package service

import (
	"strings"
	"time"

	"gorm.io/datatypes"
	"gorm.io/gorm"

	"github.com/sundynix/pets-be/internal/model"
)

// PetInput 建/改宠物入参
type PetInput struct {
	Name     string
	Emoji    string
	Type     string
	Gender   string
	Birthday *time.Time
	Weight   string
	Stage    string
	Age      string
	Color        string
	Breed        string
	AvatarFileID string
	Goals        datatypes.JSON
}

func normalizeWeight(w string) string {
	w = strings.TrimSpace(w)
	if w == "" {
		return ""
	}
	if strings.Contains(w, "kg") {
		return w
	}
	return w + "kg"
}

// ListPets 用户的全部宠物
func (s *Service) ListPets(userID string) ([]model.Pet, error) {
	var pets []model.Pet
	err := s.db.Where("user_id = ?", userID).Order("id asc").Find(&pets).Error
	ids := make([]string, 0, len(pets))
	for i := range pets {
		ids = append(ids, pets[i].AvatarFileID)
	}
	urls := s.fileURLs(ids)
	for i := range pets {
		pets[i].AvatarURL = urls[pets[i].AvatarFileID]
	}
	return pets, err
}

// GetPet 取单只宠物（校验归属）
func (s *Service) GetPet(userID, petID string) (*model.Pet, error) {
	p, err := s.ownedPet(userID, petID)
	if err == nil && p != nil {
		p.AvatarURL = s.fileURL(p.AvatarFileID)
	}
	return p, err
}

// CreatePet 新增宠物并生成默认数据
func (s *Service) CreatePet(userID string, in PetInput) (*model.Pet, error) {
	pet := model.Pet{
		UserID:       userID,
		Name:         in.Name,
		Emoji:        in.Emoji,
		Type:         in.Type,
		Gender:       in.Gender,
		Birthday:     in.Birthday,
		Weight:       normalizeWeight(in.Weight),
		Stage:        in.Stage,
		Age:          in.Age,
		Color:        in.Color,
		Breed:        in.Breed,
		AvatarFileID: in.AvatarFileID,
		HealthStatus: "正常",
		Goals:        in.Goals,
	}
	if err := s.db.Transaction(func(tx *gorm.DB) error {
		if err := tx.Create(&pet).Error; err != nil {
			return err
		}
		return s.seedPetDefaults(tx, &pet)
	}); err != nil {
		return nil, err
	}
	return &pet, nil
}

// UpdatePet 更新宠物字段
func (s *Service) UpdatePet(userID, petID string, fields map[string]any) (*model.Pet, error) {
	if _, err := s.ownedPet(userID, petID); err != nil {
		return nil, err
	}
	if w, ok := fields["weight"].(string); ok {
		fields["weight"] = normalizeWeight(w)
	}
	if err := s.db.Model(&model.Pet{}).Where("id = ?", petID).Updates(fields).Error; err != nil {
		return nil, err
	}
	return s.ownedPet(userID, petID)
}

// DeletePet 删除宠物并级联清除其记录/任务/计划/提醒/每日建议（不留孤儿数据）
func (s *Service) DeletePet(userID, petID string) error {
	if _, err := s.ownedPet(userID, petID); err != nil {
		return err
	}
	return s.db.Transaction(func(tx *gorm.DB) error {
		// 先删计划明细（按 plan_id），再删计划
		var planIDs []string
		tx.Model(&model.Plan{}).Where("pet_id = ?", petID).Pluck("id", &planIDs)
		if len(planIDs) > 0 {
			if err := tx.Where("plan_id IN ?", planIDs).Delete(&model.PlanTask{}).Error; err != nil {
				return err
			}
		}
		for _, m := range []any{
			&model.HealthRecord{}, &model.DailyTask{}, &model.Reminder{},
			&model.Plan{}, &model.DailyAdvice{},
		} {
			if err := tx.Where("pet_id = ?", petID).Delete(m).Error; err != nil {
				return err
			}
		}
		return tx.Where("id = ? AND user_id = ?", petID, userID).Delete(&model.Pet{}).Error
	})
}

// Onboarding 建首宠 + 标记用户已引导
func (s *Service) Onboarding(userID string, in PetInput) (*model.Pet, error) {
	pet, err := s.CreatePet(userID, in)
	if err != nil {
		return nil, err
	}
	if err := s.db.Model(&model.User{}).Where("id = ?", userID).Update("onboarded", true).Error; err != nil {
		return nil, err
	}
	return pet, nil
}

// seedPetDefaults 为新宠按「物种 × 阶段」养护模板生成今日任务、提醒、30 天计划
func (s *Service) seedPetDefaults(tx *gorm.DB, pet *model.Pet) error {
	today := time.Now()
	items := s.careTemplateItems(SpeciesOf(pet.Type), pet.Stage)

	var tasks []model.DailyTask
	var reminders []model.Reminder
	var planTasks []model.PlanTask
	for _, it := range items {
		switch it.Kind {
		case model.CareKindTask:
			tasks = append(tasks, model.DailyTask{
				PetID: pet.ID, UserID: pet.UserID, TaskDate: today,
				Title: it.Title, Description: it.Description, Priority: it.Priority, SheetType: it.SheetType,
			})
		case model.CareKindPlan:
			planTasks = append(planTasks, model.PlanTask{
				Day: it.Day, DayLabel: it.DayLabel, Title: it.Title, Description: it.Description, SheetType: it.SheetType,
			})
		case model.CareKindReminder:
			r := model.Reminder{
				PetID: pet.ID, UserID: pet.UserID, Type: it.ReminderType,
				Title: it.Title, Frequency: it.Frequency,
			}
			if it.OffsetDays > 0 {
				due := today.AddDate(0, 0, it.OffsetDays)
				r.NextDueDate = &due
			}
			reminders = append(reminders, r)
		}
	}

	if len(tasks) > 0 {
		if err := tx.Create(&tasks).Error; err != nil {
			return err
		}
	}
	if len(reminders) > 0 {
		if err := tx.Create(&reminders).Error; err != nil {
			return err
		}
	}

	start := today
	end := today.AddDate(0, 0, 30)
	plan := model.Plan{
		PetID: pet.ID, UserID: pet.UserID, Kind: model.PlanThirtyDay, Stage: pet.Stage,
		StartDate: &start, EndDate: &end, CompletionPct: 0, Status: "active",
		Tasks: planTasks,
	}
	return tx.Create(&plan).Error
}