Script description: Fetches similar artist tracks based on the currently playing track or all tracks in the queue.

mpdsimilar.sh

#!/usr/bin/bash

# Script description: Fetches similar artist tracks based on the currently playing track or all tracks in the queue.
# Accepts arguments:
#   -c, --current: Retrieves similar artist tracks for the currently playing track.
#   -a, --all: Retrieves similar artist tracks for each track in the current playlist.
# Configurable parameters:
#   lastfm_api_key: Last.fm API key (replace LAST_FM_API_KEY).
#   similar_limit: Limit for similar artists fetched.
#   per_artist_limit: Maximum tracks per similar artist.
#   current_total_limit: Total tracks to add to the playlist for -c/--current.
#   per_track_limit: Total tracks per individual track in the queue for -a/--all.

# Default values
lastfm_api_key="LastFMAPIKey" # Replace with your Last.fm API key
similar_limit=20
per_artist_limit=5
current_total_limit=20
per_track_limit=10

# Required applications
required_apps=("mpc" "curl" "jq")

# Function to check and install required applications
check_and_install_apps() {
  for app in "${required_apps[@]}"; do
    if ! command -v "$app" &>/dev/null; then
      echo "Required application '$app' is not installed. Installing..."
      sudo apt update && sudo apt install -y "$app"
      if [[ $? -ne 0 ]]; then
        echo "Failed to install '$app'. Please install it manually."
        exit 1
      fi
    fi
  done
}

# Run the application check
check_and_install_apps

# Display usage help
display_help() {
  echo "Usage: $0 [OPTIONS]"
  echo
  echo "Options:"
  echo "  -c, --current      Retrieves similar artist tracks for the currently playing track."
  echo "  -a, --all          Retrieves similar artist tracks for each track in the current playlist."
  echo
  echo "If no options are provided, this help message will be displayed."
  exit 0
}

# Parse script arguments
if [[ $# -eq 0 ]]; then
  display_help
fi

while [[ $# -gt 0 ]]; do
  key="$1"
  case $key in
    -c|--current)
      current_track=true
      shift
      ;;
    -a|--all)
      all_tracks=true
      shift
      ;;
    *)
      echo "Unknown option: $1"
      display_help
      ;;
  esac
done

if [[ $current_track == true ]]; then
  artist=$(mpc current -f "%artist%")
  if [[ -z $artist ]]; then
    echo "Not playing..."
    exit 1
  fi
  mpc crop

  curl --silent --get \
    --data-urlencode "api_key=${lastfm_api_key}" \
    --data-urlencode "format=json" \
    --data-urlencode "limit=${similar_limit}" \
    --data-urlencode "method=artist.getsimilar" \
    --data-urlencode "artist=${artist}" \
    "http://ws.audioscrobbler.com/2.0" |
    jq --raw-output '.similarartists.artist[]?.name' | sed "1 i\\${artist}" | while read line; do
    mpc -q search artist "$line" | shuf -n $per_artist_limit
  done | shuf -n $current_total_limit | while read track; do
    mpc -q add "$track"
  done
fi

if [[ $all_tracks == true ]]; then
  # Capture the original queue at the start
  original_queue=$(mpc playlist -f "%artist% - %title%\n")

  # Iterate only over the original queue
  while IFS= read -r line; do
    artist=$(echo "$line" | cut -d'-' -f1 | sed 's/ *$//')

    curl --silent --get \
      --data-urlencode "api_key=${lastfm_api_key}" \
      --data-urlencode "format=json" \
      --data-urlencode "limit=${similar_limit}" \
      --data-urlencode "method=artist.getsimilar" \
      --data-urlencode "artist=${artist}" \
      "http://ws.audioscrobbler.com/2.0" |
      jq --raw-output '.similarartists.artist[]?.name' | sed "1 i\\${artist}" | while read similar_artist; do
      mpc -q search artist "$similar_artist" | shuf -n $per_artist_limit
    done | shuf -n $per_track_limit | while read track; do
      mpc -q add "$track"
    done
  done <<< "$original_queue"
fi