package main

import (
	"errors"
	"net/http"
	"strings"
	"time"
)

const (
	SRC_GOCOMICS = "gocomics"
	SRC_DILBERT  = "dilbert"
	SRC_XKCD     = "xkcd"
)

func downloadComicsList() []Comic {
	var ret []Comic
	ret = append(ret, downloadGoComicsList()...)
	ret = append(ret, downloadDilbertList()...)
	ret = append(ret, downloadXKCDList()...)
	return ret
}

func getRssItem(source, slug string) (string, error) {
	switch source {
	case SRC_GOCOMICS:
		return getGoComicsRssItem(slug)
	case SRC_DILBERT:
		return getDilbertRssItem(slug)
	case SRC_XKCD:
		return getXKCDRssItem(slug)
	}
	return "", errors.New("Invalid source")
}

func getComicUrl(source, slug string, dt time.Time) (string, error) {
	switch source {
	case SRC_GOCOMICS:
		return getGoComicsComicUrl(slug, dt), nil
	case SRC_DILBERT:
		return getDilbertComicUrl(dt), nil
	case SRC_XKCD:
		return getXKCDComicUrl(dt), nil
	}
	return "", errors.New("Invalid source")
}

func getComicDesc(source, slug string, dt time.Time) (string, error) {
	switch source {
	case SRC_GOCOMICS:
		return getGoComicsFeedDesc(slug, dt)
	case SRC_DILBERT:
		return getDilbertFeedDesc(dt)
	case SRC_XKCD:
		return getXKCDFeedDesc(dt)
	}
	return "", errors.New("Unknown Comic Source")
}

func buildRssFeed(uid string) (string, error) {
	var usr *User
	var err error
	if usr, err = m.GetUser(uid); err != nil {
		return "", err
	}
	output := []string{
		"<?xml version=\"1.0\"?>",
		"<rss version=\"2.0\">",
		"  <channel>",
		"    <title>BCW Comic Feed</title>",
		"    <link>http://ribbit.bullercodeworks.com/edit/" + uid + "</link>",
		"    <description>Comic feed for " + usr.Username + "</description>",
		"    <language>en-us</language>",
		"    <lastBuildDate>" + time.Now().Format(time.RFC1123) + "</lastBuildDate>",
		"    <ttl>40</ttl>",
	}

	//date := time.Now()
	for _, slug := range usr.SubSlugs {
		pts := strings.Split(slug, ";")
		if len(pts) != 2 {
			continue
		}
		if comic, err := m.GetComic(pts[0], pts[1]); err == nil {
			output = append(output, comic.GetRssItem())
		}
	}

	output = append(output, []string{
		"  </channel>",
		"</rss>",
	}...)
	return strings.Join(output, "\n"), nil
}

func addStringIfUnique(st string, sl []string) []string {
	for i := range sl {
		if sl[i] == st {
			return sl
		}
	}
	return append(sl, st)
}

func userError(w http.ResponseWriter) {
	http.Error(w, "You did a bad", 400)
}

func serverError(w http.ResponseWriter) {
	http.Error(w, "I did a bad", 500)
}