package main

import (
	"bufio"
	"encoding/json"
	"log"
	"os"
	"strings"
	"text/template"
)

// wget http://www.iana.org/assignments/language-subtag-registry/language-subtag-registry

const (
	inFilename      = "language-subtag-registry"
	outJSONFilename = "json/language.json"
	outGoFilename   = "lang/language.go"
)

type Item struct {
	Lang        string `json:"lang"`
	Description string `json:"description"`
}

func main() {
	f, e := os.Open(inFilename)
	if e != nil {
		log.Fatal(e.Error())
	}
	scanner := bufio.NewScanner(f)
	items := []*Item{}
	for scanner.Scan() {
		if scanner.Text() == "%%" {
			item := new(Item)
			scanner.Scan()
			if scanner.Text() == "Type: language" {
				for !strings.HasPrefix(scanner.Text(), "Subtag:") {
					scanner.Scan()
				}
				if strings.HasPrefix(scanner.Text(), "Subtag:") {
					ss := strings.Split(scanner.Text(), ": ")
					item.Lang = strings.Trim(ss[1], " ")
					if len(item.Lang) > 2 {
						continue
					}
				}
				for !strings.HasPrefix(scanner.Text(), "Description:") {
					scanner.Scan()
				}
				if strings.HasPrefix(scanner.Text(), "Description:") {
					ss := strings.Split(scanner.Text(), ": ")
					item.Description = strings.Trim(ss[1], " ")
					scanner.Scan()
					if strings.HasPrefix(scanner.Text(), "  ") {
						item.Description += strings.TrimPrefix(scanner.Text(), " ")
					}
				}
				items = append(items, item)
			}

		}
	}
	if e := f.Close(); e != nil {
		log.Fatal(e.Error())
	}
	jw, e := os.Create(outJSONFilename)
	if e != nil {
		log.Fatal(e.Error())
	}
	if e := json.NewEncoder(jw).Encode(items); e != nil {
		log.Fatal(e.Error())
	}
	if e := jw.Close(); e != nil {
		log.Fatal(e.Error())
	}
	gw, e := os.Create(outGoFilename)
	if e != nil {
		log.Fatal(e.Error())
	}
	gotmpl := template.Must(template.ParseFiles("gotemplate"))
	ctx := make(map[string]interface{})
	ctx["Items"] = items
	if e := gotmpl.Execute(gw, ctx); e != nil {
		log.Fatal(e.Error())
	}
	if e := gw.Close(); e != nil {
		log.Fatal(e.Error())
	}

}