/**
 * 预订控制器
 *
 * 功能：处理预订管理的业务逻辑
 */

const Reservation = require('../models/Reservation');
const { validateRequired, validatePhone, validateBatch } = require('../utils/validator');
const { success } = require('../utils/response');
const { BusinessError, ValidationError, AuthorizationError } = require('../middleware/errorHandler');

/**
 * 获取预订列表（分页、筛选）
 * GET /api/reservations
 */
const getReservations = async (req, res, next) => {
  try {
    const {
      page = 1,
      pageSize = 10,
      type,
      status,
      date,
      table_number
    } = req.query;

    // 权限控制：顾客只能查看自己的预订
    const customer_id = req.user.role === 'customer' ? req.user.id : undefined;

    const result = await Reservation.findAll({
      page: parseInt(page),
      pageSize: parseInt(pageSize),
      customer_id,
      type,
      status,
      date,
      table_number
    });

    res.json(success({
      list: result.list,
      pagination: {
        total: result.total,
        page: result.page,
        pageSize: result.pageSize,
        totalPages: Math.ceil(result.total / result.pageSize)
      }
    }, '获取预订列表成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 获取单个预订详情
 * GET /api/reservations/:id
 */
const getReservationById = async (req, res, next) => {
  try {
    const { id } = req.params;

    const reservation = await Reservation.findById(id);
    if (!reservation) {
      throw new BusinessError('预订不存在', 404);
    }

    // 权限控制：顾客只能查看自己的预订
    if (req.user.role === 'customer' && reservation.customer_id !== req.user.id) {
      throw new AuthorizationError('您没有权限查看此预订');
    }

    res.json(success(reservation, '获取预订详情成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 创建预订
 * POST /api/reservations
 */
const createReservation = async (req, res, next) => {
  try {
    const {
      type,
      reservation_time,
      guest_count,
      table_number,
      contact_name,
      contact_phone,
      special_request
    } = req.body;

    // 数据验证
    const validation = validateBatch([
      validateRequired(type, '预订类型'),
      validateRequired(reservation_time, '预订时间'),
      validateRequired(guest_count, '客人数量'),
      validateRequired(contact_name, '联系人姓名'),
      validateRequired(contact_phone, '联系电话'),
      validatePhone(contact_phone, '联系电话')
    ]);

    if (!validation.valid) {
      throw new ValidationError('数据验证失败', validation.errors);
    }

    // 验证预订类型
    const validTypes = ['dine_in', 'takeaway'];
    if (!validTypes.includes(type)) {
      throw new ValidationError('预订类型必须是 dine_in 或 takeaway');
    }

    // 验证客人数量
    if (parseInt(guest_count) <= 0) {
      throw new ValidationError('客人数量必须大于0');
    }

    // 验证预订时间不能是过去时间
    const reservationDate = new Date(reservation_time);
    if (reservationDate < new Date()) {
      throw new ValidationError('预订时间不能早于当前时间');
    }

    // 堂食预订必须有桌号
    if (type === 'dine_in') {
      if (!table_number) {
        throw new ValidationError('堂食预订必须指定桌号');
      }

      // 检查桌位是否可用
      const isAvailable = await Reservation.isTableAvailable(table_number, reservation_time);
      if (!isAvailable) {
        throw new BusinessError('该桌位在所选时间段内已被预订，请选择其他桌位或时间');
      }
    }

    const reservation = await Reservation.create({
      customer_id: req.user.id,
      type,
      reservation_time,
      guest_count: parseInt(guest_count),
      table_number: type === 'dine_in' ? parseInt(table_number) : null,
      contact_name,
      contact_phone,
      special_request: special_request || null
    });

    res.status(201).json(success(reservation, '创建预订成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 更新预订
 * PUT /api/reservations/:id
 */
const updateReservation = async (req, res, next) => {
  try {
    const { id } = req.params;
    const {
      reservation_time,
      guest_count,
      table_number,
      contact_name,
      contact_phone,
      special_request
    } = req.body;

    // 检查预订是否存在
    const reservation = await Reservation.findById(id);
    if (!reservation) {
      throw new BusinessError('预订不存在', 404);
    }

    // 权限控制：顾客只能修改自己的预订
    if (req.user.role === 'customer' && reservation.customer_id !== req.user.id) {
      throw new AuthorizationError('您没有权限修改此预订');
    }

    // 已完成或已取消的预订不能修改
    if (['completed', 'cancelled', 'no_show'].includes(reservation.status)) {
      throw new BusinessError(`${reservation.status === 'completed' ? '已完成' : reservation.status === 'cancelled' ? '已取消' : '未到场'}的预订不能修改`);
    }

    // 验证数据
    if (guest_count !== undefined && parseInt(guest_count) <= 0) {
      throw new ValidationError('客人数量必须大于0');
    }

    if (contact_phone && !validatePhone(contact_phone).valid) {
      throw new ValidationError('联系电话格式不正确');
    }

    // 如果修改了预订时间，检查是否为过去时间
    const newReservationTime = reservation_time || reservation.reservation_time;
    if (new Date(newReservationTime) < new Date()) {
      throw new ValidationError('预订时间不能早于当前时间');
    }

    // 如果是堂食且修改了桌号或时间，检查桌位是否可用
    if (reservation.type === 'dine_in' && (table_number || reservation_time)) {
      const newTableNumber = table_number || reservation.table_number;
      const isAvailable = await Reservation.isTableAvailable(
        newTableNumber,
        newReservationTime,
        id
      );

      if (!isAvailable) {
        throw new BusinessError('该桌位在所选时间段内已被预订，请选择其他桌位或时间');
      }
    }

    const updatedReservation = await Reservation.update(id, {
      reservation_time,
      guest_count: guest_count !== undefined ? parseInt(guest_count) : undefined,
      table_number: table_number !== undefined ? (table_number ? parseInt(table_number) : null) : undefined,
      contact_name,
      contact_phone,
      special_request: special_request !== undefined ? special_request : undefined
    });

    res.json(success(updatedReservation, '更新预订成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 更新预订状态
 * PUT /api/reservations/:id/status
 * 需要管理员或服务员权限
 */
const updateReservationStatus = async (req, res, next) => {
  try {
    const { id } = req.params;
    const { status } = req.body;

    // 数据验证
    const validation = validateRequired(status, '状态');
    if (!validation.valid) {
      throw new ValidationError('数据验证失败', validation.errors);
    }

    // 验证状态值
    const validStatuses = ['pending', 'confirmed', 'completed', 'cancelled', 'no_show'];
    if (!validStatuses.includes(status)) {
      throw new ValidationError(`状态必须是以下之一: ${validStatuses.join(', ')}`);
    }

    // 检查预订是否存在
    const reservation = await Reservation.findById(id);
    if (!reservation) {
      throw new BusinessError('预订不存在', 404);
    }

    // 已完成或未到场的预订不能修改状态
    if (['completed', 'no_show'].includes(reservation.status)) {
      throw new BusinessError(`${reservation.status === 'completed' ? '已完成' : '未到场'}的预订不能修改状态`);
    }

    const updatedReservation = await Reservation.updateStatus(id, status);

    const messages = {
      pending: '预订已标记为待确认',
      confirmed: '预订已确认',
      completed: '预订已完成',
      cancelled: '预订已取消',
      no_show: '预订已标记为未到场'
    };

    res.json(success(updatedReservation, messages[status]));
  } catch (err) {
    next(err);
  }
};

/**
 * 取消预订
 * PUT /api/reservations/:id/cancel
 */
const cancelReservation = async (req, res, next) => {
  try {
    const { id } = req.params;
    const { cancel_reason } = req.body;

    // 检查预订是否存在
    const reservation = await Reservation.findById(id);
    if (!reservation) {
      throw new BusinessError('预订不存在', 404);
    }

    // 权限控制：顾客只能取消自己的预订，管理员和服务员可以取消任何预订
    if (req.user.role === 'customer' && reservation.customer_id !== req.user.id) {
      throw new AuthorizationError('您没有权限取消此预订');
    }

    // 已完成、已取消或未到场的预订不能再次取消
    if (['completed', 'cancelled', 'no_show'].includes(reservation.status)) {
      throw new BusinessError('该预订已完成或已取消');
    }

    const updatedReservation = await Reservation.cancel(id, cancel_reason || null);

    res.json(success(updatedReservation, '取消预订成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 删除预订
 * DELETE /api/reservations/:id
 * 需要管理员权限
 */
const deleteReservation = async (req, res, next) => {
  try {
    const { id } = req.params;

    // 检查预订是否存在
    const reservation = await Reservation.findById(id);
    if (!reservation) {
      throw new BusinessError('预订不存在', 404);
    }

    await Reservation.delete(id);

    res.json(success(null, '删除预订成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 获取今日预订列表
 * GET /api/reservations/today
 */
const getTodayReservations = async (req, res, next) => {
  try {
    const { type } = req.query;

    const reservations = await Reservation.getTodayReservations(type || null);

    res.json(success({
      count: reservations.length,
      reservations
    }, '获取今日预订成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 获取即将到来的预订
 * GET /api/reservations/upcoming
 */
const getUpcomingReservations = async (req, res, next) => {
  try {
    // 权限控制：顾客只能查看自己的预订
    const customer_id = req.user.role === 'customer' ? req.user.id : null;

    const reservations = await Reservation.getUpcomingReservations(customer_id);

    res.json(success({
      count: reservations.length,
      reservations
    }, '获取即将到来的预订成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 获取我的预订列表
 * GET /api/reservations/my
 */
const getMyReservations = async (req, res, next) => {
  try {
    const {
      page = 1,
      pageSize = 10,
      status
    } = req.query;

    const result = await Reservation.findAll({
      page: parseInt(page),
      pageSize: parseInt(pageSize),
      customer_id: req.user.id,
      status
    });

    res.json(success({
      list: result.list,
      pagination: {
        total: result.total,
        page: result.page,
        pageSize: result.pageSize,
        totalPages: Math.ceil(result.total / result.pageSize)
      }
    }, '获取我的预订成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 获取可用桌位
 * GET /api/reservations/available-tables
 */
const getAvailableTables = async (req, res, next) => {
  try {
    const { reservation_time, guest_count } = req.query;

    // 数据验证
    const validation = validateRequired(reservation_time, '预订时间');
    if (!validation.valid) {
      throw new ValidationError('数据验证失败', validation.errors);
    }

    const tables = await Reservation.getAvailableTables(
      reservation_time,
      guest_count ? parseInt(guest_count) : null
    );

    res.json(success({
      count: tables.length,
      tables
    }, '获取可用桌位成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 获取预订统计
 * GET /api/reservations/statistics
 */
const getStatistics = async (req, res, next) => {
  try {
    const { start_date, end_date } = req.query;

    const stats = await Reservation.getStatistics(
      start_date || null,
      end_date || null
    );

    res.json(success(stats, '获取预订统计成功'));
  } catch (err) {
    next(err);
  }
};

// 导出所有控制器函数
module.exports = {
  getReservations,
  getReservationById,
  createReservation,
  updateReservation,
  updateReservationStatus,
  cancelReservation,
  deleteReservation,
  getTodayReservations,
  getUpcomingReservations,
  getMyReservations,
  getAvailableTables,
  getStatistics
};