#!/usr/bin/env bash

declare -r config_file="${XDG_CONFIG_DIR:-$HOME/.config}/fzmp/conf"

usage() {
  LESS=-FEXR less <<HELP
fzmp [OPTIONS]

OPTIONS:
  -a --artist
    search artist then filter by album (or F3 when running)
  -A --all
    search all songs in the library (or F2 when running)
  -g --genre
    list genres (or F4 when running)
  -p --playlist
    search the current playlist (or F1 when running)
    playlist view has the following keybinds:
    >       go to the next song in the playlist
    <       go to the previous song in the playlist
    Ctrl-d  delete the selected songs from the playlist
    Ctrl-s  save current playlist
    Ctrl-p  toggle play/pause
    Ctrl-q  stop playing
  -P --playlists
    list saved playlists (or F5 when running)
  -h --help
    print this help

CONFIGURATION:
  A configuration file can be defined at $config_file
  If a line begins with '#' it is treated as a comment and ignored
  The configuration file reads the following options:

  default_view
    Must be 'artists' 'songs' 'playlist' or 'genres'
  full_song_format
    A format string to be passed directly to \`mpc format -f\` in
    'playlist' and 'all' views. Defaults to:
    [[[%artist% / ][[(%date%) ]%album% / ][[%track% - ][%title%]]]|%file%]
    For colorized output try:
    [[[\\e\\[32m%artist%\\e\\[0m / ][\\e\\[31m[(%date%) ]%album%\\e\\[0m / ][\\e\\[34m[%track% - ][%title%]\\e\\[0m]]|%file%]
  playlist_view_key (default F1)
  track_view_key (default F2)
  artist_view_key (default F3)
  genre_view_key (default F4)
    allows customizing which keys fire the different views
  findadd_key
    adds all songs under the cursor by artist/genre/album
    (default ctrl-space)
  fzf_options
    Command line options to be passed directly to fzf.
    Changing this will override the default options:
      --height='100%' +s -e -i --reverse --cycle
    To use the jump feature of fzf you can try:
      --bind=\`:jump --height='100%' +s -e -i --reverse --cycle
    It also helps to have a bind for toggle-all:
      --bind=ctrl-t:toggle-all --bind=\`:jump --height=100% +s -e -i --reverse --cycle
    individual sessions can override with the environment variable FZMP_FZF_OPTIONS
    fzmp will also inherit options from FZF_DEFAULT_OPTS
HELP
}

declare default_filter='filter_by_playlist'
declare track_format='[[[%artist% / ][[(%date%) ]%album% / ][[%track% - ][%title%]]]|%file%]'
declare -r album_listing="mpc search -f '%album%\t%track%\t%title%' artist {} | awk -F'\t' '{ if(album != \$1) { album=\$1; print album } printf \"  %2d. %s\n\", \$2, \$3 }'"
declare -a config_err

declare key_bindings
declare -A bindings
bindings=(
  [playlist]='f1'
  [track]='f2'
  [artist]='f3'
  [genre]='f4'
  [playlists]='f5'
  [findadd]='ctrl-space'
)

do_binding() {
  local b
  b=$(action_from_keybind "$1")
  shift
  case "$b" in
    playlist) filter_by_playlist ;;
    playlists) pick_playlist ;;
    track) filter_by_songs ;;
    artist) filter_by_artists ;;
    genre) filter_by_genres ;;
    *) [[ -n $1 ]] && { "$@"; return 0; } ;;
  esac
  return 1
}

action_from_keybind() {
  for a in "${!bindings[@]}"; do
    if [[ $1 == "${bindings[$a]}" ]]; then
      printf '%s' "$a"
      return 0
    fi
  done
  return 1
}

declare -A colors
colors[red]=$(tput setaf 1)
colors[green]=$(tput setaf 2)
colors[blue]=$(tput setaf 4)
colors[reset]=$(tput sgr0)

info() {
  color green "$@" >&2
}

color() {
  local c
  c="$1"
  shift
  printf '%s' "${colors[$c]}"
  printf '%s\n' "$@"
  printf '%s' "${colors[reset]}"
}

err() {
  color red "$@" >&2
}

die() {
  [[ -n "$1" ]] && err "$*"
  exit 1
}

has() {
  local loud=0
  if [[ $1 == '-v' ]]; then
    loud=1
    shift
  fi
  for c; do c="${c%% *}"
    if ! command -v "$c" &> /dev/null; then
      (( loud > 0 )) && err "$c not found"
      return 1
    fi
  done
}

is_running() {
  pgrep "$1" &> /dev/null
}

fzf() {
  local opts
  opts=( --reverse --cycle --height=100% )
  [[ -v FZMP_FZF_OPTIONS ]] && opts=( $FZMP_FZF_OPTIONS )
  if has fzf; then
    command fzf \
      --inline-info \
      --ansi \
      --no-clear \
      "${opts[@]}" "$@"
  elif has sk; then
    command sk \
      --inline-info \
      --ansi \
      "${opts[@]}" "$@"
  else
    err 'no filter found'
  fi
}

parse_config_file() {
  local line key val nr=0 e
  while IFS= read -r line; do
    (( ++nr ))
    [[ -z "$line" || "$line" = '#'* ]] && continue
    read -r key <<< "${line%% *}"
    read -r val <<< "${line#* }"
    if [[ -z "$val" ]]; then
      config_err+=( "missing value for \"$key\" in config file on line $nr" )
      continue
    fi
    case "$key" in
      full_song_format) track_format="$val" ;;
      fzf_options) FZMP_FZF_OPTIONS="$val" ;;
      default_view)
        if [[ "$val" =~ ^playlist$|^songs$|^artists$|^genres$|^playlists$ ]]; then
          default_filter="filter_by_$val"
        else
          config_err+=( "unknown format \"$val\" in config file on line $nr" )
          config_err+=( "default_view must be 'playlist' 'songs' 'artists' 'genres' or 'playlists'" )
        fi ;;
      playlist_view_key) bindings[playlist]="$val" ;;
      artist_view_key) bindings[artist]="$val" ;;
      track_view_key) bindings[track]="$val" ;;
      genre_view_key) bindings[genre]="$val" ;;
      playlists_view_key) bindings[playlists]="$val" ;;
      findadd_key) bindings[findadd]="$val" ;;
      *) config_err+=( "unknown key \"$key\" in config file on line $nr" )
    esac
  done < "$config_file"
  if (( ${#config_err[@]} > 0 )); then
    err 'there were errors parsing config file:'
    for e in "${config_err[@]}"; do
      err "  $e"
    done
  fi
}

filter_by_songs() {
  local choice
  mapfile -t choice < <(mpc listall |
    fzf --prompt='songs > ' \
      --multi \
      --bind='ctrl-space:execute-silent:printf "%s\n" {+} | cut -f1 | mpc add' \
      --expect="${key_bindings},enter" |
    cut -f1)
  case "${choice[0]}" in
    'enter') printf '%s\n' "${choice[@]:1}" | add_songs play ;;
    *) do_binding "${choice[0]}" || exit
  esac
}

filter_by_genres() {
  local choice
  mapfile -t choice < <(mpc list -f '%genre%' genre '' |
    awk 'NF' | sort | uniq -c | sort -rn |
    fzf --prompt='genres > ' \
      --preview='mpc search -f "%artist%" genre {2..} | sort -u' \
      --bind="${bindings[findadd]}:execute-silent:mpc findadd genre {2..}" \
      --expect="${key_bindings},enter" |
    sed -r 's/^\s*[0-9]+\s*//')
  (( ${#choice[@]} > 0 )) || die
  case "${choice[0]}" in
    'enter') filter_by_artist_from_genre "${choice[1]}" ;;
    *) do_binding "${choice[0]}" || "$default_filter" ;;
  esac
}

filter_by_artist_from_genre() {
  local artist genre choice
  genre="$1"
  mapfile -t choice < <(mpc search -f '%artist%' genre "$genre" |
    sort -u | awk 'NF' | sort -u |
    fzf --prompt="$genre > " \
      --preview="$album_listing" \
      --expect="${key_bindings},enter" \
      --bind="${bindings[findadd]}:execute-silent:mpc findadd artist {}")
  (( ${#choice[@]} > 0 )) || filter_by_genres
  case "${choice[0]}" in
    'enter') filter_by_album_from_artist "${choice[1]}" ;;
    *) do_binding "${choice[0]}" || filter_by_genres ;;
  esac
}

filter_by_artists() {
  local choice
  mapfile -t choice < <(mpc list artist |
    fzf --prompt='artists > ' \
      --preview="$album_listing" \
      --bind="${bindings[findadd]}:execute-silent:mpc findadd artist {}" \
      --expect="${key_bindings},enter")
  (( ${#choice[@]} > 0 )) || die
  case "${choice[0]}" in
    'enter') filter_by_album_from_artist "${choice[1]}" ;;
    *) do_binding "${choice[0]}" || "$default_filter" ;;
  esac
}

filter_by_album_from_artist() {
  local album artist choice
  [[ -z "$1" ]] && filter_by_artists
  artist="$1"
  printf -v qartist '%q' "$1"
  mapfile -t choice < <(mpc search -f '[(%date%)]\t[%album%]' artist "$artist" |
    sort -h | uniq |
    fzf --prompt="$artist > " \
      --preview="mpc search -f '[[[%track% - ][%title%]]|%file%]' artist ${qartist} album {2}" \
      --expect="${key_bindings},enter" \
      --bind="${bindings[findadd]}:execute-silent:mpc findadd album {2..} artist ${qartist}" \
      --delimiter='\t' |
      cut -f2)
  case "${choice[0]}" in
    'enter') filter_songs_from_album "$artist" "${choice[1]}" ;;
    *) do_binding "${choice[0]}" || filter_by_artists ;;
  esac
}

filter_songs_from_album() {
  local album artist choice
  [[ -z "$1" || -z "$2" ]] && exit 255
  artist="$1"
  album="$2"
  mapfile -t choice < <(mpc search -f '%file%\t[[[%track% - ][%title%]]|%file%]' artist "${artist}" album "${album}" |
    fzf --prompt="$artist - $album > " \
      --multi \
      --with-nth='2..' \
      --delimiter='\t' \
      --expect="${key_bindings},enter" |
    cut -f1)
  case "${choice[0]}" in
    'enter') printf '%s\n' "${choice[@]:1}" | add_songs play ;;
    *) do_binding "${choice[0]}" || filter_by_album_from_artist "$artist" ;;
  esac
}

filter_by_playlist() {
  local choice
  current_song=$(mpc current -f "$track_format")
  mapfile -t choice < <(mpc playlist -f "%position%\t$track_format" |
    fzf --prompt='playlist > ' \
      --multi \
      ${current_song:+--header="now playing: ${current_song}"} \
      --delimiter='\t' \
      --with-nth='2..' \
      --bind='ctrl-p:execute-silent:mpc toggle' \
      --expect="${key_bindings},>,<,ctrl-d,enter,ctrl-s,ctrl-q" |
    cut -f1) || die
  case "${choice[0]}" in
    '>') mpc -q next; filter_by_playlist ;;
    '<') mpc -q prev; filter_by_playlist ;;
    'enter') [[ -n "${choice[1]}" ]] && mpc -q play "${choice[@]:1}" && filter_by_playlist ;;
    'ctrl-d') [[ -n "${choice[1]}" ]] && mpc -q del "${choice[@]:1}" && filter_by_playlist ;;
    'ctrl-s') save_playlist; filter_by_playlist ;;
    'ctrl-q') mpc -q stop; filter_by_playlist ;;
    *) do_binding "${choice[0]}" || exit ;;
  esac
}

save_playlist() {
  local name playlists confirm
  tput clear
  # if [[ -z $(mpc playlist) ]]; then
  #   color red 'cannot save empty playlist'
  #   sleep 0.7
  #   return 1
  # fi
  read -r -e -p 'Enter playlist name: ' name
  [[ -z $name ]] && return 1
  playlists=$(mpc lsplaylists)
  if [[ $playlists = *"$name"* ]]; then
    diff -s --suppress-common-lines --color=always --label="$name" --label='playlist' <(mpc playlist -f '%file%' "$name") <(mpc playlist -f '%file%')
    read -r -n 1 -p 'Are you sure you want to overwrite this playlist? (press y) ' confirm || return
    if [[ ${confirm,} = y ]]; then
      mpc rm "$name"
    else
      return
    fi
  fi
  mpc save "$name"
}

pick_playlist() {
  local choice
  mapfile -t choice < <(mpc lsplaylists |
    fzf --prompt='playlists > ' \
      --multi \
      --preview='mpc playlist {1}' \
      --delimiter='\t' \
      --bind='ctrl-space:execute-silent:mpc load {1}' \
      --expect="${key_bindings},ctrl-d,enter")
  case "${choice[0]}" in
    'enter') mpc playlist -f '%file%' "${choice[1]}" | add_songs play && filter_by_playlist ;;
    'ctrl-d')
      tput clear
      read -r -n 1 -p 'Are you sure you want to delete this playlist? (press y) ' confirm
      if [[ ${confirm} = y ]]; then
        mpc rm "${choice[1]}"
        pick_playlist
      fi ;;
    *) do_binding "${choice[0]}" || exit
  esac
}

add_songs() {
  local songs index
  mapfile -t songs
  (( "${#songs[@]}" > 0 )) || die
  printf '%s\n' "${songs[@]}" | mpc -q add
  [[ $1 == play ]] || return
  index=$(mpc playlist | wc -l)
  if (( ${#songs[@]} > 1 )); then
    index=$(( index - ${#songs[@]} + 1))
  fi
  mpc -q play "$index"
  filter_by_playlist
}

finish() {
  tput rmcup
}
trap finish EXIT SIGINT SIGTERM

parse_config_file
IFS=',' key_bindings="${bindings[*]}"
key_bindings="${key_bindings/,${bindings[findadd]}}"

while :; do
  case "$1" in
    -A|--all) default_filter='filter_by_songs'; shift ;;
    -a|--artist) default_filter='filter_by_artists'; shift ;;
    -p|--playlist) default_filter='filter_by_playlist'; shift ;;
    -P|--playlists) default_filter='pick_playlist'; shift ;;
    -g|--genre) default_filter='filter_by_genres'; shift ;;
    -h|--help) usage; exit ;;
    *) break
  esac
done

has -v fzf mpc || die
is_running mpd || [[ -v MPD_HOST ]] || die "can't connect to mpd"

tput smcup
"$default_filter"
