package com.tcm.training.admin.member.service;

import cn.idev.excel.FastExcel;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.tcm.training.admin.app.auth.service.AppAuthSessionService;
import com.tcm.training.admin.app.member.vo.AppMemberPurchaseOrderItemVO;
import com.tcm.training.admin.common.DateTimes;
import com.tcm.training.admin.common.PageResponse;
import com.tcm.training.admin.common.PhoneMasker;
import com.tcm.training.admin.member.entity.MemberPurchaseOrder;
import com.tcm.training.admin.member.excel.MemberPurchaseOrderExcelRow;
import com.tcm.training.admin.member.mapper.MemberPurchaseOrderMapper;
import com.tcm.training.admin.member.row.MemberPurchaseOrderRow;
import com.tcm.training.admin.member.vo.MemberPurchaseOrderListItemVO;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.math.BigDecimal;
import java.net.URLEncoder;
import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.List;

@Service
public class MemberPurchaseOrderAppService {

    private static final String STATUS_WAITING_PAYMENT = "WAITING_PAYMENT";
    private static final String STATUS_PAID = "PAID";
    private static final String STATUS_REFUNDED = "REFUNDED";
    private static final String STATUS_CANCELLED = "CANCELLED";

    private static final String MEMBER_TYPE_MONTH_CARD = "MONTH_CARD";
    private static final String MEMBER_TYPE_QUARTER_CARD = "QUARTER_CARD";
    private static final String PAYMENT_METHOD_WECHAT = "WECHAT";
    private static final String PAYMENT_METHOD_ALIPAY = "ALIPAY";

    private final MemberPurchaseOrderMapper memberPurchaseOrderMapper;
    private final AppAuthSessionService appAuthSessionService;

    /**
     * 注入会员订单查询能力。
     */
    public MemberPurchaseOrderAppService(MemberPurchaseOrderMapper memberPurchaseOrderMapper,
                                         AppAuthSessionService appAuthSessionService) {
        this.memberPurchaseOrderMapper = memberPurchaseOrderMapper;
        this.appAuthSessionService = appAuthSessionService;
    }

    /**
     * 分页查询后台会员购买订单。
     */
    public PageResponse<MemberPurchaseOrderListItemVO> page(int page,
                                                            int pageSize,
                                                            String orderNo,
                                                            String userPhone,
                                                            String memberType,
                                                            String paymentMethod,
                                                            String status,
                                                            LocalDateTime createdFrom,
                                                            LocalDateTime createdTo) {
        IPage<MemberPurchaseOrderRow> result = memberPurchaseOrderMapper.selectOrderPage(
                new Page<MemberPurchaseOrderRow>(page, pageSize),
                trimToNull(orderNo),
                trimToNull(userPhone),
                trimToNull(memberType),
                trimToNull(paymentMethod),
                normalizeStatus(status),
                createdFrom,
                createdTo
        );
        return PageResponse.of(toList(result.getRecords()), result.getTotal(), result.getCurrent(), result.getSize());
    }

    /**
     * 分页查询当前登录用户的 APP 会员购买记录。
     */
    public PageResponse<AppMemberPurchaseOrderItemVO> appUserPage(int page, int pageSize) {
        Long userId = appAuthSessionService.requireLoginUserId();
        IPage<MemberPurchaseOrderRow> result = memberPurchaseOrderMapper.selectAppUserOrderPage(
                new Page<MemberPurchaseOrderRow>(page, pageSize),
                userId
        );
        return PageResponse.of(toAppList(result.getRecords()), result.getTotal(), result.getCurrent(), result.getSize());
    }

    /**
     * 导出后台会员购买订单。
     */
    public void export(String orderNo,
                       String userPhone,
                       String memberType,
                       String paymentMethod,
                       String status,
                       LocalDateTime createdFrom,
                       LocalDateTime createdTo,
                       HttpServletResponse response) throws IOException {
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
        response.setCharacterEncoding("utf-8");
        String filename = URLEncoder.encode("会员购买订单", "UTF-8").replace("+", "%20");
        response.setHeader("Content-Disposition", "attachment;filename*=utf-8''" + filename + ".xlsx");

        List<MemberPurchaseOrderRow> rows = memberPurchaseOrderMapper.selectOrderList(
                trimToNull(orderNo),
                trimToNull(userPhone),
                trimToNull(memberType),
                trimToNull(paymentMethod),
                normalizeStatus(status),
                createdFrom,
                createdTo
        );
        List<MemberPurchaseOrderExcelRow> exports = new ArrayList<MemberPurchaseOrderExcelRow>();
        for (MemberPurchaseOrderRow row : rows) {
            MemberPurchaseOrderExcelRow export = new MemberPurchaseOrderExcelRow();
            export.setOrderNo(row.getOrderNo());
            export.setUserNickname(defaultText(row.getUserNickname()));
            export.setUserPhone(PhoneMasker.mask(row.getUserPhone()));
            export.setMemberType(memberTypeText(row.getMemberType()));
            export.setMemberDaysText(memberDaysText(row.getMemberDays()));
            export.setOrderAmount(row.getOrderAmount());
            export.setPaymentMethod(paymentMethodText(row.getPaymentMethod()));
            export.setStatus(statusText(row.getStatus()));
            export.setRefundAmount(resolveRefundAmount(row.getStatus(), row.getOrderAmount(), row.getRefundAmount()));
            export.setRefundRemark(defaultText(row.getRefundRemark()));
            export.setCreatedAt(DateTimes.format(row.getCreatedAt()));
            exports.add(export);
        }
        FastExcel.write(response.getOutputStream(), MemberPurchaseOrderExcelRow.class)
                .sheet("会员购买订单")
                .doWrite(exports);
    }

    public void refund(Long id) {
        MemberPurchaseOrder order = requireOrder(id);
        if (!STATUS_PAID.equals(order.getStatus())) {
            throw new IllegalArgumentException("仅已支付订单允许退款");
        }
        // TODO: 支付方案确认后，在这里接入真实退款流程并在退款成功后更新订单状态与退款时间。
        throw new IllegalArgumentException("退款功能待支付方案确认后接入");
    }

    /**
     * 删除后台已退款会员订单。
     */
    @Transactional
    public void delete(Long id) {
        MemberPurchaseOrder order = requireOrder(id);
        if (!STATUS_REFUNDED.equals(order.getStatus())) {
            throw new IllegalArgumentException("仅已退款订单允许删除");
        }
        memberPurchaseOrderMapper.deleteById(id);
    }

    /**
     * 校验会员购买订单存在。
     */
    private MemberPurchaseOrder requireOrder(Long id) {
        MemberPurchaseOrder order = memberPurchaseOrderMapper.selectOne(new LambdaQueryWrapper<MemberPurchaseOrder>()
                .eq(MemberPurchaseOrder::getId, id)
                .eq(MemberPurchaseOrder::getDeleted, 0)
                .last("limit 1"));
        if (order == null) {
            throw new IllegalArgumentException("会员购买订单不存在");
        }
        return order;
    }

    /**
     * 将后台订单查询结果转换为后台列表响应。
     */
    private List<MemberPurchaseOrderListItemVO> toList(List<MemberPurchaseOrderRow> rows) {
        List<MemberPurchaseOrderListItemVO> list = new ArrayList<MemberPurchaseOrderListItemVO>();
        for (MemberPurchaseOrderRow row : rows) {
            MemberPurchaseOrderListItemVO item = new MemberPurchaseOrderListItemVO();
            item.setId(row.getId());
            item.setOrderNo(row.getOrderNo());
            item.setUserNickname(row.getUserNickname());
            item.setUserPhone(PhoneMasker.mask(row.getUserPhone()));
            item.setMemberType(row.getMemberType());
            item.setMemberDays(row.getMemberDays());
            item.setOrderAmount(row.getOrderAmount());
            item.setPaymentMethod(row.getPaymentMethod());
            item.setRefundAmount(resolveRefundAmount(row.getStatus(), row.getOrderAmount(), row.getRefundAmount()));
            item.setRefundRemark(row.getRefundRemark());
            item.setStatus(row.getStatus());
            item.setPaidAt(row.getPaidAt());
            item.setRefundedAt(row.getRefundedAt());
            item.setCreatedAt(row.getCreatedAt());
            list.add(item);
        }
        return list;
    }

    /**
     * 将订单查询结果转换为 APP 购买记录列表响应。
     */
    private List<AppMemberPurchaseOrderItemVO> toAppList(List<MemberPurchaseOrderRow> rows) {
        List<AppMemberPurchaseOrderItemVO> list = new ArrayList<AppMemberPurchaseOrderItemVO>();
        for (MemberPurchaseOrderRow row : rows) {
            AppMemberPurchaseOrderItemVO item = new AppMemberPurchaseOrderItemVO();
            item.setId(row.getId());
            item.setOrderNo(row.getOrderNo());
            item.setMemberType(row.getMemberType());
            item.setMemberTypeText(memberTypeText(row.getMemberType()));
            item.setOrderAmount(row.getOrderAmount());
            item.setPaymentMethod(row.getPaymentMethod());
            item.setPaymentMethodText(paymentMethodText(row.getPaymentMethod()));
            item.setStatus(row.getStatus());
            // APP 购买记录页在退款场景下要展示退款金额标签，没有单独退款额时回退订单金额。
            item.setRefundAmount(resolveRefundAmount(row.getStatus(), row.getOrderAmount(), row.getRefundAmount()));
            item.setShowRefundTag(Boolean.valueOf(STATUS_REFUNDED.equals(row.getStatus())));
            item.setPaidAt(row.getPaidAt());
            list.add(item);
        }
        return list;
    }

    /**
     * 解析订单应展示的退款金额。
     */
    private BigDecimal resolveRefundAmount(String status, BigDecimal orderAmount, BigDecimal refundAmount) {
        if (!STATUS_REFUNDED.equals(status)) {
            return null;
        }
        return refundAmount == null ? orderAmount : refundAmount;
    }

    private String normalizeStatus(String status) {
        String normalized = trimToNull(status);
        if (normalized == null) {
            return null;
        }
        if (STATUS_PAID.equals(normalized) || STATUS_REFUNDED.equals(normalized)) {
            return normalized;
        }
        return null;
    }

    /**
     * 将空白文本归一化为 null。
     */
    private String trimToNull(String value) {
        if (value == null) {
            return null;
        }
        String trimmed = value.trim();
        return trimmed.isEmpty() ? null : trimmed;
    }

    /**
     * 缺省文本展示兜底。
     */
    private String defaultText(String value) {
        return value == null || value.trim().isEmpty() ? "-" : value.trim();
    }

    /**
     * 将会员天数转换为展示文案。
     */
    private String memberDaysText(Integer memberDays) {
        return memberDays == null ? "-" : memberDays + "天";
    }

    /**
     * 将会员类型转换为展示文案。
     */
    private String memberTypeText(String memberType) {
        if (MEMBER_TYPE_MONTH_CARD.equals(memberType)) {
            return "月卡";
        }
        if (MEMBER_TYPE_QUARTER_CARD.equals(memberType)) {
            return "季度会员";
        }
        return "-";
    }

    /**
     * 将支付方式转换为展示文案。
     */
    private String paymentMethodText(String paymentMethod) {
        if (PAYMENT_METHOD_WECHAT.equals(paymentMethod)) {
            return "微信支付";
        }
        if (PAYMENT_METHOD_ALIPAY.equals(paymentMethod)) {
            return "支付宝支付";
        }
        return "-";
    }

    /**
     * 将订单状态转换为展示文案。
     */
    private String statusText(String status) {
        if (STATUS_WAITING_PAYMENT.equals(status)) {
            return "待支付";
        }
        if (STATUS_PAID.equals(status)) {
            return "已支付";
        }
        if (STATUS_REFUNDED.equals(status)) {
            return "已退款";
        }
        if (STATUS_CANCELLED.equals(status)) {
            return "已取消";
        }
        return "-";
    }
}