#!/usr/bin/env bash
#  vim:ts=4:sts=4:sw=4:et
#
#  Author: Hari Sekhon
#  Date: 2020-07-24 19:05:25 +0100 (Fri, 24 Jul 2020)
#
#  https://github.com/harisekhon/spotify-playlists
#
#  License: see accompanying Hari Sekhon LICENSE file
#
#  If you're using my code you're welcome to connect with me on LinkedIn and optionally send me feedback to help steer this or other code I publish
#
#  https://www.linkedin.com/in/harisekhon
#

set -euo pipefail
[ -n "${DEBUG:-}" ] && set -x
srcdir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

# shellcheck disable=SC1090
. "$srcdir/lib/spotify.sh"

# shellcheck disable=SC2034,SC2154
usage_description="
Deletes Spotify URIs from a given playlist

Playlist must be specified as the first argument and can be either a Spotify playlist ID or a full playlist name (see spotify_playlists.sh)

Can take file(s) with URIs as arguments or read from standard input for chaining with other tools

Input formats can be IDs or any standard Spotify URI format, eg:

spotify:track:<ID>
https://open.spotify.com/track/<ID>
<ID>

or can be prefixed with track position in the playlist (zero-indexed) if you only want to delete a single instance of the song (useful when removing only duplicates), separated by either space:

<track_position>      spotify:track:<ID>
<track_position>      https://open.spotify.com/track/<ID>
<track_position>      <ID>

or a colon:

<track_position>:spotify:track:<ID>
<track_position>:https://open.spotify.com/track/<ID>
<track_position>:<ID>


Useful for chaining with other tools (eg. spotify_playlist_tracks_uri.sh / spotify_search_uri.sh in this repo, or
tracks_already_in_playlists.sh in the HariSekhon/Spotify-Playlists github repo) or loading from saved spotify format
playlists (eg. TODO playlists dumped by spotify_backup*.sh / spotify_playlist_tracks_uri.sh)

$usage_playlist_help

$usage_auth_help
"

# used by usage() in lib/utils.sh
# shellcheck disable=SC2034
usage_args="<playlist_name_or_id> [<file1> <file2> ...]"

help_usage "$@"

min_args 1 "$@"

playlist="$1"
shift || :

# requires authorized token
export SPOTIFY_PRIVATE=1

spotify_token

# this script returns the ID if it's already in the correct format, otherwise queries and returns the playlist ID for the playlist
playlist_id="$(SPOTIFY_PLAYLIST_EXACT_MATCH=1 "$srcdir/spotify_playlist_name_to_id.sh" "$playlist")"

playlist_name="$("$srcdir/spotify_playlist_id_to_name.sh" "$playlist_id")"

# playlist ID obtained from 'spotify_playlists.sh'
url_path="/v1/playlists/$playlist_id/tracks"

count=0

snapshot_id=""

# Takes track IDs or track position:ID for more specific deletes
delete_from_playlist(){
    if [ $# -lt 1 ]; then
        echo "Error: no IDs passed to delete_from_playlist()" >&2
        exit 1
    fi
    local uri_array=""
    local track_position
    local id
    for id in "$@"; do
        if [[ "$id" =~ ^[[:digit:]]+: ]]; then
            # extract first column for track position
            track_position="${id%%:*}"
            # keep zero-indexed for compatability with other tools
            #((track_position-=1)) # convert one-indexed (eg. from grep) to zero-indexed for Spotify API
            id="${id#*:}"
            # requires explicit track URI type since could also be episodes added to playlist
            uri_array+="{\"uri\": \"spotify:track:$id\", \"positions\": [$track_position]}, "
        else
            # requires explicit track URI type since could also be episodes added to playlist
            uri_array+="{\"uri\": \"spotify:track:$id\"}, "
        fi
    done
    uri_array="${uri_array%, }"
    timestamp "removing ${#@} tracks from playlist '$playlist_name'"
    json_payload='{"tracks": '"[$uri_array]"
    #if [ -n "$snapshot_id" ] && [ "$snapshot_id" != null ]; then
    # let it send null and fail as we should never get back null
    if [ -n "$snapshot_id" ]; then
        json_payload+=", \"snapshot_id\": \"$snapshot_id\""
    fi
    json_payload+="}"
    local output
    output="$("$srcdir/spotify_api.sh" "$url_path" -X DELETE -d "$json_payload")"
    die_if_error_field "$output"
    ((count+=${#@}))
    snapshot_id="$(jq -r '.snapshot_id' <<< "$output")"
    if is_blank "$snapshot_id"; then
        die "Spotify API returned blank snapshot id, please investigate with DEBUG=1 mode"
    fi
    if [ "$snapshot_id" = null ]; then
        die "Spotify API returned snapshot_id '$snapshot_id', please investigate with DEBUG=1 mode"
    fi
}

delete_URIs_from_file(){
    declare -a ids
    ids=()
    while read -r track_uri; do
        track_position=""
        if [[ "$track_uri" =~ ^[[:digit:]]+[:[:space:]]+ ]]; then
            # extract first column for track position
            track_position="${track_uri%%[:[:space:]]*}"

            # remove first column of track position
            track_uri="${track_uri#*[:[:space:]]}"

            # strip any remaining leading whitespace without subshelling to sed
            track_uri="${track_uri#"${track_uri%%[!:[:space:]]*}"}"
        fi
        if is_blank "$track_uri"; then
            continue
        fi
        if is_local_uri "$track_uri"; then
            continue
        fi
        id="$(validate_spotify_uri "$track_uri")"

        if [ -n "$track_position" ]; then
            ids+=("$track_position:$id")
        else
            ids+=("$id")
        fi

        if [ "${#ids[@]}" -ge 100 ]; then
            delete_from_playlist "${ids[@]}"
            ids=()
        fi
    done < "$filename"

    if [ "${#ids[@]}" -gt 0 ]; then
        delete_from_playlist "${ids[@]}"
    fi
}

for filename in "${@:-/dev/stdin}"; do
    delete_URIs_from_file "$filename"
done

timestamp "$count tracks deleted from playlist '$playlist_name'"