<?php

namespace App\Http\Controllers;

use App\Services\QuestionBankService;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Log;

class ExamPdfController extends Controller
{
    /**
     * 根据题目类型字段或内容判断题型
     */
    private function determineQuestionType(array $question): string
    {
        // 1. 优先使用 question_type 字段
        if (isset($question['question_type']) && !empty($question['question_type'])) {
            $type = $question['question_type'];
            // 标准化类型值
            if (in_array($type, ['choice', 'fill', 'answer'])) {
                return $type;
            }
        }

        // 2. 根据标签判断
        $tags = $question['tags'] ?? '';
        $stem = $question['stem'] ?? '';

        if (is_string($tags)) {
            if (strpos($tags, '选择') !== false || strpos($tags, '选择题') !== false) {
                return 'choice';
            }
            if (strpos($tags, '填空') !== false || strpos($tags, '填空题') !== false) {
                return 'fill';
            }
            if (strpos($tags, '解答') !== false || strpos($tags, '简答') !== false || strpos($tags, '证明') !== false) {
                return 'answer';
            }
        }

        // 3. 根据题干内容判断 - 选择题（明确有选项）
        if (is_string($stem)) {
            // 检查选项格式 A. B. C. D.（支持跨行匹配）
            if (preg_match('/[A-D]\.\s+/m', $stem)) {
                return 'choice';
            }

            // 检查全角括号在末尾（常见于选择题题干）
            if (preg_match('/（）\s*$/', $stem)) {
                return 'choice';
            }

            // 检查全角括号在中间且没有运算内容
            if (preg_match('/（）/', $stem) && !preg_match('/[+\-*/=<>{}]/', $stem)) {
                return 'choice';
            }
        }

        // 4. 根据题干内容判断 - 填空题（有下划线）
        if (is_string($stem) && (strpos($stem, '____') !== false || strpos($stem, '______') !== false || strpos($stem, '______') !== false)) {
            return 'fill';
        }

        // 5. 根据题干内容判断（更精确的启发式）
        if (is_string($stem)) {
            // 有证明、解答、计算、化简等明确关键词的是解答题
            if (preg_match('/证明|求解|计算|化简|求证|分析|解答|画出|解方程|不等式/', $stem)) {
                return 'answer';
            }

            // 短题目且包含"下列"可能是选择题（但要谨慎）
            if (preg_match('/下列/', $stem) && mb_strlen($stem) < 80) {
                // 如果没有运算符号，更可能是选择题
                if (!preg_match('/[+\-*/=<>{}]/', $stem)) {
                    return 'choice';
                }
            }
        }

        // 默认是解答题
        return 'answer';
    }

    /**
     * 从题目内容中提取选项
     */
    private function extractOptions(string $content): array
    {
        // 匹配 A. B. C. D. 格式的选项
        if (preg_match_all('/([A-D])\.\s*(.+?)(?=[A-D]\.|$)/s', $content, $matches, PREG_SET_ORDER)) {
            $options = [];
            foreach ($matches as $match) {
                $optionText = trim($match[2]);
                // 移除末尾的换行和空白
                $optionText = preg_replace('/\s+$/', '', $optionText);
                $options[] = $optionText;
            }
            return $options;
        }

        return [];
    }

    /**
     * 分离题干内容和选项
     */
    private function separateStemAndOptions(string $content): array
    {
        // 如果没有选项，直接返回
        if (!preg_match('/[A-D]\.\s+/m', $content)) {
            return [$content, []];
        }

        // 提取选项
        $options = $this->extractOptions($content);

        // 提取题干（选项前的部分）
        $stem = preg_replace('/[A-D]\.\s+.+?(?=[A-D]\.|$)/s', '', $content);
        $stem = trim($stem);

        // 移除末尾的括号或空白
        $stem = preg_replace('/（）\s*$/', '', $stem);
        $stem = trim($stem);

        return [$stem, $options];
    }

    /**
     * 根据题型获取默认分数
     */
    private function getQuestionScore(string $type): int
    {
        switch ($type) {
            case 'choice':
                return 5; // 选择题5分
            case 'fill':
                return 5; // 填空题5分
            case 'answer':
                return 10; // 解答题10分
            default:
                return 5;
        }
    }

    /**
     * 获取学生信息
     */
    private function getStudentInfo(?string $studentId): array
    {
        if (!$studentId) {
            return [
                'name' => '未知学生',
                'grade' => '未知年级',
                'class' => '未知班级'
            ];
        }

        try {
            $student = DB::table('students')
                ->where('student_id', $studentId)
                ->first();

            if ($student) {
                return [
                    'name' => $student->name ?? $studentId,
                    'grade' => $student->grade ?? '未知',
                    'class' => $student->class ?? '未知'
                ];
            }
        } catch (\Exception $e) {
            Log::warning('获取学生信息失败', [
                'student_id' => $studentId,
                'error' => $e->getMessage()
            ]);
        }

        return [
            'name' => $studentId,
            'grade' => '未知',
            'class' => '未知'
        ];
    }

    /**
     * 为 PDF 预览筛选题目（简化版）
     */
    private function selectBestQuestionsForPdf(array $questions, int $targetCount, string $difficultyCategory): array
    {
        if (count($questions) <= $targetCount) {
            return $questions;
        }

        // 1. 按题型分类题目
        $categorizedQuestions = [
            'choice' => [],
            'fill' => [],
            'answer' => [],
        ];

        foreach ($questions as $question) {
            $type = $this->determineQuestionType($question);
            if (!isset($categorizedQuestions[$type])) {
                $type = 'answer';
            }
            $categorizedQuestions[$type][] = $question;
        }

        // 2. 默认题型配比
        $typeRatio = [
            '选择题' => 50,  // 50%
            '填空题' => 30,  // 30%
            '解答题' => 20,  // 20%
        ];

        // 3. 根据配比选择题目
        $selectedQuestions = [];
        foreach ($typeRatio as $type => $ratio) {
            $typeKey = $type === '选择题' ? 'choice' : ($type === '填空题' ? 'fill' : 'answer');
            $countForType = floor($targetCount * $ratio / 100);

            if ($countForType > 0 && !empty($categorizedQuestions[$typeKey])) {
                $availableCount = count($categorizedQuestions[$typeKey]);
                $takeCount = min($countForType, $availableCount, $targetCount - count($selectedQuestions));

                // 随机选择题目
                $keys = array_keys($categorizedQuestions[$typeKey]);
                shuffle($keys);
                $selectedKeys = array_slice($keys, 0, $takeCount);

                foreach ($selectedKeys as $key) {
                    $selectedQuestions[] = $categorizedQuestions[$typeKey][$key];
                }
            }
        }

        // 4. 如果数量不足，随机补充
        while (count($selectedQuestions) < $targetCount) {
            $randomQuestion = $questions[array_rand($questions)];
            if (!in_array($randomQuestion, $selectedQuestions)) {
                $selectedQuestions[] = $randomQuestion;
            }
        }

        // 5. 限制数量并打乱
        shuffle($selectedQuestions);
        return array_slice($selectedQuestions, 0, $targetCount);
    }

    /**
     * 获取教师信息
     */
    private function getTeacherInfo(?string $teacherId): array
    {
        if (!$teacherId) {
            return [
                'name' => '未知教师'
            ];
        }

        try {
            $teacher = DB::table('teachers')
                ->where('teacher_id', $teacherId)
                ->first();

            if ($teacher) {
                return [
                    'name' => $teacher->name ?? $teacherId
                ];
            }
        } catch (\Exception $e) {
            Log::warning('获取教师信息失败', [
                'teacher_id' => $teacherId,
                'error' => $e->getMessage()
            ]);
        }

        return [
            'name' => $teacherId
        ];
    }

    public function show(Request $request, $paper_id)
    {
        // 使用 Eloquent 模型获取试卷数据
        $paper = \App\Models\Paper::where('paper_id', $paper_id)->first();

        if (!$paper) {
            // 尝试从缓存中获取生成的试卷数据（用于 demo 试卷）
            $cached = Cache::get('generated_exam_' . $paper_id);
            if ($cached) {
                Log::info('从缓存获取试卷数据', [
                    'paper_id' => $paper_id,
                    'cached_count' => count($cached['questions'] ?? []),
                    'cached_question_types' => array_column($cached['questions'] ?? [], 'question_type')
                ]);

                // 构造临时 Paper 对象
                $paper = (object)[
                    'paper_id' => $paper_id,
                    'paper_name' => $cached['paper_name'] ?? 'Demo Paper',
                    'student_id' => $cached['student_id'] ?? null,
                    'teacher_id' => $cached['teacher_id'] ?? null,
                ];

                // 对于 demo 试卷，需要检查题目数量并限制为用户要求的数量
                $questionsData = $cached['questions'] ?? [];
                $totalQuestions = $cached['total_questions'] ?? count($questionsData);
                $difficultyCategory = $cached['difficulty_category'] ?? '中等';

                // 为 demo 试卷获取完整的题目详情（包括选项）
                if (!empty($questionsData)) {
                    $questionBankService = app(QuestionBankService::class);
                    $questionIds = array_column($questionsData, 'id');
                    $questionsResponse = $questionBankService->getQuestionsByIds($questionIds);
                    $responseData = $questionsResponse['data'] ?? [];

                    if (!empty($responseData)) {
                        $responseDataMap = [];
                        foreach ($responseData as $respQ) {
                            $responseDataMap[$respQ['id']] = $respQ;
                        }

                        // 合并题库数据
                        $questionsData = array_map(function($q) use ($responseDataMap) {
                            if (isset($responseDataMap[$q['id']])) {
                                $apiData = $responseDataMap[$q['id']];
                                $rawContent = $apiData['stem'] ?? $q['stem'] ?? $q['content'] ?? '';

                                // 分离题干和选项
                                list($stem, $extractedOptions) = $this->separateStemAndOptions($rawContent);

                                $q['stem'] = $stem;
                                $q['answer'] = $apiData['answer'] ?? $q['answer'] ?? '';
                                $q['solution'] = $apiData['solution'] ?? $q['solution'] ?? '';
                                $q['tags'] = $apiData['tags'] ?? $q['tags'] ?? '';
                                $q['options'] = $apiData['options'] ?? $extractedOptions; // 优先使用API选项，备选提取的选项
                            }
                            return $q;
                        }, $questionsData);
                    }
                }

                if (count($questionsData) > $totalQuestions) {
                    Log::info('PDF预览时发现题目过多，进行筛选', [
                        'paper_id' => $paper_id,
                        'cached_count' => count($questionsData),
                        'required_count' => $totalQuestions
                    ]);
                    $questionsData = $this->selectBestQuestionsForPdf($questionsData, $totalQuestions, $difficultyCategory);
                    Log::info('筛选后题目数据', [
                        'paper_id' => $paper_id,
                        'filtered_count' => count($questionsData),
                        'filtered_types' => array_column($questionsData, 'question_type')
                    ]);
                }
            } else {
                abort(404, '试卷未找到');
            }
        } else {
            // 获取试卷题目
            $paperQuestions = \App\Models\PaperQuestion::where('paper_id', $paper_id)
                ->orderBy('question_number')
                ->get();

            Log::info('从数据库获取题目', [
                'paper_id' => $paper_id,
                'question_count' => $paperQuestions->count()
            ]);

            // 将 paper_questions 表的数据转换为题库格式
            $questionsData = [];
            foreach ($paperQuestions as $pq) {
                $questionsData[] = [
                    'id' => $pq->question_bank_id,
                    'kp_code' => $pq->knowledge_point,
                    'question_type' => $pq->question_type ?? 'answer', // 包含题目类型
                    'stem' => $pq->question_text ?? '题目内容缺失', // 如果有存储题目文本
                    'difficulty' => $pq->difficulty ?? 0.5,
                    'tags' => '',
                    'content' => $pq->question_text ?? '',
                ];
            }

            Log::info('paper_questions表原始数据', [
                'paper_id' => $paper_id,
                'sample_questions' => array_slice($questionsData, 0, 3),
                'all_types' => array_column($questionsData, 'question_type')
            ]);

            // 如果需要完整题目详情（stem等），可以从题库获取
            // 但要严格限制只获取这8道题
            if (!empty($questionsData)) {
                $questionBankService = app(QuestionBankService::class);
                $questionIds = array_column($questionsData, 'id');

                $questionsResponse = $questionBankService->getQuestionsByIds($questionIds);
                $responseData = $questionsResponse['data'] ?? [];

                // 确保只返回请求的ID对应的题目，并保留数据库中的 question_type
                if (!empty($responseData)) {
                    // 创建题库返回数据的映射
                    $responseDataMap = [];
                    foreach ($responseData as $respQ) {
                        $responseDataMap[$respQ['id']] = $respQ;
                    }

                    // 遍历所有数据库中的题目，合并题库返回的数据
                    $questionsData = array_map(function($q) use ($responseDataMap, $paperQuestions) {
                        // 从题库API获取的详细数据（如果有）
                        if (isset($responseDataMap[$q['id']])) {
                            $apiData = $responseDataMap[$q['id']];
                            $rawContent = $apiData['stem'] ?? $q['stem'] ?? '题目内容缺失';

                            // 分离题干和选项
                            list($stem, $extractedOptions) = $this->separateStemAndOptions($rawContent);

                            // 合并数据，优先使用题库API的 stem、answer、solution、options
                            $q['stem'] = $stem;
                            $q['answer'] = $apiData['answer'] ?? $q['answer'] ?? '';
                            $q['solution'] = $apiData['solution'] ?? $q['solution'] ?? '';
                            $q['tags'] = $apiData['tags'] ?? $q['tags'] ?? '';
                            $q['options'] = $apiData['options'] ?? $extractedOptions; // 优先使用API选项，备选提取的选项
                        }

                        // 从数据库 paper_questions 表中获取 question_type（已在前面设置，这里确保有值）
                        if (!isset($q['question_type']) || empty($q['question_type'])) {
                            $dbQuestion = $paperQuestions->firstWhere('question_bank_id', $q['id']);
                            if ($dbQuestion && $dbQuestion->question_type) {
                                $q['question_type'] = $dbQuestion->question_type;
                            }
                        }

                        return $q;
                    }, $questionsData);
                }
            }
        }

        // 按题型分类（使用标准的中学数学试卷格式）
        $questions = ['choice' => [], 'fill' => [], 'answer' => []];
        foreach ($questionsData as $q) {
            // 题库API返回的是 stem 字段，不是 content
            $rawContent = $q['stem'] ?? $q['content'] ?? '题目内容缺失';

            // 分离题干和选项
            list($content, $extractedOptions) = $this->separateStemAndOptions($rawContent);

            // 如果从题库API获取了选项，优先使用
            $options = $q['options'] ?? $extractedOptions;

            $answer = $q['answer'] ?? '';
            $solution = $q['solution'] ?? '';

            // 优先使用 question_type 字段，如果没有则根据内容智能判断
            $type = $q['question_type'] ?? $this->determineQuestionType($q);

            // 详细调试：记录题目类型判断结果
            Log::info('题目类型判断', [
                'question_id' => $q['id'] ?? '',
                'has_question_type' => isset($q['question_type']),
                'question_type_value' => $q['question_type'] ?? null,
                'tags' => $q['tags'] ?? '',
                'stem_length' => mb_strlen($content),
                'stem_preview' => mb_substr($content, 0, 100),
                'has_extracted_options' => !empty($extractedOptions),
                'extracted_options_count' => count($extractedOptions),
                'has_api_options' => isset($q['options']) && !empty($q['options']),
                'api_options_count' => isset($q['options']) ? count($q['options']) : 0,
                'final_options_count' => count($options),
                'determined_type' => $type
            ]);

            if (!isset($questions[$type])) {
                $type = 'answer';
            }

            $qData = (object)[
                'id' => $q['id'] ?? $q['question_bank_id'] ?? null,
                'content' => $content,
                'answer' => $answer,
                'solution' => $solution,
                'difficulty' => $q['difficulty'] ?? 0.5,
                'kp_code' => $q['kp_code'] ?? '',
                'tags' => $q['tags'] ?? '',
                'options' => $options, // 使用分离后的选项
                'score' => $this->getQuestionScore($type), // 根据题型设置分数
            ];
            $questions[$type][] = $qData;
        }

        // 调试：记录最终分类结果
        Log::info('最终分类结果', [
            'paper_id' => $paper_id,
            'choice_count' => count($questions['choice']),
            'fill_count' => count($questions['fill']),
            'answer_count' => count($questions['answer']),
            'total' => count($questions['choice']) + count($questions['fill']) + count($questions['answer'])
        ]);

        // 渲染视图
        return view('pdf.exam-paper', [
            'paper' => $paper,
            'questions' => $questions,
            'student' => $this->getStudentInfo($paper->student_id),
            'teacher' => $this->getTeacherInfo($paper->teacher_id)
        ]);
    }
}