#!/usr/bin/env bash
# Forces a fresh download of a model file listed in models.yml, replacing the one on disk.
# Why and how: docs/operations.md#forcing-a-model-re-download
set -euo pipefail
cd "$(dirname "$0")/.."

if [ $# -gt 1 ] || [ "${1:-}" = "-h" ] || [ "${1:-}" = "--help" ]; then
  echo "Usage: $0 [model-file]   (default: LLAMA_MODEL_FILE from .env)" >&2
  exit 1
fi

file="${1:-}"
if [ -z "$file" ]; then
  [ -f .env ] || { echo ".env missing, run scripts/update.sh first" >&2; exit 1; }
  file="$(grep -m1 '^LLAMA_MODEL_FILE=' .env | cut -d= -f2- | tr -d '\r"'"'" || true)"
  [ -n "$file" ] || { echo "LLAMA_MODEL_FILE is not set in .env" >&2; exit 1; }
fi
grep -qxF "  - file: $file" models.yml || { echo "$file is not listed in models.yml" >&2; exit 1; }

# Runs a snippet against the models volume; $1 in it is the model file.
in_volume() { docker compose --profile tools run --rm --entrypoint sh downloader -c "cd /models; $1" _ "$file"; }

# Put the previous file back if the download didn't finish, so a failed run never loses the working model.
ok=false
restore() {
  $ok || in_volume '[ ! -f "$1.old" ] || { rm -f "$1" "$1.part"; mv "$1.old" "$1"; }' || true
}
trap restore EXIT

echo "==> moving aside the current $file (kept until the new download succeeds)"
in_volume '[ -f "$1" ] || { [ ! -f "$1.old" ] || mv "$1.old" "$1"; }; [ ! -f "$1" ] || mv -f "$1" "$1.old"; rm -f "$1.part"'

echo "==> downloading $file"
docker compose --profile tools run --rm downloader

ok=true
in_volume 'rm -f "$1.old"'

echo "==> restarting llama-server to load the new file"
docker compose restart llama-server