package main

import (
	"bufio"
	"bytes"
	"fmt"
	"go/format"
	"log"
	"os"
	"os/exec"
	"strings"
)

func must(err error) {
	if err == nil {
		return
	}
	log.Fatal(err)
}

func main() {
	cmd := exec.Command("ffmpeg", "-codecs")
	outputBytes, err := cmd.Output()
	must(err)

	code := `package codecs

var (
`

	bufreader := bufio.NewScanner(bytes.NewReader(outputBytes))

	/*Encoders:
	V..... = Video
	A..... = Audio
	S..... = Subtitle
	.F.... = Frame-level multithreading
	..S... = Slice-level multithreading
	...X.. = Codec is experimental
	....B. = Supports draw_horiz_band
	.....D = Supports direct rendering method 1
	------
	V..... a64multi             Multicolor charset for Commodore 64 (codec a64_multi)
	V..... a64multi5            Multicolor charset for Commodore 64, extended with 5th color (colram) (codec a64_multi5)*/

	waitingForList := true
	for bufreader.Scan() && waitingForList {
		text := bufreader.Text()
		if text == " -------" {
			waitingForList = false
		}
	}

	for bufreader.Scan() {
		text := bufreader.Text()
		//isVideo := text[1] == 'V'
		//isAudio := text[1] == 'A'
		//isSubtitle := text[1] == 'S'

		text = text[8:]
		cols := strings.Fields(text)

		id := cols[0]
		name := strings.Join(cols[1:], " ")
		code += fmt.Sprintf(`
	// %s
	Codec_%s = %q
`, name, strings.ToUpper(id), id)
	}

	code += `
)
`

	codeBytes, err := format.Source([]byte(code))
	must(err)

	f, err := os.Create("gen_codecs.go")
	must(err)
	defer f.Close()
	_, err = f.Write(codeBytes)
	must(err)
}