<?php

namespace App\Http\Controllers\Api;

use App\Http\Controllers\Controller;
use App\Models\Paper;
use App\Models\PaperQuestion;
use App\Services\LearningAnalyticsService;
use App\Services\ExamPdfExportService;
use App\Services\QuestionBankService;
use App\Services\PaperPayloadService;
use App\Services\TaskManager;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\URL;

class IntelligentExamController extends Controller
{
    private LearningAnalyticsService $learningAnalyticsService;
    private QuestionBankService $questionBankService;
    private ExamPdfExportService $pdfExportService;
    private PaperPayloadService $paperPayloadService;
    private TaskManager $taskManager;

    public function __construct(
        LearningAnalyticsService $learningAnalyticsService,
        QuestionBankService $questionBankService,
        ExamPdfExportService $pdfExportService,
        PaperPayloadService $paperPayloadService,
        TaskManager $taskManager
    ) {
        $this->learningAnalyticsService = $learningAnalyticsService;
        $this->questionBankService = $questionBankService;
        $this->pdfExportService = $pdfExportService;
        $this->paperPayloadService = $paperPayloadService;
        $this->taskManager = $taskManager;
    }

    /**
     * 外部API：生成智能试卷（异步模式）
     * 立即返回任务ID，PDF生成在后台进行，完成后通过回调通知
     */
    public function store(Request $request): JsonResponse
    {
        $normalized = $this->normalizePayload($request->all());

        $validator = validator($normalized, [
            'student_id' => 'required|string',
            'teacher_id' => 'required|string',
            'paper_name' => 'nullable|string|max:255',
            'grade' => 'nullable|string|max:50',
            'total_questions' => 'required|integer|min:6|max:100',
            'difficulty_category' => 'nullable|string',
            'kp_codes' => 'nullable|array',
            'kp_codes.*' => 'string',
            'skills' => 'array',
            'skills.*' => 'string',
            'question_type_ratio' => 'array',
            'difficulty_ratio' => 'array',
            'total_score' => 'nullable|numeric|min:1|max:1000',
        ]);

        if ($validator->fails()) {
            return response()->json([
                'success' => false,
                'message' => '参数错误',
                'errors' => $validator->errors()->toArray(),
            ], 422);
        }

        $data = $validator->validated();

        // 确保 kp_codes 是数组
        $data['kp_codes'] = $data['kp_codes'] ?? [];
        if (!is_array($data['kp_codes'])) {
            $data['kp_codes'] = [];
        }

        $questionTypeRatio = $this->normalizeQuestionTypeRatio($data['question_type_ratio'] ?? []);
        $difficultyRatio = $this->normalizeDifficultyRatio($data['difficulty_ratio'] ?? []);
        $paperName = $data['paper_name'] ?? ('智能试卷_' . now()->format('Ymd_His'));
        $difficultyCategory = $this->normalizeDifficultyCategory($data['difficulty_category'] ?? null);

        try {
            // 第一步：生成智能试卷（同步）
            $result = $this->learningAnalyticsService->generateIntelligentExam([
                'student_id' => $data['student_id'],
                'grade' => $data['grade'] ?? null,
                'total_questions' => $data['total_questions'],
                'kp_codes' => $data['kp_codes'],
                'skills' => $data['skills'] ?? [],
                'question_type_ratio' => $questionTypeRatio,
                'difficulty_ratio' => $difficultyRatio,
            ]);

            if (empty($result['success'])) {
                return response()->json([
                    'success' => false,
                    'message' => $result['message'] ?? '智能出卷失败',
                ], 400);
            }

            $questions = $this->hydrateQuestions($result['questions'] ?? [], $data['kp_codes']);

            if (empty($questions)) {
                return response()->json([
                    'success' => false,
                    'message' => '未能生成有效题目，请检查知识点或题库数据',
                ], 400);
            }

            $totalScore = array_sum(array_column($questions, 'score'));

            // 第二步：保存试卷到数据库（同步）
            $paperId = $this->questionBankService->saveExamToDatabase([
                'paper_name' => $paperName,
                'student_id' => $data['student_id'],
                'teacher_id' => $data['teacher_id'],
                'difficulty_category' => $difficultyCategory,
                'total_score' => $data['total_score'] ?? $totalScore,
                'questions' => $questions,
            ]);

            if (!$paperId) {
                return response()->json([
                    'success' => false,
                    'message' => '试卷保存失败',
                ], 500);
            }

            // 第三步：创建异步任务（使用TaskManager）
            $taskId = $this->taskManager->createTask(TaskManager::TASK_TYPE_EXAM, array_merge($data, ['paper_id' => $paperId]));

            // 生成识别码
            $codes = $this->paperPayloadService->generatePaperCodes($paperId);

            // 立即返回完整的试卷数据（不等待PDF生成）
            $paperModel = Paper::with('questions')->find($paperId);
            $examContent = $paperModel
                ? $this->paperPayloadService->buildExamContent($paperModel)
                : [];

            // 触发后台PDF生成
            $this->triggerPdfGeneration($taskId, $paperId);

            $payload = [
                'success' => true,
                'message' => '智能试卷创建成功，PDF正在后台生成...',
                'data' => [
                    'task_id' => $taskId,
                    'paper_id' => $paperId,
                    'status' => 'processing',
                    // 识别码
                    'exam_code' => $codes['exam_code'],       // 试卷识别码 (1+12位)
                    'grading_code' => $codes['grading_code'], // 判卷识别码 (2+12位)
                    'paper_id_num' => $codes['paper_id_num'], // 12位数字ID
                    'exam_content' => $examContent,
                    'urls' => [
                        'grading_url' => route('filament.admin.auth.intelligent-exam.grading', ['paper_id' => $paperId]),
                        'student_exam_url' => route('filament.admin.auth.intelligent-exam.pdf', ['paper_id' => $paperId, 'answer' => 'false']),
                    ],
                    'pdfs' => [
                        'exam_paper_pdf' => null,
                        'grading_pdf' => null,
                    ],
                    'stats' => $result['stats'] ?? null,
                    'created_at' => now()->toISOString(),
                ],
            ];

            return response()->json($payload, 200, [], JSON_UNESCAPED_SLASHES);

        } catch (\Exception $e) {
            Log::error('Intelligent exam API failed', [
                'error' => $e->getMessage(),
                'trace' => $e->getTraceAsString(),
            ]);

            return response()->json([
                'success' => false,
                'message' => '服务异常，请稍后重试',
            ], 500);
        }
    }

    /**
     * 轮询任务状态
     */
    public function status(string $taskId): JsonResponse
    {
        try {
            $task = $this->taskManager->getTaskStatus($taskId);

            if (!$task) {
                return response()->json([
                    'success' => false,
                    'message' => '任务不存在',
                ], 404);
            }

            return response()->json([
                'success' => true,
                'data' => $task,
            ]);

        } catch (\Exception $e) {
            Log::error('查询任务状态失败', [
                'task_id' => $taskId,
                'error' => $e->getMessage(),
            ]);

            return response()->json([
                'success' => false,
                'message' => '查询失败，请稍后重试',
            ], 500);
        }
    }

    /**
     * 触发PDF生成
     * 实际项目中应使用队列dispatch(new GenerateExamPdfJob($taskId, $paperId));
     */
    private function triggerPdfGeneration(string $taskId, string $paperId): void
    {
        // 实际项目中应该：
        // dispatch(new GenerateExamPdfJob($taskId, $paperId));
        // 目前使用同步调用模拟异步
        $this->processPdfGeneration($taskId, $paperId);
    }

    /**
     * 处理PDF生成（模拟后台任务）
     * 在实际项目中，这个方法应该在队列worker中执行
     */
    private function processPdfGeneration(string $taskId, string $paperId): void
    {
        try {
            $this->taskManager->updateTaskProgress($taskId, 10, '开始生成试卷PDF...');

            // 生成试卷PDF
            $pdfUrl = $this->pdfExportService->generateExamPdf($paperId)
                ?? $this->questionBankService->exportExamToPdf($paperId)
                ?? route('filament.admin.auth.intelligent-exam.pdf', ['paper_id' => $paperId, 'answer' => 'false']);

            $this->taskManager->updateTaskProgress($taskId, 50, '试卷PDF生成完成，开始生成判卷PDF...');

            // 生成判卷PDF
            $gradingPdfUrl = $this->pdfExportService->generateGradingPdf($paperId)
                ?? route('filament.admin.auth.intelligent-exam.pdf', ['paper_id' => $paperId, 'answer' => 'true']);

            // 构建完整的试卷内容
            $paperModel = Paper::with('questions')->find($paperId);
            $examContent = $paperModel
                ? $this->paperPayloadService->buildExamContent($paperModel)
                : [];

            // 标记任务完成
            $this->taskManager->markTaskCompleted($taskId, [
                'exam_content' => $examContent,
                'pdfs' => [
                    'exam_paper_pdf' => $pdfUrl,
                    'grading_pdf' => $gradingPdfUrl,
                ],
            ]);

            Log::info('异步任务完成', [
                'task_id' => $taskId,
                'paper_id' => $paperId,
                'pdf_url' => $pdfUrl,
                'grading_pdf_url' => $gradingPdfUrl,
            ]);

            // 发送回调通知
            $this->taskManager->sendCallback($taskId);

        } catch (\Exception $e) {
            Log::error('PDF生成失败', [
                'task_id' => $taskId,
                'paper_id' => $paperId,
                'error' => $e->getMessage(),
            ]);

            $this->taskManager->markTaskFailed($taskId, $e->getMessage());
        }
    }

    /**
     * 兼容字符串/数组入参
     */
    private function normalizePayload(array $payload): array
    {
        // 处理 kp_codes：空字符串或null转换为空数组
        if (isset($payload['kp_codes'])) {
            if (is_string($payload['kp_codes'])) {
                $kpCodes = trim($payload['kp_codes']);
                if (empty($kpCodes)) {
                    $payload['kp_codes'] = [];
                } else {
                    $payload['kp_codes'] = array_values(array_filter(array_map('trim', explode(',', $kpCodes))));
                }
            } elseif (!is_array($payload['kp_codes'])) {
                $payload['kp_codes'] = [];
            }
        } else {
            $payload['kp_codes'] = [];
        }

        if (isset($payload['skills']) && is_string($payload['skills'])) {
            $payload['skills'] = array_values(array_filter(array_map('trim', explode(',', $payload['skills']))));
        }

        return $payload;
    }

    private function normalizeQuestionTypeRatio(array $input): array
    {
        // 默认按 4:2:4
        $defaults = [
            '选择题' => 40,
            '填空题' => 20,
            '解答题' => 40,
        ];

        $normalized = [];
        foreach ($input as $key => $value) {
            if (!is_numeric($value)) {
                continue;
            }
            $type = $this->normalizeQuestionTypeKey($key);
            if ($type) {
                $normalized[$type] = (float) $value;
            }
        }

        $merged = array_merge($defaults, $normalized);

        // 归一化到 100%
        $sum = array_sum($merged);
        if ($sum > 0) {
            foreach ($merged as $k => $v) {
                $merged[$k] = round(($v / $sum) * 100, 2);
            }
        }

        return $merged;
    }

    private function normalizeQuestionTypeKey(string $key): ?string
    {
        $key = trim($key);
        if (in_array($key, ['choice', '选择题', 'single_choice', 'multiple_choice'])) {
            return '选择题';
        }
        if (in_array($key, ['fill', '填空题', 'blank'])) {
            return '填空题';
        }
        if (in_array($key, ['answer', '解答题', '计算题'])) {
            return '解答题';
        }

        return null;
    }

    private function normalizeDifficultyRatio(array $input): array
    {
        $defaults = [
            '基础' => 50,
            '中等' => 35,
            '拔高' => 15,
        ];

        $normalized = [];
        foreach ($input as $key => $value) {
            if (!is_numeric($value)) {
                continue;
            }
            $label = trim($key);
            if (in_array($label, ['基础', 'easy', '简单'])) {
                $normalized['基础'] = (float) $value;
            } elseif (in_array($label, ['中等', 'medium'])) {
                $normalized['中等'] = (float) $value;
            } elseif (in_array($label, ['拔高', 'hard', '困难', '竞赛'])) {
                $normalized['拔高'] = (float) $value;
            }
        }

        return array_merge($defaults, $normalized);
    }

    private function normalizeDifficultyCategory(?string $category): string
    {
        if (!$category) {
            return '基础';
        }

        $category = trim($category);
        if (in_array($category, ['基础', '进阶', '中等', 'easy'])) {
            return $category === 'easy' ? '基础' : $category;
        }
        if (in_array($category, ['拔高', '困难', 'hard', '竞赛'])) {
            return '拔高';
        }

        return '基础';
    }

    private function hydrateQuestions(array $questions, array $kpCodes): array
    {
        $normalized = [];
        foreach ($questions as $question) {
            $type = $this->normalizeQuestionTypeKey($question['question_type'] ?? $question['type'] ?? '') ?? $this->guessType($question);
            $score = $question['score'] ?? $this->defaultScore($type);

            $normalized[] = [
                'id' => $question['id'] ?? $question['question_id'] ?? null,
                'question_id' => $question['question_id'] ?? null,
                'question_type' => $type === '选择题' ? 'choice' : ($type === '填空题' ? 'fill' : 'answer'),
                'stem' => $question['stem'] ?? $question['content'] ?? ($question['question_text'] ?? ''),
                'content' => $question['content'] ?? $question['stem'] ?? '',
                'options' => $question['options'] ?? ($question['choices'] ?? []),
                'answer' => $question['answer'] ?? $question['correct_answer'] ?? '',
                'solution' => $question['solution'] ?? '',
                'difficulty' => isset($question['difficulty']) ? (float) $question['difficulty'] : 0.5,
                'score' => $score,
                'estimated_time' => $question['estimated_time'] ?? 300,
                'kp' => $question['kp_code'] ?? $question['kp'] ?? $question['knowledge_point'] ?? ($kpCodes[0] ?? ''),
                'kp_code' => $question['kp_code'] ?? $question['kp'] ?? $question['knowledge_point'] ?? ($kpCodes[0] ?? ''),
            ];
        }

        return array_values(array_filter($normalized, fn ($q) => !empty($q['id'])));
    }

    private function guessType(array $question): string
    {
        if (!empty($question['options']) && is_array($question['options'])) {
            return '选择题';
        }

        $content = $question['stem'] ?? $question['content'] ?? '';
        if (is_string($content) && (strpos($content, '____') !== false || strpos($content, '（）') !== false)) {
            return '填空题';
        }

        return '解答题';
    }

    private function defaultScore(string $type): int
    {
        if ($type === '选择题' || $type === '填空题') {
            return 5;
        }

        return 10;
    }
}