const { Student, Score, AttendanceModel, ClassModel, SubjectModel, User } = require('./models');

/**
 * 1. 定义工具描述 (Schema) - Gemini Format
 */
const mongoTools = [
  {
    functionDeclarations: [
      {
        name: "query_database",
        description: "查询学校数据库。⚠️字段名必须准确：班级字段名是 'className' (禁止用 'class')，学生姓名在Student表是 'name'，在成绩表是 'studentName'。支持的集合: 'Student', 'Score', 'Attendance', 'Class'。",
        parameters: {
          type: "OBJECT",
          properties: {
            collection: {
              type: "STRING",
              description: "集合名称",
              enum: ["Student", "Score", "Attendance", "Class"]
            },
            filter: {
              type: "OBJECT",
              description: "Mongoose查询条件JSON。例: {className:'一年级(1)班', name:'张三'}。注意：查询班级时必须使用 'className' (禁止用 'class') 字段。",
            },
            limit: {
              type: "NUMBER",
              description: "默认 5"
            }
          },
          required: ["collection", "filter"]
        }
      }
    ]
  }
];

/**
 * 转换器：将 Gemini 工具定义转换为 OpenAI/Doubao 工具定义
 */
function getOpenAITools() {
    return mongoTools[0].functionDeclarations.map(tool => ({
        type: "function",
        function: {
            name: tool.name,
            description: tool.description,
            parameters: tool.parameters
        }
    }));
}

/**
 * 2. 安全守门员 (Security Guardrail)
 */
function injectSecurityFilter(filter, user, role, schoolId) {
    const safeFilter = { ...filter, schoolId };

    if (role === 'ADMIN' || role === 'PRINCIPAL') {
        return safeFilter;
    }

    if (role === 'TEACHER') {
       // 暂时不做强制过滤，依赖业务层逻辑
    }

    if (role === 'STUDENT') {
        if (!safeFilter.studentNo && !safeFilter.name) {
             safeFilter.studentNo = user.studentNo; 
        }
    }

    return safeFilter;
}

/**
 * 辅助：递归修正查询字段名 (Deep Normalization)
 */
function normalizeQueryFields(query, collection) {
    if (!query || typeof query !== 'object') return query;
    
    if (Array.isArray(query)) {
        return query.map(item => normalizeQueryFields(item, collection));
    }

    const newQuery = {};
    for (const key in query) {
        let newKey = key;
        
        // 1. 修正班级字段
        if (key === 'class') newKey = 'className';

        // 2. 修正名字字段
        if (collection === 'Score' || collection === 'Attendance') {
            if (key === 'name') newKey = 'studentName';
        }

        // 递归处理值
        newQuery[newKey] = normalizeQueryFields(query[key], collection);
    }
    return newQuery;
}

/**
 * 🌟 核心增强：智能模糊查询构建器
 * 解决 "四年级6班" 查不到 "四年级(6)班" 的问题
 */
function buildFuzzyQuery(filter) {
    const fuzzyFilter = { ...filter };

    // 辅助：转义正则特殊字符
    const escapeRegExp = (string) => {
        return string.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
    };

    // 1. 处理 className (最常见的问题)
    if (fuzzyFilter.className && typeof fuzzyFilter.className === 'string') {
        const rawClass = fuzzyFilter.className;
        
        // 提取年级和班级号 (例如: "四年级6班" -> grade="四年级", num="6")
        // 支持中文数字 (一二三) 和 阿拉伯数字
        const match = rawClass.match(/^(.+?级).*?(\d+|[一二三四五六七八九十]+).*?班$/);
        
        if (match) {
            const gradePart = match[1]; // 四年级
            const numPart = match[2];   // 6 或 六
            
            // 构建宽容的正则：匹配年级 + 任意字符(如括号) + 数字 + 任意字符 + 班
            // 这样 "四年级6班" 可以匹配 "四年级(6)班", "四年级（6）班", "四年级六班"
            fuzzyFilter.className = { 
                $regex: new RegExp(`^${escapeRegExp(gradePart)}.*(${numPart}|${convertNum(numPart)}).*班$`), 
                $options: 'i' 
            };
        } else {
            // 如果正则没解析出来，至少做个包含匹配，且忽略括号
            // 比如搜 "1班"，能匹配 "(1)班"
            fuzzyFilter.className = { $regex: escapeRegExp(rawClass).replace(/[\(\)（）]/g, '.?'), $options: 'i' };
        }
    }

    // 2. 处理姓名 (模糊匹配)
    const nameFields = ['name', 'studentName', 'teacherName'];
    nameFields.forEach(field => {
        if (fuzzyFilter[field] && typeof fuzzyFilter[field] === 'string') {
            // 支持只搜 "张三" 匹配 "张三丰"
            fuzzyFilter[field] = { $regex: escapeRegExp(fuzzyFilter[field]), $options: 'i' };
        }
    });

    // 3. 处理 $or 数组中的模糊匹配 (递归)
    if (fuzzyFilter.$or && Array.isArray(fuzzyFilter.$or)) {
        fuzzyFilter.$or = fuzzyFilter.$or.map(subFilter => buildFuzzyQuery(subFilter));
    }

    return fuzzyFilter;
}

// 简单的数字互转辅助
function convertNum(n) {
    const map = {'1':'一','2':'二','3':'三','4':'四','5':'五','6':'六','7':'七','8':'八','9':'九','10':'十',
                 '一':'1','二':'2','三':'3','四':'4','五':'5','六':'6','七':'7','八':'8','九':'9','十':'10'};
    return map[n] || n;
}

/**
 * 3. 工具执行器 (Executor)
 */
async function executeMongoTool(functionCall, user, role, schoolId) {
    let args = functionCall.args;
    if (typeof functionCall.arguments === 'string') {
        try {
            args = JSON.parse(functionCall.arguments);
        } catch (e) {
            console.error("❌ [MCP ERROR] Invalid JSON arguments:", functionCall.arguments);
            return { error: "Invalid JSON arguments" };
        }
    }

    const { collection, filter = {}, limit = 5 } = args || {};
    
    // 1. 字段名修正 (Key Normalization)
    const normalizedFilter = normalizeQueryFields(filter, collection);

    // 2. 🛡️ 安全注入
    let safeFilter = injectSecurityFilter(normalizedFilter, user, role, schoolId);

    // 3. 🧠 智能模糊处理 (Value Normalization)
    safeFilter = buildFuzzyQuery(safeFilter);

    const safeLimit = Math.min(Math.max(limit, 1), 20); 

    // --- 🔍 MCP LOGGING ---
    console.log(`\n================= [MCP TOOL CALL] =================`);
    console.log(`🛠️  Tool:        query_database`);
    console.log(`📂 Collection:  ${collection}`);
    console.log(`📥 AI Params:   ${JSON.stringify(filter)}`);
    console.log(`🔒 Safe Query:  ${JSON.stringify(safeFilter)}`);
    console.log(`---------------------------------------------------`);

    try {
        let result = [];
        let fields = ""; 
        let relationalInfo = "";

        // 🔥 关系查询增强：Score 表没有 className，需要先查 Student 获取 studentNo
        if (collection === 'Score' && safeFilter.className) {
            console.log(`🔄 [Relational] Score query detected className filter. Searching Students first...`);
            
            // 构造 Student 查询条件
            const studentQuery = {
                schoolId: safeFilter.schoolId,
                className: safeFilter.className // 这里已经是正则了
            };
            
            const studentsInClass = await Student.find(studentQuery).select('studentNo name');
            const studentNos = studentsInClass.map(s => s.studentNo);
            
            if (studentNos.length === 0) {
                console.log(`⚠️ [Relational] No students found in class matching: ${JSON.stringify(safeFilter.className)}`);
                return { info: `未找到班级符合条件的学生（查询条件：${JSON.stringify(safeFilter.className)}），无法查询成绩。` };
            }

            console.log(`✅ [Relational] Found ${studentNos.length} students. Translating to Score query...`);
            relationalInfo = `(已找到 ${studentNos.length} 名学生，正在查询他们的成绩)`;
            
            // 替换查询条件：移除 className，添加 studentNo $in
            delete safeFilter.className;
            safeFilter.studentNo = { $in: studentNos };
        }

        switch (collection) {
            case "Student":
                fields = "name studentNo className gender flowerBalance seatNo -_id";
                result = await Student.find(safeFilter).select(fields).limit(safeLimit).lean();
                break;
            case "Score":
                fields = "studentName courseName score type examName -_id";
                result = await Score.find(safeFilter).select(fields).sort({ _id: -1 }).limit(safeLimit).lean();
                break;
            case "Attendance":
                fields = "studentName date status -_id";
                result = await AttendanceModel.find(safeFilter).select(fields).sort({ date: -1 }).limit(safeLimit).lean();
                break;
            case "Class":
                fields = "grade className teacherName studentCount -_id";
                result = await ClassModel.find(safeFilter).select("grade className teacherName").limit(safeLimit).lean();
                break;
            default:
                console.log(`❌ [MCP ERROR] Unknown collection: ${collection}`);
                return { error: "Unknown collection" };
        }

        console.log(`✅ [MCP SUCCESS] Found ${result.length} records.`);
        if (result.length > 0) {
            console.log(`📄 Sample: ${JSON.stringify(result[0])}`);
        } else {
            console.log(`⚠️ No records found.`);
        }
        console.log(`===================================================\n`);

        if (result.length === 0) {
            let msg = "未找到符合条件的数据。";
            if (relationalInfo) msg += " " + relationalInfo + " 但这些学生似乎还没有录入成绩。";
            else msg += " 请尝试放宽查询条件，或确认班级/姓名格式（例如包含括号）。";
            return { info: msg };
        }
        return result;

    } catch (error) {
        console.error("❌ [MCP EXCEPTION]", error.message);
        return { error: "Database query failed", details: error.message };
    }
}

module.exports = { mongoTools, getOpenAITools, executeMongoTool };