#!/bin/bash
# regen.sh — regenerate per-playlist sldl configs from _template.conf.
#
# Source of truth is $ALEMBIC_CONFIG_DIR/pipeline/playlists.json, written by
# the alembic app's playlist_service whenever a playlist is added/edited/
# removed via the UI. This script never edits that source of truth — it only
# renders it. Run automatically by the app before each playlist sync, or
# manually: regen.sh
#
# playlists.json shape: a JSON array of objects, each with at least
# {"name": "...", "spotify_url": "...", "active": true, "no_m3u": false}.
# Inactive playlists still get a .conf rendered (so a manual run is always
# possible) but are skipped by the scheduler.

set -euo pipefail

ALEMBIC_CONFIG_DIR="${ALEMBIC_CONFIG_DIR:-/config}"
MUSIC_DATA_DIR="${MUSIC_DATA_DIR:-/data/music}"
PIPELINE_DIR="${PIPELINE_DIR:-/app/pipeline}"

CONFIG_OUT_DIR="$ALEMBIC_CONFIG_DIR/pipeline"
PLAYLISTS_JSON="$CONFIG_OUT_DIR/playlists.json"
TEMPLATE="$PIPELINE_DIR/configs/_template.conf"
SLDL_DROPBOX_ROOT="$MUSIC_DATA_DIR/sldl-dropbox"

if [[ ! -f "$PLAYLISTS_JSON" ]]; then
  echo "ERROR: $PLAYLISTS_JSON not found — nothing to regenerate." >&2
  echo "       This file is written by the alembic app; run its playlist" >&2
  echo "       import/seed step first if this is a fresh setup." >&2
  exit 1
fi

mkdir -p "$CONFIG_OUT_DIR"

# One "name<TAB>spotify_url" line per playlist, active or not (see header).
python3 -c "
import json, sys
with open(sys.argv[1]) as f:
    playlists = json.load(f)
for p in playlists:
    print(p['name'] + '\t' + p['spotify_url'])
" "$PLAYLISTS_JSON" | while IFS=$'\t' read -r name url; do
  [[ -z "$name" ]] && continue
  sed -e "s|PLAYLIST_NAME|${name}|g" \
      -e "s|SPOTIFY_URL|${url}|g" \
      -e "s|SLDL_DROPBOX_ROOT|${SLDL_DROPBOX_ROOT}|g" \
      "$TEMPLATE" > "$CONFIG_OUT_DIR/${name}.conf"
  echo "Generated $CONFIG_OUT_DIR/${name}.conf"
done