#!/usr/bin/env bash

# Strict mode for bash; used when wanting to find errors while scripting
set -euo pipefail
IFS=$'\n\t'

RED="\033[1;31m"
RESET="\033[0m"

# Already defining the input file as a variable
# as it was being a pain to check for the input file.
input_file="$1"

# Usage for script
usage() {
  clear
  cat <<'EOF'

TUI for ffmpeg to cut & change codec.

Usage: ffut video_file

EOF

}

# Bash expanded [] conditions of "video/*" to [..] which
# is a blank string. That was why it was always giving
# error message.
check_for_vid_file() {
  if [[ ! $(file --mime-type -b "$input_file") =~ video ]]; then
    printf "\n%b\n" "${RED}Error${RESET}: video file not provided (got: %s)." && exit 1
  fi
}

# Check for audio file for audio codec converstion
check_audio_file() {
  check_input_audio_file=$(file --mime-type -b "$input_file")
  if [[ ! $(file --mime-type -b "$input_file") =~ audio ]]; then
    printf "\n%b\n" "${RED}Error${RESET}: audio file not provided." && exit 1
  fi
}

CommandArgs=$(gum choose --limit 1 --header="Choose: cut or codec" "cut" "codec" || exit 1)

case "$CommandArgs" in
# Trimming videos
cut)
  # Funcion call for checking video file
  check_for_vid_file
  # Take input from the user; what to do?
  cut_opt=$(gum choose --limit 1 --header="Choose cut option:" "1. One point to Another" "2. One point to end of video" || exit 1)
  case "$cut_opt" in
  1*)
    # First asking from where to cut and till how much
    # then takes the input of the data and applies it to
    # ffmpeg command. Finally, asks if original file
    # should be deleted.
    seek_start=$(gum input --placeholder "Start: HH:MM:SS or MM:SS or sec")
    seek_end=$(gum input --placeholder "End: HH:MM:SS or MM:SS or sec")
    ffmpeg -ss "$seek_start" -to "$seek_end" -i "$input_file" -c copy "$(date +"%Y%m%d_%H%M ")$input_file" || exit 1
    gum confirm "Delete original file?" && rm "$1"
    ;;
  2*)
    # Just does the same thing as above but only asks for
    # starting point and cuts to the end of the video.
    seek_start=$(gum input --placeholder "Start: HH:MM:SS or MM:SS or sec")
    ffmpeg -ss "$seek_start" -i "$input_file" -c copy "$(date +"%Y%m%d_%H%M ")$input_file"
    gum confirm "Delete original file?" && rm "$1"
    ;;
  *)
    # Anything which is not a file after cut option
    # will give out usage output.
    usage
    exit 1
    ;;
  esac
  ;;
# Codec change
codec)
  [[ check_for_vid_file || check_audio_file ]]
  # Take input for changin either video or audio codec.
  codec_opt=$(gum choose --limit 1 --header="Choose:" "video" "audio" || exit 1)
  # On the basis of choice choose video or audio option.
  case "$codec_opt" in
  video)
    video_codec_opt=$(gum choose --limit 1 --header="Choose: video format" "H.264" "H.265" "VP9 [webm]" || exit 1)
    case "$video_codec_opt" in
    H.264)
      ffmpeg -i "$input_file" -c:v libx264 -crf 23 -c:a copy "$(date +"%Y%m%d_%H%M")_h264_$input_file" || exit 1
      ;;
    H.265)
      ffmpeg -i "$input_file" -c:v libx265 -crf 28 -c:a copy "$(date +"%Y%m%d_%H%M")_h265_$input_file" || exit 1
      ;;
    "VP9 [webm]")
      # Take the input file name, removes extension name with dot
      # and changes codec to libvpx-vp9 and ext to webm
      output_video_file=$(basename "$input_file" | sed 's/\.[^.]*$//')
      output_video_file_name_webm=$(date +"%Y%m%d_%H%M")"_$output_video_file".webm
      ffmpeg -i "$input_file" -c:v libvpx-vp9 -crf 30 -b:v 0 -cpu-used -0 -c:a copy -compression_level 10 "$output_video_file_name_webm" || exit 1
      ;;
    *)
      usage
      exit 1
      ;;
    esac
    ;;
  audio)
    check_audio_file
    audio_codec_opt=$(gum choose --limit 1 --header="Choose:" "AAC" "OPUS" "MP3" || exit 1)
    case "$audio_codec_opt" in
    AAC)
      output_audio_file=$(basename "$input_file" | sed 's/\.[^.]*$//')
      output_audio_file_aac="$output_audio_file".m4a
      if ffmpeg -codecs 2>/dev/null | grep -q libfdk_aac; then
        ffmpeg -i "$input_file" -c:v copy -c:a libfdk_aac -b:a 192k "$output_audio_file_aac"
      else
        ffmpeg -i "$input_file" -c:v copy -c:a aac -b:a 192k "$output_audio_file_aac"
      fi
      ;;
    OPUS)
      # Basically taking audio file and changing codec to libopus
      # and file extension to .opus
      output_audio_file=$(basename "$input_file" | sed 's/\.[^.]*$//')
      output_audio_file_opus="$output_audio_file".opus
      # opus codec for best efficiency
      ffmpeg -i "$input_file" -c:a libopus -b:a 128k -vn "$output_audio_file_opus"
      ;;
    MP3)
      # Same thing changing codec to libmp3lame and file
      # extension to .mp3
      output_audio_file=$(basename "$input_file" | sed 's/\.[^.]*$//')
      output_audio_file_mp3="$output_audio_file".mp3
      # High quality mp3 conversion
      ffmpeg -i "$input_file" -c:a libmp3lame -q:a 2 -vn "$output_audio_file_mp3"
      ;;
    *)
      usage
      exit 1
      ;;
    esac
    ;;
  esac
  ;;
*)
  usage
  exit 1
  ;;
esac