#!/bin/bash
# Kao Installation Script
# Installs to /opt/kao and sets up systemd service

set -e

INSTALL_DIR="/opt/kao"
SERVICE_FILE="/etc/systemd/system/kao.service"
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

# Use SUDO_USER if running via sudo, otherwise current user
CURRENT_USER="${SUDO_USER:-$(whoami)}"
CURRENT_GROUP="$(id -gn "$CURRENT_USER")"

echo "===================================="
echo "  Kao Installer"
echo "===================================="
echo "Install directory: $INSTALL_DIR"
echo "Running as user: $CURRENT_USER"
echo "Source: $SCRIPT_DIR"
echo ""

# Check if running as root
if [ "$EUID" -ne 0 ]; then
    echo "Error: Must run as root"
    echo "Run with: sudo $0"
    exit 1
fi

if [ -z "$CURRENT_USER" ] || [ "$CURRENT_USER" = "root" ]; then
    echo "Error: Could not determine target user"
    echo "Run with: sudo $0"
    exit 1
fi

# Check for python3
if ! command -v python3 &> /dev/null; then
    echo "Error: python3 not found"
    echo "Install with: sudo apt install python3 python3-venv"
    exit 1
fi

# Check source files exist
if [ ! -f "$SCRIPT_DIR/kao.py" ]; then
    echo "Error: Source files not found in $SCRIPT_DIR"
    echo "Run this script from the Kao repository directory"
    exit 1
fi

# Create install directory
echo "[1/5] Creating install directory..."
mkdir -p "$INSTALL_DIR"
cp "$SCRIPT_DIR/aggregator.py" "$INSTALL_DIR/"
cp "$SCRIPT_DIR/kao.py" "$INSTALL_DIR/"
cp "$SCRIPT_DIR/index.html" "$INSTALL_DIR/"
cp "$SCRIPT_DIR/config.json" "$INSTALL_DIR/"
cp "$SCRIPT_DIR/requirements.txt" "$INSTALL_DIR/"
cp -r "$SCRIPT_DIR/detectors" "$INSTALL_DIR/"

# Set ownership before venv creation
chown -R "$CURRENT_USER:$CURRENT_GROUP" "$INSTALL_DIR"

# Create virtual environment as target user
echo "[2/5] Creating virtual environment..."
sudo -u "$CURRENT_USER" python3 -m venv "$INSTALL_DIR/venv"
sudo -u "$CURRENT_USER" "$INSTALL_DIR/venv/bin/pip" install --upgrade pip -q
sudo -u "$CURRENT_USER" "$INSTALL_DIR/venv/bin/pip" install -r "$INSTALL_DIR/requirements.txt" -q

# Create systemd service
echo "[3/5] Creating systemd service..."
cat > "$SERVICE_FILE" << EOF
[Unit]
Description=Kao - System Status Monitor
After=network.target

[Service]
Type=simple
User=$CURRENT_USER
Group=$CURRENT_GROUP
WorkingDirectory=$INSTALL_DIR
ExecStart=$INSTALL_DIR/venv/bin/python $INSTALL_DIR/kao.py
Restart=always
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

# Reload systemd and enable service
echo "[4/5] Enabling service..."
systemctl daemon-reload
systemctl enable kao.service

# Start service
echo "[5/5] Starting Kao..."
systemctl start kao.service

echo ""
echo "===================================="
echo "  Installation complete!"
echo "===================================="
echo ""
echo "Kao is now running at http://$(hostname -I | awk '{print $1}'):5100"
echo ""
echo "Commands:"
echo "  sudo systemctl status kao    # Check status"
echo "  sudo systemctl restart kao   # Restart"
echo "  sudo systemctl stop kao      # Stop"
echo "  sudo journalctl -u kao -f    # View logs"
echo ""
echo "Config file: $INSTALL_DIR/config.json"