/**
 * 会员控制器
 *
 * 功能：处理会员管理的业务逻辑
 */

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

// ========================================
// 会员相关控制器
// ========================================

/**
 * 获取会员列表（分页、筛选）
 * GET /api/members
 * 需要管理员权限
 */
const getMembers = async (req, res, next) => {
  try {
    const {
      page = 1,
      pageSize = 10,
      level,
      search
    } = req.query;

    const result = await Member.findAll({
      page: parseInt(page),
      pageSize: parseInt(pageSize),
      level,
      search
    });

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

/**
 * 获取会员详情
 * GET /api/members/:userId
 */
const getMemberByUserId = async (req, res, next) => {
  try {
    const { userId } = req.params;

    // 权限控制：普通用户只能查看自己的会员信息
    if (req.user.role === 'customer' && parseInt(userId) !== req.user.id) {
      throw new AuthorizationError('您没有权限查看此会员信息');
    }

    const member = await Member.findByUserId(userId);
    if (!member) {
      throw new BusinessError('会员信息不存在', 404);
    }

    res.json(success(member, '获取会员详情成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 获取我的会员信息
 * GET /api/members/my/info
 */
const getMyMemberInfo = async (req, res, next) => {
  try {
    let member = await Member.findByUserId(req.user.id);

    // 如果用户还不是会员，自动创建会员资格
    if (!member) {
      member = await Member.create(req.user.id);
    }

    // 获取会员折扣信息
    const discount = Member.getDiscount(member.level);

    res.json(success({
      ...member,
      discount,
      discount_percent: Math.round((1 - discount) * 100) // 折扣百分比
    }, '获取我的会员信息成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 创建会员
 * POST /api/members
 * 需要管理员权限
 */
const createMember = async (req, res, next) => {
  try {
    const { user_id } = req.body;

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

    // 检查用户是否已是会员
    const isMember = await Member.isMember(user_id);
    if (isMember) {
      throw new BusinessError('该用户已是会员');
    }

    const member = await Member.create(user_id);

    res.status(201).json(success(member, '创建会员成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 更新会员等级
 * PUT /api/members/:userId/level
 * 需要管理员权限
 */
const updateMemberLevel = async (req, res, next) => {
  try {
    const { userId } = req.params;
    const { level } = req.body;

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

    // 验证等级值
    const validLevels = ['bronze', 'silver', 'gold', 'diamond'];
    if (!validLevels.includes(level)) {
      throw new ValidationError(`会员等级必须是以下之一: ${validLevels.join(', ')}`);
    }

    const member = await Member.updateLevel(userId, level);

    res.json(success(member, '更新会员等级成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 增加会员积分
 * POST /api/members/:userId/points/add
 * 需要管理员权限
 */
const addMemberPoints = async (req, res, next) => {
  try {
    const { userId } = req.params;
    const { points, reason } = req.body;

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

    if (parseInt(points) <= 0) {
      throw new ValidationError('积分数量必须大于0');
    }

    const member = await Member.addPoints(
      userId,
      parseInt(points),
      reason || '管理员手动添加'
    );

    res.json(success(member, '增加积分成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 扣减会员积分
 * POST /api/members/:userId/points/deduct
 * 需要管理员权限
 */
const deductMemberPoints = async (req, res, next) => {
  try {
    const { userId } = req.params;
    const { points, reason } = req.body;

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

    if (parseInt(points) <= 0) {
      throw new ValidationError('积分数量必须大于0');
    }

    const member = await Member.deductPoints(
      userId,
      parseInt(points),
      reason || '管理员手动扣减'
    );

    res.json(success(member, '扣减积分成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 获取会员统计信息
 * GET /api/members/statistics
 * 需要管理员权限
 */
const getMemberStatistics = async (req, res, next) => {
  try {
    const stats = await Member.getStatistics();

    res.json(success(stats, '获取会员统计成功'));
  } catch (err) {
    next(err);
  }
};

// ========================================
// 优惠券相关控制器
// ========================================

/**
 * 获取优惠券列表
 * GET /api/members/coupons
 */
const getCoupons = async (req, res, next) => {
  try {
    const {
      page = 1,
      pageSize = 10,
      type,
      is_active
    } = req.query;

    const result = await Coupon.findAll({
      page: parseInt(page),
      pageSize: parseInt(pageSize),
      type,
      is_active: is_active !== undefined ? parseInt(is_active) : undefined
    });

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

/**
 * 获取优惠券详情
 * GET /api/members/coupons/:id
 */
const getCouponById = async (req, res, next) => {
  try {
    const { id } = req.params;

    const coupon = await Coupon.findById(id);
    if (!coupon) {
      throw new BusinessError('优惠券不存在', 404);
    }

    res.json(success(coupon, '获取优惠券详情成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 创建优惠券
 * POST /api/members/coupons
 * 需要管理员权限
 */
const createCoupon = async (req, res, next) => {
  try {
    const {
      name,
      type,
      discount_value,
      min_amount,
      max_discount,
      valid_from,
      valid_to,
      total_quantity,
      points_required,
      is_active
    } = req.body;

    // 数据验证
    const validation = validateBatch([
      validateRequired(name, '优惠券名称'),
      validateRequired(type, '优惠券类型'),
      validateRequired(discount_value, '优惠值'),
      validateRequired(valid_from, '有效期开始时间'),
      validateRequired(valid_to, '有效期结束时间'),
      validateRequired(total_quantity, '发放数量')
    ]);

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

    // 验证优惠券类型
    const validTypes = ['discount', 'cash'];
    if (!validTypes.includes(type)) {
      throw new ValidationError('优惠券类型必须是 discount 或 cash');
    }

    // 验证优惠值
    if (parseFloat(discount_value) <= 0) {
      throw new ValidationError('优惠值必须大于0');
    }

    if (type === 'discount' && parseFloat(discount_value) >= 1) {
      throw new ValidationError('折扣类型的优惠值必须小于1（如0.9表示9折）');
    }

    // 验证数量
    if (parseInt(total_quantity) <= 0) {
      throw new ValidationError('发放数量必须大于0');
    }

    const coupon = await Coupon.create({
      name,
      type,
      discount_value: parseFloat(discount_value),
      min_amount: min_amount ? parseFloat(min_amount) : null,
      max_discount: max_discount ? parseFloat(max_discount) : null,
      valid_from,
      valid_to,
      total_quantity: parseInt(total_quantity),
      points_required: points_required ? parseInt(points_required) : 0,
      is_active: is_active !== undefined ? parseInt(is_active) : 1
    });

    res.status(201).json(success(coupon, '创建优惠券成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 更新优惠券
 * PUT /api/members/coupons/:id
 * 需要管理员权限
 */
const updateCoupon = async (req, res, next) => {
  try {
    const { id } = req.params;
    const {
      name,
      discount_value,
      min_amount,
      max_discount,
      valid_from,
      valid_to,
      total_quantity,
      points_required,
      is_active
    } = req.body;

    // 检查优惠券是否存在
    const coupon = await Coupon.findById(id);
    if (!coupon) {
      throw new BusinessError('优惠券不存在', 404);
    }

    const updatedCoupon = await Coupon.update(id, {
      name,
      discount_value: discount_value !== undefined ? parseFloat(discount_value) : undefined,
      min_amount: min_amount !== undefined ? (min_amount ? parseFloat(min_amount) : null) : undefined,
      max_discount: max_discount !== undefined ? (max_discount ? parseFloat(max_discount) : null) : undefined,
      valid_from,
      valid_to,
      total_quantity: total_quantity !== undefined ? parseInt(total_quantity) : undefined,
      points_required: points_required !== undefined ? parseInt(points_required) : undefined,
      is_active: is_active !== undefined ? parseInt(is_active) : undefined
    });

    res.json(success(updatedCoupon, '更新优惠券成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 删除优惠券
 * DELETE /api/members/coupons/:id
 * 需要管理员权限
 */
const deleteCoupon = async (req, res, next) => {
  try {
    const { id } = req.params;

    // 检查优惠券是否存在
    const coupon = await Coupon.findById(id);
    if (!coupon) {
      throw new BusinessError('优惠券不存在', 404);
    }

    await Coupon.delete(id);

    res.json(success(null, '删除优惠券成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 领取优惠券
 * POST /api/members/coupons/:id/claim
 */
const claimCoupon = async (req, res, next) => {
  try {
    const { id } = req.params;

    const userCoupon = await Coupon.claimByUser(req.user.id, id);

    res.status(201).json(success(userCoupon, '领取优惠券成功'));
  } catch (err) {
    next(err);
  }
};

/**
 * 获取我的优惠券
 * GET /api/members/my/coupons
 */
const getMyCoupons = async (req, res, next) => {
  try {
    const { status } = req.query;

    const coupons = await Coupon.getUserCoupons(req.user.id, status || null);

    res.json(success({
      count: coupons.length,
      coupons
    }, '获取我的优惠券成功'));
  } catch (err) {
    next(err);
  }
};

// 导出所有控制器函数
module.exports = {
  // 会员相关
  getMembers,
  getMemberByUserId,
  getMyMemberInfo,
  createMember,
  updateMemberLevel,
  addMemberPoints,
  deductMemberPoints,
  getMemberStatistics,

  // 优惠券相关
  getCoupons,
  getCouponById,
  createCoupon,
  updateCoupon,
  deleteCoupon,
  claimCoupon,
  getMyCoupons
};