#!/bin/bash

# --- Configuration (Edit these before spreading) ---
TARGET_SERVICE_UUID=""
SERVER_URL="https://monitor.example.com"
AUTH_USER="monitor_user"
AUTH_PASS="monitor_user_pass"
UPDATE_INTERVAL=10

# --- Script Logic ---

# 1. Ensure the script is run as root
if [ "$EUID" -ne 0 ]; then
  echo "Please run as root (use sudo)"
  exit 1
fi

echo "Starting deployment of Monitoring Agent..."

# 2. Install dependencies (libcap2-bin is needed for setcap)
echo "Installing dependencies..."
apt-get update -qq
apt-get install -y libcap2-bin uuid-runtime -qq

# 3. Create the system user if it doesn't exist
if ! id "monitor-agent" &>/dev/null; then
    echo "Creating monitor-agent system user..."
    useradd -r -s /bin/false monitor-agent
fi

# 4. Create necessary directories
echo "Creating directories..."
mkdir -p /etc/monitor-agent
mkdir -p /var/lib/monitor-agent
chown -R monitor-agent:monitor-agent /var/lib/monitor-agent

# 5. Install the binary
if [ -f "./agent-go" ]; then
    echo "Installing binary to /usr/local/bin..."
    cp ./agent-go /usr/local/bin/monitor-agent
    chmod +x /usr/local/bin/monitor-agent
    # Grant ping capabilities without root
    setcap cap_net_raw+ep /usr/local/bin/monitor-agent
else
    echo "Error: 'monitor-agent' binary not found in current directory!"
    exit 1
fi

# 6. Generate a unique NODE_UUID for this specific server
NEW_UUID=$(uuidgen)
echo "Generated unique Node UUID: $NEW_UUID"

# 7. Create the Environment File
echo "Creating configuration file..."
cat <<EOF > /etc/monitor-agent/agent.env
NODE_UUID=$NEW_UUID
TARGET_SERVICE_UUID=$TARGET_SERVICE_UUID
SERVER_URL=$SERVER_URL
BASIC_AUTH_USERNAME=$AUTH_USER
BASIC_AUTH_PASSWORD=$AUTH_PASS
UPDATE_INTERVAL_SECONDS=$UPDATE_INTERVAL
PEERS_FILE=/var/lib/monitor-agent/known_peers.json
EOF

chmod 600 /etc/monitor-agent/agent.env
chown monitor-agent:monitor-agent /etc/monitor-agent/agent.env

# 8. Create the Systemd Service File
echo "Creating systemd service..."
cat <<EOF > /etc/systemd/system/monitor-agent.service
[Unit]
Description=Node Monitoring Agent
After=network-online.target
Wants=network-online.target

[Service]
Type=simple
User=monitor-agent
Group=monitor-agent
WorkingDirectory=/var/lib/monitor-agent
EnvironmentFile=/etc/monitor-agent/agent.env
ExecStart=/usr/local/bin/monitor-agent
CapabilityBoundingSet=CAP_NET_RAW
AmbientCapabilities=CAP_NET_RAW
Restart=always
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

# 9. Start the service
echo "Reloading systemd and starting service..."
systemctl daemon-reload
systemctl enable monitor-agent
systemctl restart monitor-agent

echo "------------------------------------------------"
echo "Deployment Complete!"
echo "Node UUID: $NEW_UUID"
echo "Check status with: systemctl status monitor-agent"
echo "View logs with: journalctl -u monitor-agent -f"
echo "------------------------------------------------"