#!/bin/bash
# gen-djmix-playlist.sh — regenerate djmix.m3u8 from the configured album list.
#
# Reads ${ALEMBIC_CONFIG_DIR:-/config}/pipeline/djmix-albums.txt (one beets query per line),
# collects all matching track paths, deduplicates, and writes
# ${MUSIC_DATA_DIR:-/data/music}/playlists/djmix.m3u8.
#
# Azuracast imports this playlist so DJ mixes can be excluded from general
# rotation. Navidrome also picks it up as a regular playlist.
#
# Runs daily from cron. Safe to run manually anytime.

set -euo pipefail

CONFIG=${ALEMBIC_CONFIG_DIR:-/config}/pipeline/djmix-albums.txt
PLAYLIST_DIR=${MUSIC_DATA_DIR:-/data/music}/playlists
OUT="${PLAYLIST_DIR}/djmix.m3u8"
LOG_DIR=${ALEMBIC_CONFIG_DIR:-/config}/logs
LOG="${LOG_DIR}/djmix-$(date +%Y%m%d).log"

mkdir -p "$LOG_DIR" "$PLAYLIST_DIR"

log() { echo "[$(date -Iseconds)] $*" | tee -a "$LOG"; }

log "=== Regenerating djmix.m3u8 ==="

if [[ ! -f "$CONFIG" ]]; then
  log "no djmix-albums.txt at $CONFIG — nothing to generate"
  exit 0
fi

TRACKS=$(mktemp)

while IFS= read -r query; do
  [[ -z "$query" || "$query" == "#"* ]] && continue
  # Split on | to support multi-field queries (e.g. "albumartist::Foo | album:Bar").
  # Each |-separated part becomes a separate beet query term (ANDed together).
  # Single-field lines (no |) are passed as one arg so commas in album names
  # don't get misinterpreted by beet's query parser.
  IFS='|' read -ra _terms <<< "$query"
  _args=()
  for _t in "${_terms[@]}"; do
    # strip leading/trailing whitespace
    _t="${_t#"${_t%%[![:space:]]*}"}"
    _t="${_t%"${_t##*[![:space:]]}"}"
    [[ -n "$_t" ]] && _args+=("$_t")
  done
  # `|| true`: a malformed single query shouldn't abort the whole regen.
  beet ls -f '$path' "${_args[@]}" 2>>"$LOG" >> "$TRACKS" || true
done < "$CONFIG"

# Deduplicate and sort
SORTED=$(sort -u "$TRACKS")
rm -f "$TRACKS"

COUNT=$(echo -n "$SORTED" | grep -c '^' || true)

if [[ "$COUNT" -gt 0 ]]; then
  {
    echo "#EXTM3U"
    echo "$SORTED"
  } > "$OUT"
  log "djmix.m3u8 updated with $COUNT tracks"
else
  log "WARNING: no tracks found — djmix.m3u8 not updated"
fi

log "=== Finished ==="