package cron

import (
	"context"
	"fmt"
	"show-rss/src/feeds"
	"time"

	"github.com/robfig/cron/v3"
)

func Main(ctx context.Context) error {
	c := time.NewTicker(time.Minute)
	defer c.Stop()
	for {
		if err := One(ctx); err != nil {
			return err
		}

		select {
		case <-ctx.Done():
		case <-c.C:
		}
	}
	return ctx.Err()
}

func One(ctx context.Context) error {
	f, err := feeds.New(ctx)
	if err != nil {
		return err
	}

	return f.ForEach(ctx, func(feed feeds.Feed) error {
		if err := one(ctx, feed); err != nil {
			return fmt.Errorf("failed to cron %s (%+v): %w", feed.Entry.ID, feed.Version, err)
		}
		return nil
	})
}

func one(ctx context.Context, feed feeds.Feed) error {
	if schedule, err := cron.NewParser(
		cron.SecondOptional |
			cron.Minute |
			cron.Hour |
			cron.Dom |
			cron.Month |
			cron.Dow |
			cron.Descriptor,
	).Parse(feed.Version.Cron); err != nil {
		return fmt.Errorf("illegal cron %q", feed.Version.Cron)
	} else if next := schedule.Next(feed.Execution.Executed); time.Now().Before(next) {
		return nil
	}

	return fmt.Errorf("should GET %s", feed.Version.URL)

	f, err := feeds.New(ctx)
	if err != nil {
		return fmt.Errorf("failed new feeds to executed %s: %w", feed.Entry.ID, err)
	}
	return f.Executed(ctx, feed.Entry.ID, feed.Version.Created)
}