#!/bin/bash

show_help() {
  echo """Usage: $(basename $0) \
    [--input|-i input_file] \
    [--crop|-c width:height] \
    [--trim-start start] \
    [--trim-end end] \
    [--crf crf_value] \
    [--fps new_fps] \
    [--scale new_video_resolution] \
    [--merge-audio] \
    [--remove-audio] \
    [--volume-multiplier] \
    --output|-o output_file"""
  echo "Options:"
  echo "  --input|-i          Specify the input video file (required)."
  echo "  --crop|-c           Specify the width:height for video cropping."
  echo "  --trim-start        Specify the start timestamp for video trimming."
  echo "  --trim-end          Specify the end timestamp for video trimming."
  echo "  --crf               Specify the CRF value for video compressing."
  echo "  --fps               Specify the new frames per second for the video."
  echo "  --scale             Scale the video to a new resolution."
  echo "  --merge-audio       Merge all audio tracks into the main track."
  echo "  --remove-audio      Suppress all audio and remove audio tracks."
  echo "  --volume-multiplier Changes the video's volume with a multiplier."
  echo "  --audio-track-no    Selects a specific audio track for the output"
  echo "  --output|-o         Specify the output filename (required)."
}

remove_audio() {
  input_file="$1"
  output_file="$2"

  ffmpeg -i "$input_file" -an "$output_file"
}

if ! command -v ffmpeg &>/dev/null; then
  echo "Error: 'ffmpeg' command not found. Please install ffmpeg."
  exit 1
fi

input_file=""
crop=""
trim_start=""
trim_end=""
crf=""
new_fps=""
scale=""
merge_audio=false
remove_audio=false
volume_multiplier=""
audio_track_no=1
output_file=""

while [ "$#" -gt 0 ]; do
  case "$1" in
  --help | -h)
    show_help
    exit
    ;;
  --input | -i)
    input_file="$2"
    shift 2
    ;;
  --crop | -c)
    crop="$2"
    shift 2
    ;;
  --trim-start)
    trim_start="$2"
    shift 2
    ;;
  --trim-end)
    trim_end="$2"
    shift 2
    ;;
  --crf)
    crf="$2"
    shift 2
    ;;
  --fps)
    new_fps="$2"
    shift 2
    ;;
  --scale)
    scale="$2"
    shift 2
    ;;
  --merge-audio)
    merge_audio=true
    shift
    ;;
  --remove-audio)
    remove_audio=true
    shift
    ;;
  --volume-multiplier)
    volume_multiplier="$2"
    shift 2
    ;;
  --audio-track-no)
    audio_track_no="$2"
    shift
    ;;
  --output | -o)
    output_file="$2"
    shift 2
    ;;
  *) shift ;;
  esac
done

if [ -z "$input_file" ]; then
  echo "Error: Input filename (--input or -i) is required."
  exit 1
fi

if [ -z "$output_file" ]; then
  echo "Error: Output filename (--output or -o) is required."
  exit 1
fi

if [ -z "$crop" ] && [ -z "$trim_start" ] && [ -z "$trim_end" ] && [ -z "$crf" ] && [ -z "$new_fps" ] && [ "$merge_audio" = false ] && [ -z "$scale" ] && [ "$remove_audio" = false ] && [ -z "$volume_multiplier" ]; then
  echo "Error: At least one optional parameter is required."
  exit 1
fi

if [ -n "$trim_start" ] && [ -z "$trim_end" ]; then
  echo "Error: If using --trim-start, you must also specify --trim-end."
  exit 1
fi

if [ -n "$trim_end" ] && [ -z "$trim_start" ]; then
  echo "Error: If using --trim-end, you must also specify --trim-start."
  exit 1
fi

if [ -n "$crop" ] && [ "$scale" = true ]; then
  echo "Error: Cannot use both --crop and --scale together."
  exit 1
fi

if [ "$merge_audio" = true ] && [ "$remove_audio" = true ]; then
  echo "Error: Cannot use both --merge-audio and --remove-audio together."
  exit 1
fi

if [ "$merge_audio" = true ] && [ "$audio_track_no" != 1 ]; then
  echo "Error: Cannot use both --merge-audio and --audio-track-no together."
  exit 1
fi

if [ "$remove_audio" = true ] && [ "$audio_track_no" != 1 ]; then
  echo "Error: Cannot use both --remove-audio and --audio-track-no together."
  exit 1
fi

ffmpeg_command="ffmpeg -i \"$input_file\""
# ffmpeg_command="/mnt/e/programs/ffmpeg-2024-08-15-git-1f801dfdb5-full_build/bin/ffmpeg.exe -i \"$input_file\""

# if command -v ffmpeg.exe &> /dev/null; then
#     ffmpeg_command="ffmpeg.exe -hwaccel d3d11va"
# fi

if [ "$remove_audio" = true ]; then
  ffmpeg_command+=" -an"
fi

if [ -n "$crop" ]; then
  ffmpeg_command+=" -vf crop=$crop"
fi

if [ -n "$trim_start" ] && [ -n "$trim_end" ]; then
  ffmpeg_command+=" -ss $trim_start -to $trim_end"
fi

if [ -n "$crf" ]; then
  ffmpeg_command+=" -c:v libx265 -crf $crf"
  # ffmpeg_command+=" -c:v hevc_amf -rc cqp -qp_i $crf -qp_p $crf"
fi

if [ -n "$new_fps" ]; then
  ffmpeg_command+=" -r $new_fps"
fi

if [ -n "$scale" ]; then
  ffmpeg_command+=" -s $scale"
fi

if [ -n "$volume_multiplier" ]; then
  ffmpeg_command+=" -filter:a \"volume=$volume_multiplier\""
fi

if [ "$merge_audio" = true ]; then
  num_audio_streams=$(ffprobe -loglevel error -select_streams a -show_entries stream=codec_type -of csv=p=0 "$input_file" | wc -l)
  ffmpeg_command+=" -filter_complex amerge=inputs=$num_audio_streams"
fi

if [ "$audio_track_no" != 1 ]; then
  ffmpeg_command+=" -map 0:0 -map 0:$audio_track_no"
fi

ffmpeg_command+=" \"$output_file\""

echo "Running ffmpeg command:"
echo "$ffmpeg_command"
eval "$ffmpeg_command"