#!/bin/bash
# Resource Monitor Service - Installation Script for Linux systemd service

SERVICE_NAME="resource-monitor"
SERVICE_DISPLAY_NAME="Resource Monitor Service v2.1"
SERVICE_DESCRIPTION="Monitors system resources with web dashboard"
INSTALL_PATH="/opt/resource-monitor"
SERVICE_FILE="/etc/systemd/system/${SERVICE_NAME}.service"

echo "=== Resource Monitor Service - Linux systemd Installer ==="
echo

# Check if running as root
if [[ $EUID -ne 0 ]]; then
    echo "ERROR: This script must be run as root (use sudo)"
    echo "Please run: sudo ./install-service-linux.sh"
    exit 1
fi

# Function to uninstall service
uninstall_service() {
    echo "Uninstalling Resource Monitor Service..."
    
    # Stop the service
    echo "Stopping service..."
    systemctl stop $SERVICE_NAME 2>/dev/null
    echo "Service stopped"
    
    # Disable the service
    echo "Disabling service..."
    systemctl disable $SERVICE_NAME 2>/dev/null
    echo "Service disabled"
    
    # Remove service file
    echo "Removing service file..."
    rm -f $SERVICE_FILE
    echo "Service file removed"
    
    # Reload systemd
    systemctl daemon-reload
    
    # Optionally remove installation directory
    read -p "Remove installation files from $INSTALL_PATH? (y/N): " removeFiles
    if [[ "$removeFiles" == "y" || "$removeFiles" == "Y" ]]; then
        rm -rf $INSTALL_PATH
        echo "Installation files removed"
    fi
    
    echo "Uninstallation complete!"
    exit 0
}

# Check for uninstall flag
if [[ "$1" == "--uninstall" || "$1" == "-u" ]]; then
    uninstall_service
fi

echo "Installing Resource Monitor Service as systemd service..."

# Check if .NET is installed
if ! command -v dotnet &> /dev/null; then
    echo "ERROR: .NET runtime is not installed"
    echo "Please install .NET 8.0 or later runtime"
    echo "See: https://docs.microsoft.com/en-us/dotnet/core/install/linux"
    exit 1
fi

# Create installation directory
echo "Creating installation directory..."
mkdir -p "$INSTALL_PATH"
if [[ $? -ne 0 ]]; then
    echo "ERROR: Failed to create installation directory"
    exit 1
fi
echo "Installation directory created: $INSTALL_PATH"

# Build the service in release mode
echo "Building service..."
dotnet publish --configuration Release --output "$INSTALL_PATH"
if [[ $? -ne 0 ]]; then
    echo "ERROR: Build failed"
    exit 1
fi
echo "Service built successfully"

# Stop existing service if running
echo "Stopping existing service (if running)..."
systemctl stop $SERVICE_NAME 2>/dev/null || echo "No existing service found"

# Create systemd service file
echo "Creating systemd service file..."
cat > $SERVICE_FILE << EOF
[Unit]
Description=$SERVICE_DESCRIPTION
After=network.target

[Service]
Type=notify
ExecStart=/usr/bin/dotnet $INSTALL_PATH/ResourceMonitorService.dll
Restart=always
RestartSec=5
SyslogIdentifier=resource-monitor
User=www-data
Environment=ASPNETCORE_ENVIRONMENT=Production
Environment=ASPNETCORE_URLS=http://localhost:5000
WorkingDirectory=$INSTALL_PATH

[Install]
WantedBy=multi-user.target
EOF

if [[ $? -ne 0 ]]; then
    echo "ERROR: Failed to create service file"
    exit 1
fi
echo "Service file created"

# Set proper permissions
chmod 644 $SERVICE_FILE
chown root:root $SERVICE_FILE

# Reload systemd
echo "Reloading systemd daemon..."
systemctl daemon-reload

# Enable the service
echo "Enabling service..."
systemctl enable $SERVICE_NAME
if [[ $? -ne 0 ]]; then
    echo "ERROR: Failed to enable service"
    exit 1
fi
echo "Service enabled"

# Start the service
echo "Starting service..."
systemctl start $SERVICE_NAME
if [[ $? -ne 0 ]]; then
    echo "ERROR: Failed to start service"
    echo "Check service status with: systemctl status $SERVICE_NAME"
    exit 1
fi
echo "Service started successfully"

# Wait a moment and check service status
sleep 3
SERVICE_STATUS=$(systemctl is-active $SERVICE_NAME)
echo "Service Status: $SERVICE_STATUS"

# Configure firewall (if ufw is available)
if command -v ufw &> /dev/null; then
    echo "Configuring firewall for web dashboard..."
    ufw allow 5000/tcp comment "Resource Monitor Service"
    echo "Firewall rule created for port 5000"
fi

echo
echo "=== Installation Complete ==="
echo "Service Name: $SERVICE_NAME"
echo "Installation Path: $INSTALL_PATH"
echo "Web Dashboard: http://localhost:5000"
echo "API Documentation: http://localhost:5000/swagger"
echo "API Health Check: http://localhost:5000/api/health"
echo
echo "The service is now running and will start automatically with the system."
echo "You can manage it using systemctl commands:"
echo "  - Stop:    sudo systemctl stop $SERVICE_NAME"
echo "  - Start:   sudo systemctl start $SERVICE_NAME"
echo "  - Status:  systemctl status $SERVICE_NAME"
echo "  - Restart: sudo systemctl restart $SERVICE_NAME"
echo "  - Logs:    journalctl -u $SERVICE_NAME -f"
echo
echo "To uninstall: sudo ./install-service-linux.sh --uninstall"

# Test the web dashboard
echo
echo "Testing web dashboard..."
sleep 5
if command -v curl &> /dev/null; then
    RESPONSE=$(curl -s -o /dev/null -w "%{http_code}" http://localhost:5000/api/health)
    if [[ "$RESPONSE" == "200" ]]; then
        echo "Web Dashboard Test: SUCCESS"
        echo
        echo "🎉 Web Dashboard is ready at: http://localhost:5000"
        echo "📖 API Documentation at: http://localhost:5000/swagger"
    else
        echo "Web Dashboard Test: FAILED (HTTP $RESPONSE)"
        echo "The service may still be starting up. Wait a few minutes and try accessing:"
        echo "http://localhost:5000"
    fi
else
    echo "curl not available for testing. Please check manually:"
    echo "http://localhost:5000"
fi