// server/routes/admin.ts
import express from 'express';
import { adminAuth } from '../middleware/auth';
import { User } from '../models/User';
import bcrypt from 'bcrypt';
import { OAuth2Client } from '../models/oauth2';
import { AdminController } from './admin.controller';
import multer from 'multer';
import fs from 'fs';
import path from 'path';
import csv from 'csv-parser';
import { Word, WordRecord, WordSet, VocabularyTestAttempt, VocabularyTestRecord } from '../models/Vocabulary';
import mongoose from 'mongoose';

const router = express.Router();
const adminController = new AdminController();

// 配置 multer 用于文件上传
const storage = multer.diskStorage({
  destination: function (req, file, cb) {
    const uploadDir = path.join(__dirname, '../uploads');
    // 确保上传目录存在
    if (!fs.existsSync(uploadDir)) {
      fs.mkdirSync(uploadDir, { recursive: true });
    }
    cb(null, uploadDir);
  },
  filename: function (req, file, cb) {
    cb(null, `${Date.now()}-${file.originalname}`);
  }
});

const upload = multer({ 
  storage: storage,
  limits: {
    fileSize: 5 * 1024 * 1024 // 限制5MB
  },
  fileFilter: function (req, file, cb) {
    // 只允许上传CSV文件
    if (file.mimetype === 'text/csv' || file.originalname.endsWith('.csv')) {
      cb(null, true);
    } else {
      cb(new Error('只支持CSV文件'));
    }
  }
});

type VocabularyTestType = 'chinese-to-english' | 'audio-to-english' | 'multiple-choice';
type WordRecordModeKey = 'chineseToEnglish' | 'audioToEnglish' | 'multipleChoice';

const TEST_TYPE_TO_MODE: Record<VocabularyTestType, WordRecordModeKey> = {
  'chinese-to-english': 'chineseToEnglish',
  'audio-to-english': 'audioToEnglish',
  'multiple-choice': 'multipleChoice'
};

const WORD_RECORD_MODES: WordRecordModeKey[] = [
  'chineseToEnglish',
  'audioToEnglish',
  'multipleChoice'
];

const INVALIDATING_VOCABULARY_RISK_FLAGS = [
  'too_fast',
  'too_slow',
  'missing_input_value_trace',
  'input_value_mismatch',
  'uniform_answer_intervals',
  'repeated_whole_second_intervals'
];

const parseAdminDateRange = (source: Record<string, any>) => {
  const start = new Date(String(source.start || source.startTime || ''));
  const end = new Date(String(source.end || source.endTime || ''));

  if (Number.isNaN(start.getTime()) || Number.isNaN(end.getTime())) {
    return { error: '请选择有效的开始和结束时间' };
  }

  if (start > end) {
    return { error: '开始时间不能晚于结束时间' };
  }

  return { start, end };
};

const createEmptyModeStats = () => ({
  streak: 0,
  totalCorrect: 0,
  totalWrong: 0,
  mastered: false,
  inWrongBook: false,
  lastTestedAt: undefined as Date | undefined,
  lastMasteredAt: undefined as Date | undefined
});

const applyVocabularyAnswer = (modeStats: ReturnType<typeof createEmptyModeStats>, isCorrect: boolean, testedAt: Date) => {
  if (isCorrect) {
    modeStats.streak = (modeStats.streak || 0) + 1;
    modeStats.totalCorrect = (modeStats.totalCorrect || 0) + 1;
  } else {
    modeStats.streak = 0;
    modeStats.totalWrong = (modeStats.totalWrong || 0) + 1;
  }

  modeStats.lastTestedAt = testedAt;

  if (modeStats.streak >= 1) {
    modeStats.mastered = true;
    modeStats.lastMasteredAt = testedAt;
    modeStats.inWrongBook = false;
  }

  if (!modeStats.mastered && modeStats.totalWrong >= 5) {
    modeStats.inWrongBook = true;
  }
};

const getLatestMasteredAt = (state: Record<WordRecordModeKey, ReturnType<typeof createEmptyModeStats>>): Date | undefined => {
  let latest: Date | undefined;
  WORD_RECORD_MODES.forEach(mode => {
    [state[mode].lastMasteredAt, state[mode].lastTestedAt].forEach(value => {
      if (!value) return;
      if (!latest || value > latest) latest = value;
    });
  });
  return latest;
};

const rebuildVocabularyWordRecordsForUser = async (
  userId: string,
  wordIds: string[]
) => {
  const uniqueWordIds = Array.from(new Set(wordIds.filter(id => mongoose.isValidObjectId(id))));
  if (uniqueWordIds.length === 0) return { affectedWords: 0, rebuiltWords: 0 };

  const userObjectId = new mongoose.Types.ObjectId(userId);
  const wordObjectIds = uniqueWordIds.map(id => new mongoose.Types.ObjectId(id));
  const wordIdSet = new Set(uniqueWordIds);
  const states = new Map<string, Record<WordRecordModeKey, ReturnType<typeof createEmptyModeStats>>>();

  const records = await VocabularyTestRecord.find({
    user: userObjectId,
    invalidated: { $ne: true },
    'results.word': { $in: wordObjectIds }
  })
    .select('testType stats.endTime createdAt results attempt')
    .sort({ 'stats.endTime': 1, createdAt: 1 })
    .lean();

  const attemptIds = records
    .map((record: any) => record.attempt?.toString?.() || '')
    .filter(id => mongoose.isValidObjectId(id));
  const attempts = attemptIds.length > 0
    ? await VocabularyTestAttempt.find({ _id: { $in: attemptIds } }).select('riskFlags').lean()
    : [];
  const invalidatedAttemptIds = new Set(
    attempts
      .filter((attempt: any) => (attempt.riskFlags || []).some((flag: string) => INVALIDATING_VOCABULARY_RISK_FLAGS.includes(flag)))
      .map((attempt: any) => attempt._id.toString())
  );

  records.forEach((record: any) => {
    const attemptId = record.attempt?.toString?.() || '';
    if (attemptId && invalidatedAttemptIds.has(attemptId)) return;

    const modeKey = TEST_TYPE_TO_MODE[record.testType as VocabularyTestType];
    if (!modeKey) return;

    const testedAt = new Date(record.stats?.endTime || record.createdAt || Date.now());
    (record.results || []).forEach((result: any) => {
      const wordId = result.word?.toString?.() || String(result.word || '');
      if (!wordIdSet.has(wordId)) return;

      if (!states.has(wordId)) {
        states.set(wordId, {
          chineseToEnglish: createEmptyModeStats(),
          audioToEnglish: createEmptyModeStats(),
          multipleChoice: createEmptyModeStats()
        });
      }

      const state = states.get(wordId)!;
      applyVocabularyAnswer(state[modeKey], Boolean(result.isCorrect), testedAt);
    });
  });

  await WordRecord.deleteMany({ user: userObjectId, word: { $in: wordObjectIds } });

  const rebuiltDocs = Array.from(states.entries()).map(([wordId, state]) => {
    const isFullyMastered = WORD_RECORD_MODES.every(mode => state[mode].mastered);
    return {
      user: userObjectId,
      word: new mongoose.Types.ObjectId(wordId),
      chineseToEnglish: state.chineseToEnglish,
      audioToEnglish: state.audioToEnglish,
      multipleChoice: state.multipleChoice,
      isFullyMastered,
      lastFullyMasteredAt: isFullyMastered ? getLatestMasteredAt(state) : undefined,
      createdAt: new Date()
    };
  });

  if (rebuiltDocs.length > 0) {
    await WordRecord.insertMany(rebuiltDocs);
  }

  return {
    affectedWords: uniqueWordIds.length,
    rebuiltWords: rebuiltDocs.length
  };
};

router.get('/users', adminAuth, async (req, res) => {
  try {
    const users = await User.find()
      .select('-password')
      .sort({ createdAt: -1 });
    res.json(users);
  } catch (error) {
    res.status(500).json({ message: '获取用户列表失败' });
  }
});
// 添加 PUT 路由用于更新用户
router.put('/users/:id', adminAuth, async (req, res) => {
  try {
    // 检查用户名是否已存在（排除当前用户）
    const existingUser = await User.findOne({
      username: req.body.username,
      _id: { $ne: req.params.id }
    });
    
    if (existingUser) {
      return res.status(400).json({ message: '用户名已被使用' });
    }

    // 检查邮箱是否已存在（排除当前用户）
    if (req.body.email) {
      const existingEmail = await User.findOne({
        email: req.body.email,
        _id: { $ne: req.params.id }
      });
      
      if (existingEmail) {
        return res.status(400).json({ message: '邮箱已被使用' });
      }
    }

    const user = await User.findByIdAndUpdate(
      req.params.id,
      req.body,
      { new: true, select: '-password' }
    );

    if (!user) {
      return res.status(404).json({ message: '用户不存在' });
    }

    res.json(user);
  } catch (error) {
    console.error('Error updating user:', error);
    res.status(500).json({ message: '更新用户失败' });
  }
});
router.post('/users', adminAuth, async (req, res) => {
  try {
    const { username, email, password, fullname, isAdmin } = req.body;
    // 验证必填字段
    if (!username || !email || !password || !fullname) {
      return res.status(400).json({ message: '请填写所有必填字段' });
    }

    // 检查用户名是否已存在
    const existingUser = await User.findOne({ username });
    if (existingUser) {
      return res.status(400).json({ message: '用户名已被使用' });
    }

    // 检查邮箱是否已存在
    const existingEmail = await User.findOne({ email });
    if (existingEmail) {
      return res.status(400).json({ message: '邮箱已被使用' });
    }

    // 创建新用户

    const newUser = new User({
      username,
      email,
      password: password,
      fullname,
      isAdmin: isAdmin || false
    });

    await newUser.save();

    // 返回用户信息（不包含密码）
    const userResponse = await User.findById(newUser._id).select('-password');
    res.status(201).json(userResponse);
  } catch (error) {
    console.error('Error creating user:', error);
    res.status(500).json({ message: '创建用户失败' });
  }
});
// 添加删除用户路由
router.delete('/users/:id', adminAuth, async (req, res) => {
  try {
    const user = await User.findById(req.params.id);
    
    if (!user) {
      return res.status(404).json({ message: '用户不存在' });
    }

    // 防止删除最后一个管理员
    if (user.isAdmin) {
      const adminCount = await User.countDocuments({ isAdmin: true });
      if (adminCount <= 1) {
        return res.status(400).json({ message: '不能删除最后一个管理员' });
      }
    }

    await User.findByIdAndDelete(req.params.id);
    res.json({ message: '用户已删除' });
  } catch (error) {
    console.error('Error deleting user:', error);
    res.status(500).json({ message: '删除用户失败' });
  }
});

// OAuth2 客户端管理路由
router.get('/oauth2/clients', adminAuth, (req, res) => adminController.listOAuth2Clients(req, res));

router.post('/oauth2/clients', adminAuth, (req, res) => adminController.createOAuth2Client(req, res));

router.put('/oauth2/clients/:id', adminAuth, (req, res) => adminController.updateOAuth2Client(req, res));

router.delete('/oauth2/clients/:id', adminAuth, (req, res) => adminController.deleteOAuth2Client(req, res));

// ===== 单词库管理路由 =====

// 获取所有单词集
router.get('/vocabulary/word-sets', adminAuth, async (req, res) => {
  try {
    const wordSets = await WordSet.find()
      .select('name description totalWords createdAt owner')
      .populate('owner', 'username fullname')
      .sort({ createdAt: -1 });
    
    res.json(wordSets);
  } catch (error) {
    console.error('获取单词集失败:', error);
    res.status(500).json({ message: '获取单词集失败' });
  }
});

// 上传单词文件并创建单词集（管理员版本）
router.post('/vocabulary/upload', adminAuth, upload.single('file'), async (req, res) => {
  if (!req.file) {
    return res.status(400).json({ message: '请上传文件' });
  }
  
  try {
    const { name, description, ownerId } = req.body;
    const fileName = req.file.filename;
    const filePath = req.file.path;
    
    // 如果没有指定所有者，默认为当前管理员
    const owner = ownerId || req.user._id;
    
    // 检查是否已存在同名单词集
    const existingSet = await WordSet.findOne({ 
      name: name || path.basename(fileName, '.csv'),
      owner: owner
    });
    
    if (existingSet) {
      // 删除上传的文件
      fs.unlinkSync(filePath);
      return res.status(400).json({ message: '已存在同名单词集' });
    }
    
    // 创建单词集
    const wordSet = await WordSet.create({
      name: name || path.basename(fileName, '.csv'),
      description: description || '',
      owner: owner,
      totalWords: 0
    });
    
    const results: any[] = [];
    let wordCount = 0;
    
    // 处理CSV文件
    fs.createReadStream(filePath)
      .pipe(csv())
      .on('data', (data) => {
        // 检查必要的字段是否存在
        if (data.word && data.translation) {
          results.push({
            word: data.word.trim(),
            translation: data.translation.trim(),
            pronunciation: data.pronunciation?.trim(),
            example: data.example?.trim(),
            wordSet: wordSet._id
          });
          wordCount++;
        }
      })
      .on('end', async () => {
        try {
          // 批量插入单词
          if (results.length > 0) {
            await Word.insertMany(results);
            
            // 更新单词集的单词数量
            await WordSet.findByIdAndUpdate(wordSet._id, { totalWords: wordCount });
          }
          
          // 删除上传的文件
          fs.unlinkSync(filePath);
          
          res.status(201).json({ 
            message: `成功创建单词集并导入${wordCount}个单词`,
            wordSet
          });
        } catch (error) {
          // 如果插入单词失败，删除创建的单词集
          await WordSet.findByIdAndDelete(wordSet._id);
          
          console.error('导入单词失败:', error);
          res.status(500).json({ message: '导入单词失败' });
        }
      })
      .on('error', (error) => {
        console.error('处理CSV文件失败:', error);
        res.status(500).json({ message: '处理CSV文件失败' });
      });
  } catch (error) {
    console.error('上传文件失败:', error);
    res.status(500).json({ message: '上传文件失败' });
  }
});

// 删除单词集
router.delete('/vocabulary/word-sets/:id', adminAuth, async (req, res) => {
  try {
    const { id } = req.params;
    
    // 检查单词集是否存在
    const wordSet = await WordSet.findById(id);
    if (!wordSet) {
      return res.status(404).json({ message: '未找到单词集' });
    }
    
    // 删除单词集及其关联的所有单词
    await Word.deleteMany({ wordSet: id });
    await WordSet.findByIdAndDelete(id);
    
    res.json({ message: '单词集已删除' });
  } catch (error) {
    console.error('删除单词集失败:', error);
    res.status(500).json({ message: '删除单词集失败' });
  }
});

// 单词集详情（包括所有单词）
router.get('/vocabulary/word-sets/:id/words', adminAuth, async (req, res) => {
  try {
    const { id } = req.params;
    
    // 检查单词集是否存在
    const wordSet = await WordSet.findById(id);
    if (!wordSet) {
      return res.status(404).json({ message: '未找到单词集' });
    }
    
    // 获取单词集中的所有单词
    const words = await Word.find({ wordSet: id });
    
    res.json({
      wordSet,
      words
    });
  } catch (error) {
    console.error('获取单词集详情失败:', error);
    res.status(500).json({ message: '获取单词集详情失败' });
  }
});

// 按时间段汇总学生词汇测试通过情况
router.get('/vocabulary/test-pass-summary', adminAuth, async (req, res) => {
  try {
    const range = parseAdminDateRange(req.query as Record<string, any>);
    if (range.error) {
      return res.status(400).json({ message: range.error });
    }

    const { start, end } = range as { start: Date; end: Date };
    const items = await VocabularyTestRecord.aggregate([
      {
        $match: {
          invalidated: { $ne: true },
          'stats.endTime': { $gte: start, $lte: end },
          'stats.correctWords': { $gt: 0 }
        }
      },
      { $unwind: '$results' },
      { $match: { 'results.isCorrect': true } },
      {
        $group: {
          _id: '$user',
          passedWords: { $sum: 1 },
          uniqueWordIds: { $addToSet: '$results.word' },
          testRecordIds: { $addToSet: '$_id' },
          wordSetIds: { $addToSet: '$wordSet' },
          testTypes: { $addToSet: '$testType' },
          firstPassedAt: { $min: '$stats.endTime' },
          lastPassedAt: { $max: '$stats.endTime' }
        }
      },
      {
        $lookup: {
          from: 'users',
          localField: '_id',
          foreignField: '_id',
          as: 'user'
        }
      },
      { $unwind: { path: '$user', preserveNullAndEmptyArrays: true } },
      {
        $project: {
          _id: 0,
          userId: { $toString: '$_id' },
          username: '$user.username',
          fullname: '$user.fullname',
          email: '$user.email',
          passedWords: 1,
          uniqueWords: { $size: '$uniqueWordIds' },
          testRecords: { $size: '$testRecordIds' },
          wordSets: { $size: '$wordSetIds' },
          testTypes: 1,
          firstPassedAt: 1,
          lastPassedAt: 1
        }
      },
      { $sort: { passedWords: -1, lastPassedAt: -1 } }
    ]);

    res.json({
      start,
      end,
      totalStudents: items.length,
      totalPassedWords: items.reduce((sum: number, item: any) => sum + (item.passedWords || 0), 0),
      items
    });
  } catch (error) {
    console.error('获取词汇测试通过统计失败:', error);
    res.status(500).json({ message: '获取词汇测试通过统计失败' });
  }
});

// 清除某个学生在指定时间段内的词汇测试成绩，并重算掌握状态
router.post('/vocabulary/test-pass-summary/clear', adminAuth, async (req, res) => {
  try {
    const range = parseAdminDateRange(req.body || {});
    if (range.error) {
      return res.status(400).json({ message: range.error });
    }

    const { start, end } = range as { start: Date; end: Date };
    const { userId } = req.body || {};
    if (!mongoose.isValidObjectId(userId)) {
      return res.status(400).json({ message: '学生ID无效' });
    }

    const user = await User.findById(userId).select('_id username fullname');
    if (!user) {
      return res.status(404).json({ message: '学生不存在' });
    }

    const records = await VocabularyTestRecord.find({
      user: user._id,
      invalidated: { $ne: true },
      'stats.endTime': { $gte: start, $lte: end },
      'stats.correctWords': { $gt: 0 }
    })
      .select('_id stats.correctWords results.word results.isCorrect')
      .lean();

    if (records.length === 0) {
      return res.json({
        message: '没有找到需要清除的词汇测试成绩',
        deletedRecords: 0,
        removedPassedWords: 0,
        affectedWords: 0,
        rebuiltWords: 0
      });
    }

    const recordIds = records.map(record => record._id);
    const affectedWordIds = new Set<string>();
    let removedPassedWords = 0;

    records.forEach((record: any) => {
      removedPassedWords += Number(record.stats?.correctWords || 0);
      (record.results || []).forEach((result: any) => {
        const wordId = result.word?.toString?.() || String(result.word || '');
        if (wordId) affectedWordIds.add(wordId);
      });
    });

    await VocabularyTestRecord.deleteMany({ _id: { $in: recordIds } });
    const rebuildResult = await rebuildVocabularyWordRecordsForUser(userId, Array.from(affectedWordIds));

    res.json({
      message: '词汇测试成绩已清除',
      userId,
      username: user.username,
      fullname: user.fullname,
      deletedRecords: records.length,
      removedPassedWords,
      affectedWords: rebuildResult.affectedWords,
      rebuiltWords: rebuildResult.rebuiltWords
    });
  } catch (error) {
    console.error('清除词汇测试成绩失败:', error);
    res.status(500).json({ message: '清除词汇测试成绩失败' });
  }
});

export default router;