package scheduler

import (
	"fmt"
	"log"
	"time"

	"github.com/robfig/cron/v3"
	"github.com/daniil/homelab-api/internal/bot"
	"github.com/daniil/homelab-api/internal/model"
	"github.com/daniil/homelab-api/internal/repository"
)

type Scheduler struct {
	cron      *cron.Cron
	bot       *bot.Bot
	userRepo  *repository.UserRepository
	taskRepo  *repository.TaskRepository
	habitRepo *repository.HabitRepository
}

func New(b *bot.Bot, userRepo *repository.UserRepository, taskRepo *repository.TaskRepository, habitRepo *repository.HabitRepository) *Scheduler {
	return &Scheduler{
		cron:      cron.New(),
		bot:       b,
		userRepo:  userRepo,
		taskRepo:  taskRepo,
		habitRepo: habitRepo,
	}
}

func (s *Scheduler) Start() {
	if s.bot == nil || s.bot.GetAPI() == nil {
		log.Println("Scheduler: bot not configured, skipping")
		return
	}

	// Run every minute
	s.cron.AddFunc("* * * * *", s.checkNotifications)

	s.cron.Start()
	log.Println("Scheduler started")
}

func (s *Scheduler) Stop() {
	s.cron.Stop()
}

func (s *Scheduler) checkNotifications() {
	users, err := s.userRepo.GetUsersWithNotifications()
	if err != nil {
		log.Printf("Scheduler: error getting users: %v", err)
		return
	}

	for _, user := range users {
		go s.checkUserNotifications(user)
	}
}

func (s *Scheduler) checkUserNotifications(user model.User) {
	if !user.TelegramChatID.Valid {
		return
	}

	chatID := user.TelegramChatID.Int64
	
	// Get user timezone
	loc, err := time.LoadLocation(user.Timezone)
	if err != nil {
		loc = time.FixedZone("Europe/Moscow", 3*60*60)
	}

	now := time.Now().In(loc)
	currentTime := now.Format("15:04")
	today := now.Format("2006-01-02")
	weekday := int(now.Weekday())

	// 1. Morning briefing at 09:00
	if currentTime == "09:00" {
		s.sendMorningBriefing(user.ID, chatID, loc)
	}

	// 2. Task reminders
	s.checkTaskReminders(user.ID, chatID, currentTime, today)

	// 3. Habit reminders
	s.checkHabitReminders(user.ID, chatID, currentTime, weekday)
}

func (s *Scheduler) sendMorningBriefing(userID, chatID int64, loc *time.Location) {
	tasks, err := s.taskRepo.GetTodayTasks(userID)
	if err != nil {
		log.Printf("Scheduler: error getting tasks for user %d: %v", userID, err)
		return
	}

	habits, err := s.habitRepo.ListByUser(userID, false)
	if err != nil {
		log.Printf("Scheduler: error getting habits for user %d: %v", userID, err)
		return
	}

	// Filter habits for today
	weekday := int(time.Now().In(loc).Weekday())
	var todayHabits int
	for _, habit := range habits {
		if habit.Frequency == "daily" {
			todayHabits++
		} else {
			for _, day := range habit.TargetDays {
				if day == weekday {
					todayHabits++
					break
				}
			}
		}
	}

	if len(tasks) == 0 && todayHabits == 0 {
		return // Nothing to report
	}

	text := "☀️ <b>Доброе утро!</b>\n\n"
	
	if len(tasks) > 0 {
		text += fmt.Sprintf("📋 Задач на сегодня: <b>%d</b>\n", len(tasks))
		for i, task := range tasks {
			if i >= 3 {
				text += fmt.Sprintf("   ... и ещё %d\n", len(tasks)-3)
				break
			}
			text += fmt.Sprintf("   • %s %s\n", task.Icon, task.Title)
		}
		text += "\n"
	}

	if todayHabits > 0 {
		text += fmt.Sprintf("🎯 Привычек: <b>%d</b>\n", todayHabits)
	}

	text += "\n/tasks — посмотреть задачи\n/habits — посмотреть привычки"

	s.bot.SendMessage(chatID, text)
}

func (s *Scheduler) checkTaskReminders(userID, chatID int64, currentTime, today string) {
	tasks, err := s.taskRepo.GetTasksWithReminder(currentTime, today)
	if err != nil {
		log.Printf("Scheduler: error getting task reminders: %v", err)
		return
	}

	for _, task := range tasks {
		if task.UserID != userID {
			continue
		}

		text := fmt.Sprintf("⏰ <b>Напоминание о задаче:</b>\n\n%s <b>%s</b>", task.Icon, task.Title)
		if task.Description != "" {
			text += fmt.Sprintf("\n<i>%s</i>", task.Description)
		}
		text += fmt.Sprintf("\n\n/done_%d — отметить выполненной", task.ID)

		s.bot.SendMessage(chatID, text)
	}
}

func (s *Scheduler) checkHabitReminders(userID, chatID int64, currentTime string, weekday int) {
	habits, err := s.habitRepo.GetHabitsWithReminder(currentTime, weekday)
	if err != nil {
		log.Printf("Scheduler: error getting habit reminders: %v", err)
		return
	}

	for _, habit := range habits {
		if habit.UserID != userID {
			continue
		}

		// Check if already completed today
		completed, _ := s.habitRepo.IsHabitCompletedToday(habit.ID, userID)
		if completed {
			continue
		}

		text := fmt.Sprintf("⏰ <b>Напоминание о привычке:</b>\n\n%s <b>%s</b>", habit.Icon, habit.Name)
		if habit.Description != "" {
			text += fmt.Sprintf("\n<i>%s</i>", habit.Description)
		}
		text += fmt.Sprintf("\n\n/check_%d — отметить выполненной", habit.ID)

		s.bot.SendMessage(chatID, text)
	}
}