package data

import (
	"encoding/gob"
	"fmt"
	"os"

	"github.com/gorilla/feeds"
)

type Feed struct {
	feeds.Feed
	addChan chan *feeds.Item
}

func (f *Feed) start() {
	for item := range f.addChan {
		f.Items = append(f.Items, item)
	}
}

func NewFeed(title, link, desc string) *Feed {
	feed := &Feed{
		Feed: feeds.Feed{
			Title:       title,
			Link:        &feeds.Link{Href: link},
			Description: desc,
		},
		addChan: make(chan *feeds.Item),
	}
	feed.start()
	return feed
}

func (f *Feed) Close() {
	close(f.addChan)
}

func OpenFeed(filename string) (*Feed, error) {
	file, err := os.Open(filename)
	if err != nil {
		return nil, fmt.Errorf("error opening file %v: %v", filename, err)
	}
	defer file.Close()

	feed := new(Feed)
	decoder := gob.NewDecoder(file)
	err = decoder.Decode(&feed.Feed)
	if err != nil {
		return nil, fmt.Errorf("error decoding file %v: %v", filename, err)
	}
	feed.addChan = make(chan *feeds.Item)
	feed.start()

	return feed, nil
}

func (f *Feed) Save(filename string) error {
	file, err := os.Create(filename)
	if err != nil {
		return fmt.Errorf("error creating file %v: %v", filename, err)
	}
	defer file.Close()

	encoder := gob.NewEncoder(file)
	err = encoder.Encode(f.Feed)
	if err != nil {
		return fmt.Errorf("error encoding file %v: %v", filename, err)
	}

	return nil
}

func (f *Feed) Add(i *feeds.Item) {
	f.addChan <- i
}