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

usage() {
  cat >&2 <<'EOF'
Usage:
  deploy/semantic-index/install.sh [--dry-run] [--apply] [--start] [--no-system] [--skip-deps]

Modes:
  --dry-run   Print commands that would run. This is the default.
  --apply     Install files, venv, dependencies, env template, and systemd units.
  --start     With --apply, reload systemd and start only semantic-index.service.
  --no-system Skip sudo/systemd operations. Useful for tests and local validation.
  --skip-deps Skip venv creation and dependency install.

The installer never runs backfill, never enables the refresh timer, and never
passes --force-rebuild.
EOF
}

mode=dry-run
start_service=0
system_ops=1
skip_deps=0

while [[ $# -gt 0 ]]; do
  case "$1" in
    --dry-run)
      mode=dry-run
      shift
      ;;
    --apply)
      mode=apply
      shift
      ;;
    --start)
      start_service=1
      shift
      ;;
    --no-system)
      system_ops=0
      shift
      ;;
    --skip-deps)
      skip_deps=1
      shift
      ;;
    -h|--help)
      usage
      exit 0
      ;;
    *)
      usage
      exit 2
      ;;
  esac
done

if [[ "$start_service" -eq 1 && "$mode" != "apply" ]]; then
  echo "--start requires --apply" >&2
  exit 2
fi

repo_root=$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)
install_dir=${SEMANTIC_INDEX_INSTALL_DIR:-/opt/semantic-index}
env_file=${SEMANTIC_INDEX_ENV_FILE:-/etc/semantic-index.env}
state_dir=${SEMANTIC_INDEX_STATE_DIR:-/var/lib/semantic-index}
log_dir=${SEMANTIC_INDEX_LOG_DIR:-/var/log/semantic-index}
systemd_dir=${SEMANTIC_INDEX_SYSTEMD_DIR:-/etc/systemd/system}
python_bin=${PYTHON:-python3}

run() {
  if [[ "$mode" == "dry-run" ]]; then
    printf 'would run:'
    printf ' %q' "$@"
    printf '\n'
  else
    "$@"
  fi
}

run_sudo() {
  if [[ "$system_ops" -eq 0 ]]; then
    run "$@"
  else
    run sudo "$@"
  fi
}

install_env_template() {
  if [[ "$mode" == "dry-run" ]]; then
    echo "would copy env template only if missing: $env_file"
    return
  fi
  if [[ -e "$env_file" ]]; then
    echo "keeping existing $env_file"
    return
  fi
  if [[ "$system_ops" -eq 0 ]]; then
    mkdir -p "$(dirname "$env_file")"
    cp "$repo_root/deploy/semantic-index/semantic-index.env.example" "$env_file"
  else
    sudo install -m 0640 "$repo_root/deploy/semantic-index/semantic-index.env.example" "$env_file"
  fi
}

print_next_steps_warning() {
  cat <<EOF

Semantic Index installed, but deployment is not complete.

Required manual steps:
1. Edit $env_file and fill real secrets/URLs.
2. Start or restart the HTTP service:
   sudo systemctl daemon-reload
   sudo systemctl start semantic-index.service
3. Validate:
   curl -sS http://127.0.0.1:8787/health
   $install_dir/semantic_index/search.sh "goods return" customer-service 3
4. Before enabling scheduled refresh, run:
   SEMANTIC_INDEX_PROJECT_LIMITS='customer-service=5' $install_dir/semantic_index/refresh.sh
   $install_dir/semantic_index/refresh.sh --apply
5. Create/confirm a Qdrant snapshot before any production-scale backfill.

The refresh timer was NOT enabled automatically.
Do not use --force-rebuild unless you intentionally want to pay to re-embed unchanged documents.
EOF
}

echo "mode=$mode"
echo "install_dir=$install_dir"
echo "env_file=$env_file"
echo "state_dir=$state_dir"
echo "log_dir=$log_dir"

run_sudo mkdir -p "$install_dir" "$state_dir" "$log_dir" "$systemd_dir"
run_sudo rsync -a \
  --exclude ".env" \
  --exclude "__pycache__/" \
  --exclude "*.pyc" \
  "$repo_root/semantic_index" \
  "$repo_root/tests" \
  "$repo_root/docs" \
  "$repo_root/deploy" \
  "$repo_root/dist" \
  "$install_dir/"

if [[ "$skip_deps" -eq 1 ]]; then
  echo "skipping venv/dependency install because --skip-deps was used"
elif [[ "$mode" == "apply" && "$system_ops" -eq 0 ]]; then
  run "$python_bin" -m venv "$install_dir/.venv"
  run "$install_dir/.venv/bin/pip" install openai qdrant-client fastapi uvicorn
else
  run_sudo "$python_bin" -m venv "$install_dir/.venv"
  run_sudo "$install_dir/.venv/bin/pip" install openai qdrant-client fastapi uvicorn
fi

install_env_template

run_sudo install -m 0644 "$repo_root/deploy/semantic-index/semantic-index.service" "$systemd_dir/semantic-index.service"
run_sudo install -m 0644 "$repo_root/deploy/semantic-index/semantic-index-refresh.service" "$systemd_dir/semantic-index-refresh.service"
run_sudo install -m 0644 "$repo_root/deploy/semantic-index/semantic-index-refresh.timer" "$systemd_dir/semantic-index-refresh.timer"

if [[ "$mode" == "apply" && "$skip_deps" -eq 0 ]]; then
  "$install_dir/.venv/bin/python" -m py_compile "$install_dir"/semantic_index/*.py
  "$install_dir/.venv/bin/python" -m unittest discover -s "$install_dir/tests/semantic_index"
  bash -n "$install_dir/semantic_index/refresh.sh"
elif [[ "$mode" == "apply" ]]; then
  echo "skipping installed-code validation because --skip-deps was used"
fi

if [[ "$mode" == "apply" && "$start_service" -eq 1 ]]; then
  if [[ "$system_ops" -eq 0 ]]; then
    echo "skipping systemctl start because --no-system was used"
  else
    sudo systemctl daemon-reload
    sudo systemctl start semantic-index.service
  fi
fi

if [[ "$mode" == "apply" ]]; then
  print_next_steps_warning
fi