package main

import (
	"C"
	"errors"
	"fmt"
	"net/http"
	"time"

	"github.com/PuerkitoBio/goquery"
)

func getFeedList() []Feed {
	var ret []Feed
	ret = append(ret, *NewFeed("xkcd", "XKCD", "Randall Munroe", "xkcd"))
	return ret
}

func getRssItem(slug string) (string, error) {
	desc, err := getFeedDesc(time.Now())
	if err != nil {
		return "", err
	}
	feed, err := m.GetFeed(SRC_XKCD, slug)
	if err != nil {
		return "", err
	}
	desc = "<![CDATA[" + desc + "]]>"
	ret := "    <item>\n"
	ret += "      <title>" + feed.Name + "</title>\n"
	ret += "      <pubDate>" + feed.LastUpdate.Format(time.RFC1123Z) + "</pubDate>\n"
	ret += "      <guid>xkcd;" + slug + ";" + feed.LastUpdate.Format(time.RFC1123Z) + "</guid>\n"
	ret += "      <link>" + getUrl(time.Now()) + "</link>\n"
	ret += "      <description>" + desc + "</description>\n"
	ret += "    </item>\n"
	return ret, nil
}

func getFeedUrl(date time.Time) (string, error) {
	var isComicDay = func(dt time.Time) bool {
		return dt.Weekday() == time.Monday || dt.Weekday() == time.Wednesday || dt.Weekday() == time.Friday
	}
	if !isComicDay(dt) {
		return "", errors.New("No URL for the given day")
	}
	var num int
	wrkDate := time.Date(2005, time.August, 19, 0, 0, 0, 0, time.UTC)
	for wrkDate.Before(dt) {
		if isComicDay(wrkDate) {
			num++
		}
		wrkDate = wrkDate.Add(time.Hour * 24)
	}
	return fmt.Sprintf("https://xkcd.com/%d", num), nil
}

func getFeedDesc(date time.Time) (string, error) {
	res, err := http.Get(getUrl(date))
	if err != nil {
		return "", err
	}
	defer res.Body.Close()
	if res.StatusCode != 200 {
		return "", errors.New(fmt.Sprintf("Status code error: %d %s", res.StatusCode, res.Status))
	}

	// Load the HTML document
	doc, err := goquery.NewDocumentFromReader(res.Body)
	if err != nil {
		return "", err
	}
	// Find the Picture
	sel := doc.Find("div#comic>img")
	src, exists := sel.Attr("src")
	if !exists {
		return "", errors.New("Couldn't find image source")
	}
	src = "https:" + src
	title, exists := sel.Attr("title")
	if !exists {
		title = ""
	}
	return "<img src=\"" + src + "\" /><p>" + title + "</p>", nil
}