#!/usr/bin/env bash

# exit if a command fails
set -o errexit

# exit if required variables are not set
set -o nounset

# check for dependencies
script_commands="AtomicParsley attr ffmpeg ffprobe yt-dlp"
missing_counter=0
for needed_command in ${script_commands}; do
  if ! hash "${needed_command}" >/dev/null 2>&1; then
    printf "Command not found in PATH: %s\n" "${needed_command}" >&2
    ((missing_counter++))
  fi
done
if ((missing_counter > 0)); then
  printf "Minimum %d commands are missing in PATH, aborting.\n" "${missing_counter}" >&2
  exit 1
fi

# make sure the correct number of arguments are passed; if not, output syntax and exit
if [ "$#" -ne 2 ]; then
  echo -e "\nUsage: $0 <rate limit> <youtube channel>\n"
  exit 1
else
  rate_limit="$1"
  video_url="$2"
fi

# update youtube-dl if needed
yt-dlp --update

# download channel, preserving metadata, combining into single .mkv per video
yt-dlp \
        --concurrent-fragments 8 \
        --console-title \
        --continue \
        --convert-thumbnails png \
        --download-archive .archive \
        --embed-metadata \
        --embed-subs \
        --embed-thumbnail \
        --format 'bv*+ba/b' \
        --fragment-retries infinite \
        --geo-bypass \
        --limit-rate "${rate_limit}" \
        --merge-output-format mkv \
        --output '%(playlist_autonumber)000006d - %(title)s.%(ext)s' \
        --prefer-free-formats \
        --restrict-filenames \
        --retries infinite \
        --sponsorblock-mark "all" \
        --sub-langs "en.*,live_chat" \
        --write-annotations \
        --write-auto-subs \
        --write-comments \
        --write-description \
        --write-info-json \
        --write-playlist-metafiles \
        --write-subs \
        --write-thumbnail \
        --xattrs \
        --yes-playlist \
        "${video_url}"