package invite

import (
	"context"
	"strings"
)

type inviteRankRow struct {
	UserID          int64
	Nickname        string
	Avatar          string
	InviteCount     int64
	RewardGoldCoins int64
}

// GetRank 返回累计邀请排行榜。排行榜不按月重置。
func (s *InviteService) GetRank(ctx context.Context, user AuthUser, limit int) (*InviteRankResponse, error) {
	limit = normalizeInviteRankLimit(limit)
	rows := make([]inviteRankRow, 0, limit)
	if err := s.repo.DB.WithContext(ctx).Raw(`
		SELECT
			invite_rank.user_id AS user_id,
			COALESCE(NULLIF(user_info.user_nickname, ''), invite_code.account, '') AS nickname,
			COALESCE(user_info.user_avatar, '') AS avatar,
			invite_rank.invite_count AS invite_count,
			COALESCE(reward_rank.reward_gold_coins, 0) AS reward_gold_coins
		FROM (
			SELECT inviter_user_id AS user_id, COUNT(1) AS invite_count
			FROM invite_campaign_relation
			WHERE sys_origin = ? AND eligible_status = ?
			GROUP BY inviter_user_id
		) invite_rank
		LEFT JOIN (
			SELECT target_user_id AS user_id, COALESCE(SUM(gold_amount), 0) AS reward_gold_coins
			FROM invite_campaign_reward_log
			WHERE sys_origin = ? AND status = ? AND target_user_id = inviter_user_id
			GROUP BY target_user_id
		) reward_rank ON reward_rank.user_id = invite_rank.user_id
		LEFT JOIN user_base_info user_info ON user_info.id = invite_rank.user_id
		LEFT JOIN invite_code_mapping invite_code ON invite_code.user_id = invite_rank.user_id
		ORDER BY invite_rank.invite_count DESC, reward_gold_coins DESC, invite_rank.user_id ASC
		LIMIT ?
	`, user.SysOrigin, relationStatusEligible, user.SysOrigin, rewardLogStatusSuccess, limit).Scan(&rows).Error; err != nil {
		return nil, err
	}

	items := make([]InviteRankItem, 0, len(rows))
	for index, row := range rows {
		items = append(items, InviteRankItem{
			Rank:            index + 1,
			UserID:          row.UserID,
			Nickname:        strings.TrimSpace(row.Nickname),
			Avatar:          strings.TrimSpace(row.Avatar),
			InviteCount:     row.InviteCount,
			RewardGoldCoins: row.RewardGoldCoins,
		})
	}
	return &InviteRankResponse{
		SysOrigin: user.SysOrigin,
		Limit:     limit,
		Items:     items,
	}, nil
}

func normalizeInviteRankLimit(limit int) int {
	if limit <= 0 {
		return defaultInviteRankLimit
	}
	if limit > maxInviteRankLimit {
		return maxInviteRankLimit
	}
	return limit
}