package main

import (
	"bufio"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"path"
	"strings"
)

const (
	subExt       = ".vtt"
	outdir       = "/mnt/desktop/media/datasets/nesfatelp_voice/utterances"
	ffCmdOut     = "./ff_commands"
	timeSep      = "-->"
	metadataPath = "/mnt/desktop/media/datasets/nesfatelp_voice/metadata.json"
)

type Utterance struct {
	LeftTime  string
	RightTime string
	Text      string
	OutPath   string
}

type FileData struct {
	VttPath   string
	AudioPath string
	AudioBase string
}

func NewFileData(vttPath string) *FileData {
	fd := &FileData{
		VttPath:   vttPath,
		AudioPath: strings.Trim(vttPath, subExt),
	}
	fd.AudioBase = path.Base(fd.AudioPath)
	return fd
}

func linesToUtterances(lines []string, fd *FileData) []*Utterance {
	resp := []*Utterance{}
	for i, line := range lines {
		if !strings.Contains(line, timeSep) {
			continue
		}
		// get times
		splitted := strings.Split(line, timeSep)

		u := &Utterance{
			Text:      lines[i+1],
			LeftTime:  strings.TrimSpace(splitted[0]),
			RightTime: strings.TrimSpace(splitted[1]),
		}
		u.OutPath = fmt.Sprintf("%s/%s_%s_%s.wav", outdir, fd.AudioBase,
			u.LeftTime, u.RightTime)
		resp = append(resp, u)

	}
	return resp
}

func readLines(filepath string) []string {
	file, err := os.Open(filepath)
	if err != nil {
		log.Fatal(err)
	}
	defer file.Close()

	resp := []string{}
	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		resp = append(resp, scanner.Text())
	}

	if err := scanner.Err(); err != nil {
		log.Fatal(err)
	}
	return resp
}

// writeLines writes the lines to the given file.
func writeLines(lines []string, path string) error {
	file, err := os.Create(path)
	if err != nil {
		return err
	}
	defer file.Close()

	w := bufio.NewWriter(file)
	for _, line := range lines {
		fmt.Fprintln(w, line)
	}
	return w.Flush()
}

func readJson(filepath string) map[string]string {
	plan, _ := ioutil.ReadFile(filepath)
	data := make(map[string]string)
	err := json.Unmarshal(plan, &data)
	if err != nil {
		log.Fatal(err)
	}
	return data
}

func writeJson(data map[string]string) {
	metadataJson, _ := json.MarshalIndent(data, "", "  ")
	err := ioutil.WriteFile(metadataPath, metadataJson, 0644)
	if err != nil {
		log.Fatal(err)
	}
}

func buildFFmpegCall(fd *FileData, ut *Utterance) string {
	return fmt.Sprintf(
		`ffmpeg -i %s -ss %s -to %s \
		-metadata text_source="%s" \
		-ar 22050 %s`,
		fd.AudioPath, ut.LeftTime, ut.RightTime,
		fd.VttPath, ut.OutPath,
	)
}

func utterancesToFileTextMap(utterances []*Utterance) map[string]string {
	resp := make(map[string]string)
	for _, ut := range utterances {
		resp[ut.OutPath] = ut.Text
	}
	return resp
}

func main() {
	vttFilepath := os.Args[1]

	fd := NewFileData(vttFilepath)
	fmt.Println("working with:", fd)

	lines := readLines(vttFilepath)
	utterances := linesToUtterances(lines, fd)

	ffmpegCommands := make([]string, len(utterances))
	for i, ut := range utterances {
		ffmpegCommands[i] = buildFFmpegCall(fd, ut)
	}
	fmt.Println("utterances len:", len(utterances))
	writeLines(ffmpegCommands, ffCmdOut)

	metadata := readJson(metadataPath)
	newMeta := utterancesToFileTextMap(utterances)

	for k, v := range newMeta {
		metadata[k] = v
	}

	writeJson(metadata)
}