// vim:ts=4:sts=4:sw=4:noet:tw=72
//
// This code is mostly derived from the example code by Jim Teeuwen
// and is subject to the CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
// license.

package news

import (
	"bufio"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"time"

	rss "github.com/jteeuwen/go-pkg-rss"
	"github.com/jteeuwen/go-pkg-xmlx"
)

var sayCh chan string
var hideOutput = true

func Init(ch chan string, path string) {
	log.Printf("Initializing news module")
	sayCh = ch
	file, err := os.Open(path)
	if err != nil {
		log.Fatal(err)
	}
	defer file.Close()
	scanner := bufio.NewScanner(file)
	<-time.After(60 * time.Second)
	for scanner.Scan() {
		go PollFeed(scanner.Text(), 5, charsetReader)
	}
	if err := scanner.Err(); err != nil {
		log.Fatal(err)
	}
	time.Sleep(60 * time.Second)
	hideOutput = false
}

func PollFeed(uri string, timeout int, cr xmlx.CharsetFunc) {
	feed := rss.New(timeout, true, chanHandler, itemHandler)
	for {
		log.Printf("Polling feed: %s", uri)
		if err := feed.Fetch(uri, cr); err != nil {
			log.Printf("[e] %s: %s", "*", uri, err)
			//sayCh <- fmt.Sprintf("%s\n[e] %s: %s", "*", uri, err)
			return
		}
		<-time.After(time.Duration(feed.SecondsTillUpdate() * 1e9))
	}
}

func chanHandler(feed *rss.Feed, newchannels []*rss.Channel) {
	//sayCh <- fmt.Sprintf("%s\n%d new channel(s) in %s", "*", len(newchannels), feed.Url)
}

func itemHandler(feed *rss.Feed, ch *rss.Channel, newitems []*rss.Item) {
	if hideOutput {
		return
	}
	for _, ni := range newitems {
		sayCh <- fmt.Sprintf("%s\n*** [NEWS] %v - %v", "*", ni.Title, ni.Links[0].Href)
	}
}

func charsetReader(charset string, r io.Reader) (io.Reader, error) {
	if charset == "ISO-8859-1" || charset == "iso-8859-1" {
		return r, nil
	}
	return nil, errors.New("Unsupported character set encoding: " + charset)
}