package main

import (
	"flag"
	"fmt"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"strings"
	"time"
)

func GetVideoLength(ffprobeLocation string, fileName string) (seconds int, err error) {
	var out []byte
	out, err = exec.Command("/bin/sh", "-c", fmt.Sprintf("%s -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 \"%s\"", ffprobeLocation, fileName)).CombinedOutput()
	if err != nil {
		return
	}

	var secondsf float64
	secondsf, err = strconv.ParseFloat(strings.TrimSuffix(string(out), "\n"), 64)
	if err != nil {
		return
	}

	seconds = int(secondsf)

	return
}

func ProcessFileName(filename string) string {
	return strings.TrimSuffix(filepath.Base(filename), ".mkv")
}
func main() {
	filename := flag.String("filename", "", "video to make clips of")
	raw_clip_length := flag.String("clip_length", "2s", "how many seconds long each clip should be")
	clips_folder := flag.String("clips_folder", "clips", "folder to store clips in")
	ffmpegLocation := flag.String("ffmpeg", "ffmpeg", "specify ffmpeg location if its not in path")
	ffprobeLocation := flag.String("ffprobe", "ffprobe", "specify ffprobe location if its not in path")

	flag.Parse()

	clip_lenght_f, err := time.ParseDuration(*raw_clip_length)
	if err != nil {
		log.Fatal(err)
	}

	clip_length := int(clip_lenght_f.Seconds())

	if clip_length < 1 {
		log.Fatal("Please choose length longer than a second")
	}

	if *filename == "" {
		log.Fatalln("Please insert video to make clips of")
	}

	fmt.Println("Creating clips folder:", *clips_folder)
	if err := os.MkdirAll(*clips_folder, 0777); err != nil {
		log.Fatal(err)
	}

	length, err := GetVideoLength(*ffprobeLocation, *filename)
	if err != nil {
		log.Fatal(err)
	}

	for start := 0; start <= length; start += clip_length {
		fmt.Printf("Creating clip for seconds %d to %d\n", start, start+clip_length)
		out, err := exec.Command("/bin/sh", "-c", fmt.Sprintf("%s -ss %d -i \"%s\" -c copy -t %d \"%s/%s seconds %d to %d.mp4\"", *ffmpegLocation, start, *filename, clip_length, *clips_folder, ProcessFileName(*filename), start, start+clip_length)).CombinedOutput()
		if err != nil {
			fmt.Print(string(out))
			log.Fatal(err)
		}
	}
}