const express = require('express');
const http = require('http');
const { WebSocketServer } = require('ws');
const jwt = require('jsonwebtoken');
const multer = require('multer');
const path = require('path');
const fs = require('fs');
const { v4: uuidv4 } = require('uuid');
const db = require('./db');

const app = express();
const server = http.createServer(app);
const wss = new WebSocketServer({ server });

// 环境变量
const USERS = {};
(process.env.USERS || '').split(',').forEach(u => {
  const [name, pass] = u.split(':');
  if (name) USERS[name] = pass;
});
const ADMINS = (process.env.ADMINS || '').split(',');
const DEEPSEEK_API_KEY = process.env.DEEPSEEK_API_KEY;
const JWT_SECRET = process.env.JWT_SECRET || 'xiaocai-secret-' + Date.now();

// 时区
const TIMEZONE = 'Asia/Shanghai';
function timestamp() {
  return new Date().toLocaleString('zh-CN', { timeZone: TIMEZONE, hour12: false });
}
function currentTimeStr() {
  return timestamp();
}

// 初始化用户
const insertUser = db.prepare('INSERT OR IGNORE INTO users (username, password, is_admin) VALUES (?, ?, ?)');
for (const [username, password] of Object.entries(USERS)) {
  const isAdmin = ADMINS.includes(username) ? 1 : 0;
  insertUser.run(username, password, isAdmin);
}

// 上传配置
const uploadsDir = '/app/data/uploads';
if (!fs.existsSync(uploadsDir)) fs.mkdirSync(uploadsDir, { recursive: true });
const storage = multer.diskStorage({
  destination: uploadsDir,
  filename: (req, file, cb) => {
    const ext = path.extname(file.originalname) || '.jpg';
    const safeName = Date.now() + '-' + Math.random().toString(36).substring(2, 8) + ext;
    cb(null, safeName);
  }
});
const upload = multer({
  storage,
  limits: { fileSize: 5 * 1024 * 1024 },
  fileFilter: (req, file, cb) => {
    const allowed = ['image/jpeg','image/png','image/gif'];
    cb(null, allowed.includes(file.mimetype));
  }
});

app.use(express.json());
app.use(express.static(path.join(__dirname, 'public')));
app.use('/uploads', express.static(uploadsDir));

// 登录
app.post('/api/login', (req, res) => {
  const { username, password } = req.body;
  if (USERS[username] && USERS[username] === password) {
    const token = jwt.sign({ username, isAdmin: ADMINS.includes(username) }, JWT_SECRET, { expiresIn: '7d' });
    return res.json({ token, username, isAdmin: ADMINS.includes(username) });
  }
  res.status(401).json({ error: '用户名或密码错误' });
});

const auth = (req, res, next) => {
  const authHeader = req.headers.authorization;
  if (!authHeader) return res.status(401).json({ error: '未登录' });
  const token = authHeader.split(' ')[1];
  try {
    const decoded = jwt.verify(token, JWT_SECRET);
    req.user = decoded;
    next();
  } catch (e) {
    res.status(401).json({ error: '登录已过期' });
  }
};

const adminOnly = (req, res, next) => {
  if (!req.user.isAdmin) return res.status(403).json({ error: '仅管理员可执行此操作' });
  next();
};

app.get('/api/user', auth, (req, res) => {
  res.json({ username: req.user.username, isAdmin: req.user.isAdmin });
});

app.get('/api/rooms', auth, (req, res) => {
  const rooms = db.prepare('SELECT * FROM rooms').all();
  const result = rooms.map(room => {
    const lastMsg = db.prepare('SELECT text, timestamp FROM messages WHERE room_id = ? ORDER BY timestamp DESC LIMIT 1').get(room.id);
    return {
      ...room,
      last_message: lastMsg ? lastMsg.text : '',
      last_time: lastMsg ? lastMsg.timestamp : ''
    };
  });
  res.json(result);
});

app.post('/api/rooms', auth, adminOnly, (req, res) => {
  const { name, whiteList } = req.body;
  const id = uuidv4();
  const now = timestamp();
  db.prepare('INSERT INTO rooms (id, name, created_by, white_list, created_at) VALUES (?,?,?,?,?)').run(id, name, req.user.username, whiteList || '', now);
  broadcast({ type: 'room_created', room: { id, name, white_list: whiteList || '' } });
  res.json({ id, name });
});

app.put('/api/rooms/:roomId', auth, adminOnly, (req, res) => {
  const { name, whiteList } = req.body;
  const roomId = req.params.roomId;
  const room = db.prepare('SELECT * FROM rooms WHERE id = ?').get(roomId);
  if (!room) return res.status(404).json({ error: '群聊不存在' });
  db.prepare('UPDATE rooms SET name = ?, white_list = ? WHERE id = ?').run(name, whiteList || '', roomId);
  broadcast({ type: 'room_updated', room: { id: roomId, name, white_list: whiteList || '' } });
  res.json({ success: true });
});

app.delete('/api/rooms/:roomId', auth, adminOnly, (req, res) => {
  const roomId = req.params.roomId;
  db.prepare('DELETE FROM messages WHERE room_id = ?').run(roomId);
  db.prepare('DELETE FROM purchase_attachments WHERE purchase_id IN (SELECT id FROM purchases WHERE room_id = ?)').run(roomId);
  db.prepare('DELETE FROM purchase_history WHERE purchase_id IN (SELECT id FROM purchases WHERE room_id = ?)').run(roomId);
  db.prepare('DELETE FROM purchases WHERE room_id = ?').run(roomId);
  db.prepare('DELETE FROM rooms WHERE id = ?').run(roomId);
  broadcast({ type: 'room_deleted', roomId });
  res.json({ success: true });
});

app.get('/api/rooms/:roomId/messages', auth, (req, res) => {
  const msgs = db.prepare('SELECT * FROM messages WHERE room_id = ? ORDER BY timestamp ASC').all(req.params.roomId);
  res.json(msgs);
});

app.post('/api/rooms/:roomId/messages', auth, async (req, res) => {
  const { text, attachments } = req.body;
  const roomId = req.params.roomId;
  const username = req.user.username;
  const now = timestamp();

  const result = db.prepare('INSERT INTO messages (room_id, user, text, attachments, timestamp) VALUES (?,?,?,?,?)').run(
    roomId, username, text || '', attachments ? JSON.stringify(attachments) : null, now
  );
  const msg = {
    id: result.lastInsertRowid,
    room_id: roomId,
    user: username,
    text: text || '',
    attachments: attachments || [],
    timestamp: now
  };

  const lastMsg = db.prepare('SELECT text, timestamp FROM messages WHERE room_id = ? ORDER BY timestamp DESC LIMIT 1').get(roomId);
  broadcastToRoomExcludeSelf(roomId, username, {
    type: 'new_message',
    message: msg,
    room_preview: { room_id: roomId, last_message: lastMsg ? lastMsg.text : '', last_time: lastMsg ? lastMsg.timestamp : '' }
  });

  addToHistory(roomId, 'user', `${username}: ${text || '图片'}`);
  res.json(msg);

  if (text && text.trim() === '确认' && hasPendingAction(roomId, username)) {
    executePendingAction(roomId, username);
    return;
  }

  try {
    const history = getHistory(roomId);
    const historyMessages = history.map(e => ({ role: e.role, content: e.content }));
    const aiResponse = await analyzeWithDeepSeek(text || '', historyMessages, username, req.user.isAdmin);
    if (aiResponse && aiResponse.action !== 'ignore') {
      handleAIResult(aiResponse, roomId, username, text || '', attachments || []);
    }
  } catch (e) {
    console.error('AI 分析失败:', e);
  }
});

app.post('/api/upload', auth, upload.single('file'), (req, res) => {
  if (!req.file) return res.status(400).json({ error: '请上传图片' });
  res.json({ path: '/uploads/' + req.file.filename });
});

app.get('/api/rooms/:roomId/purchases', auth, (req, res) => {
  const purchases = db.prepare('SELECT * FROM purchases WHERE room_id = ? ORDER BY created_at DESC').all(req.params.roomId);
  res.json(purchases);
});

app.get('/api/purchases/:id', auth, (req, res) => {
  const pur = db.prepare('SELECT * FROM purchases WHERE id = ?').get(req.params.id);
  if (!pur) return res.status(404).json({ error: '未找到' });
  const history = db.prepare('SELECT * FROM purchase_history WHERE purchase_id = ? ORDER BY timestamp ASC').all(req.params.id);
  const attachments = db.prepare('SELECT * FROM purchase_attachments WHERE purchase_id = ?').all(req.params.id);
  res.json({ ...pur, history, attachments });
});

app.get('/api/summary', auth, (req, res) => {
  const rooms = db.prepare('SELECT id, name FROM rooms').all();
  const summary = rooms.map(room => {
    const stats = db.prepare(`SELECT COUNT(*) as count, SUM(amount) as total FROM purchases WHERE room_id = ?`).get(room.id);
    return {
      room_id: room.id,
      room_name: room.name,
      purchase_count: stats.count || 0,
      total_amount: stats.total || 0
    };
  });
  res.json(summary);
});

app.get('/api/rooms/:roomId/purchases/export', auth, (req, res) => {
  const purchases = db.prepare('SELECT * FROM purchases WHERE room_id = ?').all(req.params.roomId);
  let csv = '时间,事项,数量,单价,金额,邮费,付款方式,发票类型,状态,申请人,备注\n';
  purchases.forEach(p => {
    csv += `${p.created_at},"${p.item||''}",${p.quantity},${p.unit_price},${p.amount},${p.freight},"${p.payment_method||''}","${p.invoice_type||''}","${p.status}","${p.applicant}","${p.remarks||''}"\n`;
  });
  res.setHeader('Content-Type', 'text/csv; charset=utf-8');
  res.setHeader('Content-Disposition', `attachment; filename="purchases-${req.params.roomId}.csv"`);
  res.send('\uFEFF' + csv);
});

// WebSocket 管理
const clients = new Map();
wss.on('connection', (ws, req) => {
  console.log('✅ WebSocket 客户端已连接');
  const url = new URL(req.url, 'http://localhost');
  const token = url.searchParams.get('token');
  if (!token) return ws.close();

  let username;
  try {
    const decoded = jwt.verify(token, JWT_SECRET);
    username = decoded.username;
  } catch (e) {
    return ws.close();
  }

  ws.username = username;
  ws.isAdmin = ADMINS.includes(username);
  clients.set(ws, { username, roomId: null, isAdmin: ws.isAdmin });

  ws.on('message', (data) => {
    try {
      const msg = JSON.parse(data);
      if (msg.type === 'join') {
        ws.roomId = msg.roomId;
        clients.set(ws, { username, roomId: msg.roomId, isAdmin: ws.isAdmin });
      }
    } catch (e) {}
  });

  ws.on('close', () => {
    clients.delete(ws);
  });
});

function broadcastToRoomExcludeSelf(roomId, excludeUsername, data) {
  const message = JSON.stringify(data);
  clients.forEach((info, ws) => {
    if (info.roomId === roomId && info.username !== excludeUsername && ws.readyState === 1) {
      ws.send(message);
    }
  });
}

function broadcastToRoom(roomId, data) {
  const message = JSON.stringify(data);
  clients.forEach((info, ws) => {
    if (info.roomId === roomId && ws.readyState === 1) {
      ws.send(message);
    }
  });
}

function broadcast(data) {
  const message = JSON.stringify(data);
  clients.forEach((ws) => {
    if (ws.readyState === 1) ws.send(message);
  });
}

function storeAndBroadcastText(roomId, user, text) {
  const now = timestamp();
  const result = db.prepare('INSERT INTO messages (room_id, user, text, timestamp) VALUES (?,?,?,?)').run(roomId, user, text, now);
  const msg = { id: result.lastInsertRowid, room_id: roomId, user, text, attachments: [], timestamp: now };
  const lastMsg = db.prepare('SELECT text, timestamp FROM messages WHERE room_id = ? ORDER BY timestamp DESC LIMIT 1').get(roomId);
  broadcastToRoom(roomId, {
    type: 'new_message',
    message: msg,
    room_preview: { room_id: roomId, last_message: lastMsg ? lastMsg.text : '', last_time: lastMsg ? lastMsg.timestamp : '' }
  });
  return msg;
}

// 待处理操作
const pendingActions = new Map();
function hasPendingAction(roomId, username) { return pendingActions.has(`${roomId}:${username}`); }
function setPendingAction(roomId, username, action) { pendingActions.set(`${roomId}:${username}`, action); }
function clearPendingAction(roomId, username) { pendingActions.delete(`${roomId}:${username}`); }
function executePendingAction(roomId, username) {
  const action = pendingActions.get(`${roomId}:${username}`);
  if (!action) return false;
  clearPendingAction(roomId, username);
  const now = timestamp();
  try {
    if (action.type === 'delete') {
      const { itemName, purchaseIds } = action.data;
      const deleteAttachments = db.prepare('DELETE FROM purchase_attachments WHERE purchase_id = ?');
      const deleteHistory = db.prepare('DELETE FROM purchase_history WHERE purchase_id = ?');
      const deletePurchase = db.prepare('DELETE FROM purchases WHERE id = ?');
      for (const id of purchaseIds) { deleteAttachments.run(id); deleteHistory.run(id); deletePurchase.run(id); }
      const reply = `✅ 已删除采购记录：${itemName}（共 ${purchaseIds.length} 条）`;
      storeAndBroadcastText(roomId, '小财', reply);
      addToHistory(roomId, 'assistant', reply);
    } else if (action.type === 'clear') {
      db.prepare('DELETE FROM purchase_attachments WHERE purchase_id IN (SELECT id FROM purchases WHERE room_id = ?)').run(roomId);
      db.prepare('DELETE FROM purchase_history WHERE purchase_id IN (SELECT id FROM purchases WHERE room_id = ?)').run(roomId);
      db.prepare('DELETE FROM purchases WHERE room_id = ?').run(roomId);
      const reply = '✅ 已清空当前房间的所有采购数据。';
      storeAndBroadcastText(roomId, '小财', reply);
      addToHistory(roomId, 'assistant', reply);
    }
    broadcastToRoom(roomId, { type: 'purchase_updated' });
    return true;
  } catch (e) { console.error('执行待处理操作失败:', e); storeAndBroadcastText(roomId, '小财', '❌ 操作执行失败，请重试。'); return false; }
}

// 对话历史
const conversationHistory = new Map();
function getHistory(roomId) { if (!conversationHistory.has(roomId)) conversationHistory.set(roomId, []); return conversationHistory.get(roomId); }
function addToHistory(roomId, role, content) { const history = getHistory(roomId); history.push({ role, content }); if (history.length > 60) conversationHistory.set(roomId, history.slice(-40)); }

// AI 分析
async function analyzeWithDeepSeek(text, historyMessages, username, isAdmin) {
  const systemPrompt = `你是智能财务助手“小财”。当前服务器时间：${currentTimeStr()}。结合对话历史理解用户意图，只返回JSON。

意图分类：
- 采购/付款/发票相关：action="purchase"，提取以下字段（所有字段可选，缺失则不返回）：
  purchase_item (物品名称), quantity (数量，默认1), unit_price (单价，默认0), amount (总金额，默认0),
  freight (邮费，默认0), payment_method (付款方式：支付宝/微信/对公转账/现金等，淘宝购买默认支付宝),
  invoice_type (发票类型：增票/普票/无票，默认无票), status (待采购/已采购/发票已收), applicant (申请人),
  remarks (备注，重要信息如“下次换商家”“缺少配件”等), created_time (如果用户提到具体时间则按yyyy/MM/dd HH:mm:ss格式输出)
- 查询汇总：action="query"
- 聊天：action="chat"，reply简短回复
- 删除指定物品：action="delete"，delete_item为物品名
- 清空所有采购数据：action="clear_all"
- 忽略：action="ignore"

权限规则：删除和清空仅限管理员。当前用户${username}，管理员状态：${isAdmin}。
采购规则：用户补充信息时更新已有记录。更新时请返回完整字段值，包括未变化的字段。
如果用户要求修改时间，请生成正确的created_time字段。`;

  const messages = [
    { role: 'system', content: systemPrompt },
    ...historyMessages.slice(-30),
    { role: 'user', content: `${username}: ${text}` }
  ];

  console.log('🤖 调用 DeepSeek...');
  const res = await fetch('https://api.deepseek.com/chat/completions', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json', 'Authorization': `Bearer ${DEEPSEEK_API_KEY}` },
    body: JSON.stringify({ model: 'deepseek-v4-flash', messages, temperature: 0.1, stream: false })
  });
  const data = await res.json();
  const content = data.choices[0].message.content;
  console.log('🤖 AI 返回:', content);
  return JSON.parse(content.replace(/```json|```/g, '').trim());
}

function handleAIResult(aiResult, roomId, username, originalText, attachments) {
  const now = timestamp();

  if (aiResult.action === 'ask') {
    storeAndBroadcastText(roomId, '小财', aiResult.question);
    addToHistory(roomId, 'assistant', aiResult.question);
    return;
  }

  if (aiResult.action === 'delete') {
    const itemName = aiResult.delete_item;
    const purchases = db.prepare('SELECT id, item, amount, payment_method, status, applicant, created_at FROM purchases WHERE room_id = ? AND item LIKE ?').all(roomId, `%${itemName}%`);
    if (purchases.length === 0) {
      storeAndBroadcastText(roomId, '小财', `没有找到与“${itemName}”相关的采购记录。`);
      addToHistory(roomId, 'assistant', `没有找到与“${itemName}”相关的采购记录。`);
      return;
    }
    let confirmText = `⚠️ 即将删除以下 ${purchases.length} 条采购记录，请回复“确认”继续：\n\n`;
    purchases.forEach(p => {
      confirmText += `• ${p.item} | ¥${p.amount} | ${p.status} | ${p.applicant} | ${p.created_at}\n`;
    });
    confirmText += `\n如果不删除，请忽略此消息。`;
    storeAndBroadcastText(roomId, '小财', confirmText);
    addToHistory(roomId, 'assistant', confirmText);
    setPendingAction(roomId, username, { type: 'delete', data: { itemName, purchaseIds: purchases.map(p => p.id) } });
    return;
  }

  if (aiResult.action === 'clear_all') {
    const count = db.prepare('SELECT COUNT(*) as count FROM purchases WHERE room_id = ?').get(roomId).count;
    if (count === 0) {
      storeAndBroadcastText(roomId, '小财', '当前房间没有采购记录，无需清空。');
      addToHistory(roomId, 'assistant', '当前房间没有采购记录，无需清空。');
      return;
    }
    const confirmText = `⚠️ 即将清空当前房间的 ${count} 条采购数据，请回复“确认”继续，否则忽略。`;
    storeAndBroadcastText(roomId, '小财', confirmText);
    addToHistory(roomId, 'assistant', confirmText);
    setPendingAction(roomId, username, { type: 'clear', data: {} });
    return;
  }

  if (aiResult.action === 'purchase') {
    const createdTime = aiResult.created_time || now;
    let purchase = db.prepare('SELECT * FROM purchases WHERE room_id = ? AND item LIKE ? AND status != ?').get(roomId, `%${aiResult.purchase_item}%`, '已完成');
    let replyText = '';

    // 计算总金额：优先使用 AI 提供的 amount，否则根据单价*数量+邮费计算
    const quantity = aiResult.quantity || 1;
    const unitPrice = aiResult.unit_price || 0;
    const freight = aiResult.freight || 0;
    let amount;
    if (aiResult.amount !== undefined && aiResult.amount !== null) {
      amount = aiResult.amount;
    } else {
      amount = unitPrice * quantity + freight;
    }

    if (!purchase) {
      const id = uuidv4();
      const item = aiResult.purchase_item;
      const paymentMethod = aiResult.payment_method || (aiResult.method === '淘宝' ? '支付宝' : (aiResult.method || '未指定'));
      const invoiceType = aiResult.invoice_type || '无票';
      const status = aiResult.status || '待处理';
      const applicant = aiResult.applicant || username;
      const remarks = aiResult.remarks || '';

      db.prepare(`INSERT INTO purchases (id, room_id, item, quantity, unit_price, amount, freight, payment_method, invoice_type, status, applicant, remarks, created_at)
        VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?)`).run(
        id, roomId, item, quantity, unitPrice, amount, freight, paymentMethod, invoiceType, status, applicant, remarks, createdTime
      );
      db.prepare('INSERT INTO purchase_history (purchase_id, action, user, timestamp) VALUES (?,?,?,?)').run(id, `创建采购：${item}，数量${quantity}，金额¥${amount}，状态${status}`, '小财', now);
      replyText = `✅ 已记录采购：${item}，数量 ${quantity}，金额 ¥${amount}，状态 ${status}`;
      purchase = { id };
    } else {
      const old = purchase;
      // 合并新值
      const newVals = {
        quantity: aiResult.quantity ?? old.quantity,
        unit_price: aiResult.unit_price ?? old.unit_price,
        freight: aiResult.freight ?? old.freight,
        payment_method: aiResult.payment_method || (aiResult.method === '淘宝' ? '支付宝' : (aiResult.method || old.payment_method)),
        invoice_type: aiResult.invoice_type || old.invoice_type,
        status: aiResult.status || old.status,
        applicant: aiResult.applicant || old.applicant,
        remarks: aiResult.remarks !== undefined ? aiResult.remarks : old.remarks,
        created_at: aiResult.created_time || old.created_at
      };
      // 重新计算金额，除非 AI 明确给了 amount
      if (aiResult.amount !== undefined && aiResult.amount !== null) {
        newVals.amount = aiResult.amount;
      } else {
        newVals.amount = newVals.unit_price * newVals.quantity + newVals.freight;
      }

      const historyChanges = [];
      let changed = false;
      for (const [field, newVal] of Object.entries(newVals)) {
        if (String(newVal) !== String(old[field])) {
          changed = true;
          historyChanges.push(`${field}: ${old[field]} → ${newVal}`);
          db.prepare(`UPDATE purchases SET ${field} = ? WHERE id = ?`).run(newVal, purchase.id);
        }
      }

      if (changed) {
        db.prepare('UPDATE purchases SET updated_at = ? WHERE id = ?').run(now, purchase.id);
        db.prepare('INSERT INTO purchase_history (purchase_id, action, user, timestamp) VALUES (?,?,?,?)').run(purchase.id, `更新：${historyChanges.join('；')}`, username, now);
        replyText = `🔄 已更新「${aiResult.purchase_item}」：${historyChanges.join('，')}`;
      } else {
        replyText = `ℹ️ 采购「${aiResult.purchase_item}」的信息没有发生变化。`;
      }
    }

    if (attachments?.length) {
      const insertAttach = db.prepare('INSERT INTO purchase_attachments (purchase_id, file_path, uploaded_by, timestamp) VALUES (?,?,?,?)');
      attachments.forEach(fp => insertAttach.run(purchase.id, fp, username, now));
    }

    storeAndBroadcastText(roomId, '小财', replyText);
    addToHistory(roomId, 'assistant', replyText);
    broadcastToRoom(roomId, { type: 'purchase_updated' });
    return;
  }

  if (aiResult.action === 'query') {
    const purchaseData = db.prepare('SELECT item, amount, payment_method, status FROM purchases WHERE room_id = ? ORDER BY created_at DESC').all(roomId)
      .map(p => `${p.item} ¥${p.amount} ${p.payment_method||''} ${p.status}`).join('\n');
    const summaryPrompt = `根据以下采购记录，用自然语言回答用户查询“${originalText}”。采购记录：\n${purchaseData || '暂无记录'}`;
    callDeepSeekForSummary(summaryPrompt).then(reply => {
      storeAndBroadcastText(roomId, '小财', reply);
      addToHistory(roomId, 'assistant', reply);
    });
    return;
  }

  if (aiResult.action === 'chat') {
    const reply = aiResult.reply || '好的，有什么需要帮助的吗？';
    storeAndBroadcastText(roomId, '小财', reply);
    addToHistory(roomId, 'assistant', reply);
    return;
  }
}

async function callDeepSeekForSummary(prompt) {
  const res = await fetch('https://api.deepseek.com/chat/completions', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json', 'Authorization': `Bearer ${DEEPSEEK_API_KEY}` },
    body: JSON.stringify({
      model: 'deepseek-v4-flash',
      messages: [
        { role: 'system', content: '你是一个财务助手，请根据采购记录生成简洁回复。' },
        { role: 'user', content: prompt }
      ],
      temperature: 0.3, stream: false
    })
  });
  const data = await res.json();
  return data.choices[0].message.content;
}

server.listen(process.env.PORT || 3000, () => {
  console.log(`Server running on port ${process.env.PORT || 3000}`);
});