#!/bin/bash
# install_service.sh
# This script must be run with sudo on the target machine.
# It installs the Wilcon Agent as a systemd service.

set -e # Exit immediately if a command exits with a non-zero status.

echo "--- Wilcon Agent Service Installer ---"

# Check if running as root
if [ "$EUID" -ne 0 ]; then
    echo "Please run this script with sudo: sudo ./install_service.sh"
    exit 1
fi

# --- Configuration ---
AGENT_USER="agent_user"
SERVICE_NAME="wilcon-agent"
BACKEND_SCRIPT="wilcon.py"
FRONTEND_FILE="index.html"

# Determine the script's own directory to find project files
# This makes the script location-independent.
INSTALL_PATH=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" &>/dev/null && pwd)
echo "Installation path detected: $INSTALL_PATH"

# Determine the primary IP address of the machine for configuration
# This is needed for CORS and the frontend API URL.
TARGET_IP=$(hostname -I | awk '{print $1}')
if [ -z "$TARGET_IP" ]; then
    echo "Error: Could not determine the IP address of this machine."
    exit 1
fi
echo "Machine IP address detected: $TARGET_IP"
BACKEND_PORT="8080" # This should match the port in wilcon.py

LOG_DIR="/var/log/wilcon-agent"

# --- Installation Steps ---

# 1. Create log directory
echo "   Creating log directory at $LOG_DIR..."
mkdir -p "$LOG_DIR"

# 2. Create a non-login system user to run the service
if ! id -u "$AGENT_USER" >/dev/null 2>&1; then
    echo "   Creating system user '$AGENT_USER'..."
    useradd -r -s /bin/false "$AGENT_USER"
else
    echo "   System user '$AGENT_USER' already exists."
fi

# Set ownership of the log directory now that the user is guaranteed to exist
chown "${AGENT_USER}:${AGENT_USER}" "$LOG_DIR"

# 3. Check for Python and install if necessary
echo "   Checking for Python 3.10..."
# On Debian/Ubuntu, python3-venv is a separate package needed for creating virtual environments.
# We check for both the python command and the venv package.
if ! command -v python3.10 &>/dev/null || ! dpkg -s python3.10-venv &>/dev/null; then
    echo "   Python 3.10 and/or python3.10-venv not found. Attempting to install..."
    apt update && apt install -y python3.10 python3.10-venv
    if [ $? -ne 0 ]; then
        echo "   Error: Failed to install Python 3.10 and/or python3.10-venv. Please install them manually."
        exit 1
    fi
fi

# 4. Create virtual environment and install dependencies
echo "   Creating Python virtual environment in $INSTALL_PATH/venv..."
echo "   Ensuring clean state for virtual environment..."
rm -rf "$INSTALL_PATH/venv"
python3.10 -m venv "$INSTALL_PATH/venv"

echo "   Installing Python dependencies..."
# Activate venv and install
"$INSTALL_PATH/venv/bin/pip" install -r "$INSTALL_PATH/requirements.txt"
if [ $? -ne 0 ]; then
    echo "   Error: Failed to install Python dependencies. Check requirements.txt."
    exit 1
fi

# 5. Configure application files
echo "   Configuring frontend API URL in $FRONTEND_FILE..."
sed -i "s|const API_BASE_URL = \".*\";|const API_BASE_URL = \"http://${TARGET_IP}:${BACKEND_PORT}\";|" "$INSTALL_PATH/$FRONTEND_FILE"

echo "   Modifying $BACKEND_SCRIPT for network access..."
# This sed command inserts the new origin after the line containing "http://127.0.0.1:8080","
sed -i "/\"http:\/\/127.0.0.1:8080\",/a \ \ \ \ \"http://${TARGET_IP}:${BACKEND_PORT}\"," "$INSTALL_PATH/$BACKEND_SCRIPT"

# 6. Set final ownership for the application directory
echo "   Setting final ownership for '$AGENT_USER'..."
chown -R "${AGENT_USER}:${AGENT_USER}" "$INSTALL_PATH"

# 7. Create systemd service file
echo "   Creating systemd service file..."
SERVICE_FILE_PATH="/etc/systemd/system/${SERVICE_NAME}.service"
tee "$SERVICE_FILE_PATH" >/dev/null <<EOF_SERVICE
[Unit]
Description=Wilcon Client Dashboard Agent
After=network.target

[Service]
User=${AGENT_USER}
Group=${AGENT_USER}
WorkingDirectory=${INSTALL_PATH}
ExecStart=${INSTALL_PATH}/venv/bin/uvicorn wilcon:app --host 0.0.0.0 --port 8080
Restart=always
Environment="LOG_DIR=${LOG_DIR}"
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF_SERVICE

# 8. Reload systemd, enable and start the service
echo "   Reloading systemd, enabling and starting service..."
systemctl daemon-reload
systemctl enable "$SERVICE_NAME.service"
systemctl restart "$SERVICE_NAME.service"
echo "   Service status:"
systemctl status "$SERVICE_NAME.service" --no-pager

echo ""
echo "--- Installation Complete! ---"
echo "The Wilcon Client Dashboard is now running as a service."
echo "You can access the dashboard from any browser on your network at:"
echo "  => http://$TARGET_IP:$BACKEND_PORT/$FRONTEND_FILE"
echo ""
echo "To manage the service, you can use these commands:"
echo "  sudo systemctl status $SERVICE_NAME"
echo "  sudo systemctl stop $SERVICE_NAME"
echo "  sudo systemctl start $SERVICE_NAME"
echo "  sudo journalctl -u $SERVICE_NAME -f  (to view logs)"