package main

import (
	"log"
	"os"
	"time"

	"github.com/BurntSushi/toml"
	"github.com/mmcdole/gofeed"
)

type Config struct {
	Urls []string
}

type Item struct {
	Title, Description, Url, Filename string
}

type Podcast struct {
	Title, Description string
	Items []Item
}

type pcList struct {
	Podcasts []Podcast
}

func (p *pcList) Add(x *Podcast) {
	(*p).Podcasts = append((*p).Podcasts,*x)
}

type Db struct {
	Podcasts []Podcast
}

type Selector func(*gofeed.Item) bool

func Any(ss []Selector, i *gofeed.Item) bool {
	for _, s := range ss {
		if s(i) {
			return true
		}
	}
	return false
}

func All(ss []Selector, i *gofeed.Item) bool {
	for _, s := range ss {
		if !s(i) {
			return false
		}
	}
	return true
}

func newerThan(t time.Time) Selector {
	return func(i *gofeed.Item) bool {
		if i.PublishedParsed.After(t) {
			return true
		}
		return false
	}
}

func readFeed(url string,ss ...Selector) *Podcast {
	fp := gofeed.NewParser()
	feed, err := fp.ParseURL(url)
	if err != nil {
		log.Fatal(err)
	}
	pc := Podcast{ feed.Title, feed.Description, []Item{} }
	for _, i := range feed.Items {
		if All(ss,i) {
			it := Item{ Title: i.Title, Description: i.Description }
			pc.Items = append(pc.Items,it)
		}
	}
	return &pc
}

func main() {
	log.Print("rssd")
	log.Print("reading configuration")
	var conf Config
	if _, err := toml.DecodeFile("rssd.conf", &conf); err != nil {
		log.Fatal("Error reading config file:",err)
	}
	pl := &pcList{}
	pl.Podcasts = make([]Podcast,0)

	d := time.Now()
	lastMonth := newerThan(time.Date(d.Year(),d.Month()-1,d.Day(),0,0,0,0,time.Local))

	for _,url := range conf.Urls {
		log.Print("  -> ",url)
		pl.Add(readFeed(url,lastMonth))
	}
	of,err := os.Create("output.conf")
	if err != nil {
		log.Fatal("Cannot open output file")
	}
	enc := toml.NewEncoder(of)
	log.Print("writing output")
	enc.Encode(pl)
	of.Close()
	log.Print("done")
}