progressbar

#!/bin/bash

readonly program="$(basename "${0}")"

# Defaults
bar_color='#f12b24'
bar_height_percent='1'
bar_pos='bottom'
seconds_delay='1.5'
output_file='output.gif'

function message {
  echo "${1}"
}

function wrong_arguments {
  tput setaf 1
  echo 'You need either give multiple images or one video file as arguments' >&2
  tput sgr0
  usage
  exit 1
}

function depends_on {
  readonly local all_deps=("${@}")
  local missing_deps=()

  for dep in "${all_deps[@]}"; do
    if ! command -v "${dep}" &>/dev/null; then
      missing_deps+=("${dep}")
    fi
  done

  if [[ "${#missing_deps[@]}" -gt 0 ]]; then
    tput setaf 1
    echo -e '\nThis script has unmet dependencies. You need to install these first:'
    printf '  %s\n' "${missing_deps[@]}"
    tput sgr0
    exit 1
  fi
}

function syntax_error {
  echo -e "${program}: ${1}\nTry \`${program} --help\` for more information." >&2
  exit 1
}

function usage {
  echo "
    Usage:
      ${program} [options] <file...>

    Options:
      -c, --bar-color <color>           Default: #f12b24.
      -s, --bar-height <integer>        Bar’s height as a percent of the total height. Default: 1.
      -p, --bar-position [top|bottom]   Default: bottom.
      -d, --delay <number>              Delay between each frame, in seconds. Default: 1.5.
      -o, --output-file <file>          File to output to. Default: output.gif in current directory. Saves to video when given the .mov extension.
      -g, --gifski                      Use gifski for the conversion.
      -h, --help                        Show this help.
  " | sed -E 's/^ {4}//'
}

# Available flags
args=()
while [[ "${1}" ]]; do
  case "${1}" in
    -h | --help)
      usage
      exit 0
      ;;
    -c | --bar-color)
      bar_color="${2}"
      shift
      ;;
    -s | --bar-height)
      bar_height_percent="${2}"
      shift
      ;;
    -p | --bar-position)
      bar_pos="${2}"
      shift
      ;;
    -d | --delay)
      seconds_delay="${2}"
      shift
      ;;
    -o | --output-file)
      output_file="${2}"
      shift
      ;;
    -g | --gifski)
      use_gifski='true'
      ;;
    --)
      shift
      args+=("${@}")
      break
      ;;
    -*)
      syntax_error "unrecognized option: ${1}"
      ;;
    *)
      args+=("${1}")
      ;;
  esac
  shift
done
set -- "${args[@]}"

trap 'exit 1' SIGINT

depends_on 'convert' 'identify' 'ffmpeg' 'ffprobe' 'gfv'

# Determine if working from images or video
[[ "${#}" -eq 0 ]] && wrong_arguments

if [[ "${#}" -eq 1 ]]; then
  [[ "$(file --mime-type --brief "${1}")" != 'video'* ]] && wrong_arguments

  readonly background_video="${1}"
else
  readonly background_video="$(mktemp).mov"
  readonly images=("${@}")

  for file in "${images[@]}"; do
    [[ "$(file --mime-type --brief "${file}")" != 'image'* ]] && wrong_arguments
  done

  readonly frame_delay="$(bc <<< "${seconds_delay} * 100")"

  message 'Generating intermediary video file…'
  convert -delay "${frame_delay}" "${images[@]}" "${background_video}"
fi

message 'Generating progress bar…'
readonly total_frames="$(ffprobe -loglevel error -count_frames -select_streams v:0 -show_entries stream=nb_read_frames -of default=nokey=1:noprint_wrappers=1 "${background_video}")"
readonly total_steps="$(bc <<< "${total_frames} - 1")" # Remove one from the total since we will start counting steps from 0. This is for the logic of having no bar on the first step and to map to the array correctly.

readonly canvas_width="$(ffprobe -loglevel error -count_frames -show_entries stream=width -of default=nokey=1:noprint_wrappers=1 "${background_video}")"
readonly canvas_height="$(ffprobe -loglevel error -count_frames -show_entries stream=height -of default=nokey=1:noprint_wrappers=1 "${background_video}")"
readonly bar_height_px="$(bc <<< "${canvas_height} * ${bar_height_percent} / 100")"

[[ "${bar_pos}" == 'top' ]] && readonly bar_ystart='0' || readonly bar_ystart="$(bc <<< "${canvas_height} - ${bar_height_px}")"
readonly bar_yend="$(bc <<< "${bar_ystart} + ${bar_height_px}")"

readonly tmp_bar_graphics_dir="$(mktemp -d)"
readonly tmp_bar_video="$(mktemp).mov"

# Make bar graphics.
for step_name in $(seq -w 0 "${total_steps}"); do
  [[ "${step_name}" =~ ^0+$ ]] && step_number='0' || step_number="$(sed -E 's/^0+//' <<< "${step_name}")" # Remove leading zeros

  if [[ "${step_number}" -eq 0 ]]; then
    bar_width='0' # First frame shold never have a bar. Without this we'd have to divide by zero.
  elif [[ "${step_number}" -eq "${total_steps}" ]]; then
    bar_width="${canvas_width}" # Last frame should always fill the full width. Without this we may get a fractional result slightly smaller.
  else
    bar_width="$(bc -l <<< "${canvas_width} / ${total_steps} * ${step_number}")"
  fi

  convert -size "${canvas_width}"x"${canvas_height}" canvas:transparent -fill "${bar_color}" -draw "rectangle 0,${bar_ystart} ${bar_width},${bar_yend}" "${tmp_bar_graphics_dir}/${step_name}.png"
done

# Make bar graphics into a video and superimpose on the original.
ffmpeg -loglevel error -pattern_type glob -i "${tmp_bar_graphics_dir}/*.png" -vcodec png "${tmp_bar_video}"

readonly tmp_superimposed_video="$(mktemp).mov"
ffmpeg -i "${background_video}" -i "${tmp_bar_video}" -filter_complex overlay "${tmp_superimposed_video}"

# Make gif
message 'Creating gif…'

if [[ "${output_file}" == *'.mov' ]]; then
  mv "${tmp_superimposed_video}" "${output_file}"
else
  options=()
  [[ -n "${use_gifski}" ]] && options+=('--gifski')

  gfv "${options[@]}" "${tmp_superimposed_video}" --output-file "${output_file}"
fi

message "Saved to ${output_file}"