package invite

import (
	"chatapp3-golang/internal/model"
	"context"
	"net/url"
	"sort"
	"time"
)

// GetHome 返回邀请活动首页所需的配置、任务、月度进度和累计统计。
func (s *InviteService) GetHome(ctx context.Context, user AuthUser) (*HomeResponse, error) {
	bundle, err := s.loadBundle(ctx, user.SysOrigin)
	if err != nil {
		return nil, err
	}
	inviteCode, err := s.ensureInviteCode(ctx, user)
	if err != nil {
		return nil, err
	}

	// 首页需要同时返回当前月进度、累计统计、邀请码和任务配置。
	now := time.Now()
	timezone := normalizeTimezone(bundle.Config.Timezone)
	monthKey := monthKeyAt(now, timezone)
	periodEndAt, secondsToReset := monthResetInfoAt(now, timezone)
	monthly, err := s.findMonthlyProgress(ctx, user.SysOrigin, user.UserID, monthKey)
	if err != nil {
		return nil, err
	}
	stats, err := s.loadStats(ctx, user.SysOrigin, user.UserID)
	if err != nil {
		return nil, err
	}
	claims, err := s.loadClaimedRuleIDs(ctx, user.SysOrigin, user.UserID, monthKey)
	if err != nil {
		return nil, err
	}

	inviterBindRule := firstRule(bundle.Rules, ruleTypeInviterBind)
	inviteeBindRule := firstRule(bundle.Rules, ruleTypeInviteeBind)
	inviteeRechargeRules := rulesByType(bundle.Rules, ruleTypeInviteeRecharge)
	validCountRules := rulesByType(bundle.Rules, ruleTypeInviterValidCount)
	totalRechargeRules := rulesByType(bundle.Rules, ruleTypeInviterTotalRecharge)

	resp := &HomeResponse{
		CampaignEnabled:    bundle.Config.Enabled,
		SysOrigin:          user.SysOrigin,
		InviteCode:         inviteCode,
		InviteLink:         s.cfg.Invite.PublicBaseURL + "/public/h5/invite-campaign/landing?code=" + url.QueryEscape(inviteCode),
		ShareTitle:         defaultIfBlank(bundle.Config.ShareTitle, defaultShareTitle),
		ShareDesc:          defaultIfBlank(bundle.Config.ShareDesc, defaultShareDesc),
		DownloadURL:        bundle.Config.DownloadURL,
		ServiceContact:     bundle.Config.ServiceContact,
		Timezone:           timezone,
		MonthKey:           monthKey,
		ServerTimeMs:       now.UnixMilli(),
		PeriodEndAtMs:      periodEndAt.UnixMilli(),
		SecondsToReset:     secondsToReset,
		ValidUserThreshold: effectiveValidThreshold(inviteeRechargeRules),
		InviterBindReward:  rewardFromRule(inviterBindRule),
		InviteeBindReward:  rewardFromRule(inviteeBindRule),
		InviteeRecharge:    rewardsFromRules(inviteeRechargeRules),
		Stats:              stats,
	}
	resp.MonthlyProgress.InviteCount = monthly.InviteCount
	resp.MonthlyProgress.ValidUserCount = monthly.ValidUserCount
	resp.MonthlyProgress.TotalRecharge = monthly.TotalRecharge
	resp.MonthlyProgress.RewardGoldCoins = monthly.RewardGoldCoins
	resp.ValidCountTasks = buildTaskViews(validCountRules, monthly.InviteCount, claims)
	resp.TotalRechargeTasks = buildTaskViews(totalRechargeRules, monthly.TotalRecharge, claims)
	return resp, nil
}

// buildTaskViews 根据规则、进度和领取状态生成任务展示列表。
func buildTaskViews(rules []model.InviteCampaignRewardRule, progress int64, claimed map[int64]bool) []TaskView {
	result := make([]TaskView, 0, len(rules))
	for _, rule := range rules {
		if !rule.Enabled {
			continue
		}
		result = append(result, TaskView{
			RuleID:        rule.ID,
			RuleType:      rule.RuleType,
			Threshold:     rule.ThresholdValue,
			Progress:      progress,
			GoldAmount:    rule.GoldAmount,
			RewardGroupID: rule.RewardGroupID,
			Achieved:      progress >= rule.ThresholdValue,
			Claimed:       claimed[rule.ID],
		})
	}
	return result
}

// firstRule 返回某类规则里的第一条规则。
func firstRule(rules []model.InviteCampaignRewardRule, ruleType string) *model.InviteCampaignRewardRule {
	for _, item := range rules {
		if item.RuleType == ruleType && item.Enabled {
			rule := item
			return &rule
		}
	}
	return nil
}

// rulesByType 返回某类规则的有序列表。
func rulesByType(rules []model.InviteCampaignRewardRule, ruleType string) []model.InviteCampaignRewardRule {
	result := make([]model.InviteCampaignRewardRule, 0)
	for _, item := range rules {
		if item.RuleType == ruleType && item.Enabled {
			result = append(result, item)
		}
	}
	sort.SliceStable(result, func(i, j int) bool {
		if result[i].Sort == result[j].Sort {
			if result[i].ThresholdValue == result[j].ThresholdValue {
				return result[i].ID < result[j].ID
			}
			return result[i].ThresholdValue < result[j].ThresholdValue
		}
		return result[i].Sort < result[j].Sort
	})
	return result
}

// findRuleByID 按规则 ID 从规则列表中查找规则。
func findRuleByID(rules []model.InviteCampaignRewardRule, ruleID int64) *model.InviteCampaignRewardRule {
	for _, item := range rules {
		if item.ID == ruleID {
			rule := item
			return &rule
		}
	}
	return nil
}

// rewardFromRule 把规则转换成对外奖励视图。
func rewardFromRule(rule *model.InviteCampaignRewardRule) RewardView {
	if rule == nil {
		return RewardView{}
	}
	return RewardView{
		RuleID:        rule.ID,
		RuleType:      rule.RuleType,
		Threshold:     rule.ThresholdValue,
		GoldAmount:    rule.GoldAmount,
		RewardGroupID: rule.RewardGroupID,
	}
}

// rewardsFromRules 把规则列表转换成奖励视图列表。
func rewardsFromRules(rules []model.InviteCampaignRewardRule) []RewardView {
	result := make([]RewardView, 0, len(rules))
	for _, item := range rules {
		result = append(result, rewardFromRule(&item))
	}
	return result
}

// effectiveValidThreshold 计算“有效用户”判定使用的最低充值门槛。
func effectiveValidThreshold(rules []model.InviteCampaignRewardRule) int64 {
	var threshold int64
	for _, rule := range rules {
		if !rule.Enabled || rule.ThresholdValue <= 0 {
			continue
		}
		if threshold == 0 || rule.ThresholdValue < threshold {
			threshold = rule.ThresholdValue
		}
	}
	if threshold == 0 {
		return defaultValidRechargeCoins
	}
	return threshold
}