package main

import (
	e "codeberg.org/pebbe/errors"

	"bufio"
	"encoding/xml"
	"fmt"
	"html"
	"os"
	"strings"
	"time"
)

type Item struct {
	XMLName  xml.Name `xml:"item"`
	UnixTime int64    `xml:"unixTime"`
}

var (
	x        = e.ExitErr
	escape   = html.EscapeString
	data     = make(map[string][]string)
	location *time.Location
)

func main() {
	var err error
	location, err = time.LoadLocation("Europe/Amsterdam")
	x(err)

	files, err := os.ReadDir("..")
	x(err)
	for _, file := range files {
		filename := file.Name()
		if strings.HasSuffix(filename, ".txt") {
			doText(filename)
		} else if strings.HasSuffix(filename, ".xml") {
			doXml(filename)
		}
	}

	files, err = os.ReadDir("xml")
	x(err)
	for _, file := range files {
		filename := file.Name()
		if !strings.HasSuffix(filename, ".xml") {
			continue
		}
		aa := strings.Split(filename, ".")
		base := strings.Join(aa[1:len(aa)-2], ".")
		b, err := os.ReadFile("xml/" + filename)
		x(err)
		s := string(b)
		i := strings.Index(s, "<alpino") + 1
		i += strings.Index(s[i:], "<")
		fp, err := os.Create("xml/" + filename + ".tmp")
		x(err)
		x(fp.WriteString(s[:i]))
		x(fp.WriteString("<metadata>\n    <meta type=\"text\" name=\"source\" value=\"VRT\"/>\n"))
		for _, m := range data[base] {
			x(fp.WriteString("    " + m + "\n"))
		}
		x(fp.WriteString("  </metadata>\n  "))
		x(fp.WriteString(stripMeta(s[i:])))
		x(fp.Close())
		x(os.Rename("xml/"+filename+".tmp", "xml/"+filename))
	}
}

func doText(filename string) {
	base := filename[:len(filename)-4]
	if _, ok := data[base]; !ok {
		data[base] = make([]string, 0)
	}
	fp, err := os.Open("../" + filename)
	x(err)
	defer func() { x(fp.Close()) }()
	scanner := bufio.NewScanner(fp)
	for scanner.Scan() {
		line := scanner.Text()
		if !strings.HasPrefix(line, "##META") {
			continue
		}
		aa := strings.Fields(line)
		if len(aa) > 4 {
			data[base] = append(data[base],
				fmt.Sprintf(`<meta type="%s" name="%s" value="%s"/>`,
					aa[1],
					escape(aa[2]),
					escape(strings.Join(aa[4:], " "))))
		}
	}
	x(scanner.Err())
}

func doXml(filename string) {
	base := filename[:len(filename)-4]
	if _, ok := data[base]; !ok {
		data[base] = make([]string, 0)
	}
	b, err := os.ReadFile("../" + filename)
	x(err)
	var item Item
	x(xml.Unmarshal(b, &item))
	t := time.Unix(item.UnixTime, 0).In(location)
	data[base] = append(data[base],
		fmt.Sprintf(`<meta type="date" name="pubdate" value="%d-%02d-%02d"/>`,
			t.Year(),
			int(t.Month()),
			t.Day()))
}

func stripMeta(s string) string {
	i1 := strings.Index(s, "<metadata>")
	if i1 < 0 {
		return s
	}
	i2 := i1 + strings.Index(s[i1:], "</metadata>") + 11
	return s[:i1] + strings.TrimLeft(s[i2:], " \t\r\n")
}