package rechargeagency

import (
	"context"
	"net/http"
	"strings"

	"chatapp3-golang/internal/integration"
	"chatapp3-golang/internal/model"
)

// PageSellers 返回当前用户可见的 H5 币商名单。
func (s *Service) PageSellers(ctx context.Context, user AuthUser, cursor int, limit int) (*SellerListResponse, error) {
	if s.java == nil {
		return nil, NewAppError(http.StatusServiceUnavailable, "java_gateway_unavailable", "java gateway is unavailable")
	}
	if strings.TrimSpace(user.Authorization) == "" {
		return nil, NewAppError(http.StatusUnauthorized, "missing_authorization", "authorization is required")
	}

	sysOrigin := normalizeSysOrigin(user.SysOrigin)
	if sysOrigin == "" {
		return nil, NewAppError(http.StatusUnauthorized, "invalid_sys_origin", "authenticated sysOrigin is required")
	}
	cursor, limit = normalizePage(cursor, limit)

	page, err := s.java.PageFreightSellers(ctx, user.Authorization, sysOrigin, cursor, limit)
	if err != nil {
		return nil, NewAppError(http.StatusBadGateway, "freight_seller_list_failed", err.Error())
	}

	records := make([]SellerView, 0, len(page.Records))
	for _, record := range page.Records {
		records = append(records, buildSellerView(record))
	}
	if s.db != nil {
		whatsapps, err := s.loadSellerWhatsapps(ctx, sysOrigin, collectSellerUserIDs(records))
		if err != nil {
			return nil, err
		}
		for i := range records {
			if whatsapp := strings.TrimSpace(whatsapps[records[i].UserID]); whatsapp != "" {
				records[i].Whatsapp = whatsapp
			}
		}
	}

	return &SellerListResponse{
		SysOrigin: sysOrigin,
		Cursor:    cursor,
		Limit:     limit,
		Total:     page.Total,
		Records:   records,
	}, nil
}

func buildSellerView(record integration.FreightSellerRecord) SellerView {
	profile := record.UserBaseInfo
	return SellerView{
		ID:                 int64(record.ID),
		SysOrigin:          strings.TrimSpace(record.SysOrigin),
		UserID:             int64(record.UserID),
		Account:            firstNonBlank(profile.Account, formatInt64(int64(record.UserID))),
		UserAvatar:         strings.TrimSpace(profile.UserAvatar),
		UserNickname:       firstNonBlank(profile.UserNickname, profile.Account, formatInt64(int64(record.UserID))),
		CountryCode:        strings.TrimSpace(profile.CountryCode),
		CountryName:        strings.TrimSpace(profile.CountryName),
		RegionCode:         strings.TrimSpace(profile.RegionCode),
		Balance:            normalizeDecimalString(string(record.Balance)),
		ContactInfo:        strings.TrimSpace(record.ContactInfo),
		SupportedCountries: strings.TrimSpace(record.SupportedCountries),
		NationalFlag:       normalizeFlags(record.NationalFlag),
		OwnNationalFlag:    strings.TrimSpace(record.OwnNationalFlag),
		BecomeDays:         record.BecomeDays,
		TransactionCount:   record.TransactionCount,
		IsFollow:           record.IsFollow,
		SuperDealer:        record.SuperDealer,
	}
}

func collectSellerUserIDs(records []SellerView) []int64 {
	seen := make(map[int64]struct{}, len(records))
	userIDs := make([]int64, 0, len(records))
	for _, record := range records {
		if record.UserID <= 0 {
			continue
		}
		if _, ok := seen[record.UserID]; ok {
			continue
		}
		seen[record.UserID] = struct{}{}
		userIDs = append(userIDs, record.UserID)
	}
	return userIDs
}

func (s *Service) loadSellerWhatsapps(ctx context.Context, sysOrigin string, userIDs []int64) (map[int64]string, error) {
	whatsapps := make(map[int64]string, len(userIDs))
	if len(userIDs) == 0 {
		return whatsapps, nil
	}

	var rows []model.RechargeAgencySellerInfo
	err := s.db.WithContext(ctx).
		Select("user_id", "whatsapp").
		Where("sys_origin = ? AND user_id IN ?", sysOrigin, userIDs).
		Find(&rows).Error
	if err != nil {
		return nil, NewAppError(http.StatusInternalServerError, "seller_whatsapp_query_failed", err.Error())
	}

	for _, row := range rows {
		if whatsapp := strings.TrimSpace(row.Whatsapp); whatsapp != "" {
			whatsapps[row.UserID] = whatsapp
		}
	}
	return whatsapps, nil
}