package registerreward

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

	"chatapp3-golang/internal/model"

	"gorm.io/gorm"
)

// registerRewardDailyRecordRow 是后台分页查询时使用的中间结果，补齐了用户展示资料。
type registerRewardDailyRecordRow struct {
	model.ResidentRegisterRewardLog
	Account      string `gorm:"column:account"`       // 用户账号
	UserAvatar   string `gorm:"column:user_avatar"`   // 用户头像
	UserNickname string `gorm:"column:user_nickname"` // 用户昵称
	CountryCode  string `gorm:"column:country_code"`  // 国家编码
	CountryName  string `gorm:"column:country_name"`  // 国家名称
}

// PageDailyRecords 分页返回指定日期的注册奖励领取记录，供后台查看当日限额使用情况。
func (s *RegisterRewardService) PageDailyRecords(
	ctx context.Context,
	sysOrigin string,
	claimDate string,
	cursor int,
	limit int,
) (*RegisterRewardDailyRecordPageResponse, error) {
	normalizedSysOrigin := strings.ToUpper(strings.TrimSpace(sysOrigin))
	if normalizedSysOrigin == "" {
		return nil, NewAppError(http.StatusBadRequest, "bad_request", "sysOrigin is required")
	}

	resolvedClaimDate := normalizeRegisterRewardClaimDate(claimDate)
	page, size := normalizeRegisterRewardPage(cursor, limit)

	configRow, err := s.loadRegisterRewardConfig(ctx, normalizedSysOrigin)
	if err != nil {
		return nil, err
	}
	dailyLimit := int64(0)
	if configRow != nil {
		dailyLimit = configRow.DailyLimit
	}

	var total int64
	if err := s.newDailyRecordBaseQuery(ctx, normalizedSysOrigin, resolvedClaimDate).
		Count(&total).Error; err != nil {
		return nil, err
	}

	occupiedCount, err := s.countDailyRecordsByGrantMode(
		ctx,
		normalizedSysOrigin,
		resolvedClaimDate,
		registerRewardGrantModeIssueReward,
		"",
	)
	if err != nil {
		return nil, err
	}
	issuedCount, err := s.countDailyRecordsByGrantMode(
		ctx,
		normalizedSysOrigin,
		resolvedClaimDate,
		registerRewardGrantModeIssueReward,
		registerRewardStatusSuccess,
	)
	if err != nil {
		return nil, err
	}
	successCount, err := s.countDailyRecordsByStatus(
		ctx,
		normalizedSysOrigin,
		resolvedClaimDate,
		registerRewardStatusSuccess,
	)
	if err != nil {
		return nil, err
	}

	records := make([]RegisterRewardDailyRecordView, 0)
	if total > 0 {
		var rows []registerRewardDailyRecordRow
		if err := s.newDailyRecordBaseQuery(ctx, normalizedSysOrigin, resolvedClaimDate).
			Select("log.*, user.account, user.user_avatar, user.user_nickname, user.country_code, user.country_name").
			Joins("LEFT JOIN user_base_info AS user ON user.id = log.user_id").
			Order("log.create_time desc").
			Order("log.id desc").
			Offset((page - 1) * size).
			Limit(size).
			Find(&rows).Error; err != nil {
			return nil, err
		}

		records = make([]RegisterRewardDailyRecordView, 0, len(rows))
		for _, row := range rows {
			records = append(records, toRegisterRewardDailyRecordView(row))
		}
	}

	resp := &RegisterRewardDailyRecordPageResponse{
		Date:          resolvedClaimDate,
		LimitEnabled:  dailyLimit > 0,
		DailyLimit:    dailyLimit,
		OccupiedCount: occupiedCount,
		IssuedCount:   issuedCount,
		SuccessCount:  successCount,
		RemainingCount: resolveRegisterRewardRemainingCount(
			dailyLimit,
			occupiedCount,
		),
		Records: records,
		Total:   total,
	}
	return resp, nil
}

// newDailyRecordBaseQuery 创建后台领取记录分页的基础查询。
func (s *RegisterRewardService) newDailyRecordBaseQuery(
	ctx context.Context,
	sysOrigin string,
	claimDate string,
) *gorm.DB {
	return s.repo.DB.WithContext(ctx).
		Table("resident_register_reward_log AS log").
		Where("log.sys_origin = ? AND log.claim_date = ?", sysOrigin, claimDate)
}

// countDailyRecordsByGrantMode 统计某天某系统在指定发奖模式下的记录数。
func (s *RegisterRewardService) countDailyRecordsByGrantMode(
	ctx context.Context,
	sysOrigin string,
	claimDate string,
	grantMode string,
	status string,
) (int64, error) {
	query := s.newDailyRecordBaseQuery(ctx, sysOrigin, claimDate).
		Where("log.grant_mode = ?", grantMode)
	if strings.TrimSpace(status) != "" {
		query = query.Where("log.status = ?", strings.ToUpper(strings.TrimSpace(status)))
	}

	var total int64
	if err := query.Count(&total).Error; err != nil {
		return 0, err
	}
	return total, nil
}

// countDailyRecordsByStatus 统计某天某系统在指定处理状态下的记录数。
func (s *RegisterRewardService) countDailyRecordsByStatus(
	ctx context.Context,
	sysOrigin string,
	claimDate string,
	status string,
) (int64, error) {
	var total int64
	if err := s.newDailyRecordBaseQuery(ctx, sysOrigin, claimDate).
		Where("log.status = ?", strings.ToUpper(strings.TrimSpace(status))).
		Count(&total).Error; err != nil {
		return 0, err
	}
	return total, nil
}

// toRegisterRewardDailyRecordView 把数据库行转换成后台页面直接可用的结构。
func toRegisterRewardDailyRecordView(row registerRewardDailyRecordRow) RegisterRewardDailyRecordView {
	claimResult := deriveRegisterRewardClaimResult(row.Status, row.GrantMode)
	return RegisterRewardDailyRecordView{
		ID:              row.ID,
		SysOrigin:       row.SysOrigin,
		UserID:          row.UserID,
		Account:         row.Account,
		UserAvatar:      row.UserAvatar,
		UserNickname:    row.UserNickname,
		CountryCode:     row.CountryCode,
		CountryName:     row.CountryName,
		ClaimDate:       row.ClaimDate,
		GrantMode:       row.GrantMode,
		ClaimResult:     claimResult,
		ClaimResultText: formatRegisterRewardClaimResultText(claimResult),
		GoldAmount:      row.GoldAmount,
		RewardGroupID:   row.RewardGroupID,
		Status:          strings.ToUpper(strings.TrimSpace(row.Status)),
		ErrorMessage:    strings.TrimSpace(row.ErrorMessage),
		CreateTime:      formatRegisterRewardTime(row.CreateTime),
		UpdateTime:      formatRegisterRewardTime(row.UpdateTime),
	}
}

// normalizeRegisterRewardPage 规范分页参数，避免非法页码或 pageSize。
func normalizeRegisterRewardPage(cursor int, limit int) (int, int) {
	if cursor <= 0 {
		cursor = 1
	}
	if limit <= 0 {
		limit = 20
	}
	if limit > 100 {
		limit = 100
	}
	return cursor, limit
}

// resolveRegisterRewardRemainingCount 计算当前日期还剩余多少可发名额。
func resolveRegisterRewardRemainingCount(dailyLimit int64, occupiedCount int64) int64 {
	if dailyLimit <= 0 {
		return 0
	}
	if occupiedCount >= dailyLimit {
		return 0
	}
	return dailyLimit - occupiedCount
}

// deriveRegisterRewardClaimResult 统一归并后台页面展示的领取结果。
func deriveRegisterRewardClaimResult(status string, grantMode string) string {
	normalizedStatus := strings.ToUpper(strings.TrimSpace(status))
	normalizedGrantMode := strings.ToUpper(strings.TrimSpace(grantMode))

	switch {
	case normalizedGrantMode == registerRewardGrantModeQuotaExhausted && normalizedStatus == registerRewardStatusSuccess:
		return registerRewardClaimResultQuotaExhausted
	case normalizedGrantMode == registerRewardGrantModeIssueReward && normalizedStatus == registerRewardStatusSuccess:
		return registerRewardClaimResultRewarded
	case normalizedGrantMode == registerRewardGrantModeIssueReward && normalizedStatus == registerRewardStatusFailed:
		return registerRewardClaimResultFailed
	case normalizedGrantMode == registerRewardGrantModeIssueReward && normalizedStatus == registerRewardStatusPending:
		return registerRewardClaimResultPending
	case normalizedStatus == registerRewardStatusSkipped:
		return registerRewardClaimResultSkipped
	default:
		return registerRewardClaimResultPending
	}
}

// formatRegisterRewardClaimResultText 返回后台页面展示用的中文领取结果文案。
func formatRegisterRewardClaimResultText(claimResult string) string {
	switch strings.ToUpper(strings.TrimSpace(claimResult)) {
	case registerRewardClaimResultRewarded:
		return "已发放"
	case registerRewardClaimResultQuotaExhausted:
		return "名额已满，视为领取成功"
	case registerRewardClaimResultFailed:
		return "发奖失败，待补发"
	case registerRewardClaimResultSkipped:
		return "已跳过"
	default:
		return "发放中"
	}
}