#!/bin/bash

# C-Relay-PG PostgreSQL Deployment Script
# Deploys static relay binary and configures PostgreSQL 18 + systemd service on remote server.

set -euo pipefail

# Configuration
REMOTE_HOST="ubuntu@laantungir.net"
LOCAL_BINARY="build/c_relay_pg_static_x86_64"
LOCAL_CACHING_BINARY="build/caching_relay"
REMOTE_BINARY_DIR="/usr/local/bin/c_relay_pg"
REMOTE_BINARY_PATH="/usr/local/bin/c_relay_pg/c_relay_pg"
REMOTE_CACHING_BINARY_PATH="/opt/c-relay-pg/caching_relay"
SERVICE_NAME="c-relay-pg"

LOCAL_SERVICE_FILE="systemd/c-relay.service"
LOCAL_PG_SETUP_SCRIPT="systemd/setup_postgres_18.sh"

if [ ! -f "$LOCAL_BINARY" ]; then
    echo "ERROR: Binary not found: $LOCAL_BINARY"
    echo "Build it first (e.g. ./make_and_restart_relay.sh)"
    exit 1
fi

if [ ! -f "$LOCAL_SERVICE_FILE" ]; then
    echo "ERROR: Service file not found: $LOCAL_SERVICE_FILE"
    exit 1
fi

if [ ! -f "$LOCAL_PG_SETUP_SCRIPT" ]; then
    echo "ERROR: PostgreSQL setup script not found: $LOCAL_PG_SETUP_SCRIPT"
    exit 1
fi

echo "==> Uploading artifacts to $REMOTE_HOST"
scp "$LOCAL_BINARY" "$REMOTE_HOST:/tmp/c_relay_pg.tmp"
scp "$LOCAL_SERVICE_FILE" "$REMOTE_HOST:/tmp/c-relay-pg.service"
scp "$LOCAL_PG_SETUP_SCRIPT" "$REMOTE_HOST:/tmp/setup_postgres_18.sh"
# Upload the caching_relay binary if it was built locally. The caching
# service is NOT started by this deploy (the systemd unit does not pass
# --start-caching), but the binary is placed in the relay's WorkingDirectory
# so it is ready for when caching is enabled via event-based config.
if [ -f "$LOCAL_CACHING_BINARY" ]; then
    scp "$LOCAL_CACHING_BINARY" "$REMOTE_HOST:/tmp/caching_relay.tmp"
else
    echo "WARNING: caching_relay binary not found locally ($LOCAL_CACHING_BINARY) — skipping caching binary upload"
fi

echo "==> Running remote install/configuration"
ssh "$REMOTE_HOST" 'bash -s' <<'EOF'
set -euo pipefail

SERVICE_NAME="c-relay-pg"
RELAY_USER="c-relay-pg"
REMOTE_BINARY_DIR="/usr/local/bin/c_relay_pg"
REMOTE_BINARY_PATH="/usr/local/bin/c_relay_pg/c_relay_pg"
REMOTE_CACHING_BINARY_PATH="/opt/c-relay-pg/caching_relay"

echo "[remote] Ensuring service user exists"
if ! id "$RELAY_USER" >/dev/null 2>&1; then
  sudo useradd --system --home-dir /opt/c-relay-pg --shell /usr/sbin/nologin "$RELAY_USER"
fi

echo "[remote] Ensuring required directories exist"
sudo mkdir -p "$REMOTE_BINARY_DIR" /opt/c-relay-pg /etc/c-relay-pg
sudo chown "$RELAY_USER:$RELAY_USER" /opt/c-relay-pg

echo "[remote] Installing PostgreSQL 18 (PGDG) if missing"
if ! dpkg -s postgresql-18 >/dev/null 2>&1; then
  sudo apt-get update
  sudo apt-get install -y curl ca-certificates lsb-release gnupg
  sudo install -d /usr/share/postgresql-common/pgdg
  sudo curl -fsSL https://www.postgresql.org/media/keys/ACCC4CF8.asc -o /usr/share/postgresql-common/pgdg/apt.postgresql.org.asc
  echo "deb [signed-by=/usr/share/postgresql-common/pgdg/apt.postgresql.org.asc] https://apt.postgresql.org/pub/repos/apt $(lsb_release -cs)-pgdg main" | sudo tee /etc/apt/sources.list.d/pgdg.list >/dev/null
  sudo apt-get update
  sudo apt-get install -y postgresql-18
fi

sudo systemctl enable postgresql
sudo systemctl restart postgresql

echo "[remote] Configuring PostgreSQL role/database"
sudo chmod +x /tmp/setup_postgres_18.sh
sudo /tmp/setup_postgres_18.sh

echo "[remote] Installing relay binary"
if [ -f "$REMOTE_BINARY_PATH" ]; then
  sudo cp "$REMOTE_BINARY_PATH" "${REMOTE_BINARY_PATH}.backup.$(date +%Y%m%d_%H%M%S)"
fi
sudo mv /tmp/c_relay_pg.tmp "$REMOTE_BINARY_PATH"
sudo chown "$RELAY_USER:$RELAY_USER" "$REMOTE_BINARY_PATH"
sudo chmod +x "$REMOTE_BINARY_PATH"

echo "[remote] Installing caching_relay binary (if uploaded)"
if [ -f /tmp/caching_relay.tmp ]; then
  sudo mv /tmp/caching_relay.tmp "$REMOTE_CACHING_BINARY_PATH"
  sudo chown "$RELAY_USER:$RELAY_USER" "$REMOTE_CACHING_BINARY_PATH"
  sudo chmod +x "$REMOTE_CACHING_BINARY_PATH"
  echo "  -> caching_relay installed at $REMOTE_CACHING_BINARY_PATH (not started; enable via config when ready)"
else
  echo "  -> no caching_relay binary uploaded, skipping"
fi

echo "[remote] Installing systemd unit"
sudo mv /tmp/c-relay-pg.service /etc/systemd/system/c-relay-pg.service
sudo chown root:root /etc/systemd/system/c-relay-pg.service
sudo chmod 644 /etc/systemd/system/c-relay-pg.service

echo "[remote] Killing stale caching_relay processes (safety)"
# The caching service is forked by the relay with setsid(), so it detaches
# from the relay's process group and survives when the relay is killed.
# Without this, every restart orphans the previous caching_relay child and
# a new relay forks another, leading to many stale processes with dead PG
# connections spamming errors. Kill them here so the new relay starts clean.
CACHING_PIDS=$(pgrep -f "caching_relay" || echo "")
if [ -n "$CACHING_PIDS" ]; then
  echo "  -> killing stale caching_relay PIDs: $CACHING_PIDS"
  kill -9 $CACHING_PIDS 2>/dev/null || true
  sleep 1
else
  echo "  -> no stale caching_relay processes found"
fi

echo "[remote] Reloading and restarting service"
sudo systemctl daemon-reload
sudo systemctl enable "$SERVICE_NAME"
sudo systemctl restart "$SERVICE_NAME"

echo "[remote] Health checks"
sudo systemctl --no-pager --full status "$SERVICE_NAME" | sed -n '1,25p'
sudo -u "$RELAY_USER" psql -d crelay -c "SELECT current_user, current_database();"
EOF

echo "Deployment complete: $REMOTE_HOST"