<?php

namespace App\Services;

use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Collection;

/**
 * 考试答题分析服务（步骤级分析）
 * 基于卷子分析思考文档的思路实现
 *
 * 核心流程：
 * 1. 接收卷子ID和每道题的对错、简答题的分步骤对错
 * 2. 将原子信息映射到知识点/技能
 * 3. 计算知识点掌握度向量
 * 4. 生成详细分析报告
 * 5. 提供智能出卷推荐依据
 */
class ExamAnswerAnalysisService
{
    public function __construct(
        private readonly MasteryCalculator $masteryCalculator,
        private readonly KnowledgeMasteryService $knowledgeMasteryService,
        private readonly LocalAIAnalysisService $aiAnalysisService,
        private readonly QuestionBankService $questionBankService
    ) {}

    /**
     * 分析考试答题数据
     *
     * @param array $examData 考试数据
     * [
     *   'exam_id' => 'exam_001',
     *   'student_id' => 'student_001',
     *   'questions' => [
     *     [
     *       'question_id' => 'Q1',
     *       'score' => 5,
     *       'score_obtained' => 5,
     *       'steps' => [
     *         ['step_index' => 1, 'is_correct' => true, 'kp_id' => 'K-SQRT-SIMPLE'],
     *         ['step_index' => 2, 'is_correct' => true, 'kp_id' => 'K-NUM-ADD-SUB']
     *       ]
     *     ]
     *   ]
     * ]
     *
     * @return array 分析结果
     */
    public function analyzeExamAnswers(array $examData): array
    {
        Log::info('开始分析考试答题', [
            'exam_id' => $examData['exam_id'] ?? 'unknown',
            'student_id' => $examData['student_id'] ?? 'unknown',
            'question_count' => count($examData['questions'] ?? [])
        ]);

        $studentId = $examData['student_id'];
        $questions = $examData['questions'] ?? [];

        // 1. 保存答题记录到数据库
        $this->saveExamAnswerRecords($examData);

        // 2. 获取题目知识点映射
        $questionMappings = $this->getQuestionKnowledgeMappings($questions);

        // 3. 计算每个知识点的加权掌握度
        $knowledgeMasteryVector = $this->calculateKnowledgeMasteryVector($questions, $questionMappings);

        // 4. 更新学生掌握度
        $updatedMastery = $this->updateStudentMastery($studentId, $knowledgeMasteryVector);

        // 5. 生成题目维度分析
        $questionAnalysis = $this->analyzeQuestions($questions, $questionMappings);

        // 6. 生成知识点维度分析
        $knowledgePointAnalysis = $this->analyzeKnowledgePoints($knowledgeMasteryVector, $questionMappings);

        // 7. 生成整体掌握度总结
        $overallSummary = $this->generateOverallSummary($updatedMastery);

        // 8. 生成智能出卷推荐依据
        $smartQuizRecommendation = $this->generateSmartQuizRecommendation($updatedMastery);

        // 9. 保存分析结果
        $analysisResult = [
            'exam_id' => $examData['exam_id'],
            'student_id' => $studentId,
            'timestamp' => now()->toISOString(),
            'question_analysis' => $questionAnalysis,
            'knowledge_point_analysis' => $knowledgePointAnalysis,
            'overall_summary' => $overallSummary,
            'smart_quiz_recommendation' => $smartQuizRecommendation,
            'mastery_vector' => $updatedMastery,
        ];

        $this->saveAnalysisResult($studentId, $examData['exam_id'], $analysisResult);

        Log::info('考试答题分析完成', [
            'student_id' => $studentId,
            'exam_id' => $examData['exam_id'],
            'analyzed_knowledge_points' => count($knowledgeMasteryVector)
        ]);

        return $analysisResult;
    }

    /**
     * 获取题目知识点映射
     */
    private function getQuestionKnowledgeMappings(array $questions): array
    {
        $mappings = [];
        $questionIds = array_column($questions, 'question_id');

        // 从题库获取题目知识点映射
        try {
            $response = $this->questionBankService->getQuestionsKnowledgeMapping($questionIds);

            foreach ($response as $mapping) {
                $mappings[$mapping['question_id']] = $mapping;
            }
        } catch (\Exception $e) {
            Log::warning('获取题目知识点映射失败，使用默认映射', [
                'error' => $e->getMessage(),
                'question_ids' => $questionIds
            ]);

            // 使用默认映射：每道题至少映射到一个知识点
            foreach ($questions as $question) {
                $mappings[$question['question_id']] = [
                    'question_id' => $question['question_id'],
                    'kp_mapping' => [
                        ['kp_id' => 'K-GENERAL', 'kp_name' => '综合', 'weight' => 1.0]
                    ]
                ];
            }
        }

        return $mappings;
    }

    /**
     * 计算知识点掌握度向量
     * 基于文档中的简单实用更新公式
     */
    private function calculateKnowledgeMasteryVector(array $questions, array $questionMappings): array
    {
        $knowledgeScores = [];

        foreach ($questions as $question) {
            $questionId = $question['question_id'];
            $score = floatval($question['score_obtained'] ?? 0);
            $maxScore = floatval($question['score'] ?? $score);
            $steps = $question['steps'] ?? [];

            $mapping = $questionMappings[$questionId] ?? null;
            if (!$mapping || !isset($mapping['kp_mapping'])) {
                continue;
            }

            // 如果有步骤级分析，使用步骤分析
            if (!empty($steps)) {
                foreach ($steps as $step) {
                    $kpId = $step['kp_id'] ?? 'K-GENERAL';
                    $stepScore = floatval($step['score'] ?? ($maxScore / count($steps)));
                    $stepWeight = floatval($step['weight'] ?? 1.0);

                    if (!isset($knowledgeScores[$kpId])) {
                        $knowledgeScores[$kpId] = [
                            'total_weight' => 0,
                            'correct_weight' => 0,
                            'step_details' => []
                        ];
                    }

                    $knowledgeScores[$kpId]['total_weight'] += $stepScore * $stepWeight;
                    if ($step['is_correct']) {
                        $knowledgeScores[$kpId]['correct_weight'] += $stepScore * $stepWeight;
                    }

                    $knowledgeScores[$kpId]['step_details'][] = [
                        'question_id' => $questionId,
                        'step_index' => $step['step_index'],
                        'score' => $stepScore,
                        'is_correct' => $step['is_correct']
                    ];
                }
            } else {
                // 没有步骤级分析，使用题目整体分析
                foreach ($mapping['kp_mapping'] as $kpMapping) {
                    $kpId = $kpMapping['kp_id'];
                    $weight = floatval($kpMapping['weight'] ?? 1.0);
                    $kpMaxScore = $maxScore * $weight;

                    if (!isset($knowledgeScores[$kpId])) {
                        $knowledgeScores[$kpId] = [
                            'total_weight' => 0,
                            'correct_weight' => 0,
                            'step_details' => []
                        ];
                    }

                    $knowledgeScores[$kpId]['total_weight'] += $kpMaxScore;
                    if ($score > 0) {
                        $knowledgeScores[$kpId]['correct_weight'] += $score * $weight;
                    }
                }
            }
        }

        // 计算掌握度
        $masteryVector = [];
        foreach ($knowledgeScores as $kpId => $data) {
            $mastery = $data['total_weight'] > 0
                ? $data['correct_weight'] / $data['total_weight']
                : 0;

            // 置信度校正：考得越多，评价越稳定
            $confidence = 1 - exp(-$data['total_weight'] / 5);

            $masteryVector[$kpId] = [
                'kp_id' => $kpId,
                'mastery' => $mastery,
                'confidence' => $confidence,
                'total_weight' => $data['total_weight'],
                'correct_weight' => $data['correct_weight'],
                'step_details' => $data['step_details'],
            ];
        }

        return $masteryVector;
    }

    /**
     * 更新学生掌握度（与历史数据合并）
     */
    private function updateStudentMastery(string $studentId, array $knowledgeMasteryVector): array
    {
        $updatedMastery = [];

        foreach ($knowledgeMasteryVector as $kpId => $data) {
            // 获取历史掌握度
            $historyMastery = DB::connection('pgsql')
                ->table('student_knowledge_mastery')
                ->where('student_id', $studentId)
                ->where('kp_code', $kpId)
                ->first();

            $historyMasteryLevel = $historyMastery->mastery_level ?? 0.5;
            $historyWeight = $historyMastery->total_attempts ?? 0;
            $currentWeight = $data['total_weight'];

            // 合并计算：历史权重 + 当前权重
            $newMastery = $historyWeight > 0
                ? ($historyWeight * $historyMasteryLevel + $currentWeight * $data['mastery'])
                  / ($historyWeight + $currentWeight)
                : $data['mastery'];

            $newConfidence = $data['confidence'];

            // 保存到数据库
            DB::connection('pgsql')
                ->table('student_knowledge_mastery')
                ->updateOrInsert(
                    ['student_id' => $studentId, 'kp_code' => $kpId],
                    [
                        'mastery_level' => $newMastery,
                        'confidence_level' => $newConfidence,
                        'total_attempts' => ($historyMastery->total_attempts ?? 0) + 1,
                        'correct_attempts' => ($historyMastery->correct_attempts ?? 0) + intval($data['correct_weight'] > 0),
                        'mastery_trend' => $this->determineMasteryTrend($historyMasteryLevel, $newMastery),
                        'last_mastery_update' => now(),
                        'updated_at' => now(),
                    ]
                );

            $updatedMastery[$kpId] = [
                'kp_id' => $kpId,
                'current_mastery' => $newMastery,
                'previous_mastery' => $historyMasteryLevel,
                'confidence' => $newConfidence,
                'change' => $newMastery - $historyMasteryLevel,
                'weight' => $currentWeight
            ];
        }

        return $updatedMastery;
    }

    /**
     * 生成题目维度分析
     */
    private function analyzeQuestions(array $questions, array $questionMappings): array
    {
        $analysis = [];

        foreach ($questions as $question) {
            $questionId = $question['question_id'];
            $score = floatval($question['score_obtained'] ?? 0);
            $maxScore = floatval($question['score'] ?? $score);
            $steps = $question['steps'] ?? [];

            $mapping = $questionMappings[$questionId] ?? ['kp_mapping' => []];

            // 步骤分析
            $stepAnalysis = [];
            if (!empty($steps)) {
                foreach ($steps as $step) {
                    $kpId = $step['kp_id'] ?? 'K-GENERAL';
                    $stepAnalysis[] = [
                        'step_index' => $step['step_index'],
                        'is_correct' => $step['is_correct'],
                        'kp_id' => $kpId,
                        'description' => $step['description'] ?? ''
                    ];
                }
            }

            // 知识点关联
            $knowledgePoints = array_map(function($kp) {
                return [
                    'kp_id' => $kp['kp_id'],
                    'kp_name' => $kp['kp_name'] ?? $kp['kp_id'],
                    'weight' => $kp['weight'] ?? 1.0
                ];
            }, $mapping['kp_mapping']);

            $analysis[] = [
                'question_id' => $questionId,
                'score_obtained' => $score,
                'max_score' => $maxScore,
                'accuracy_rate' => $maxScore > 0 ? $score / $maxScore : 0,
                'step_analysis' => $stepAnalysis,
                'knowledge_points' => $knowledgePoints,
                'performance_summary' => $this->generateQuestionPerformanceSummary($question, $stepAnalysis)
            ];
        }

        return $analysis;
    }

    /**
     * 生成知识点维度分析
     */
    private function analyzeKnowledgePoints(array $knowledgeMasteryVector, array $questionMappings): array
    {
        $analysis = [];

        foreach ($knowledgeMasteryVector as $kpId => $data) {
            $analysis[] = [
                'kp_id' => $kpId,
                'mastery_level' => $data['mastery'],
                'confidence_level' => $data['confidence'],
                'performance_in_exam' => $this->evaluatePerformanceLevel($data['mastery']),
                'evidence_count' => count($data['step_details']),
                'step_evidence' => $data['step_details'],
                'recommendation' => $this->generateKnowledgePointRecommendation($data)
            ];
        }

        return $analysis;
    }

    /**
     * 生成整体掌握度总结
     */
    private function generateOverallSummary(array $updatedMastery): array
    {
        $knowledgePoints = array_values($updatedMastery);

        if (empty($knowledgePoints)) {
            return [
                'total_knowledge_points' => 0,
                'average_mastery' => 0,
                'mastery_distribution' => [
                    'mastered' => 0,
                    'good' => 0,
                    'weak' => 0
                ],
                'top_strengths' => [],
                'top_weaknesses' => []
            ];
        }

        // 计算平均掌握度
        $averageMastery = array_sum(array_column($knowledgePoints, 'current_mastery')) / count($knowledgePoints);

        // 掌握度分布
        $mastered = array_filter($knowledgePoints, fn($kp) => $kp['current_mastery'] >= 0.85);
        $good = array_filter($knowledgePoints, fn($kp) => $kp['current_mastery'] >= 0.70 && $kp['current_mastery'] < 0.85);
        $weak = array_filter($knowledgePoints, fn($kp) => $kp['current_mastery'] < 0.70);

        // 排序找出优势和薄弱点
        usort($knowledgePoints, fn($a, $b) => $b['current_mastery'] <=> $a['current_mastery']);
        $topStrengths = array_slice($knowledgePoints, 0, 3);
        $topWeaknesses = array_slice(array_reverse($knowledgePoints), 0, 3);

        return [
            'total_knowledge_points' => count($knowledgePoints),
            'average_mastery' => round($averageMastery, 4),
            'mastery_distribution' => [
                'mastered' => count($mastered),
                'good' => count($good),
                'weak' => count($weak)
            ],
            'top_strengths' => $topStrengths,
            'top_weaknesses' => $topWeaknesses,
            'overall_performance' => $this->evaluateOverallPerformance($averageMastery)
        ];
    }

    /**
     * 生成智能出卷推荐依据
     * 基于文档中的推荐优先级算法
     */
    private function generateSmartQuizRecommendation(array $updatedMastery): array
    {
        $recommendations = [];

        foreach ($updatedMastery as $kpId => $data) {
            $mastery = $data['current_mastery'];
            $confidence = $data['confidence'];
            $weight = $data['weight'];

            // 推荐优先级 = (1 - 掌握度) * 重要性 * 覆盖需求
            // 重要性可以根据知识点在中考/阶段考试中的权重，这里简化为1.0
            $importance = 1.0;

            // 覆盖需求：最近没考过或考得少，值大
            $coverageNeed = max(1.0, 1.5 - ($weight / 10));

            $priority = (1 - $mastery) * $importance * $coverageNeed;

            $recommendations[] = [
                'kp_id' => $kpId,
                'current_mastery' => $mastery,
                'priority' => $priority,
                'recommended_questions' => $this->calculateRecommendedQuestions($mastery),
                'focus_type' => $this->determineFocusType($mastery)
            ];
        }

        // 按优先级排序
        usort($recommendations, fn($a, $b) => $b['priority'] <=> $a['priority']);

        // 控制难度节奏：40%巩固型 + 40%修补型 + 20%挑战型
        $totalRecommendations = count($recommendations);
        $consolidation = array_slice($recommendations, 0, intval($totalRecommendations * 0.4));
        $remediation = array_slice($recommendations, intval($totalRecommendations * 0.4), intval($totalRecommendations * 0.4));
        $challenge = array_slice($recommendations, intval($totalRecommendations * 0.8));

        return [
            'priority_list' => $recommendations,
            'quiz_structure' => [
                'consolidation_type' => $consolidation,
                'remediation_type' => $remediation,
                'challenge_type' => $challenge
            ],
            'total_recommended_questions' => array_sum(array_column($recommendations, 'recommended_questions'))
        ];
    }

    /**
     * 保存考试答题记录
     */
    private function saveExamAnswerRecords(array $examData): void
    {
        $studentId = $examData['student_id'];
        $examId = $examData['exam_id'];

        foreach ($examData['questions'] as $question) {
            $questionId = $question['question_id'];
            $steps = $question['steps'] ?? [];

            // 保存步骤级记录
            if (!empty($steps)) {
                foreach ($steps as $step) {
                    DB::connection('pgsql')->table('student_answer_steps')->insert([
                        'student_id' => $studentId,
                        'exam_id' => $examId,
                        'question_id' => $questionId,
                        'step_index' => $step['step_index'],
                        'kp_id' => $step['kp_id'] ?? 'K-GENERAL',
                        'is_correct' => $step['is_correct'],
                        'step_score' => $step['score'] ?? 0,
                        'created_at' => now(),
                        'updated_at' => now(),
                    ]);
                }
            } else {
                // 保存题目级记录
                DB::connection('pgsql')->table('student_answer_questions')->insert([
                    'student_id' => $studentId,
                    'exam_id' => $examId,
                    'question_id' => $questionId,
                    'score_obtained' => $question['score_obtained'] ?? 0,
                    'max_score' => $question['score'] ?? 0,
                    'created_at' => now(),
                    'updated_at' => now(),
                ]);
            }
        }
    }

    /**
     * 保存分析结果
     */
    private function saveAnalysisResult(string $studentId, string $examId, array $result): void
    {
        DB::connection('pgsql')->table('exam_analysis_results')->insert([
            'student_id' => $studentId,
            'exam_id' => $examId,
            'analysis_data' => json_encode($result),
            'created_at' => now(),
            'updated_at' => now(),
        ]);
    }

    /**
     * 判断掌握度趋势
     */
    private function determineMasteryTrend(float $previous, float $current): string
    {
        $change = $current - $previous;

        if ($change > 0.1) {
            return 'improving';
        } elseif ($change < -0.1) {
            return 'declining';
        } else {
            return 'stable';
        }
    }

    /**
     * 评估表现水平
     */
    private function evaluatePerformanceLevel(float $mastery): string
    {
        if ($mastery >= 0.85) {
            return 'excellent';
        } elseif ($mastery >= 0.70) {
            return 'good';
        } elseif ($mastery >= 0.50) {
            return 'fair';
        } else {
            return 'poor';
        }
    }

    /**
     * 生成题目表现总结
     */
    private function generateQuestionPerformanceSummary(array $question, array $stepAnalysis): string
    {
        if (empty($stepAnalysis)) {
            return '整题作答';
        }

        $correctSteps = count(array_filter($stepAnalysis, fn($s) => $s['is_correct']));
        $totalSteps = count($stepAnalysis);

        if ($correctSteps === $totalSteps) {
            return '所有步骤正确';
        } elseif ($correctSteps > 0) {
            return "部分正确 ({$correctSteps}/{$totalSteps} 步骤正确)";
        } else {
            return '所有步骤错误';
        }
    }

    /**
     * 生成知识点建议
     */
    private function generateKnowledgePointRecommendation(array $data): string
    {
        $mastery = $data['mastery'];

        if ($mastery >= 0.85) {
            return '掌握良好，可安排综合练习';
        } elseif ($mastery >= 0.70) {
            return '基本掌握，建议加强练习';
        } elseif ($mastery >= 0.50) {
            return '需要重点练习，建议安排专项训练';
        } else {
            return '薄弱知识点，建议系统学习和大量练习';
        }
    }

    /**
     * 评估整体表现
     */
    private function evaluateOverallPerformance(float $averageMastery): string
    {
        if ($averageMastery >= 0.85) {
            return '优秀';
        } elseif ($averageMastery >= 0.70) {
            return '良好';
        } elseif ($averageMastery >= 0.50) {
            return '一般';
        } else {
            return '需加强';
        }
    }

    /**
     * 计算推荐题目数量
     */
    private function calculateRecommendedQuestions(float $mastery): int
    {
        if ($mastery >= 0.85) {
            return 1; // 巩固型：1题
        } elseif ($mastery >= 0.50) {
            return 2; // 修补型：2题
        } else {
            return 3; // 挑战型：3题
        }
    }

    /**
     * 确定重点类型
     */
    private function determineFocusType(float $mastery): string
    {
        if ($mastery >= 0.70 && $mastery < 0.85) {
            return 'consolidation'; // 巩固型
        } elseif ($mastery < 0.70) {
            return 'remediation'; // 修补型
        } else {
            return 'challenge'; // 挑战型
        }
    }
}