package service

import (
	"time"

	"github.com/daniil/homelab-api/internal/model"
	"github.com/daniil/homelab-api/internal/repository"
)

type HabitService struct {
	habitRepo *repository.HabitRepository
}

func NewHabitService(habitRepo *repository.HabitRepository) *HabitService {
	return &HabitService{habitRepo: habitRepo}
}

func (s *HabitService) Create(userID int64, req *model.CreateHabitRequest) (*model.Habit, error) {
	habit := &model.Habit{
		UserID:      userID,
		Name:        req.Name,
		Description: req.Description,
		Color:       defaultString(req.Color, "#6366f1"),
		Icon:        defaultString(req.Icon, "check"),
		Frequency:   defaultString(req.Frequency, "daily"),
		TargetDays:  req.TargetDays,
		TargetCount: defaultInt(req.TargetCount, 1),
	}

	if err := s.habitRepo.Create(habit); err != nil {
		return nil, err
	}

	return habit, nil
}

func (s *HabitService) Get(id, userID int64) (*model.Habit, error) {
	return s.habitRepo.GetByID(id, userID)
}

func (s *HabitService) List(userID int64, includeArchived bool) ([]model.Habit, error) {
	habits, err := s.habitRepo.ListByUser(userID, includeArchived)
	if err != nil {
		return nil, err
	}
	if habits == nil {
		habits = []model.Habit{}
	}
	return habits, nil
}

func (s *HabitService) Update(id, userID int64, req *model.UpdateHabitRequest) (*model.Habit, error) {
	habit, err := s.habitRepo.GetByID(id, userID)
	if err != nil {
		return nil, err
	}

	if req.Name != nil {
		habit.Name = *req.Name
	}
	if req.Description != nil {
		habit.Description = *req.Description
	}
	if req.Color != nil {
		habit.Color = *req.Color
	}
	if req.Icon != nil {
		habit.Icon = *req.Icon
	}
	if req.Frequency != nil {
		habit.Frequency = *req.Frequency
	}
	if req.TargetDays != nil {
		habit.TargetDays = req.TargetDays
	}
	if req.TargetCount != nil {
		habit.TargetCount = *req.TargetCount
	}
	if req.IsArchived != nil {
		habit.IsArchived = *req.IsArchived
	}

	if err := s.habitRepo.Update(habit); err != nil {
		return nil, err
	}

	return habit, nil
}

func (s *HabitService) Delete(id, userID int64) error {
	return s.habitRepo.Delete(id, userID)
}

func (s *HabitService) Log(habitID, userID int64, req *model.LogHabitRequest) (*model.HabitLog, error) {
	// Verify habit exists and belongs to user
	if _, err := s.habitRepo.GetByID(habitID, userID); err != nil {
		return nil, err
	}

	date := time.Now().Truncate(24 * time.Hour)
	if req.Date != "" {
		parsed, err := time.Parse("2006-01-02", req.Date)
		if err != nil {
			return nil, err
		}
		date = parsed
	}

	log := &model.HabitLog{
		HabitID: habitID,
		UserID:  userID,
		Date:    date,
		Count:   defaultInt(req.Count, 1),
		Note:    req.Note,
	}

	if err := s.habitRepo.CreateLog(log); err != nil {
		return nil, err
	}

	return log, nil
}

func (s *HabitService) GetLogs(habitID, userID int64, days int) ([]model.HabitLog, error) {
	// Verify habit exists and belongs to user
	if _, err := s.habitRepo.GetByID(habitID, userID); err != nil {
		return nil, err
	}

	to := time.Now()
	from := to.AddDate(0, 0, -days)

	logs, err := s.habitRepo.GetLogs(habitID, userID, from, to)
	if err != nil {
		return nil, err
	}
	if logs == nil {
		logs = []model.HabitLog{}
	}
	return logs, nil
}

func (s *HabitService) DeleteLog(logID, userID int64) error {
	return s.habitRepo.DeleteLog(logID, userID)
}

func (s *HabitService) GetHabitStats(habitID, userID int64) (*model.HabitStats, error) {
	// Verify habit exists and belongs to user
	if _, err := s.habitRepo.GetByID(habitID, userID); err != nil {
		return nil, err
	}

	return s.habitRepo.GetStats(habitID, userID)
}

func (s *HabitService) GetOverallStats(userID int64) (*model.OverallStats, error) {
	habits, err := s.habitRepo.ListByUser(userID, false)
	if err != nil {
		return nil, err
	}

	allHabits, err := s.habitRepo.ListByUser(userID, true)
	if err != nil {
		return nil, err
	}

	todayLogs, err := s.habitRepo.GetUserLogsForDate(userID, time.Now().Truncate(24*time.Hour))
	if err != nil {
		return nil, err
	}

	return &model.OverallStats{
		TotalHabits:    len(allHabits),
		ActiveHabits:   len(habits),
		TodayCompleted: len(todayLogs),
	}, nil
}

func defaultString(val, def string) string {
	if val == "" {
		return def
	}
	return val
}

func defaultInt(val, def int) int {
	if val == 0 {
		return def
	}
	return val
}