package service

import (
	"context"
	"log/slog"

	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/global"
	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/internal/dto"
	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/internal/mysqldao"
	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/internal/mysqlmodel"
	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/pkg/errcode"
)

// QuotaService 额度业务服务。
type QuotaService struct {
	quotaDao   *mysqldao.QuotaDao
	flowLogDao *mysqldao.QuotaFlowLogDao
}

// NewQuotaService 创建额度服务。
func NewQuotaService() *QuotaService {
	return &QuotaService{
		quotaDao:   mysqldao.NewQuotaDao(),
		flowLogDao: mysqldao.NewQuotaFlowLogDao(),
	}
}

// InfoGetBySelf 获取当前用户各类额度概览。
// Cos 返回永久总额度/累计已用/剩余；AI/Outfit/Closet 返回每日总额度/当日已用/当日剩余。
func (s *QuotaService) InfoGetBySelf(ctx context.Context, userID int64) (*dto.QuotaInfoGetBySelfResponse, *errcode.Error) {
	ctx, span := global.Tracer.Start(ctx, "svc.QuotaInfoGetBySelf")
	defer span.End()

	types := []int8{QuotaTypeCos, QuotaTypeAI, QuotaTypeOutfitShare, QuotaTypeClosetShare}
	items := make([]dto.QuotaItemResponse, 0, len(types))
	for _, quotaType := range types {
		eff, err := getEffectiveQuota(ctx, userID, quotaType)
		if err != nil {
			slog.ErrorContext(ctx, "quota info: calc effective quota failed",
				"user_id", userID, "quota_type", quotaType, "error", err)
			return nil, err
		}
		items = append(items, dto.QuotaItemResponse{
			QuotaType: quotaType,
			Total:     eff.Total,
			Used:      eff.Used,
			Remain:    eff.Remain,
		})
	}

	return &dto.QuotaInfoGetBySelfResponse{Quotas: items}, nil
}

// FlowList 分页查询当前用户的额度流水。
func (s *QuotaService) FlowList(ctx context.Context, userID int64, request *dto.QuotaFlowListRequest) (*dto.QuotaFlowListResponse, *errcode.Error) {
	ctx, span := global.Tracer.Start(ctx, "svc.QuotaFlowList")
	defer span.End()

	page, pageSize := normalizePage(request.Page, request.PageSize)

	list, total, err := s.flowLogDao.QuotaFlowLogListByUserID(ctx, userID, request.QuotaType, page, pageSize)
	if err != nil {
		slog.ErrorContext(ctx, "quota flow list: query failed", "user_id", userID, "error", err)
		return nil, errcode.DatabaseError
	}

	items := make([]dto.QuotaFlowItemResponse, 0, len(list))
	for _, f := range list {
		items = append(items, dto.QuotaFlowItemResponse{
			QuotaFlowUUID: f.QuotaFlowUUID,
			QuotaType:     f.QuotaType,
			ChangeTarget:  f.ChangeTarget,
			ChangeType:    f.ChangeType,
			ChangeNum:     f.ChangeNum,
			NewValue:      f.NewValue,
			Reason:        f.Reason,
			OrderNo:       f.OrderNo,
			CreatedAt:     f.CreatedAt,
		})
	}

	return &dto.QuotaFlowListResponse{
		PageResponse: dto.PageResponse{Total: total, Page: page, PageSize: pageSize},
		List:         items,
	}, nil
}

// ensureDefaultQuota 为新用户初始化 Cos 永久免费额度底值。
// AI/Outfit/Closet 为每日额度，不落库，由 getEffectiveQuota 动态计算，无需初始化。
// 事务内「创建 + 写流水」强一致，依赖 uk_user_quota 唯一索引实现并发安全幂等；
// best-effort：失败仅告警，不阻断登录主流程。
func ensureDefaultQuota(ctx context.Context, userID int64) {
	quotaDao := mysqldao.NewQuotaDao()
	total := defaultQuotaValue(QuotaTypeCos)

	flow := &mysqlmodel.QuotaFlowLog{
		QuotaFlowUUID: genUUID(),
		UserID:        userID,
		ChangeTarget:  QuotaChangeTargetAdjust,
		ChangeType:    QuotaChangeTypeActivity,
		ChangeNum:     total,
		QuotaType:     QuotaTypeCos,
		Reason:        "新用户默认上传额度",
	}
	if err := quotaDao.QuotaInitWithFlow(ctx, userID, QuotaTypeCos, total, flow); err != nil {
		slog.WarnContext(ctx, "init default cos quota failed", "user_id", userID, "error", err)
	}
}

// defaultQuotaValue 返回某类额度的新用户默认值：
// 优先取 global.UserDefaultQuotaSetting 的配置值，配置为 0 时同样生效（表示不赠送该类免费额度）；
// 未配置（整段缺失或该项缺失，指针为 nil）或配置为负数时，回落内置常量。
func defaultQuotaValue(quotaType int8) int64 {
	cfg := global.UserDefaultQuotaSetting

	switch quotaType {
	case QuotaTypeCos:
		if cfg != nil && cfg.Cos != nil && *cfg.Cos >= 0 {
			return *cfg.Cos
		}
		return DefaultQuotaCos
	case QuotaTypeAI:
		if cfg != nil && cfg.AI != nil && *cfg.AI >= 0 {
			return *cfg.AI
		}
		return DefaultQuotaAI
	case QuotaTypeOutfitShare:
		if cfg != nil && cfg.OutfitShare != nil && *cfg.OutfitShare >= 0 {
			return *cfg.OutfitShare
		}
		return DefaultQuotaOutfitShare
	case QuotaTypeClosetShare:
		if cfg != nil && cfg.ClosetShare != nil && *cfg.ClosetShare >= 0 {
			return *cfg.ClosetShare
		}
		return DefaultQuotaClosetShare
	default:
		return 0
	}
}