const { query } = require('../config/database')
const crypto = require('crypto')
const { paginate } = require('../utils/pagination')
const { DEFAULT_PASSWORD } = require('../config/constants')

function md5(str) {
  return crypto.createHash('md5').update(str).digest('hex')
}

function generateToken() {
  return crypto.randomBytes(32).toString('hex')
}

// 用户登录（支持双重身份）
async function login(ctx) {
  const { phone, password, loginType } = ctx.request.body
  
  if (!phone || !password) {
    ctx.body = {
      code: 400,
      message: '请输入手机号和密码'
    }
    return
  }
  
  const users = await query('SELECT * FROM users WHERE phone = ?', [phone])
  
  if (users.length === 0) {
    ctx.body = {
      code: 401,
      message: '用户不存在'
    }
    return
  }
  
  const user = users[0]
  
  if (user.status === 0) {
    ctx.body = {
      code: 401,
      message: '账号已被禁用'
    }
    return
  }
  
  if (user.password !== md5(password)) {
    ctx.body = {
      code: 401,
      message: '密码错误'
    }
    return
  }
  
  // 店员登录需要验证角色
  if (loginType === 'staff' && user.role !== 1) {
    ctx.body = {
      code: 401,
      message: '该账号不是店员账号'
    }
    return
  }
  
  const token = generateToken()
  await query('UPDATE users SET token = ? WHERE id = ?', [token, user.id])
  
  const userInfo = {
    id: user.id,
    phone: user.phone,
    name: user.name,
    avatar: user.avatar,
    points: user.points,
    role: user.role,
    token
  }
  
  ctx.body = {
    code: 200,
    data: userInfo
  }
}

// 用户注册（普通用户）
async function register(ctx) {
  const { phone, password, name } = ctx.request.body
  if (!phone || !password || !name) {
    ctx.body = { code: 400, message: '请填写完整信息' }
    return
  }

  const existing = await query('SELECT * FROM users WHERE phone = ?', [phone])
  if (existing.length > 0) {
    ctx.body = { code: 400, message: '该手机号已注册' }
    return
  }

  const result = await query(
    'INSERT INTO users (phone, password, name, avatar, points, role) VALUES (?, ?, ?, ?, ?, ?)',
    [phone, md5(password), name, '', 0, 0]
  )

  ctx.body = {
    code: 200,
    message: '注册成功',
    data: { id: result.insertId, phone, name, avatar: '', points: 0, role: 0 }
  }
}


async function requireStaffAuth(ctx) {
  const authHeader = ctx.headers.authorization || ''
  const token = authHeader.replace('Bearer ', '')
  if (!token) {
    ctx.body = { code: 401, message: '未登录，请先登录店员账号' }
    return null
  }
  const operators = await query('SELECT * FROM users WHERE token = ? AND role = 1 AND status = 1', [token])
  if (operators.length === 0) {
    ctx.body = { code: 401, message: '权限不足，仅店员可操作' }
    return null
  }
  return operators[0]
}

async function createUser(phone, name, role) {
  const existing = await query('SELECT * FROM users WHERE phone = ?', [phone])
  if (existing.length > 0) return { conflict: true }

  const result = await query(
    'INSERT INTO users (phone, password, name, avatar, points, role) VALUES (?, ?, ?, ?, ?, ?)',
    [phone, md5(DEFAULT_PASSWORD), name, '', 0, role]
  )

  return {
    conflict: false,
    data: {
      id: result.insertId,
      phone,
      name,
      avatar: '',
      points: 0,
      role
    }
  }
}

// 店员注册（需要店员权限）
async function registerStaff(ctx) {
  const { phone, name } = ctx.request.body
  if (!phone || !name) {
    ctx.body = { code: 400, message: '请填写手机号和姓名' }
    return
  }

  const operator = await requireStaffAuth(ctx)
  if (!operator) return

  const result = await createUser(phone, name, 1)
  if (result.conflict) {
    ctx.body = { code: 400, message: '该手机号已注册' }
    return
  }

  ctx.body = {
    code: 200,
    message: `店员注册成功，默认密码为${DEFAULT_PASSWORD}`,
    data: result.data
  }
}

// 店员帮助用户注册（需要店员权限）
async function registerByStaff(ctx) {
  const { phone, name } = ctx.request.body
  if (!phone || !name) {
    ctx.body = { code: 400, message: '请填写手机号和姓名' }
    return
  }

  const operator = await requireStaffAuth(ctx)
  if (!operator) return

  const result = await createUser(phone, name, 0)
  if (result.conflict) {
    ctx.body = { code: 400, message: '该手机号已注册' }
    return
  }

  ctx.body = {
    code: 200,
    message: `用户注册成功，默认密码为${DEFAULT_PASSWORD}`,
    data: result.data
  }
}

// 获取用户信息
async function getUserInfo(ctx) {
  const userId = parseInt(ctx.query.id)
  
  if (!userId) {
    ctx.body = { code: 400, message: '缺少用户ID' }
    return
  }
  
  const users = await query('SELECT * FROM users WHERE id = ? AND status = 1', [userId])
  
  if (users.length > 0) {
    const user = users[0]
    ctx.body = {
      code: 200,
      data: {
        id: user.id,
        phone: user.phone,
        name: user.name,
        avatar: user.avatar,
        points: user.points,
        role: user.role
      }
    }
  } else {
    ctx.body = {
      code: 404,
      message: '用户不存在'
    }
  }
}

// 获取用户列表
async function getUsers(ctx) {
  let sql = 'SELECT id, phone, name, points, role, status, created_at FROM users WHERE status = 1'
  const params = []
  
  if (ctx.query.role !== undefined) {
    sql += ' AND role = ?'
    params.push(parseInt(ctx.query.role))
  }
  
  if (ctx.query.keyword) {
    sql += ' AND (phone LIKE ? OR name LIKE ?)'
    params.push(`%${ctx.query.keyword}%`, `%${ctx.query.keyword}%`)
  }
  
  sql += ' ORDER BY created_at DESC'
  
  const result = await paginate(query, sql, params, ctx.query.page, ctx.query.pageSize)
  
  ctx.body = {
    code: 200,
    ...result
  }
}

// 更新用户信息
async function updateUser(ctx) {
  const userId = parseInt(ctx.params.id)
  const { name, avatar, points, status } = ctx.request.body
  
  const updateFields = []
  const updateParams = []
  
  if (name !== undefined) {
    updateFields.push('name = ?')
    updateParams.push(name)
  }
  if (avatar !== undefined) {
    updateFields.push('avatar = ?')
    updateParams.push(avatar)
  }
  if (points !== undefined) {
    updateFields.push('points = ?')
    updateParams.push(parseInt(points))
  }
  if (status !== undefined) {
    updateFields.push('status = ?')
    updateParams.push(parseInt(status))
  }
  
  if (updateFields.length === 0) {
    ctx.body = {
      code: 400,
      message: '没有需要更新的字段'
    }
    return
  }
  
  updateParams.push(userId)
  
  const result = await query(`UPDATE users SET ${updateFields.join(', ')} WHERE id = ?`, updateParams)
  
  if (result.affectedRows > 0) {
    ctx.body = {
      code: 200,
      message: '更新成功'
    }
  } else {
    ctx.body = {
      code: 404,
      message: '用户不存在'
    }
  }
}

// 删除用户
async function deleteUser(ctx) {
  const userId = parseInt(ctx.params.id)
  
  const result = await query('UPDATE users SET status = 0 WHERE id = ?', [userId])
  
  if (result.affectedRows > 0) {
    ctx.body = {
      code: 200,
      message: '禁用成功'
    }
  } else {
    ctx.body = {
      code: 404,
      message: '用户不存在'
    }
  }
}

// 修改密码
async function changePassword(ctx) {
  const { phone, oldPassword, newPassword } = ctx.request.body
  
  if (!phone || !oldPassword || !newPassword) {
    ctx.body = {
      code: 400,
      message: '请填写完整信息'
    }
    return
  }
  
  const users = await query('SELECT * FROM users WHERE phone = ? AND status = 1', [phone])
  
  if (users.length === 0) {
    ctx.body = {
      code: 404,
      message: '用户不存在'
    }
    return
  }
  
  const user = users[0]
  
  if (user.password !== md5(oldPassword)) {
    ctx.body = {
      code: 400,
      message: '原密码错误'
    }
    return
  }
  
  await query('UPDATE users SET password = ? WHERE id = ?', [md5(newPassword), user.id])
  
  ctx.body = {
    code: 200,
    message: '密码修改成功'
  }
}

// 重置密码（店员操作）
async function resetPassword(ctx) {
  const { userId } = ctx.request.body
  
  if (!userId) {
    ctx.body = {
      code: 400,
      message: '请指定用户ID'
    }
    return
  }
  
  const defaultPassword = DEFAULT_PASSWORD

  const result = await query('UPDATE users SET password = ? WHERE id = ?', [md5(defaultPassword), userId])

  if (result.affectedRows > 0) {
    ctx.body = {
      code: 200,
      message: `密码已重置为${DEFAULT_PASSWORD}`
    }
  } else {
    ctx.body = {
      code: 404,
      message: '用户不存在'
    }
  }
}

// 调整积分
async function addPoints(ctx) {
  const { userId, points, description } = ctx.request.body
  
  if (!userId || points === undefined) {
    ctx.body = {
      code: 400,
      message: '请指定用户ID和积分变动值'
    }
    return
  }
  
  const pointsInt = parseInt(points)
  if (isNaN(pointsInt)) {
    ctx.body = {
      code: 400,
      message: '积分值无效'
    }
    return
  }
  
  // 检查用户是否存在
  const users = await query('SELECT * FROM users WHERE id = ? AND status = 1', [userId])
  if (users.length === 0) {
    ctx.body = {
      code: 404,
      message: '用户不存在'
    }
    return
  }
  
  const user = users[0]
  const newPoints = Math.max(0, user.points + pointsInt)
  
  // 更新用户积分
  await query('UPDATE users SET points = ? WHERE id = ?', [newPoints, userId])
  
  // 记录积分变动日志
  await query(
    'INSERT INTO points_logs (user_id, type, amount, description) VALUES (?, ?, ?, ?)',
    [userId, pointsInt >= 0 ? 'earn' : 'spend', Math.abs(pointsInt), description || '管理员调整积分']
  )
  
  ctx.body = {
    code: 200,
    message: '积分调整成功',
    data: {
      userId,
      oldPoints: user.points,
      newPoints,
      change: pointsInt
    }
  }
}

// 获取积分记录
async function getPointsLogs(ctx) {
  const userId = parseInt(ctx.query.userId)
  
  if (!userId) {
    ctx.body = {
      code: 400,
      message: '请指定用户ID'
    }
    return
  }
  
  const logs = await query(
    'SELECT * FROM points_logs WHERE user_id = ? ORDER BY created_at DESC',
    [userId]
  )
  
  ctx.body = {
    code: 200,
    data: logs
  }
}

module.exports = {
  login,
  register,
  registerStaff,
  registerByStaff,
  getUserInfo,
  getUsers,
  updateUser,
  deleteUser,
  changePassword,
  resetPassword,
  addPoints,
  getPointsLogs
}