<?php

namespace App\Services;

class KnowledgeGraphService
{
    protected MathRecSysService $mathRecSys;

    public function __construct(MathRecSysService $mathRecSys)
    {
        $this->mathRecSys = $mathRecSys;
    }

    /**
     * 获取知识图谱数据（格式化后）
     *
     * @param string|null $focus 焦点知识点
     * @return array
     */
    public function getGraphData(?string $focus = null): array
    {
        try {
            $graphData = $this->mathRecSys->getKnowledgeGraph($focus);

            return [
                'success' => true,
                'nodes' => $this->formatNodes($graphData['nodes'] ?? []),
                'edges' => $this->formatEdges($graphData['edges'] ?? []),
                'categories' => $this->extractCategories($graphData['nodes'] ?? []),
                'metadata' => [
                    'total_nodes' => count($graphData['nodes'] ?? []),
                    'total_edges' => count($graphData['edges'] ?? []),
                    'focus' => $focus
                ]
            ];

        } catch (\Exception $e) {
            \Log::error('获取知识图谱数据失败', ['error' => $e->getMessage()]);
            return [
                'success' => false,
                'nodes' => [],
                'edges' => [],
                'categories' => [],
                'error' => $e->getMessage()
            ];
        }
    }

    /**
     * 获取知识点详情
     *
     * @param string $kpId 知识点ID
     * @return array
     */
    public function getKnowledgePointDetail(string $kpId): array
    {
        try {
            // 从MathRecSys获取
            $detail = $this->mathRecSys->getKnowledgePoint($kpId);

            // 从本地获取相关题目（这里需要实现）
            $relatedQuestions = $this->getRelatedQuestions($kpId);

            return [
                'success' => true,
                'data' => array_merge($detail['data'] ?? [], [
                    'related_questions' => $relatedQuestions
                ])
            ];

        } catch (\Exception $e) {
            \Log::error('获取知识点详情失败', [
                'kp_id' => $kpId,
                'error' => $e->getMessage()
            ]);
            return [
                'success' => false,
                'error' => $e->getMessage()
            ];
        }
    }

    /**
     * 获取知识点依赖关系
     *
     * @param string $kpId 知识点ID
     * @return array
     */
    public function getKnowledgePointDependencies(string $kpId): array
    {
        try {
            $graphData = $this->mathRecSys->getKnowledgeGraph($kpId);

            $dependencies = [
                'prerequisites' => [], // 前置知识点
                'advances' => [],      // 后续知识点
                'contrasts' => []      // 对比知识点
            ];

            foreach ($graphData['edges'] ?? [] as $edge) {
                if ($edge['start_uuid'] === $kpId) {
                    // 该知识点指向其他知识点
                    if ($edge['type'] === 'AdvancesTo') {
                        $dependencies['advances'][] = [
                            'target' => $edge['end_uuid'],
                            'description' => $edge['properties']['description'] ?? ''
                        ];
                    } elseif ($edge['type'] === 'ContrastsWith') {
                        $dependencies['contrasts'][] = [
                            'target' => $edge['end_uuid'],
                            'description' => $edge['properties']['description'] ?? ''
                        ];
                    }
                } elseif ($edge['end_uuid'] === $kpId) {
                    // 其他知识点指向该知识点
                    if ($edge['type'] === 'Prerequisite') {
                        $dependencies['prerequisites'][] = [
                            'source' => $edge['start_uuid'],
                            'description' => $edge['properties']['description'] ?? ''
                        ];
                    }
                }
            }

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

        } catch (\Exception $e) {
            \Log::error('获取知识点依赖关系失败', [
                'kp_id' => $kpId,
                'error' => $e->getMessage()
            ]);
            return [
                'success' => false,
                'error' => $e->getMessage()
            ];
        }
    }

    /**
     * 获取学习路径建议
     *
     * @param string $studentId 学生ID
     * @param string $targetKp 目标知识点
     * @return array
     */
    public function getLearningPath(string $studentId, string $targetKp): array
    {
        try {
            // 获取学生画像
            $profile = $this->mathRecSys->getStudentProfile($studentId);

            // 获取知识图谱
            $graphData = $this->mathRecSys->getKnowledgeGraph($targetKp);

            // 分析前置知识点掌握情况
            $prerequisites = [];
            foreach ($graphData['edges'] ?? [] as $edge) {
                if ($edge['end_uuid'] === $targetKp && $edge['type'] === 'Prerequisite') {
                    $prereqId = $edge['start_uuid'];
                    $mastery = $this->getMasteryFromProfile($profile, $prereqId);

                    $prerequisites[] = [
                        'kp_id' => $prereqId,
                        'description' => $edge['properties']['description'] ?? '',
                        'current_mastery' => $mastery,
                        'is_ready' => $mastery >= 0.6,
                        'priority' => $this->calculatePriority($mastery)
                    ];
                }
            }

            // 按优先级排序
            usort($prerequisites, function ($a, $b) {
                return $b['priority'] <=> $a['priority'];
            });

            // 生成学习路径
            $learningPath = [];
            foreach ($prerequisites as $prereq) {
                if (!$prereq['is_ready']) {
                    $learningPath[] = [
                        'type' => 'review',
                        'kp_id' => $prereq['kp_id'],
                        'reason' => '需要先掌握前置知识点',
                        'priority' => $prereq['priority']
                    ];
                }
            }

            // 添加目标知识点
            $learningPath[] = [
                'type' => 'learn',
                'kp_id' => $targetKp,
                'reason' => '学习目标知识点',
                'priority' => 100
            ];

            return [
                'success' => true,
                'data' => [
                    'student_id' => $studentId,
                    'target_kp' => $targetKp,
                    'learning_path' => $learningPath,
                    'total_steps' => count($learningPath),
                    'estimated_hours' => count($learningPath) * 2 // 假设每个知识点需要2小时
                ]
            ];

        } catch (\Exception $e) {
            \Log::error('获取学习路径失败', [
                'student_id' => $studentId,
                'target_kp' => $targetKp,
                'error' => $e->getMessage()
            ]);
            return [
                'success' => false,
                'error' => $e->getMessage()
            ];
        }
    }

    /**
     * 格式化节点数据
     *
     * @param array $nodes 原始节点数据
     * @return array
     */
    private function formatNodes(array $nodes): array
    {
        return array_map(function ($node) {
            $props = $node['properties'] ?? [];

            return [
                'id' => $props['uuid'] ?? $props['kp_id'] ?? uniqid(),
                'name' => $props['node_name'] ?? $props['kp_name'] ?? '未知知识点',
                'category' => $props['grade'] ?? $props['grade_label'] ?? '未分类',
                'description' => $props['description'] ?? '',
                'value' => $props['mastery'] ?? 0.6,
                'difficulty' => $props['difficulty'] ?? 0.5,
                'book' => $props['book'] ?? '',
                'chapter' => $props['chapter'] ?? '',
                'keywords' => $props['keywords'] ?? '',
                'uuid' => $props['uuid'] ?? null,
                'kp_id' => $props['kp_id'] ?? null
            ];
        }, $nodes);
    }

    /**
     * 格式化边数据
     *
     * @param array $edges 原始边数据
     * @return array
     */
    private function formatEdges(array $edges): array
    {
        return array_map(function ($edge) {
            return [
                'source' => $edge['start_uuid'] ?? $edge['parent_kp'] ?? '',
                'target' => $edge['end_uuid'] ?? $edge['child_kp'] ?? '',
                'type' => $edge['type'] ?? $edge['relation_type'] ?? 'Prerequisite',
                'description' => $edge['properties']['description'] ?? '',
                'strength' => $edge['properties']['strength'] ?? 0.8
            ];
        }, $edges);
    }

    /**
     * 提取分类
     *
     * @param array $nodes 节点数据
     * @return array
     */
    private function extractCategories(array $nodes): array
    {
        $categories = [];
        foreach ($nodes as $node) {
            $props = $node['properties'] ?? [];
            $category = $props['grade'] ?? $props['grade_label'] ?? '未分类';
            if (!in_array($category, $categories)) {
                $categories[] = $category;
            }
        }

        // 为每个分类分配颜色
        return array_map(function ($category, $index) {
            return [
                'name' => $category,
                'color' => $this->getCategoryColor($index)
            ];
        }, $categories, array_keys($categories));
    }

    /**
     * 获取分类颜色
     *
     * @param int $index 分类索引
     * @return string
     */
    private function getCategoryColor(int $index): string
    {
        $colors = [
            '#3b82f6', // 蓝色
            '#10b981', // 绿色
            '#f59e0b', // 黄色
            '#ef4444', // 红色
            '#8b5cf6', // 紫色
            '#ec4899', // 粉色
            '#06b6d4', // 青色
            '#84cc16', // 青柠
        ];

        return $colors[$index % count($colors)];
    }

    /**
     * 从画像中获取掌握度
     *
     * @param array $profile 学生画像
     * @param string $kpId 知识点ID
     * @return float
     */
    private function getMasteryFromProfile(array $profile, string $kpId): float
    {
        $masteryData = $profile['data']['mastery'] ?? $profile['mastery'] ?? [];
        foreach ($masteryData as $mastery) {
            if (($mastery['kp'] ?? $mastery['kp_id'] ?? '') === $kpId) {
                return floatval($mastery['level'] ?? $mastery['mastery_level'] ?? 0);
            }
        }
        return 0.0;
    }

    /**
     * 计算优先级
     *
     * @param float $mastery 掌握度
     * @return int
     */
    private function calculatePriority(float $mastery): int
    {
        if ($mastery < 0.3) {
            return 90; // 急需掌握
        } elseif ($mastery < 0.6) {
            return 70; // 需要复习
        } elseif ($mastery < 0.8) {
            return 50; // 适当巩固
        } else {
            return 10; // 已经掌握
        }
    }

    /**
     * 获取相关题目（需要根据实际题库实现）
     *
     * @param string $kpId 知识点ID
     * @return array
     */
    private function getRelatedQuestions(string $kpId): array
    {
        // 这里需要实现从本地题库查询相关题目的逻辑
        // 暂时返回空数组
        return [];
    }
}