#!/usr/bin/env bash
# Zero-downtime prod deploy: pull, sync deps, build front, migrate, then
# gracefully reload gunicorn (see polylan-submitter.service, installed and
# restarted instead when it changed) and restart the RQ worker (see
# polylan-submitter-worker.conf).
#
# Run from anywhere as the user owning the checkout, needs sudo for
# systemctl/supervisorctl (no-op when already root):
#   ./deploy/systemd/deploy.sh
#
# Migrations run while the old code still serves requests, so keep them
# backward compatible (nullable/default columns, drop/rename in a later deploy).

set -euo pipefail

SERVICE="${SERVICE:-polylan-submitter}"
WORKER="${WORKER:-polylan-submitter-worker}"
SUPERVISOR_CONF_DIR="${SUPERVISOR_CONF_DIR:-/etc/supervisor/conf.d}"
WEB_URL="${WEB_URL:-https://polylan-submitter.legrems.xyz/}"

REPO_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
DEPLOY_DIR="$REPO_DIR/deploy/systemd"
APP_DIR="$REPO_DIR/polylan_submitter"
PYTHON="$REPO_DIR/.venv/bin/python"
# Same as the unit's Environment=, so migrate/collectstatic see the prod settings.
# Relative to $APP_DIR, where manage.py runs.
export SETTINGS_ENV_FILE_LOCATION="${SETTINGS_ENV_FILE_LOCATION:-polylan_submitter/.env}"

# gunicorn's master doesn't reload itself on HUP, so a server upgrade needs a
# full restart instead.
server_versions() {
    "$PYTHON" - <<'EOF' 2>/dev/null || true
import importlib.metadata as m
for pkg in ("gunicorn", "uvicorn", "uvicorn-worker"):
    try:
        print(pkg, m.version(pkg))
    except m.PackageNotFoundError:
        print(pkg, "missing")
EOF
}

# wait_for <description> <command...>: retry for ~30s, fail the deploy if it
# never succeeds.
wait_for() {
    local what="$1"
    shift
    for _ in $(seq 1 30); do
        if "$@" >/dev/null 2>&1; then
            echo "    $what: ok"
            return 0
        fi
        sleep 1
    done
    echo "    $what: FAILED" >&2
    return 1
}

web_responds() {
    # 000 = nothing listening, 5xx = Caddy up but gunicorn down (502) or broken.
    local code
    code="$(curl -s -o /dev/null -w '%{http_code}' "$WEB_URL")"
    [ "$code" != "000" ] && [ "$code" -lt 500 ]
}

worker_running() {
    sudo supervisorctl status "$WORKER" | grep -q RUNNING
}

cd "$REPO_DIR"

echo "==> git pull"
git pull --ff-only

before="$(server_versions)"

echo "==> uv sync"
uv sync --frozen --no-dev

after="$(server_versions)"

echo "==> frontend build"
cd "$APP_DIR"
pnpm install --frozen-lockfile
pnpm build

echo "==> migrate"
"$PYTHON" manage.py migrate --noinput

echo "==> collectstatic"
"$PYTHON" manage.py collectstatic --noinput

echo "==> $SERVICE (systemd)"
unit_changed=false
if ! cmp -s "$DEPLOY_DIR/$SERVICE.service" "/etc/systemd/system/$SERVICE.service"; then
    sudo install -m 644 "$DEPLOY_DIR/$SERVICE.service" "/etc/systemd/system/$SERVICE.service"
    sudo systemctl daemon-reload
    sudo systemctl enable "$SERVICE"
    unit_changed=true
fi

# HUP re-forks workers with the master's original args, so a new ExecStart
# (unit change) or a new gunicorn/uvicorn needs a full restart.
if [ "$unit_changed" = true ]; then
    echo "==> unit file changed, full restart of $SERVICE"
    sudo systemctl restart "$SERVICE"
elif [ "$before" != "$after" ]; then
    echo "==> server packages changed, full restart of $SERVICE"
    sudo systemctl restart "$SERVICE"
else
    echo "==> graceful reload of $SERVICE"
    sudo systemctl reload "$SERVICE"
fi
wait_for "$SERVICE active" systemctl is-active --quiet "$SERVICE"
wait_for "$SERVICE responds on $WEB_URL" web_responds

echo "==> $WORKER (supervisor)"
sudo install -m 644 "$DEPLOY_DIR/$WORKER.conf" "$SUPERVISOR_CONF_DIR/$WORKER.conf"
# reread+update picks up config changes (and starts it on first install),
# restart loads the new code - TERM is a warm shutdown, the running job ends first.
sudo supervisorctl reread
sudo supervisorctl update "$WORKER"
sudo supervisorctl restart "$WORKER"
wait_for "$WORKER running" worker_running

echo "==> done"