package scheduler

import (
	"context"
	"time"

	"autostore/internal/application/commands"
	"autostore/internal/application/interfaces"
)

type ExpiredItemsScheduler struct {
	handleExpiredItemsCmd *commands.HandleExpiredItemsCommand
	logger                interfaces.ILogger
	ticker                *time.Ticker
	done                  chan struct{}
}

func NewExpiredItemsScheduler(
	handleExpiredItemsCmd *commands.HandleExpiredItemsCommand,
	logger interfaces.ILogger,
) *ExpiredItemsScheduler {
	return &ExpiredItemsScheduler{
		handleExpiredItemsCmd: handleExpiredItemsCmd,
		logger:                logger,
		done:                  make(chan struct{}),
	}
}

func (s *ExpiredItemsScheduler) Start(ctx context.Context) error {
	s.logger.Info(ctx, "Starting expired items scheduler")

	// Process expired items immediately on startup
	if err := s.processExpiredItems(ctx); err != nil {
		s.logger.Error(ctx, "Failed to process expired items on startup", "error", err)
		return err
	}

	// Calculate duration until next midnight
	now := time.Now()
	midnight := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
	if now.After(midnight) {
		midnight = midnight.Add(24 * time.Hour)
	}
	durationUntilMidnight := midnight.Sub(now)

	// Start a timer for the first midnight
	firstMidnightTimer := time.NewTimer(durationUntilMidnight)

	go func() {
		for {
			select {
			case <-firstMidnightTimer.C:
				s.processExpiredItems(ctx)

				// After first midnight, set up daily ticker
				s.ticker = time.NewTicker(24 * time.Hour)
				firstMidnightTimer.Stop()

				for {
					select {
					case <-s.ticker.C:
						s.processExpiredItems(ctx)
					case <-s.done:
						s.ticker.Stop()
						return
					case <-ctx.Done():
						s.ticker.Stop()
						return
					}
				}
			case <-s.done:
				firstMidnightTimer.Stop()
				return
			case <-ctx.Done():
				firstMidnightTimer.Stop()
				return
			}
		}
	}()

	s.logger.Info(ctx, "Expired items scheduler started", "next_run", midnight.Format(time.RFC3339))
	return nil
}

func (s *ExpiredItemsScheduler) Stop() error {
	s.logger.Info(context.Background(), "Stopping expired items scheduler")
	close(s.done)
	if s.ticker != nil {
		s.ticker.Stop()
	}
	return nil
}

func (s *ExpiredItemsScheduler) processExpiredItems(ctx context.Context) error {
	s.logger.Info(ctx, "Running scheduled expired items processing")

	if err := s.handleExpiredItemsCmd.Execute(ctx); err != nil {
		s.logger.Error(ctx, "Scheduled expired items processing failed", "error", err)
		return err
	}

	s.logger.Info(ctx, "Scheduled expired items processing completed")
	return nil
}