package main

import (
  "fmt"
  "path/filepath"
  "runtime"
  "log"
  "os"
  "math/rand"
  "strings"
  "lcthw.dev/vidcrunch/config"
  "github.com/modfy/fluent-ffmpeg"
)

func ModFile(fname string, scale string) string {
  cleaned := filepath.Clean(fname)
  dir, file := filepath.Split(cleaned)
  ext := filepath.Ext(file)

  base, found := strings.CutSuffix(file, ext)
  if !found { panic("no extension found?!") }

  dim := strings.Replace(scale, ":", ".", 1)
  renamed := fmt.Sprint(base, ".", dim, ext)
  return filepath.Join(dir, renamed)
}


func Run(pass int, pid int, input string, output string) {
  encode := fluentffmpeg.NewCommand("")

  mp4_opts := []string{
    "-vf", fmt.Sprintf("scale=%s:flags=lanczos", config.Settings.Scale),
    "-aspect", config.Settings.Scale,
    "-pix_fmt", "yuv420p",
    "-tune", config.Settings.Tune,
    "-movflags", "faststart",
    "-pass", fmt.Sprint(pass),
    "-passlogfile", fmt.Sprintf("ffmpeg2pass-%x.log", pid),
    "-preset", config.Settings.Speed,
  }

  if pass != 3 {
    mp4_opts = append(mp4_opts, "-an")
  } else {
    encode.AudioCodec("aac")
    mp4_opts = append(mp4_opts,
      "-b:a", fmt.Sprint(config.Settings.AudioBitrate * 1024))
  }

  if config.Settings.Test > 0 {
    encode.InputOptions(
      "-ss", fmt.Sprintf("00:%d", config.Settings.TestStart))
    mp4_opts = append(mp4_opts, "-t", fmt.Sprint(config.Settings.Test))
  }

  encode.VideoCodec("libx264").
    VideoBitRate(config.Settings.VideoBitrate * 1024).
    FrameRate(config.Settings.FPS).
    ConstantRateFactor(config.Settings.CRF)

  encode.OutputOptions(mp4_opts...)

  cmd := encode.InputPath(input).
    OutputFormat("mp4").
    OutputPath(output).
    Build()

  fmt.Println(">", cmd.String())

  err := cmd.Run()
  if err != nil { log.Fatalf("%v", err) }
}

func DevNull() string {
  if runtime.GOOS == "windows" {
    return "NUL"
  } else {
    return "/dev/null"
  }
}

func RenderFile(pid int, path string, target string) {
  target = ModFile(target, config.Settings.Scale)
  Run(1, pid, path, DevNull())
  Run(2, pid, path, DevNull())
  Run(3, pid, path, target)
}

func RenderToDir() {
  matches, err := filepath.Glob(config.Settings.Input)
  if err != nil { log.Fatalf("%v", err) }

  for _, path := range matches {
    base := filepath.Base(path)
    target := filepath.Join(config.Settings.OutDir, base)

    _, err := os.Stat(target)

    if err != nil {
      fmt.Println("--- PATH", path, "->", target)
      RenderFile(rand.Int(), path, target)
    } else {
      fmt.Println("^^^ SKIP", path, "->", target)
    }
  }
}

func main() {
  config.Load()

  if config.Settings.Output != "" {
    RenderFile(rand.Int(), config.Settings.Input, config.Settings.Output)
  } else if config.Settings.OutDir != "" {
    RenderToDir()
  } else {
    log.Fatal("config file needs either Output or OutDir")
  }
}