package main

import (
	"github.com/pebbe/util"

	"encoding/xml"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"os"
	"strings"
	"time"
)

type Rss struct {
	XMLName xml.Name `xml:"rss"`
	Items   []ItemT  `xml:"channel>item"`
}

type ItemT struct {
	PubDate  string `xml:"pubDate"`
	UnixTime int64  `xml:"unixTime"`
	Guid     string `xml:"guid"`
	Data     []byte `xml:",innerxml"`
}

var (
	x     = util.CheckErr
	agent = "AhrefsBot/7.0"
)

func exists(filename string) bool {
	_, err := os.Stat(filename)
	return err == nil
}

func main() {
	req, err := http.NewRequest("GET", "https://rss.at5.nl/rss", nil)
	x(err)
	req.Header.Set("User-Agent", agent)

	client := &http.Client{}
	resp, err := client.Do(req)
	x(err)
	body, err := io.ReadAll(resp.Body)
	x(err)
	x(resp.Body.Close())

	var rss Rss
	x(xml.Unmarshal(body, &rss))

	if len(rss.Items) == 0 {
		x(fmt.Errorf("len(rss.Items) == 0"))
	}

	for _, item := range rss.Items {
		t, err := time.Parse(time.RFC1123Z, item.PubDate)
		if err != nil {
			t, err = time.Parse(time.RFC1123, item.PubDate)
		}
		x(err)
		year, week := t.ISOWeek()
		dirname := fmt.Sprintf("/net/corpora/nlnieuws/AT5/%d/%02d", year, week)
		if exists(dirname + "/lock") {
			continue
		}
		basename := strings.TrimPrefix(item.Guid, "https://www.at5.nl/artikelen/")
		if i := strings.LastIndex(basename, "/"); i > 0 {
			basename = basename[:i]
		}
		filename := dirname + "/" + url.PathEscape(basename)

		x(os.MkdirAll(dirname, 0777))
		fp, err := os.Create(filename + ".xml")
		x(err)
		_, err = fp.WriteString("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<item>\n")
		x(err)
		_, err = fmt.Fprintf(fp, "<unixTime>%d</unixTime>", t.Unix())
		x(err)
		_, err = fp.Write(item.Data)
		x(err)
		_, err = fp.WriteString("</item>\n")
		x(err)
		x(fp.Close())
		x(os.Chtimes(filename+".xml", t, t))
	}

}