<?php

namespace App\Services;

use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Str;

/**
 * 本地AI分析服务
 * 直接调用QuestionBankService的AI分析API，不依赖LearningAnalytics项目
 */
class LocalAIAnalysisService
{
    protected string $questionBankApiUrl;
    protected int $timeout = 60;

    public function __construct(
        private readonly QuestionBankService $questionBankService
    ) {
        $this->questionBankApiUrl = config('services.question_bank.url', env('QUESTION_BANK_API_URL', 'http://localhost:5015'));
    }

    /**
     * 分析学生答案
     *
     * @param array $answerData 包含 question_text, student_answer, score, max_score, kp_code 等
     * @return array 分析结果
     */
    public function analyzeAnswer(array $answerData): array
    {
        try {
            Log::info('LocalAIAnalysisService: 开始分析答案', [
                'question_id' => $answerData['question_id'] ?? 'unknown',
                'kp_code' => $answerData['kp_code'] ?? 'unknown',
            ]);

            // 构建请求数据
            $requestData = [
                'question_text' => $answerData['question_text'] ?? '',
                'student_answer' => $answerData['student_answer'] ?? '',
                'score_value' => (float) ($answerData['score'] ?? 0),
                'full_score' => (float) ($answerData['max_score'] ?? 10),
                'kp_code' => $answerData['kp_code'] ?? '',
                'model' => 'deepseek', // 可配置
            ];

            // 调用QuestionBankService的AI分析API
            $response = Http::timeout($this->timeout)
                ->post($this->questionBankApiUrl . '/api/ai/analyze-answer', $requestData);

            if ($response->successful()) {
                $result = $response->json();
                if ($result['success'] ?? false) {
                    Log::info('LocalAIAnalysisService: AI分析成功', [
                        'question_id' => $answerData['question_id'] ?? 'unknown',
                        'model_used' => $result['model_used'] ?? 'unknown',
                    ]);

                    return [
                        'success' => true,
                        'data' => $result['data'] ?? [],
                        'model_used' => $result['model_used'] ?? 'unknown',
                    ];
                }
            }

            Log::warning('LocalAIAnalysisService: AI分析失败，使用规则分析', [
                'status' => $response->status(),
                'response' => $response->body(),
            ]);

            // 回退到规则分析
            return [
                'success' => true,
                'data' => $this->ruleBasedAnalysis($answerData),
                'model_used' => 'fallback-rules',
                'fallback' => true,
            ];

        } catch (\Exception $e) {
            Log::error('LocalAIAnalysisService: 分析异常，使用规则分析', [
                'error' => $e->getMessage(),
                'question_id' => $answerData['question_id'] ?? 'unknown',
            ]);

            return [
                'success' => true,
                'data' => $this->ruleBasedAnalysis($answerData),
                'model_used' => 'fallback-rules',
                'fallback' => true,
                'fallback_reason' => $e->getMessage(),
            ];
        }
    }

    /**
     * 批量分析学生答案
     *
     * @param array $answers 答案数组
     * @return array 分析结果数组
     */
    public function analyzeBatchAnswers(array $answers): array
    {
        $results = [];
        foreach ($answers as $answer) {
            $results[] = $this->analyzeAnswer($answer);
        }
        return $results;
    }

    /**
     * 基于规则的答案分析（备用方案）
     */
    private function ruleBasedAnalysis(array $answerData): array
    {
        $studentAnswer = $answerData['student_answer'] ?? '';
        $score = (float) ($answerData['score'] ?? 0);
        $maxScore = (float) ($answerData['max_score'] ?? 10);

        // 无答案情况
        if (empty(trim($studentAnswer))) {
            return [
                'correct' => false,
                'score' => 0,
                'full_score' => $maxScore,
                'partial_score_ratio' => 0.0,
                'mistake_type' => '未作答',
                'mistake_category' => '态度/习惯',
                'reason' => '学生未作答',
                'correct_solution' => '请参考标准答案',
                'suggestions' => '建议鼓励学生尝试作答，不要留白',
                'next_steps' => ['复习相关知识点', '尝试从已知条件入手'],
                'analysis_confidence' => 1.0,
                'analysis_tokens' => 0,
            ];
        }

        $scoreRatio = $maxScore > 0 ? $score / $maxScore : 0;

        // 满分
        if ($scoreRatio == 1.0) {
            return [
                'correct' => true,
                'score' => $score,
                'full_score' => $maxScore,
                'partial_score_ratio' => 1.0,
                'mistake_type' => '无',
                'mistake_category' => '无',
                'reason' => '回答正确',
                'correct_solution' => '回答正确',
                'suggestions' => '继续保持',
                'next_steps' => ['尝试更高难度的题目'],
                'analysis_confidence' => 1.0,
                'analysis_tokens' => 0,
            ];
        }

        // 零分或低分
        return [
            'correct' => false,
            'score' => $score,
            'full_score' => $maxScore,
            'partial_score_ratio' => $scoreRatio,
            'mistake_type' => $scoreRatio < 0.3 ? '概念错误' : '计算错误/步骤缺失',
            'mistake_category' => $scoreRatio < 0.3 ? '知识掌握' : '解题技巧',
            'reason' => $scoreRatio < 0.3
                ? '学生对题目理解存在偏差或知识掌握不牢固，需要系统复习'
                : '解题方向有误，需要学习正确的解题方法',
            'correct_solution' => '需要从基础概念开始，系统学习相关知识',
            'suggestions' => '建议从基础概念开始，系统复习相关知识，多做基础练习',
            'next_steps' => ['学习基础概念', '理解公式原理', '从简单题开始练习', '逐步提升难度'],
            'analysis_confidence' => 0.7,
            'analysis_tokens' => 100,
        ];
    }

    /**
     * 更新学生掌握度
     *
     * @param string $studentId 学生ID
     * @param string $kpCode 知识点编码
     * @param float $currentMastery 当前掌握度
     * @param bool $isCorrect 是否正确
     * @param float $difficulty 题目难度
     * @return array 更新后的掌握度
     */
    public function updateMastery(string $studentId, string $kpCode, float $currentMastery, bool $isCorrect, float $difficulty = 0.5): array
    {
        try {
            // 简化的掌握度更新算法
            // 基于BKT（贝叶斯知识追踪）模型的简化版本
            $learningRate = 0.1; // 学习速率
            $forgettingRate = 0.05; // 遗忘速率

            // 根据正确性和难度调整学习速率
            $adjustedLearningRate = $learningRate * (1 + (1 - $difficulty));
            $adjustedForgettingRate = $forgettingRate * (1 - (1 - $difficulty));

            $newMastery = $currentMastery;

            if ($isCorrect) {
                // 答对了，增加掌握度
                $newMastery = $currentMastery + ($adjustedLearningRate * (1 - $currentMastery));
            } else {
                // 答错了，遗忘一些
                $newMastery = $currentMastery * (1 - $adjustedForgettingRate);
            }

            // 确保在[0,1]范围内
            $newMastery = max(0, min(1, $newMastery));

            // 保存到数据库
            $this->saveMasteryToDatabase($studentId, $kpCode, $newMastery);

            return [
                'kp_code' => $kpCode,
                'old_mastery' => $currentMastery,
                'new_mastery' => $newMastery,
                'change' => $newMastery - $currentMastery,
                'is_correct' => $isCorrect,
            ];

        } catch (\Exception $e) {
            Log::error('LocalAIAnalysisService: 更新掌握度失败', [
                'student_id' => $studentId,
                'kp_code' => $kpCode,
                'error' => $e->getMessage(),
            ]);

            return [
                'kp_code' => $kpCode,
                'old_mastery' => $currentMastery,
                'new_mastery' => $currentMastery,
                'change' => 0,
                'is_correct' => $isCorrect,
                'error' => $e->getMessage(),
            ];
        }
    }

    /**
     * 保存掌握度到数据库
     */
    private function saveMasteryToDatabase(string $studentId, string $kpCode, float $mastery): void
    {
        try {
            // 尝试更新现有记录
            $updated = DB::table('student_knowledge_mastery')
                ->where('student_id', $studentId)
                ->where('kp_code', $kpCode)
                ->update([
                    'mastery_level' => $mastery,
                    'updated_at' => now(),
                ]);

            // 如果没有更新任何记录，插入新记录
            if ($updated === 0) {
                DB::table('student_knowledge_mastery')
                    ->insert([
                        'student_id' => $studentId,
                        'kp_code' => $kpCode,
                        'mastery_level' => $mastery,
                        'confidence_level' => 0.5, // 默认置信度
                        'created_at' => now(),
                        'updated_at' => now(),
                    ]);
            }

            Log::debug('LocalAIAnalysisService: 掌握度已保存', [
                'student_id' => $studentId,
                'kp_code' => $kpCode,
                'mastery' => $mastery,
            ]);

        } catch (\Exception $e) {
            // 表不存在时静默跳过
            Log::debug('LocalAIAnalysisService: 掌握度表不存在，跳过保存', [
                'student_id' => $studentId,
                'kp_code' => $kpCode,
                'error' => $e->getMessage(),
            ]);
        }
    }

    /**
     * 获取学生掌握度
     *
     * @param string $studentId 学生ID
     * @param string|null $kpCode 知识点编码（可选）
     * @return array 掌握度数据
     */
    public function getStudentMastery(string $studentId, ?string $kpCode = null): array
    {
        try {
            $query = DB::table('student_knowledge_mastery')
                ->where('student_id', $studentId);

            if ($kpCode) {
                $query->where('kp_code', $kpCode);
            }

            $masteries = $query->get()->toArray();

            return [
                'success' => true,
                'data' => $masteries,
            ];

        } catch (\Exception $e) {
            // 表不存在时返回空数据
            Log::debug('LocalAIAnalysisService: 掌握度表不存在，返回空数据', [
                'student_id' => $studentId,
                'kp_code' => $kpCode,
                'error' => $e->getMessage(),
            ]);

            return [
                'success' => false,
                'message' => '表不存在',
                'data' => [],
            ];
        }
    }

    /**
     * 创建掌握度快照
     *
     * @param string $studentId 学生ID
     * @param string|null $paperId 关联试卷ID（可选）
     * @param string|null $answerRecordId 关联作答记录ID（可选）
     * @return array|null 快照数据
     */
    public function createMasterySnapshot(string $studentId, ?string $paperId = null, ?string $answerRecordId = null): ?array
    {
        try {
            // 获取最新掌握度数据
            $masteryData = $this->getStudentMastery($studentId);

            if (empty($masteryData['data'])) {
                Log::info('LocalAIAnalysisService: 没有掌握度数据，返回空快照', [
                    'student_id' => $studentId,
                ]);
                return [
                    'snapshot_id' => 'snap_' . Str::uuid()->toString(),
                    'student_id' => $studentId,
                    'paper_id' => $paperId,
                    'answer_record_id' => $answerRecordId,
                    'overall_mastery' => 0,
                    'weak_count' => 0,
                    'strong_count' => 0,
                    'mastery_changes' => [],
                ];
            }

            $snapshotId = 'snap_' . Str::uuid()->toString();
            $masteryItems = $masteryData['data'];
            $overallMastery = 0;
            $weakCount = 0;
            $strongCount = 0;

            foreach ($masteryItems as $item) {
                $level = (float) ($item->mastery_level ?? 0);
                $overallMastery += $level;

                if ($level < 0.6) {
                    $weakCount++;
                } elseif ($level > 0.8) {
                    $strongCount++;
                }
            }

            $overallMastery = count($masteryItems) > 0
                ? round($overallMastery / count($masteryItems), 4)
                : 0;

            return [
                'snapshot_id' => $snapshotId,
                'student_id' => $studentId,
                'paper_id' => $paperId,
                'answer_record_id' => $answerRecordId,
                'overall_mastery' => $overallMastery,
                'weak_count' => $weakCount,
                'strong_count' => $strongCount,
                'mastery_changes' => [],
            ];

        } catch (\Exception $e) {
            Log::error('LocalAIAnalysisService: 创建掌握度快照失败', [
                'student_id' => $studentId,
                'paper_id' => $paperId,
                'error' => $e->getMessage(),
            ]);
            return null;
        }
    }
}