<?php

namespace App\Services;

use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Cache;

/**
 * 知识点掌握情况服务
 *
 * 提供：
 * 1. 获取学生知识点掌握情况统计
 * 2. 获取知识点图谱数据（考试快照）
 * 3. 获取知识点图谱快照列表
 */
class KnowledgeMasteryService
{
    protected string $learningAnalyticsBase;
    protected string $knowledgeServiceBase;
    protected int $timeout;

    public function __construct(?string $learningAnalyticsBase = null, ?string $knowledgeServiceBase = null, ?int $timeout = null)
    {
        $this->learningAnalyticsBase = rtrim(
            $learningAnalyticsBase
                ?: config('services.learning_analytics.url', env('LEARNING_ANALYTICS_API_BASE', 'http://localhost:5016')),
            '/'
        );

        $this->knowledgeServiceBase = rtrim(
            $knowledgeServiceBase
                ?: config('services.knowledge_service.url', env('KNOWLEDGE_SERVICE_API_BASE', 'http://localhost:5011')),
            '/'
        );

        $this->timeout = $timeout ?? (int) config('services.learning_analytics.timeout', 20);
    }

    /**
     * 获取学生知识点掌握情况统计
     *
     * @param string $studentId 学生ID
     * @return array
     */
    public function getStats(string $studentId): array
    {
        try {
            $response = Http::timeout($this->timeout)
                ->get($this->learningAnalyticsBase . '/api/knowledge-mastery/stats/' . $studentId);

            if ($response->successful()) {
                $body = $response->json();

                // 丰富知识点名称
                $body = $this->enrichWithKnowledgePointNames($body);

                // 添加知识图谱总数统计
                $graphStats = $this->getKnowledgeGraphStats();
                $body['graph_total_knowledge_points'] = $graphStats['total'] ?? 0;

                Log::info('KnowledgeMasteryService::getStats', ['student_id' => $studentId]);
                return [
                    'success' => true,
                    'data' => $body,
                ];
            }

            Log::warning('Knowledge mastery stats request failed', [
                'student_id' => $studentId,
                'status' => $response->status(),
                'body' => $response->body(),
            ]);

            return [
                'success' => false,
                'error' => '获取知识点掌握情况失败: ' . $response->status(),
            ];
        } catch (\Throwable $e) {
            Log::error('Knowledge mastery stats exception', [
                'student_id' => $studentId,
                'error' => $e->getMessage(),
            ]);

            return [
                'success' => false,
                'error' => '获取知识点掌握情况异常: ' . $e->getMessage(),
            ];
        }
    }

    /**
     * 丰富知识点名称
     */
    private function enrichWithKnowledgePointNames(array $data): array
    {
        if (empty($data['details'])) {
            return $data;
        }

        // 收集所有kp_code
        $kpCodes = array_column($data['details'], 'kp_code');
        if (empty($kpCodes)) {
            return $data;
        }

        // 批量获取知识点名称
        $kpNames = $this->getKnowledgePointNames($kpCodes);

        // 丰富details数据
        foreach ($data['details'] as &$detail) {
            $kpCode = $detail['kp_code'] ?? null;
            if ($kpCode && isset($kpNames[$kpCode])) {
                $detail['kp_name'] = $kpNames[$kpCode];
            } else {
                $detail['kp_name'] = $kpCode; // fallback to code
            }
        }

        return $data;
    }

    /**
     * 批量获取知识点名称
     */
    private function getKnowledgePointNames(array $kpCodes): array
    {
        $result = [];

        foreach ($kpCodes as $kpCode) {
            $name = $this->getKnowledgePointName($kpCode);
            if ($name) {
                $result[$kpCode] = $name;
            }
        }

        return $result;
    }

    /**
     * 获取单个知识点名称（带缓存）
     */
    private function getKnowledgePointName(string $kpCode): ?string
    {
        $cacheKey = "kp_name_{$kpCode}";

        return Cache::remember($cacheKey, 3600, function () use ($kpCode) {
            try {
                $response = Http::timeout(5)
                    ->get($this->knowledgeServiceBase . '/knowledge-points/' . $kpCode);

                if ($response->successful()) {
                    $data = $response->json();
                    return $data['cn_name'] ?? $data['en_name'] ?? null;
                }
            } catch (\Throwable $e) {
                Log::debug('Failed to get knowledge point name', [
                    'kp_code' => $kpCode,
                    'error' => $e->getMessage(),
                ]);
            }

            return null;
        });
    }

    /**
     * 获取知识图谱统计信息（带缓存）
     */
    public function getKnowledgeGraphStats(): array
    {
        return Cache::remember('knowledge_graph_stats', 3600, function () {
            try {
                $response = Http::timeout(10)
                    ->get($this->knowledgeServiceBase . '/knowledge-points/');

                if ($response->successful()) {
                    $data = $response->json();
                    $items = $data['data'] ?? $data ?? [];

                    return [
                        'total' => count($items),
                        'updated_at' => now()->toISOString(),
                    ];
                }
            } catch (\Throwable $e) {
                Log::error('Failed to get knowledge graph stats', [
                    'error' => $e->getMessage(),
                ]);
            }

            return ['total' => 0];
        });
    }

    /**
     * 获取学生知识点图谱数据
     *
     * @param string $studentId 学生ID
     * @param string|null $examId 考试ID（可选，不指定则返回最新快照）
     * @return array
     */
    public function getGraph(string $studentId, ?string $examId = null): array
    {
        try {
            $query = array_filter(['exam_id' => $examId], fn($v) => filled($v));

            $response = Http::timeout($this->timeout)
                ->get($this->learningAnalyticsBase . '/api/knowledge-mastery/graph/' . $studentId, $query);

            if ($response->successful()) {
                $body = $response->json();
                Log::info('KnowledgeMasteryService::getGraph', ['student_id' => $studentId, 'exam_id' => $examId]);
                return [
                    'success' => true,
                    'data' => $body,
                ];
            }

            Log::warning('Knowledge graph request failed', [
                'student_id' => $studentId,
                'exam_id' => $examId,
                'status' => $response->status(),
                'body' => $response->body(),
            ]);

            return [
                'success' => false,
                'error' => '获取知识点图谱失败: ' . $response->status(),
            ];
        } catch (\Throwable $e) {
            Log::error('Knowledge graph exception', [
                'student_id' => $studentId,
                'exam_id' => $examId,
                'error' => $e->getMessage(),
            ]);

            return [
                'success' => false,
                'error' => '获取知识点图谱异常: ' . $e->getMessage(),
            ];
        }
    }

    /**
     * 获取学生知识点图谱快照列表
     *
     * @param string $studentId 学生ID
     * @param int $limit 返回数量限制
     * @return array
     */
    public function getGraphSnapshots(string $studentId, int $limit = 10): array
    {
        try {
            $response = Http::timeout($this->timeout)
                ->get($this->learningAnalyticsBase . '/api/knowledge-mastery/graph/snapshots/' . $studentId, [
                    'limit' => $limit,
                ]);

            if ($response->successful()) {
                $body = $response->json();
                Log::info('KnowledgeMasteryService::getGraphSnapshots', ['student_id' => $studentId, 'limit' => $limit]);
                return [
                    'success' => true,
                    'data' => $body,
                ];
            }

            Log::warning('Knowledge graph snapshots request failed', [
                'student_id' => $studentId,
                'limit' => $limit,
                'status' => $response->status(),
                'body' => $response->body(),
            ]);

            return [
                'success' => false,
                'error' => '获取知识点图谱快照列表失败: ' . $response->status(),
            ];
        } catch (\Throwable $e) {
            Log::error('Knowledge graph snapshots exception', [
                'student_id' => $studentId,
                'limit' => $limit,
                'error' => $e->getMessage(),
            ]);

            return [
                'success' => false,
                'error' => '获取知识点图谱快照列表异常: ' . $e->getMessage(),
            ];
        }
    }

    /**
     * 获取学生知识点掌握摘要（简化版）
     *
     * @param string $studentId 学生ID
     * @return array
     */
    public function getSummary(string $studentId): array
    {
        $stats = $this->getStats($studentId);

        if (!$stats['success']) {
            return $stats;
        }

        $data = $stats['data'];

        return [
            'success' => true,
            'data' => [
                'student_id' => $data['student_id'] ?? $studentId,
                'total' => $data['total_knowledge_points'] ?? 0,
                'mastered' => $data['mastered_knowledge_points'] ?? 0,
                'unmastered' => $data['unmastered_knowledge_points'] ?? 0,
                'mastery_rate' => $data['mastery_rate'] ?? 0.0,
                'mastery_percentage' => round(($data['mastery_rate'] ?? 0) * 100, 1) . '%',
                'graph_total' => $data['graph_total_knowledge_points'] ?? 0,
            ],
        ];
    }

    /**
     * 创建知识点掌握度快照
     *
     * @param string $studentId 学生ID
     * @param string $snapshotType 快照类型 (exam/report/manual/scheduled)
     * @param string|null $sourceId 来源ID
     * @param string|null $sourceName 来源名称
     * @param string|null $notes 备注
     * @return array
     */
    public function createSnapshot(
        string $studentId,
        string $snapshotType = 'report',
        ?string $sourceId = null,
        ?string $sourceName = null,
        ?string $notes = null
    ): array {
        try {
            $response = Http::timeout($this->timeout)
                ->post($this->learningAnalyticsBase . '/api/knowledge-mastery/snapshot/' . $studentId, [
                    'snapshot_type' => $snapshotType,
                    'source_id' => $sourceId,
                    'source_name' => $sourceName,
                    'notes' => $notes,
                ]);

            if ($response->successful()) {
                $body = $response->json();
                Log::info('KnowledgeMasteryService::createSnapshot', [
                    'student_id' => $studentId,
                    'snapshot_type' => $snapshotType,
                    'snapshot_id' => $body['data']['snapshot_id'] ?? null,
                ]);
                return [
                    'success' => true,
                    'data' => $body['data'] ?? $body,
                ];
            }

            Log::warning('Create knowledge mastery snapshot failed', [
                'student_id' => $studentId,
                'status' => $response->status(),
                'body' => $response->body(),
            ]);

            return [
                'success' => false,
                'error' => '创建知识点掌握度快照失败: ' . $response->status(),
            ];
        } catch (\Throwable $e) {
            Log::error('Create knowledge mastery snapshot exception', [
                'student_id' => $studentId,
                'error' => $e->getMessage(),
            ]);

            return [
                'success' => false,
                'error' => '创建知识点掌握度快照异常: ' . $e->getMessage(),
            ];
        }
    }
}