package service

import (
	"context"
	"errors"
	"fmt"
	"sort"
	"strings"
	"time"

	quitmodel "wx_service/internal/quitcheckin/model"

	"gorm.io/gorm"
)

var (
	// ErrProfileNotFound 表示用户尚未完成基础资料配置。
	ErrProfileNotFound = errors.New("未找到无烟打卡资料")
	// ErrAlreadyRelapsed 表示当天已经记录过复吸，不能重复记录。
	ErrAlreadyRelapsed = errors.New("当天已记录复吸")
	// ErrRewardGoalNotFound 表示指定梦想目标不存在。
	ErrRewardGoalNotFound = errors.New("梦想目标不存在")
	// ErrInvalidRange 表示统计范围不在允许值内。
	ErrInvalidRange = errors.New("统计范围不合法")
)

const (
	dateLayout     = "2006-01-02"
	timeOnlyLayout = "15:04"
	resetRule      = "relapse_clears_streak"
)

var milestoneDays = []int{1, 3, 7, 14, 21, 30, 60, 90, 180, 365}

type Service struct {
	db *gorm.DB
}

// NewService 创建无烟打卡 V2 服务。
func NewService(db *gorm.DB) *Service {
	return &Service{db: db}
}

// ProfileView 表示“我的”页面所需的资料和旅程摘要。
type ProfileView struct {
	Profile *ProfileResult `json:"profile"`
	Journey JourneyResult  `json:"journey"`
}

// ProfileResult 表示用户基础资料。
type ProfileResult struct {
	UserID             int    `json:"user_id"`
	Nickname           string `json:"nickname,omitempty"`
	AvatarURL          string `json:"avatar_url,omitempty"`
	QuitStartDate      string `json:"quit_start_date"`
	PackPriceCent      int    `json:"pack_price_cent"`
	BaselineCigsPerDay int    `json:"baseline_cigs_per_day"`
	Motivation         string `json:"motivation,omitempty"`
	NotifyTime         string `json:"notify_time,omitempty"`
	ResetRule          string `json:"reset_rule"`
	CreatedAt          string `json:"created_at"`
	UpdatedAt          string `json:"updated_at"`
}

// JourneyResult 表示当前戒烟旅程状态。
type JourneyResult struct {
	JourneyID         uint    `json:"journey_id"`
	UserID            int     `json:"user_id"`
	StartDate         string  `json:"start_date"`
	CurrentStreakDays int     `json:"current_streak_days"`
	MaxStreakDays     int     `json:"max_streak_days"`
	LastCheckinDate   *string `json:"last_checkin_date"`
	LastRelapseAt     *string `json:"last_relapse_at"`
	Status            string  `json:"status"`
}

// UpsertProfileRequest 表示资料保存请求。
type UpsertProfileRequest struct {
	QuitStartDate      *time.Time
	PackPriceCent      *int
	BaselineCigsPerDay *int
	Motivation         *string
	NotifyTime         *string
}

// DailyStatusResult 表示某一天的打卡状态。
type DailyStatusResult struct {
	Date       string  `json:"date"`
	Status     string  `json:"status"`
	CheckinAt  *string `json:"checkin_at"`
	RelapsedAt *string `json:"relapsed_at"`
	RelapseNum *int    `json:"relapse_num"`
	Note       *string `json:"note"`
}

// SummaryResult 表示首页和统计页共用的汇总数据。
type SummaryResult struct {
	CurrentStreakDays     int    `json:"current_streak_days"`
	MaxStreakDays         int    `json:"max_streak_days"`
	MilestoneDays         int    `json:"milestone_days"`
	DaysToNextMilestone   int    `json:"days_to_next_milestone"`
	SavedMoneyCent        int    `json:"saved_money_cent"`
	AvoidedCigs           int    `json:"avoided_cigs"`
	AvoidedCigsMode       string `json:"avoided_cigs_mode"`
	HealthRecoveryPercent int    `json:"health_recovery_percent"`
}

// RewardGoalResult 表示梦想目标展示数据。
type RewardGoalResult struct {
	ID                uint    `json:"id"`
	UserID            int     `json:"user_id"`
	Title             string  `json:"title"`
	TargetAmountCent  int     `json:"target_amount_cent"`
	CurrentAmountCent int     `json:"current_amount_cent"`
	ProgressPercent   int     `json:"progress_percent"`
	CoverImage        string  `json:"cover_image,omitempty"`
	Status            string  `json:"status"`
	CompletedAt       *string `json:"completed_at"`
	CreatedAt         string  `json:"created_at"`
}

// HomeResult 表示首页聚合返回数据。
type HomeResult struct {
	DailyStatus DailyStatusResult `json:"daily_status"`
	Summary     SummaryResult     `json:"summary"`
	Goal        *RewardGoalResult `json:"goal,omitempty"`
	Badges      map[string]int    `json:"badges"`
}

// CheckinRequest 表示打卡请求参数。
type CheckinRequest struct {
	Date time.Time
	Note string
}

// CheckinResult 表示打卡后的返回结果。
type CheckinResult struct {
	DailyStatus DailyStatusResult `json:"daily_status"`
	Summary     SummaryResult     `json:"summary"`
}

// RelapseRequest 表示复吸记录请求参数。
type RelapseRequest struct {
	Date       time.Time
	RelapseAt  time.Time
	RelapseNum int
	Reason     string
	Note       string
}

// RelapseEventResult 表示复吸事件返回数据。
type RelapseEventResult struct {
	ID           uint   `json:"id"`
	UserID       int    `json:"user_id"`
	Date         string `json:"date"`
	RelapseAt    string `json:"relapse_at"`
	RelapseNum   int    `json:"relapse_num"`
	Reason       string `json:"reason,omitempty"`
	Note         string `json:"note,omitempty"`
	AffectStreak bool   `json:"affect_streak"`
	CreatedAt    string `json:"created_at"`
}

// RelapseResult 表示记录复吸后的聚合结果。
type RelapseResult struct {
	DailyStatus  DailyStatusResult  `json:"daily_status"`
	RelapseEvent RelapseEventResult `json:"relapse_event"`
	Summary      SummaryResult      `json:"summary"`
}

// StatsOverviewResult 表示统计页概览数据。
type StatsOverviewResult struct {
	Range            string            `json:"range"`
	Summary          SummaryResult     `json:"summary"`
	Trend            []TrendItemResult `json:"trend"`
	HealthMilestones []HealthMilestone `json:"health_milestones"`
}

// TrendItemResult 表示趋势图中的单日数据点。
type TrendItemResult struct {
	Date       string `json:"date"`
	Status     string `json:"status"`
	RelapseNum int    `json:"relapse_num"`
}

// HealthMilestone 表示健康恢复里程碑。
type HealthMilestone struct {
	Code     string `json:"code"`
	Title    string `json:"title"`
	Percent  int    `json:"percent"`
	Unlocked bool   `json:"unlocked"`
}

// BadgeResult 表示勋章展示数据。
type BadgeResult struct {
	ID              int     `json:"id"`
	Code            string  `json:"code"`
	Title           string  `json:"title"`
	Description     string  `json:"description"`
	Icon            string  `json:"icon,omitempty"`
	UnlockRule      string  `json:"unlock_rule"`
	Unlocked        bool    `json:"unlocked"`
	UnlockedAt      *string `json:"unlocked_at"`
	ProgressPercent int     `json:"progress_percent"`
}

// BadgeListResult 表示勋章列表返回结果。
type BadgeListResult struct {
	Items         []BadgeResult `json:"items"`
	UnlockedCount int           `json:"unlocked_count"`
	TotalCount    int           `json:"total_count"`
}

// RelapseListResult 表示复吸历史分页结果。
type RelapseListResult struct {
	Items    []RelapseEventResult `json:"items"`
	Total    int64                `json:"total"`
	Page     int                  `json:"page"`
	PageSize int                  `json:"page_size"`
}

// RewardGoalListResult 表示梦想目标列表结果。
type RewardGoalListResult struct {
	Items []RewardGoalResult `json:"items"`
	Total int                `json:"total"`
}

// CreateRewardGoalRequest 表示创建梦想目标请求。
type CreateRewardGoalRequest struct {
	Title            string
	TargetAmountCent int
	CoverImage       string
}

// UpdateRewardGoalRequest 表示更新梦想目标请求。
type UpdateRewardGoalRequest struct {
	Title            *string
	TargetAmountCent *int
	CoverImage       *string
	Status           *string
}

// PosterGenerateRequest 表示海报生成请求。
type PosterGenerateRequest struct {
	TemplateCode string
	ShowFields   []string
}

// PosterDataResult 表示海报预览数据。
type PosterDataResult struct {
	Nickname              string `json:"nickname,omitempty"`
	StreakDays            int    `json:"streak_days"`
	SavedMoneyCent        int    `json:"saved_money_cent"`
	AvoidedCigs           int    `json:"avoided_cigs"`
	HealthRecoveryPercent int    `json:"health_recovery_percent"`
	TemplateCode          string `json:"template_code"`
	ShareTitle            string `json:"share_title"`
}

// PosterGenerateResult 表示海报生成结果。
type PosterGenerateResult struct {
	TemplateCode string   `json:"template_code"`
	ImageURL     string   `json:"image_url"`
	ShareTitle   string   `json:"share_title"`
	ShowFields   []string `json:"show_fields"`
}

// GetProfile 返回用户资料与旅程概览。
func (s *Service) GetProfile(ctx context.Context, uid int, nickname, avatarURL string, now time.Time) (ProfileView, error) {
	profile, err := s.loadProfile(ctx, uid)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return ProfileView{
				Profile: nil,
				Journey: JourneyResult{
					UserID:            uid,
					CurrentStreakDays: 0,
					MaxStreakDays:     0,
					Status:            "pending_profile",
				},
			}, nil
		}
		return ProfileView{}, err
	}

	summary, lastCheckin, lastRelapse, _, err := s.computeSummary(ctx, uid, *profile, now)
	if err != nil {
		return ProfileView{}, err
	}

	return ProfileView{
		Profile: &ProfileResult{
			UserID:             uid,
			Nickname:           nickname,
			AvatarURL:          avatarURL,
			QuitStartDate:      formatDate(profile.QuitStartDate),
			PackPriceCent:      profile.PackPriceCent,
			BaselineCigsPerDay: profile.BaselineCigsPerDay,
			Motivation:         profile.Motivation,
			NotifyTime:         profile.NotifyTime,
			ResetRule:          profile.ResetRule,
			CreatedAt:          profile.CreatedAt.Format(time.RFC3339),
			UpdatedAt:          profile.UpdatedAt.Format(time.RFC3339),
		},
		Journey: JourneyResult{
			JourneyID:         profile.ID,
			UserID:            uid,
			StartDate:         formatDate(profile.QuitStartDate),
			CurrentStreakDays: summary.CurrentStreakDays,
			MaxStreakDays:     summary.MaxStreakDays,
			LastCheckinDate:   lastCheckin,
			LastRelapseAt:     lastRelapse,
			Status:            "active",
		},
	}, nil
}

// UpsertProfile 创建或更新用户资料。
func (s *Service) UpsertProfile(ctx context.Context, uid int, req UpsertProfileRequest, nickname, avatarURL string, now time.Time) (ProfileView, error) {
	var profile quitmodel.Profile
	err := s.db.WithContext(ctx).Where("uid = ?", uid).First(&profile).Error
	if err != nil {
		if !errors.Is(err, gorm.ErrRecordNotFound) {
			return ProfileView{}, err
		}
		profile = quitmodel.Profile{
			UID:       uid,
			ResetRule: resetRule,
		}
	}

	if req.QuitStartDate != nil {
		profile.QuitStartDate = normalizeDate(*req.QuitStartDate)
	}
	if req.PackPriceCent != nil {
		profile.PackPriceCent = *req.PackPriceCent
	}
	if req.BaselineCigsPerDay != nil {
		profile.BaselineCigsPerDay = *req.BaselineCigsPerDay
	}
	if req.Motivation != nil {
		profile.Motivation = strings.TrimSpace(*req.Motivation)
	}
	if req.NotifyTime != nil {
		profile.NotifyTime = strings.TrimSpace(*req.NotifyTime)
	}
	if profile.ResetRule == "" {
		profile.ResetRule = resetRule
	}

	if err := s.db.WithContext(ctx).Save(&profile).Error; err != nil {
		return ProfileView{}, err
	}

	return s.GetProfile(ctx, uid, nickname, avatarURL, now)
}

// Home 返回首页聚合数据。
func (s *Service) Home(ctx context.Context, uid int, now time.Time) (HomeResult, error) {
	profile, err := s.loadProfile(ctx, uid)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return HomeResult{}, ErrProfileNotFound
		}
		return HomeResult{}, err
	}

	today := normalizeDate(now)
	dailyStatus, err := s.getOrBuildDailyStatus(ctx, uid, today, now)
	if err != nil {
		return HomeResult{}, err
	}

	summary, _, _, unlockedCount, err := s.computeSummary(ctx, uid, *profile, now)
	if err != nil {
		return HomeResult{}, err
	}

	activeGoal, err := s.firstActiveGoal(ctx, uid, summary.SavedMoneyCent)
	if err != nil {
		return HomeResult{}, err
	}

	return HomeResult{
		DailyStatus: toDailyStatusResult(dailyStatus),
		Summary:     summary,
		Goal:        activeGoal,
		Badges: map[string]int{
			"unlocked_count": unlockedCount,
			"total_count":    len(milestoneDays),
		},
	}, nil
}

// Checkin 执行当日打卡。
func (s *Service) Checkin(ctx context.Context, uid int, req CheckinRequest, now time.Time) (CheckinResult, error) {
	profile, err := s.loadProfile(ctx, uid)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return CheckinResult{}, ErrProfileNotFound
		}
		return CheckinResult{}, err
	}

	date := normalizeDate(req.Date)
	var status quitmodel.DailyStatus
	err = s.db.WithContext(ctx).Where("uid = ? AND date = ?", uid, date).First(&status).Error
	if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
		return CheckinResult{}, err
	}

	checkinAt := now
	if errors.Is(err, gorm.ErrRecordNotFound) {
		status = quitmodel.DailyStatus{
			UID:       uid,
			Date:      date,
			Status:    quitmodel.DailyStatusCheckedIn,
			CheckInAt: &checkinAt,
			Note:      strings.TrimSpace(req.Note),
		}
		if err := s.db.WithContext(ctx).Create(&status).Error; err != nil {
			return CheckinResult{}, err
		}
	} else {
		if status.Status == quitmodel.DailyStatusRelapsed {
			return CheckinResult{}, ErrAlreadyRelapsed
		}
		if status.Status != quitmodel.DailyStatusCheckedIn {
			status.Status = quitmodel.DailyStatusCheckedIn
			status.CheckInAt = &checkinAt
			status.Note = strings.TrimSpace(req.Note)
			if err := s.db.WithContext(ctx).Save(&status).Error; err != nil {
				return CheckinResult{}, err
			}
		}
	}

	summary, _, _, _, err := s.computeSummary(ctx, uid, *profile, now)
	if err != nil {
		return CheckinResult{}, err
	}

	return CheckinResult{
		DailyStatus: toDailyStatusResult(status),
		Summary:     summary,
	}, nil
}

// Relapse 记录当日复吸并清零连续天数。
func (s *Service) Relapse(ctx context.Context, uid int, req RelapseRequest, now time.Time) (RelapseResult, error) {
	profile, err := s.loadProfile(ctx, uid)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return RelapseResult{}, ErrProfileNotFound
		}
		return RelapseResult{}, err
	}

	date := normalizeDate(req.Date)
	var status quitmodel.DailyStatus
	err = s.db.WithContext(ctx).Where("uid = ? AND date = ?", uid, date).First(&status).Error
	if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
		return RelapseResult{}, err
	}
	if err == nil && status.Status == quitmodel.DailyStatusRelapsed {
		return RelapseResult{}, ErrAlreadyRelapsed
	}

	relapsedAt := req.RelapseAt
	if relapsedAt.IsZero() {
		relapsedAt = now
	}

	err = s.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			status = quitmodel.DailyStatus{
				UID:        uid,
				Date:       date,
				Status:     quitmodel.DailyStatusRelapsed,
				RelapsedAt: &relapsedAt,
				RelapseNum: req.RelapseNum,
				Reason:     strings.TrimSpace(req.Reason),
				Note:       strings.TrimSpace(req.Note),
				CheckInAt:  nil,
			}
			if e := tx.Create(&status).Error; e != nil {
				return e
			}
		} else {
			status.Status = quitmodel.DailyStatusRelapsed
			status.CheckInAt = nil
			status.RelapsedAt = &relapsedAt
			status.RelapseNum = req.RelapseNum
			status.Reason = strings.TrimSpace(req.Reason)
			status.Note = strings.TrimSpace(req.Note)
			if e := tx.Save(&status).Error; e != nil {
				return e
			}
		}

		event := quitmodel.RelapseEvent{
			UID:          uid,
			Date:         date,
			RelapseAt:    relapsedAt,
			RelapseNum:   req.RelapseNum,
			Reason:       strings.TrimSpace(req.Reason),
			Note:         strings.TrimSpace(req.Note),
			AffectStreak: true,
		}
		return tx.Create(&event).Error
	})
	if err != nil {
		return RelapseResult{}, err
	}

	var event quitmodel.RelapseEvent
	if err := s.db.WithContext(ctx).Where("uid = ? AND date = ?", uid, date).Order("id desc").First(&event).Error; err != nil {
		return RelapseResult{}, err
	}

	summary, _, _, _, err := s.computeSummary(ctx, uid, *profile, now)
	if err != nil {
		return RelapseResult{}, err
	}

	return RelapseResult{
		DailyStatus: toDailyStatusResult(status),
		RelapseEvent: RelapseEventResult{
			ID:           event.ID,
			UserID:       uid,
			Date:         formatDate(event.Date),
			RelapseAt:    event.RelapseAt.Format(time.RFC3339),
			RelapseNum:   event.RelapseNum,
			Reason:       event.Reason,
			Note:         event.Note,
			AffectStreak: event.AffectStreak,
			CreatedAt:    event.CreatedAt.Format(time.RFC3339),
		},
		Summary: summary,
	}, nil
}

// StatsOverview 返回统计概览。
func (s *Service) StatsOverview(ctx context.Context, uid int, rangeName string, now time.Time) (StatsOverviewResult, error) {
	profile, err := s.loadProfile(ctx, uid)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return StatsOverviewResult{}, ErrProfileNotFound
		}
		return StatsOverviewResult{}, err
	}

	rangeName = strings.TrimSpace(strings.ToLower(rangeName))
	if rangeName == "" {
		rangeName = "week"
	}

	var start time.Time
	end := normalizeDate(now)
	switch rangeName {
	case "week":
		start = end.AddDate(0, 0, -6)
	case "month":
		start = end.AddDate(0, 0, -29)
	case "year":
		start = end.AddDate(0, 0, -364)
	default:
		return StatsOverviewResult{}, ErrInvalidRange
	}

	var dailyStatuses []quitmodel.DailyStatus
	if err := s.db.WithContext(ctx).
		Where("uid = ? AND date >= ? AND date <= ?", uid, start, end).
		Order("date asc").
		Find(&dailyStatuses).Error; err != nil {
		return StatsOverviewResult{}, err
	}

	statusMap := make(map[string]quitmodel.DailyStatus, len(dailyStatuses))
	for _, item := range dailyStatuses {
		statusMap[formatDate(item.Date)] = item
	}

	trend := make([]TrendItemResult, 0, daysBetweenInclusive(start, end))
	for cursor := start; !cursor.After(end); cursor = cursor.AddDate(0, 0, 1) {
		key := formatDate(cursor)
		item, ok := statusMap[key]
		if !ok {
			status := quitmodel.DailyStatusMissed
			if isSameDate(cursor, end) {
				status = quitmodel.DailyStatusPending
			}
			trend = append(trend, TrendItemResult{Date: key, Status: status, RelapseNum: 0})
			continue
		}
		trend = append(trend, TrendItemResult{Date: key, Status: item.Status, RelapseNum: item.RelapseNum})
	}

	summary, _, _, _, err := s.computeSummary(ctx, uid, *profile, now)
	if err != nil {
		return StatsOverviewResult{}, err
	}

	return StatsOverviewResult{
		Range:   rangeName,
		Summary: summary,
		Trend:   trend,
		HealthMilestones: []HealthMilestone{
			{
				Code:     "lung_recovery",
				Title:    "肺部功能改善",
				Percent:  summary.HealthRecoveryPercent,
				Unlocked: summary.CurrentStreakDays >= 7,
			},
		},
	}, nil
}

// ListBadges 返回勋章清单。
func (s *Service) ListBadges(ctx context.Context, uid int, now time.Time) (BadgeListResult, error) {
	profile, err := s.loadProfile(ctx, uid)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return BadgeListResult{Items: []BadgeResult{}}, nil
		}
		return BadgeListResult{}, err
	}

	summary, _, _, _, err := s.computeSummary(ctx, uid, *profile, now)
	if err != nil {
		return BadgeListResult{}, err
	}

	badges := make([]BadgeResult, 0, len(milestoneDays))
	unlockedCount := 0
	for idx, day := range milestoneDays {
		unlocked := summary.MaxStreakDays >= day
		progress := 0
		if unlocked {
			progress = 100
			unlockedCount++
		} else if day > 0 {
			progress = minInt((summary.CurrentStreakDays*100)/day, 99)
		}
		var unlockedAt *string
		if unlocked {
			v := fmt.Sprintf("%d 天里程碑", day)
			unlockedAt = &v
		}
		badges = append(badges, BadgeResult{
			ID:              idx + 1,
			Code:            fmt.Sprintf("streak_%d", day),
			Title:           fmt.Sprintf("%d 天里程碑", day),
			Description:     fmt.Sprintf("连续无烟 %d 天", day),
			UnlockRule:      fmt.Sprintf("连续无烟 %d 天", day),
			Unlocked:        unlocked,
			UnlockedAt:      unlockedAt,
			ProgressPercent: progress,
		})
	}

	return BadgeListResult{
		Items:         badges,
		UnlockedCount: unlockedCount,
		TotalCount:    len(badges),
	}, nil
}

// ListRelapses 分页查询复吸历史。
func (s *Service) ListRelapses(ctx context.Context, uid, page, pageSize int) (RelapseListResult, error) {
	if page <= 0 {
		page = 1
	}
	if pageSize <= 0 {
		pageSize = 20
	}
	if pageSize > 100 {
		pageSize = 100
	}

	var total int64
	if err := s.db.WithContext(ctx).Model(&quitmodel.RelapseEvent{}).Where("uid = ?", uid).Count(&total).Error; err != nil {
		return RelapseListResult{}, err
	}

	var items []quitmodel.RelapseEvent
	if err := s.db.WithContext(ctx).
		Where("uid = ?", uid).
		Order("date desc, relapse_at desc, id desc").
		Offset((page - 1) * pageSize).
		Limit(pageSize).
		Find(&items).Error; err != nil {
		return RelapseListResult{}, err
	}

	result := make([]RelapseEventResult, 0, len(items))
	for _, item := range items {
		result = append(result, RelapseEventResult{
			ID:           item.ID,
			UserID:       uid,
			Date:         formatDate(item.Date),
			RelapseAt:    item.RelapseAt.Format(time.RFC3339),
			RelapseNum:   item.RelapseNum,
			Reason:       item.Reason,
			Note:         item.Note,
			AffectStreak: item.AffectStreak,
			CreatedAt:    item.CreatedAt.Format(time.RFC3339),
		})
	}

	return RelapseListResult{
		Items:    result,
		Total:    total,
		Page:     page,
		PageSize: pageSize,
	}, nil
}

// ListRewardGoals 查询梦想目标列表。
func (s *Service) ListRewardGoals(ctx context.Context, uid int, status string, now time.Time) (RewardGoalListResult, error) {
	status = strings.TrimSpace(strings.ToLower(status))
	query := s.db.WithContext(ctx).Where("uid = ?", uid)
	if status != "" && status != "all" {
		query = query.Where("status = ?", status)
	}

	var goals []quitmodel.RewardGoal
	if err := query.Order("created_at desc").Find(&goals).Error; err != nil {
		return RewardGoalListResult{}, err
	}

	currentAmount, err := s.currentSavedMoney(ctx, uid, now)
	if err != nil {
		return RewardGoalListResult{}, err
	}

	items := make([]RewardGoalResult, 0, len(goals))
	for _, goal := range goals {
		items = append(items, toRewardGoalResult(goal, uid, currentAmount))
	}

	return RewardGoalListResult{
		Items: items,
		Total: len(items),
	}, nil
}

// CreateRewardGoal 创建梦想目标。
func (s *Service) CreateRewardGoal(ctx context.Context, uid int, req CreateRewardGoalRequest, now time.Time) (RewardGoalResult, error) {
	goal := quitmodel.RewardGoal{
		UID:              uid,
		Title:            strings.TrimSpace(req.Title),
		TargetAmountCent: req.TargetAmountCent,
		CoverImage:       strings.TrimSpace(req.CoverImage),
		Status:           quitmodel.RewardGoalStatusActive,
	}
	if err := s.db.WithContext(ctx).Create(&goal).Error; err != nil {
		return RewardGoalResult{}, err
	}

	currentAmount, err := s.currentSavedMoney(ctx, uid, now)
	if err != nil {
		return RewardGoalResult{}, err
	}

	return toRewardGoalResult(goal, uid, currentAmount), nil
}

// UpdateRewardGoal 更新梦想目标。
func (s *Service) UpdateRewardGoal(ctx context.Context, uid, id int, req UpdateRewardGoalRequest, now time.Time) (RewardGoalResult, error) {
	var goal quitmodel.RewardGoal
	if err := s.db.WithContext(ctx).Where("uid = ? AND id = ?", uid, id).First(&goal).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return RewardGoalResult{}, ErrRewardGoalNotFound
		}
		return RewardGoalResult{}, err
	}

	if req.Title != nil {
		goal.Title = strings.TrimSpace(*req.Title)
	}
	if req.TargetAmountCent != nil {
		goal.TargetAmountCent = *req.TargetAmountCent
	}
	if req.CoverImage != nil {
		goal.CoverImage = strings.TrimSpace(*req.CoverImage)
	}
	if req.Status != nil {
		goal.Status = strings.TrimSpace(strings.ToLower(*req.Status))
		if goal.Status == quitmodel.RewardGoalStatusCompleted {
			nowCopy := now
			goal.CompletedAt = &nowCopy
		}
	}
	if err := s.db.WithContext(ctx).Save(&goal).Error; err != nil {
		return RewardGoalResult{}, err
	}

	currentAmount, err := s.currentSavedMoney(ctx, uid, now)
	if err != nil {
		return RewardGoalResult{}, err
	}

	return toRewardGoalResult(goal, uid, currentAmount), nil
}

// PosterData 返回海报预览数据。
func (s *Service) PosterData(ctx context.Context, uid int, nickname string, templateCode string, now time.Time) (PosterDataResult, error) {
	profile, err := s.loadProfile(ctx, uid)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return PosterDataResult{}, ErrProfileNotFound
		}
		return PosterDataResult{}, err
	}

	summary, _, _, _, err := s.computeSummary(ctx, uid, *profile, now)
	if err != nil {
		return PosterDataResult{}, err
	}

	if strings.TrimSpace(templateCode) == "" {
		templateCode = "vibrant_1"
	}

	return PosterDataResult{
		Nickname:              nickname,
		StreakDays:            summary.CurrentStreakDays,
		SavedMoneyCent:        summary.SavedMoneyCent,
		AvoidedCigs:           summary.AvoidedCigs,
		HealthRecoveryPercent: summary.HealthRecoveryPercent,
		TemplateCode:          templateCode,
		ShareTitle:            fmt.Sprintf("我已经坚持戒烟 %d 天", summary.CurrentStreakDays),
	}, nil
}

// GeneratePoster 返回海报生成结果。
func (s *Service) GeneratePoster(ctx context.Context, uid int, nickname string, req PosterGenerateRequest, now time.Time) (PosterGenerateResult, error) {
	data, err := s.PosterData(ctx, uid, nickname, req.TemplateCode, now)
	if err != nil {
		return PosterGenerateResult{}, err
	}

	showFields := normalizeShowFields(req.ShowFields)
	if len(showFields) == 0 {
		showFields = []string{"streak_days", "saved_money_cent", "health_recovery_percent"}
	}

	return PosterGenerateResult{
		TemplateCode: data.TemplateCode,
		ImageURL: fmt.Sprintf(
			"https://static.nepiedg.top/quit-checkin/posters/%d/%s/%d.png",
			uid,
			data.TemplateCode,
			now.Unix(),
		),
		ShareTitle: data.ShareTitle,
		ShowFields: showFields,
	}, nil
}

func (s *Service) loadProfile(ctx context.Context, uid int) (*quitmodel.Profile, error) {
	var profile quitmodel.Profile
	if err := s.db.WithContext(ctx).Where("uid = ?", uid).First(&profile).Error; err != nil {
		return nil, err
	}
	return &profile, nil
}

func (s *Service) getOrBuildDailyStatus(ctx context.Context, uid int, date, now time.Time) (quitmodel.DailyStatus, error) {
	var status quitmodel.DailyStatus
	err := s.db.WithContext(ctx).Where("uid = ? AND date = ?", uid, date).First(&status).Error
	if err == nil {
		return status, nil
	}
	if !errors.Is(err, gorm.ErrRecordNotFound) {
		return quitmodel.DailyStatus{}, err
	}
	return quitmodel.DailyStatus{
		Date:   date,
		Status: quitmodel.DailyStatusPending,
	}, nil
}

func (s *Service) firstActiveGoal(ctx context.Context, uid int, currentAmount int) (*RewardGoalResult, error) {
	var goal quitmodel.RewardGoal
	if err := s.db.WithContext(ctx).Where("uid = ? AND status = ?", uid, quitmodel.RewardGoalStatusActive).Order("created_at asc").First(&goal).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, nil
		}
		return nil, err
	}
	result := toRewardGoalResult(goal, uid, currentAmount)
	return &result, nil
}

func (s *Service) currentSavedMoney(ctx context.Context, uid int, now time.Time) (int, error) {
	profile, err := s.loadProfile(ctx, uid)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return 0, nil
		}
		return 0, err
	}
	summary, _, _, _, err := s.computeSummary(ctx, uid, *profile, now)
	if err != nil {
		return 0, err
	}
	return summary.SavedMoneyCent, nil
}

func (s *Service) computeSummary(ctx context.Context, uid int, profile quitmodel.Profile, now time.Time) (SummaryResult, *string, *string, int, error) {
	today := normalizeDate(now)

	var statuses []quitmodel.DailyStatus
	if err := s.db.WithContext(ctx).
		Where("uid = ? AND date >= ? AND date <= ?", uid, profile.QuitStartDate, today).
		Order("date asc").
		Find(&statuses).Error; err != nil {
		return SummaryResult{}, nil, nil, 0, err
	}

	statusMap := make(map[string]quitmodel.DailyStatus, len(statuses))
	var lastCheckin *string
	var lastRelapse *string
	totalRelapseNum := 0
	for _, item := range statuses {
		key := formatDate(item.Date)
		statusMap[key] = item
		if item.Status == quitmodel.DailyStatusCheckedIn {
			v := key
			lastCheckin = &v
		}
		if item.Status == quitmodel.DailyStatusRelapsed && item.RelapsedAt != nil {
			v := item.RelapsedAt.Format(time.RFC3339)
			lastRelapse = &v
			totalRelapseNum += item.RelapseNum
		}
	}

	currentStreak := 0
	maxStreak := 0
	runningStreak := 0
	for cursor := normalizeDate(profile.QuitStartDate); !cursor.After(today); cursor = cursor.AddDate(0, 0, 1) {
		key := formatDate(cursor)
		item, ok := statusMap[key]
		status := quitmodel.DailyStatusMissed
		if ok {
			status = item.Status
		} else if isSameDate(cursor, today) {
			status = quitmodel.DailyStatusPending
		}

		if status == quitmodel.DailyStatusCheckedIn {
			runningStreak++
			if runningStreak > maxStreak {
				maxStreak = runningStreak
			}
		} else {
			runningStreak = 0
		}
	}

	todayKey := formatDate(today)
	if item, ok := statusMap[todayKey]; ok && item.Status == quitmodel.DailyStatusRelapsed {
		currentStreak = 0
	} else {
		cursor := today
		if _, ok := statusMap[todayKey]; !ok {
			cursor = today.AddDate(0, 0, -1)
		}
		for !cursor.Before(normalizeDate(profile.QuitStartDate)) {
			item, ok := statusMap[formatDate(cursor)]
			if !ok || item.Status != quitmodel.DailyStatusCheckedIn {
				break
			}
			currentStreak++
			cursor = cursor.AddDate(0, 0, -1)
		}
	}

	milestone := nextMilestone(currentStreak)
	daysToNext := 0
	if milestone > currentStreak {
		daysToNext = milestone - currentStreak
	}

	elapsedDays := daysBetween(normalizeDate(profile.QuitStartDate), today)
	if currentStreak > elapsedDays {
		elapsedDays = currentStreak
	}
	theoreticalCigs := elapsedDays * profile.BaselineCigsPerDay
	avoidedCigs := theoreticalCigs - totalRelapseNum
	if avoidedCigs < 0 {
		avoidedCigs = 0
	}
	savedMoney := 0
	if profile.PackPriceCent > 0 {
		savedMoney = (avoidedCigs * profile.PackPriceCent) / 20
	}
	healthPercent := minInt(currentStreak*5, 100)

	unlockedCount := 0
	for _, day := range milestoneDays {
		if maxStreak >= day {
			unlockedCount++
		}
	}

	return SummaryResult{
		CurrentStreakDays:     currentStreak,
		MaxStreakDays:         maxStreak,
		MilestoneDays:         milestone,
		DaysToNextMilestone:   daysToNext,
		SavedMoneyCent:        savedMoney,
		AvoidedCigs:           avoidedCigs,
		AvoidedCigsMode:       "exact",
		HealthRecoveryPercent: healthPercent,
	}, lastCheckin, lastRelapse, unlockedCount, nil
}

func toDailyStatusResult(status quitmodel.DailyStatus) DailyStatusResult {
	result := DailyStatusResult{
		Date:   formatDate(status.Date),
		Status: status.Status,
	}
	if result.Date == "0001-01-01" {
		result.Date = formatDate(normalizeDate(time.Now()))
	}
	if status.CheckInAt != nil {
		v := status.CheckInAt.Format(time.RFC3339)
		result.CheckinAt = &v
	}
	if status.RelapsedAt != nil {
		v := status.RelapsedAt.Format(time.RFC3339)
		result.RelapsedAt = &v
		num := status.RelapseNum
		result.RelapseNum = &num
	}
	if strings.TrimSpace(status.Note) != "" {
		v := status.Note
		result.Note = &v
	}
	return result
}

func toRewardGoalResult(goal quitmodel.RewardGoal, uid int, currentAmount int) RewardGoalResult {
	progress := 0
	if goal.TargetAmountCent > 0 {
		progress = minInt((currentAmount*100)/goal.TargetAmountCent, 100)
	}
	var completedAt *string
	if goal.CompletedAt != nil {
		v := goal.CompletedAt.Format(time.RFC3339)
		completedAt = &v
	}
	current := currentAmount
	if goal.TargetAmountCent > 0 && current > goal.TargetAmountCent {
		current = goal.TargetAmountCent
	}
	return RewardGoalResult{
		ID:                goal.ID,
		UserID:            uid,
		Title:             goal.Title,
		TargetAmountCent:  goal.TargetAmountCent,
		CurrentAmountCent: current,
		ProgressPercent:   progress,
		CoverImage:        goal.CoverImage,
		Status:            goal.Status,
		CompletedAt:       completedAt,
		CreatedAt:         goal.CreatedAt.Format(time.RFC3339),
	}
}

func nextMilestone(current int) int {
	for _, item := range milestoneDays {
		if item > current {
			return item
		}
	}
	return milestoneDays[len(milestoneDays)-1]
}

func normalizeDate(t time.Time) time.Time {
	return time.Date(t.Year(), t.Month(), t.Day(), 0, 0, 0, 0, time.Local)
}

func formatDate(t time.Time) string {
	return normalizeDate(t).Format(dateLayout)
}

func daysBetween(start, end time.Time) int {
	start = normalizeDate(start)
	end = normalizeDate(end)
	if end.Before(start) {
		return 0
	}
	return int(end.Sub(start).Hours() / 24)
}

func daysBetweenInclusive(start, end time.Time) int {
	return daysBetween(start, end) + 1
}

func isSameDate(a, b time.Time) bool {
	return normalizeDate(a).Equal(normalizeDate(b))
}

func minInt(a, b int) int {
	if a < b {
		return a
	}
	return b
}

// ParseNotifyTime 校验提醒时间是否符合 HH:MM 格式。
func ParseNotifyTime(v string) bool {
	if strings.TrimSpace(v) == "" {
		return true
	}
	_, err := time.ParseInLocation(timeOnlyLayout, v, time.Local)
	return err == nil
}

// SortRelapses 按日期和复吸时间倒序整理复吸列表。
func SortRelapses(items []RelapseEventResult) {
	sort.Slice(items, func(i, j int) bool {
		if items[i].Date == items[j].Date {
			return items[i].RelapseAt > items[j].RelapseAt
		}
		return items[i].Date > items[j].Date
	})
}

// ListDreamPresets 返回启用的预设梦想目标列表。
func (s *Service) ListDreamPresets(ctx context.Context) ([]quitmodel.DreamPreset, error) {
	var presets []quitmodel.DreamPreset
	if err := s.db.WithContext(ctx).
		Where("is_active = ?", true).
		Order("sort_order ASC, id ASC").
		Find(&presets).Error; err != nil {
		return nil, fmt.Errorf("list dream presets: %w", err)
	}
	return presets, nil
}

func normalizeShowFields(items []string) []string {
	allowed := map[string]struct{}{
		"streak_days":             {},
		"saved_money_cent":        {},
		"avoided_cigs":            {},
		"health_recovery_percent": {},
	}
	result := make([]string, 0, len(items))
	seen := make(map[string]struct{}, len(items))
	for _, item := range items {
		key := strings.TrimSpace(strings.ToLower(item))
		if key == "" {
			continue
		}
		if _, ok := allowed[key]; !ok {
			continue
		}
		if _, ok := seen[key]; ok {
			continue
		}
		seen[key] = struct{}{}
		result = append(result, key)
	}
	return result
}