#!/usr/bin/env bash
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
RUNTIME_DIR="$REPO_ROOT/runtime"
LOG_FILE="$RUNTIME_DIR/lstm_retrain.log"
LOCK_FILE="$RUNTIME_DIR/lstm_retrain.lock"

mkdir -p "$RUNTIME_DIR"

log() {
  printf '[%s] %s\n' "$(date -Is)" "$*" | tee -a "$LOG_FILE"
}

if command -v flock >/dev/null 2>&1; then
  exec 9>"$LOCK_FILE"
  if ! flock -n 9; then
    log "Another LSTM retrain is already running; skipping."
    exit 0
  fi
else
  LOCK_DIR="$LOCK_FILE.d"
  if ! mkdir "$LOCK_DIR" 2>/dev/null; then
    log "Another LSTM retrain is already running; skipping."
    exit 0
  fi
  trap 'rmdir "$LOCK_DIR"' EXIT
fi

if [[ -x "$REPO_ROOT/.venv/bin/python" ]]; then
  PYTHON="$REPO_ROOT/.venv/bin/python"
elif command -v python3 >/dev/null 2>&1; then
  PYTHON="$(command -v python3)"
elif command -v python >/dev/null 2>&1; then
  PYTHON="$(command -v python)"
else
  log "ERROR: Python was not found."
  exit 1
fi

SYMBOLS="${LSTM_RETRAIN_SYMBOLS:-}"
LIMIT="${LSTM_RETRAIN_LIMIT:-1000}"
LOOKBACKS="${LSTM_RETRAIN_LOOKBACKS:-16,32}"
UNITS="${LSTM_RETRAIN_UNITS:-4,6}"
RIDGES="${LSTM_RETRAIN_RIDGES:-0.001}"
INTERVAL="${LSTM_RETRAIN_INTERVAL:-}"
ENV_FILE="${LSTM_RETRAIN_ENV:-}"

if [[ -z "$ENV_FILE" && -f "$REPO_ROOT/.env" ]]; then
  ENV_FILE="$REPO_ROOT/.env"
fi

args=(
  "tools/train_lstm_forecaster.py"
  "--limit" "$LIMIT"
  "--lookbacks" "$LOOKBACKS"
  "--units" "$UNITS"
  "--ridges" "$RIDGES"
)

if [[ -n "$SYMBOLS" ]]; then args+=("--symbols" "$SYMBOLS"); fi
if [[ -n "$INTERVAL" ]]; then args+=("--interval" "$INTERVAL"); fi
if [[ -n "$ENV_FILE" ]]; then args+=("--env" "$ENV_FILE"); fi

cd "$REPO_ROOT"
log "Starting LSTM retrain: $PYTHON -u ${args[*]}"
"$PYTHON" -u "${args[@]}" 2>&1 | tee -a "$LOG_FILE"
log "Finished LSTM retrain."