#!/bin/bash

set -e

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

echo -e "${GREEN}Oculog Client Installation${NC}"
echo "=================================="
echo ""

# Check if running as root
if [ "$EUID" -ne 0 ]; then 
    echo -e "${RED}Please run as root (use sudo)${NC}"
    exit 1
fi

# Check if Python 3 is installed
if ! command -v python3 &> /dev/null; then
    echo -e "${RED}Python 3 is not installed. Please install it first:${NC}"
    echo "  sudo apt update && sudo apt install -y python3 python3-pip"
    exit 1
fi

# Get installation directory
SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
INSTALL_DIR="/opt/oculog"

# Check if this is an upgrade
IS_UPGRADE=false
SERVICE_WAS_RUNNING=false
SERVICE_WAS_ENABLED=false

# Check if service unit file exists
if [ -f /etc/systemd/system/oculog-client.service ] || systemctl list-unit-files | grep -q "^oculog-client.service"; then
    IS_UPGRADE=true
    echo -e "${YELLOW}Detected existing installation - performing upgrade...${NC}"
    echo ""
    
    # Check if service is enabled
    if systemctl is-enabled --quiet oculog-client.service 2>/dev/null; then
        SERVICE_WAS_ENABLED=true
    fi
    
    # Check if service is running
    if systemctl is-active --quiet oculog-client.service 2>/dev/null; then
        SERVICE_WAS_RUNNING=true
        echo -e "${YELLOW}Service is currently running. Stopping it...${NC}"
        systemctl stop oculog-client.service || true
        sleep 1
        if systemctl is-active --quiet oculog-client.service 2>/dev/null; then
            echo -e "${RED}Warning: Service did not stop cleanly${NC}"
        else
            echo -e "${GREEN}Service stopped${NC}"
        fi
    fi
else
    echo -e "${GREEN}Fresh installation detected${NC}"
    echo ""
fi

echo -e "${GREEN}Step 1: Creating installation directory...${NC}"
mkdir -p "$INSTALL_DIR"
mkdir -p /var/log/oculog
mkdir -p /etc/oculog

echo -e "${GREEN}Step 2: Copying client files...${NC}"
cp "$SCRIPT_DIR/client.py" "$INSTALL_DIR/"
chmod +x "$INSTALL_DIR/client.py"

echo -e "${GREEN}Step 3: Installing Python dependencies...${NC}"

# Try to install via apt first (for newer Ubuntu versions with externally-managed environment)
if apt-cache show python3-psutil >/dev/null 2>&1 && apt-cache show python3-requests >/dev/null 2>&1; then
    echo -e "${YELLOW}Installing via apt (system-managed packages)...${NC}"
    apt-get update
    if apt-get install -y python3-psutil python3-requests; then
        PYTHON_BIN="/usr/bin/python3"
        echo -e "${GREEN}System packages installed successfully${NC}"
    else
        echo -e "${YELLOW}Apt installation failed, using virtual environment...${NC}"
        USE_VENV=1
    fi
else
    echo -e "${YELLOW}System packages not available, using virtual environment...${NC}"
    USE_VENV=1
fi

# If apt packages aren't available, use a virtual environment
if [ "$USE_VENV" = "1" ]; then
    if [ -d "$INSTALL_DIR/venv" ]; then
        echo -e "${YELLOW}Updating existing virtual environment...${NC}"
        PYTHON_BIN="$INSTALL_DIR/venv/bin/python3"
    else
        echo -e "${YELLOW}Setting up virtual environment...${NC}"
        apt-get update
        apt-get install -y python3-venv python3-pip || true
        
        # Create virtual environment
        python3 -m venv "$INSTALL_DIR/venv"
        PYTHON_BIN="$INSTALL_DIR/venv/bin/python3"
    fi
    
    # Install/upgrade packages in virtual environment
    "$INSTALL_DIR/venv/bin/pip" install --quiet --upgrade pip
    "$INSTALL_DIR/venv/bin/pip" install --quiet --upgrade -r "$SCRIPT_DIR/requirements.txt"
    
    echo -e "${GREEN}Virtual environment ready and packages installed${NC}"
fi

# Update shebang in client script to use correct Python
sed -i "1s|.*|#!${PYTHON_BIN}|" "$INSTALL_DIR/client.py"

echo -e "${GREEN}Step 4: Creating symlink...${NC}"
ln -sf "$INSTALL_DIR/client.py" /usr/local/bin/oculog-client

echo -e "${GREEN}Step 5: Setting up configuration...${NC}"
if [ ! -f /etc/oculog/client.conf ]; then
    # Fresh installation - create new config
    if [ -f "$SCRIPT_DIR/client.conf.example" ]; then
        cp "$SCRIPT_DIR/client.conf.example" /etc/oculog/client.conf
        echo -e "${YELLOW}Configuration file created at /etc/oculog/client.conf${NC}"
        echo -e "${YELLOW}Please edit it with your server URL and server ID${NC}"
    else
        cat > /etc/oculog/client.conf << EOF
{
  "server_url": "http://localhost:3001",
  "server_id": "$(hostname)",
  "interval": 30
}
EOF
        echo -e "${YELLOW}Default configuration created at /etc/oculog/client.conf${NC}"
    fi
else
    # Existing installation - preserve config
    if [ "$IS_UPGRADE" = true ]; then
        # Backup existing config before upgrade
        BACKUP_FILE="/etc/oculog/client.conf.backup.$(date +%Y%m%d_%H%M%S)"
        cp /etc/oculog/client.conf "$BACKUP_FILE"
        echo -e "${GREEN}Configuration file preserved (backup: $BACKUP_FILE)${NC}"
    else
        echo -e "${GREEN}Configuration file already exists, preserving...${NC}"
    fi
fi

echo -e "${GREEN}Step 6: Installing systemd service...${NC}"
# Update service file to use correct Python binary
sed "s|ExecStart=/usr/local/bin/oculog-client|ExecStart=${PYTHON_BIN} $INSTALL_DIR/client.py|" "$SCRIPT_DIR/oculog-client.service" > /etc/systemd/system/oculog-client.service
systemctl daemon-reload
systemctl enable oculog-client.service

# Restart service if it was running before upgrade
if [ "$IS_UPGRADE" = true ]; then
    if [ "$SERVICE_WAS_RUNNING" = true ] || [ "$SERVICE_WAS_ENABLED" = true ]; then
        echo -e "${GREEN}Step 7: Starting service...${NC}"
        systemctl start oculog-client.service || true
        sleep 2
        if systemctl is-active --quiet oculog-client.service 2>/dev/null; then
            echo -e "${GREEN}Service started successfully${NC}"
        else
            echo -e "${YELLOW}Warning: Service may have failed to start. Check status with: systemctl status oculog-client${NC}"
        fi
    fi
fi

echo ""
if [ "$IS_UPGRADE" = true ]; then
    echo -e "${GREEN}Upgrade completed successfully!${NC}"
else
    echo -e "${GREEN}Installation completed successfully!${NC}"
fi
echo ""
if [ "$IS_UPGRADE" = false ]; then
    echo "Next steps:"
    echo "1. Edit /etc/oculog/client.conf with your server URL"
    echo "2. Start the service: sudo systemctl start oculog-client"
    echo "3. Check status: sudo systemctl status oculog-client"
    echo "4. View logs: sudo journalctl -u oculog-client -f"
else
    echo "Upgrade complete. Service status:"
    systemctl status oculog-client.service --no-pager -l || true
    echo ""
    echo "View logs: sudo journalctl -u oculog-client -f"
fi
echo ""