<?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 Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\URL;

class IntelligentExamController extends Controller
{
    private LearningAnalyticsService $learningAnalyticsService;
    private QuestionBankService $questionBankService;
    private ExamPdfExportService $pdfExportService;

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

    /**
     * 外部API：生成智能试卷，保存并返回 PDF/判卷链接
     */
    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' => 'required|array|min:1',
            '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();

        $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 {
            $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'));

            $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);
            }

            $paperPayload = $this->buildPaperPayload($paperId);

            // 生成真实 PDF（试卷 + 判卷），若失败则回退到 HTML 预览
            $pdfUrl = $this->pdfExportService->generateExamPdf($paperId)
                ?? $this->questionBankService->exportExamToPdf($paperId)
                ?? route('filament.admin.auth.intelligent-exam.pdf', ['paper_id' => $paperId, 'answer' => 'false']);

            $gradingUrl = $this->pdfExportService->generateGradingPdf($paperId)
                ?? route('filament.admin.auth.intelligent-exam.grading', ['paper_id' => $paperId]);

            $payload = [
                'success' => true,
                'message' => '智能试卷生成成功',
                'data' => [
                    'paper' => $paperPayload,
                    'pdf_url' => $pdfUrl,
                    'grading_url' => $gradingUrl,
                    'stats' => $result['stats'] ?? null,
                ],
            ];

            // 返回不转义的完整 URL
            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);
        }
    }

    /**
     * 兼容字符串/数组入参
     */
    private function normalizePayload(array $payload): array
    {
        if (isset($payload['kp_codes']) && is_string($payload['kp_codes'])) {
            $payload['kp_codes'] = array_values(array_filter(array_map('trim', explode(',', $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
    {
        $defaults = [
            '选择题' => 40,
            '填空题' => 30,
            '解答题' => 30,
        ];

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

        return array_merge($defaults, $normalized);
    }

    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;
    }

    private function buildPaperPayload(string $paperId): array
    {
        $paper = Paper::with('questions')->find($paperId);
        $questions = $paper ? $paper->questions : collect();

        return [
            'paper_id' => $paperId,
            'paper_name' => $paper?->paper_name ?? '',
            'student_id' => $paper?->student_id ?? '',
            'teacher_id' => $paper?->teacher_id ?? '',
            'total_questions' => $questions->count(),
            'total_score' => $paper?->total_score ?? 0,
            'difficulty_category' => $paper?->difficulty_category ?? '基础',
            'questions' => $questions->map(function (PaperQuestion $q) {
                return [
                    'question_bank_id' => $q->question_bank_id,
                    'question_number' => $q->question_number,
                    'question_type' => $q->question_type,
                    'knowledge_point' => $q->knowledge_point,
                    'difficulty' => $q->difficulty,
                    'score' => $q->score,
                    'estimated_time' => $q->estimated_time,
                ];
            })->toArray(),
        ];
    }
}