML为空', [
                    'paper_id' => $paperId,
                    'include_answer' => $includeAnswer,
                    'use_grading_view' => $useGradingView,
                ]);
                return null;
            }

            $pdfBinary = $this->buildPdf($html);
            if (!$pdfBinary) {
                return null;
            }

            $path = "exams/{$paperId}_{$suffix}.pdf";
            $url = $this->pdfStorageService->put($path, $pdfBinary);
            if (!$url) {
                Log::error('ExamPdfExportService: 保存PDF失败', ['path' => $path]);
                return null;
            }

            return $url;

        } catch (\Throwable $e) {
            Log::error('ExamPdfExportService: 生成PDF失败', [
                'paper_id' => $paperId,
                'suffix' => $suffix,
                'error' => $e->getMessage(),
                'exception' => get_class($e),
                'trace' => $e->getTraceAsString(),
            ]);
            return null;
        }
    }

    /**
     * 渲染试卷HTML（重构版）
     */
    private function renderExamHtml(string $paperId, bool $includeAnswer, bool $useGradingView): ?string
    {
        // 直接构造请求URL，使用路由生成HTML
        $routeName = $useGradingView
            ? 'filament.admin.auth.intelligent-exam.grading'
            : 'filament.admin.auth.intelligent-exam.pdf';

        $url = route($routeName, ['paper_id' => $paperId, 'answer' => $includeAnswer ? 'true' : 'false']);

        // 使用HTTP客户端获取渲染后的HTML
        try {
            $response = Http::get($url);
            if ($response->successful()) {
                return $this->ensureUtf8Html($response->body());
            }
        } catch (\Exception $e) {
            Log::warning('ExamPdfExportService: 通过HTTP获取HTML失败，使用备用方案', [
                'paper_id' => $paperId,
                'error' => $e->getMessage(),
            ]);
        }

        // 备用方案：直接渲染视图（如果路由不可用）
        try {
            $paper = Paper::with('questions')->find($paperId);
            if (!$paper) {
                return null;
            }

            $viewName = $useGradingView ? 'exam-pdf.grading' : 'exam-pdf.student';
            $html = view($viewName, compact('paper'))->render();
            return $this->ensureUtf8Html($html);

        } catch (\Exception $e) {
            Log::error('ExamPdfExportService: 备用方案渲染失败', [
                'paper_id' => $paperId,
                'error' => $e->getMessage(),
            ]);
            return null;
        }
    }

    /**
     * 构建分析数据（重构版）
     */
    private function buildAnalysisData(string $paperId, string $studentId): ?array
    {
        $paper = Paper::with(['questions' => function ($query) {
            $query->orderBy('question_number')->orderBy('id');
        }])->find($paperId);

        if (!$paper) {
            Log::error('ExamPdfExportService: 未找到试卷', [
                'paper_id' => $paperId,
                'student_id' => $studentId,
            ]);
            return null;
        }

        $student = Student::find($studentId);
        $studentInfo = [
            'id' => $student?->student_id ?? $studentId,
            'name' => $student?->name ?? $studentId,
            'grade' => $student?->grade ?? '未知年级',
            'class' => $student?->class_name ?? '未知班级',
        ];

        // 获取分析数据
        $analysisData = [];
        if (!empty($paper->analysis_id)) {
            $analysis = $this->learningAnalyticsService->getAnalysisResult($paper->analysis_id);
            if (!empty($analysis['data'])) {
                $analysisData = $analysis['data'];
            }
        }

        // 获取掌握度数据
        $masteryData = [];
        $masteryResponse = $this->learningAnalyticsService->getStudentMastery($studentId);
        if (!empty($masteryResponse['data'])) {
            $masteryData = $masteryResponse['data'];
        }

        // 获取学习建议
        $recommendations = [];
        $recommendationResponse = $this->learningAnalyticsService->getLearningRecommendations($studentId);
        if (!empty($recommendationResponse['data'])) {
            $recommendations = $recommendationResponse['data'];
        }

        // 获取知识点名称映射
        $kpNameMap = $this->buildKnowledgePointNameMap();

        // 获取题目详情
        $questionDetails = $this->getQuestionDetailsFromPaper($paper);

        // 处理题目数据
        $questions = $this->processQuestionsForReport($paper, $questionDetails, $kpNameMap);

        return [
            'paper' => [
                'id' => $paper->paper_id,
                'name' => $paper->paper_name,
                'total_questions' => $paper->question_count,
                'total_score' => $paper->total_score,
                'created_at' => $paper->created_at,
            ],
            'student' => $studentInfo,
            'questions' => $questions,
            'mastery' => $this->buildMasterySummary($masteryData, $kpNameMap),
            'insights' => $analysisData['question_results'] ?? [],
            'recommendations' => $recommendations,
            'analysis_data' => $analysisData,
        ];
    }

    /**
     * 获取题目详情
     */
    private function getQuestionDetailsFromPaper(Paper $paper): array
    {
        $details = [];
        $questionIds = $paper->questions->pluck('question_id')->filter()->unique()->values();

        foreach ($questionIds as $qid) {
            try {
                $detail = $this->questionBankService->getQuestion((string) $qid);
                if (!empty($detail)) {
                    $details[(string) $qid] = $detail;
                }
            } catch (\Throwable $e) {
                Log::warning('ExamPdfExportService: 获取题目详情失败', [
                    'question_id' => $qid,
                    'error' => $e->getMessage(),
                ]);
            }
        }

        return $details;
    }

    /**
     * 处理题目数据（用于报告）
     */
    private function processQuestionsForReport(Paper $paper, array $questionDetails, array $kpNameMap): array
    {
        $grouped = [
            'choice' => [],
            'fill' => [],
            'answer' => [],
        ];

        $sortedQuestions = $paper->questions
            ->sortBy(function (PaperQuestion $q, int $idx) {
                $number = $q->question_number ?? $idx + 1;
                return is_numeric($number) ? (float) $number : ($q->id ?? $idx);
            });

        foreach ($sortedQuestions as $idx => $question) {
            $kpCode = $question->knowledge_point ?? '';
            $kpName = $kpNameMap[$kpCode] ?? $kpCode ?: '未标注';
            $detail = $questionDetails[(string) ($question->question_id ?? '')] ?? [];
            $solution = $detail['solution'] ?? $detail['解析'] ?? $detail['analysis'] ?? null;
            $typeRaw = $question->question_type ?? ($detail['question_type'] ?? $detail['type'] ?? '');
            $normalizedType = $this->normalizeQuestionType($typeRaw);
            $number = $question->question_number ?? ($idx + 1);

            $payload = [
                'question_number' => $number,
                'question_text' => is_array($question->question_text)
                    ? json_encode($question->question_text, JSON_UNESCAPED_UNICODE)
                    : ($question->question_text ?? ''),
                'question_type' => $normalizedType,
                'knowledge_point' => $kpCode,
                'knowledge_point_name' => $kpName,
                'score' => $question->score,
                'solution' => $solution,
            ];

            $grouped[$normalizedType][] = $payload;
        }

        $ordered = array_merge($grouped['choice'], $grouped['fill'], $grouped['answer']);

        // 按卷面顺序重新编号
        foreach ($ordered as $i => &$q) {
            $q['display_number'] = $i + 1;
        }
        unset($q);

        return $ordered;
    }

    /**
     * 构建PDF
     */
    private function buildPdf(string $html): ?string
    {
        $tmpHtml = tempnam(sys_get_temp_dir(), 'exam_html_') . '.html';
        $utf8Html = $this->ensureUtf8Html($html);
        file_put_contents($tmpHtml, $utf8Html);

        // 仅使用Chrome渲染
        $chromePdf = $this->renderWithChrome($tmpHtml);
        @unlink($tmpHtml);
        return $chromePdf;
    }

    /**
     * 使用Chrome渲染PDF
     */
    private function renderWithChrome(string $htmlPath): ?string
    {
        $tmpPdf = tempnam(sys_get_temp_dir(), 'exam_pdf_') . '.pdf';
        $userDataDir = sys_get_temp_dir() . '/chrome-profile-' . uniqid();

        $chromeBinary = $this->findChromeBinary();
        if (!$chromeBinary) {
            Log::error('ExamPdfExportService: 未找到可用的Chrome/Chromium');
            return null;
        }

        // 设置运行时目录
        $runtimeHome = sys_get_temp_dir() . '/chrome-home';
        $runtimeXdg = sys_get_temp_dir() . '/chrome-xdg';
        if (!File::exists($runtimeHome)) {
            @File::makeDirectory($runtimeHome, 0755, true);
        }
        if (!File::exists($runtimeXdg)) {
            @File::makeDirectory($runtimeXdg, 0755, true);
        }

        $process = new Process([
            $chromeBinary,
            '--headless',
            '--disable-gpu',
            '--no-sandbox',
            '--disable-setuid-sandbox',
            '--disable-dev-shm-usage',
            '--no-zygote',
            '--disable-features=VizDisplayCompositor',
            '--disable-software-rasterizer',
            '--disable-extensions',
            '--disable-background-networking',
            '--disable-component-update',
            '--disable-client-side-phishing-detection',
            '--disable-default-apps',
            '--disable-domain-reliability',
            '--disable-sync',
            '--safebrowsing-disable-auto-update',
            '--no-first-run',
            '--no-default-browser-check',
            '--disable-crash-reporter',
            '--disable-print-preview',
            '--disable-features=PrintHeaderFooter',
            '--disable-features=TranslateUI',
            '--disable-features=OptimizationHints',
            '--disable-ipc-flooding-protection',
            '--disable-background-networking',
            '--disable-background-timer-throttling',
            '--disable-backgrounding-occluded-windows',
            '--disable-renderer-backgrounding',
            '--disable-features=AudioServiceOutOfProcess',
            '--user-data-dir=' . $userDataDir,
            '--print-to-pdf=' . $tmpPdf,
            '--print-to-pdf-no-header',
            '--allow-file-access-from-files',
            'file://' . $htmlPath,
        ], null, [
            'HOME' => $runtimeHome,
            'XDG_RUNTIME_DIR' => $runtimeXdg,
        ]);

        $process->setTimeout(60);
        $killSignal = \defined('SIGKILL') ? \SIGKILL : 9;

        try {
            $startedAt = microtime(true);
            $process->start();
            $pdfGenerated = false;

            // 轮询检测PDF是否生成
            $pollStart = microtime(true);
            $maxPollSeconds = 30;
            while ($process->isRunning() && (microtime(true) - $pollStart) < $maxPollSeconds) {
                if (file_exists($tmpPdf) && filesize($tmpPdf) > 0) {
                    $pdfGenerated = true;
                    $process->stop(5, $killSignal);
                    break;
                }
                usleep(200_000);
            }

            if ($process->isRunning()) {
                $process->stop(5, $killSignal);
            }

            $process->wait();

        } catch (ProcessTimedOutException|ProcessSignaledException $e) {
            if ($process->isRunning()) {
                $process->stop(5, $killSignal);
            }
            return $this->handleChromeProcessResult($tmpPdf, $userDataDir, $process, $startedAt);
        } catch (\Throwable $e) {
            if ($process->isRunning()) {
                $process->stop(5, $killSignal);
            }
            return $this->handleChromeProcessResult($tmpPdf, $userDataDir, $process, null);
        }

        return $this->handleChromeProcessResult($tmpPdf, $userDataDir, $process, null);
    }

    /**
     * 处理Chrome进程结果
     */
    private function handleChromeProcessResult(string $tmpPdf, string $userDataDir, Process $process, ?float $startedAt): ?string
    {
        $pdfExists = file_exists($tmpPdf);
        $pdfSize = $pdfExists ? filesize($tmpPdf) : null;

        if (!$process->isSuccessful()) {
            if ($pdfExists && $pdfSize > 0) {
                Log::warning('ExamPdfExportService: Chrome进程异常但生成了PDF', [
                    'exit_code' => $process->getExitCode(),
                    'tmp_pdf_size' => $pdfSize,
                ]);
            } else {
                Log::error('ExamPdfExportService: Chrome渲染失败', [
                    'exit_code' => $process->getExitCode(),
                    'error' => $process->getErrorOutput(),
                ]);
                @unlink($tmpPdf);
                File::deleteDirectory($userDataDir);
                return null;
            }
        }

        $pdfBinary = $pdfExists ? file_get_contents($tmpPdf) : null;
        @unlink($tmpPdf);
        File::deleteDirectory($userDataDir);
        return $pdfBinary ?: null;
    }

    /**
     * 查找Chrome二进制文件
     */
    private function findChromeBinary(): ?string
    {
        $candidates = [
            env('PDF_CHROME_BINARY'),
            '/Applications/Google Chrome.app/Contents/MacOS/Google Chrome',
            '/usr/bin/google-chrome-stable',
            '/usr/bin/google-chrome',
            '/usr/bin/chromium-browser',
            '/usr/bin/chromium',
        ];

        foreach ($candidates as $path) {
            if ($path && is_file($path) && is_executable($path)) {
                return $path;
            }
        }

        return null;
    }

    /**
     * 确保HTML为UTF-8编码
     */
    private function ensureUtf8Html(string $html): string
    {
        $meta = '<meta charset="UTF-8">';
        if (stripos($html, '<head>') !== false) {
            return preg_replace('/<head>/i', "<head>{$meta}", $html, 1);
        }
        return $meta . $html;
    }

    /**
     * 构建知识点名称映射
     */
    private function buildKnowledgePointNameMap(): array
    {
        try {
            $options = $this->questionServiceApi->getKnowledgePointOptions();
            return $options ?: [];
        } catch (\Throwable $e) {
            Log::warning('ExamPdfExportService: 获取知识点名称失败', [
                'error' => $e->getMessage(),
            ]);
            return [];
        }
    }

    /**
     * 构建掌握度摘要
     */
    private function buildMasterySummary(array $masteryData, array $kpNameMap): array
    {
        $items = [];
        $total = 0;
        $count = 0;
        $hasMap = !empty($kpNameMap);

        foreach ($masteryData as $row) {
            $code = $row['kp_code'] ?? null;
            if ($hasMap && $code && !isset($kpNameMap[$code])) {
                continue;
            }
            $name = $row['kp_name'] ?? ($code ? ($kpNameMap[$code] ?? $code) : '未知知识点');
            $level = (float) ($row['mastery_level'] ?? 0);
            $delta = $row['mastery_change'] ?? null;

            $items[] = [
                'kp_code' => $code,
                'kp_name' => $name,
                'mastery_level' => $level,
                'mastery_change' => $delta,
            ];

            $total += $level;
            $count++;
        }

        $average = $count > 0 ? round($total / $count, 2) : null;

        // 按掌握度从低到高排序
        usort($items, fn($a, $b) => ($a['mastery_level'] <=> $b['mastery_level']));

        return [
            'items' => $items,
            'average' => $average,
            'weak_list' => array_slice($items, 0, 5),
        ];
    }

    /**
     * 标准化题型
     */
    private function normalizeQuestionType(string $type): string
    {
        $t = strtolower(trim($type));
        return match (true) {
            str_contains($t, 'choice') || str_contains($t, '选择') => 'choice',
            str_contains($t, 'fill') || str_contains($t, 'blank') || str_contains($t, '填空') => 'fill',
            default => 'answer',
        };
    }

    /**
     * 保存PDF URL到数据库
     */
    private function savePdfUrlToDatabase(string $paperId, string $field, string $url): void
    {
        try {
            $paper = Paper::where('paper_id', $paperId)->first();
            if ($paper) {
                $paper->update([$field => $url]);
                Log::info('ExamPdfExportService: PDF URL已写入数据库', [
                    'paper_id' => $paperId,
                    'field' => $field,
                    'url' => $url,
                ]);
            }
        } catch (\Throwable $e) {
            Log::error('ExamPdfExportService: 写入PDF URL失败', [
                'paper_id' => $paperId,
                'field' => $field,
                'error' => $e->getMessage(),
            ]);
        }
    }

    /**
     * 保存学情分析PDF URL
     */
    private function saveAnalysisPdfUrl(string $paperId, string $studentId, ?string $recordId, string $url): void
    {
        try {
            if ($recordId) {
                // OCR记录
                $ocrRecord = \App\Models\OCRRecord::find($recordId);
                if ($ocrRecord) {
                    $ocrRecord->update(['analysis_pdf_url' => $url]);
                    Log::info('ExamPdfExportService: OCR记录学情分析PDF URL已写入数据库', [
                        'record_id' => $recordId,
                        'paper_id' => $paperId,
                        'student_id' => $studentId,
                        'url' => $url,
                    ]);
                }
            } else {
                // 学生记录 - 使用新的 student_reports 表
                \App\Models\StudentReport::updateOrCreate(
                    [
                        'student_id' => $studentId,
                        'report_type' => 'exam_analysis',
                        'exam_id' => $paperId,
                    ],
                    [
                        'pdf_url' => $url,
                        'generation_status' => 'completed',
                        'generated_at' => now(),
                        'updated_at' => now(),
                    ]
                );

                Log::info('ExamPdfExportService: 学生学情报告PDF URL已保存到student_reports表', [
                    'student_id' => $studentId,
                    'paper_id' => $paperId,
                    'url' => $url,
                ]);
            }
        } catch (\Throwable $e) {
            Log::error('ExamPdfExportService: 写入学情分析PDF URL失败', [
                'paper_id' => $paperId,
                'student_id' => $studentId,
                'record_id' => $recordId,
                'error' => $e->getMessage(),
            ]);
        }
    }
}