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

import com.tcm.training.admin.app.member.vo.AppMemberBenefitVO;
import com.tcm.training.admin.app.member.vo.AppMemberOpenPackageVO;
import com.tcm.training.admin.app.member.vo.AppMemberOpenPageVO;
import com.tcm.training.admin.member.service.MemberSettingsAppService;
import com.tcm.training.admin.member.vo.MemberIntroModuleVO;
import com.tcm.training.admin.member.vo.MemberIntroSettingsVO;
import com.tcm.training.admin.member.vo.MemberPriceSettingsVO;
import org.springframework.stereotype.Service;

import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * APP 会员开通页聚合服务。
 */
@Service
public class AppMemberOpenPageService {

    private static final String PACKAGE_TYPE_MONTH = "MONTH";
    private static final String PACKAGE_TYPE_QUARTER = "QUARTER";

    private final MemberSettingsAppService memberSettingsAppService;

    /**
     * 注入会员价格配置服务。
     */
    public AppMemberOpenPageService(MemberSettingsAppService memberSettingsAppService) {
        this.memberSettingsAppService = memberSettingsAppService;
    }

    /**
     * 获取 APP 会员开通页所需数据。
     */
    public AppMemberOpenPageVO getOpenPage() {
        AppMemberOpenPageVO result = new AppMemberOpenPageVO();
        MemberPriceSettingsVO settings = memberSettingsAppService.currentPrice();
        if (settings != null) {
            List<AppMemberOpenPackageVO> packages = new ArrayList<AppMemberOpenPackageVO>(2);
            addEnabledPackage(packages,
                    PACKAGE_TYPE_MONTH,
                    "月会员",
                    settings.getMonthCardEnabled(),
                    settings.getMonthCardPrice(),
                    settings.getMonthCardDays());
            addEnabledPackage(packages,
                    PACKAGE_TYPE_QUARTER,
                    "季度会员",
                    settings.getQuarterCardEnabled(),
                    settings.getQuarterCardPrice(),
                    settings.getQuarterCardDays());
            result.setPackages(packages);
            result.setMinPrice(resolveMinPrice(packages));
        }
        fillIntro(result, memberSettingsAppService.currentIntro());
        return result;
    }

    /**
     * 将后台启用的会员配置转换为 APP 套餐卡片。
     */
    private void addEnabledPackage(List<AppMemberOpenPackageVO> packages,
                                   String type,
                                   String title,
                                   Boolean enabled,
                                   BigDecimal price,
                                   Integer days) {
        if (!Boolean.TRUE.equals(enabled) || price == null || price.compareTo(BigDecimal.ZERO) <= 0 || days == null || days <= 0) {
            return;
        }
        AppMemberOpenPackageVO item = new AppMemberOpenPackageVO();
        item.setType(type);
        item.setTitle(title);
        item.setPrice(price);
        item.setDays(days);
        packages.add(item);
    }

    /**
     * 计算当前已启用套餐中的最低价格，供课程详情页展示“xx起”。
     */
    private BigDecimal resolveMinPrice(List<AppMemberOpenPackageVO> packages) {
        BigDecimal minPrice = null;
        for (AppMemberOpenPackageVO item : packages) {
            if (item.getPrice() == null) {
                continue;
            }
            if (minPrice == null || item.getPrice().compareTo(minPrice) < 0) {
                minPrice = item.getPrice();
            }
        }
        return minPrice;
    }

    /**
     * 将后台会员介绍配置写入 APP 开通页响应。
     */
    private void fillIntro(AppMemberOpenPageVO result, MemberIntroSettingsVO introSettings) {
        if (introSettings == null) {
            result.setBenefits(Collections.<AppMemberBenefitVO>emptyList());
            result.setDescription("");
            return;
        }
        result.setBenefits(toBenefits(introSettings.getBenefits()));
        result.setDescription(trimToEmpty(introSettings.getDescription()));
    }

    /**
     * 将后台权益配置转换为 APP 可直接渲染的权益网格数据。
     */
    private List<AppMemberBenefitVO> toBenefits(List<MemberIntroModuleVO> benefits) {
        if (benefits == null || benefits.isEmpty()) {
            return Collections.emptyList();
        }
        List<AppMemberBenefitVO> result = new ArrayList<AppMemberBenefitVO>(benefits.size());
        for (MemberIntroModuleVO item : benefits) {
            AppMemberBenefitVO benefitVO = new AppMemberBenefitVO();
            benefitVO.setId(item.getId());
            benefitVO.setIconUrl(trimToEmpty(item.getIconUrl()));
            benefitVO.setName(trimToEmpty(item.getName()));
            benefitVO.setSort(item.getSort());
            result.add(benefitVO);
        }
        return result;
    }

    /**
     * 将可空文本转换为空字符串，便于 APP 直接展示。
     */
    private String trimToEmpty(String value) {
        if (value == null) {
            return "";
        }
        String trimmed = value.trim();
        return trimmed.isEmpty() ? "" : trimmed;
    }
}