#!/usr/bin/env bash
#
# Installation script for email_tunnel systemd service
#
# This script will:
# 1. Verify prerequisites
# 2. Copy service file to systemd directory with correct paths/user
# 3. Enable and start the service
# 4. Show status and usage information

set -euo pipefail

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

# Get script directory
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

echo "======================================"
echo "email_tunnel Service Installer"
echo "======================================"
echo ""

# Check if running as root
if [ "$EUID" -eq 0 ]; then
    echo -e "${RED}Error: Do not run this script as root or with sudo${NC}"
    echo "The script will request sudo privileges when needed."
    exit 1
fi

# Verify required files exist
echo "Checking required files..."
REQUIRED_FILES=(
    "$SCRIPT_DIR/email_tunnel.py"
    "$SCRIPT_DIR/.env"
    "$SCRIPT_DIR/email_tunnel.service"
)

for file in "${REQUIRED_FILES[@]}"; do
    if [ ! -f "$file" ]; then
        echo -e "${RED}Error: Required file not found: $file${NC}"
        exit 1
    fi
done
echo -e "${GREEN}✓ All required files found${NC}"
echo ""

# Check for required commands
echo "Checking dependencies..."
MISSING_DEPS=()
for cmd in python3 systemctl; do
    if ! command -v "$cmd" &> /dev/null; then
        MISSING_DEPS+=("$cmd")
    fi
done

if [ ${#MISSING_DEPS[@]} -gt 0 ]; then
    echo -e "${RED}Error: Missing required dependencies: ${MISSING_DEPS[*]}${NC}"
    echo "Please install them and try again."
    exit 1
fi
echo -e "${GREEN}✓ All dependencies installed${NC}"
echo ""

# Verify .env file has required variables
echo "Validating .env configuration..."
REQUIRED_VARS=(IMAP_IP IMAP_PORT IMAP_USER IMAP_PASSWORD IMAP_FOLDER SMTP_PORT SMTP_IP)
MISSING_ENV=()
for var in "${REQUIRED_VARS[@]}"; do
    if ! grep -q "^${var}=" "$SCRIPT_DIR/.env"; then
        MISSING_ENV+=("$var")
    fi
done

if [ ${#MISSING_ENV[@]} -gt 0 ]; then
    echo -e "${YELLOW}Warning: .env may be missing: ${MISSING_ENV[*]}${NC}"
    read -p "Continue anyway? (y/N) " -n 1 -r
    echo ""
    if [[ ! $REPLY =~ ^[Yy]$ ]]; then
        exit 1
    fi
else
    echo -e "${GREEN}✓ .env configuration looks good${NC}"
fi
echo ""

# Test script syntax
echo "Testing email_tunnel.py byte-compile..."
if python3 -m py_compile "$SCRIPT_DIR/email_tunnel.py"; then
    echo -e "${GREEN}✓ Byte-compile succeeded${NC}"
else
    echo -e "${RED}Error: Byte-compile failed${NC}"
    exit 1
fi
echo ""

# Check if service is already installed
SERVICE_NAME="email_tunnel.service"
if systemctl list-unit-files | grep -q "$SERVICE_NAME"; then
    echo -e "${YELLOW}Warning: $SERVICE_NAME is already installed${NC}"
    read -p "Reinstall? (y/N) " -n 1 -r
    echo ""
    if [[ ! $REPLY =~ ^[Yy]$ ]]; then
        exit 0
    fi
    echo "Stopping existing service..."
    sudo systemctl stop "$SERVICE_NAME" 2>/dev/null || true
    sudo systemctl disable "$SERVICE_NAME" 2>/dev/null || true
fi

# Prepare service file with correct paths
echo "Preparing service file..."
TEMP_SERVICE=$(mktemp)
sed "s|/opt/email-tunnel|$SCRIPT_DIR|g" "$SCRIPT_DIR/email_tunnel.service" > "$TEMP_SERVICE"

# Update user/group in service file
CURRENT_USER=$(whoami)
CURRENT_GROUP=$(id -gn)
sed -i "s|User=email-tunnel|User=$CURRENT_USER|g" "$TEMP_SERVICE"
sed -i "s|Group=email-tunnel|Group=$CURRENT_GROUP|g" "$TEMP_SERVICE"

# Install service file
echo "Installing systemd service file..."
sudo cp "$TEMP_SERVICE" /etc/systemd/system/$SERVICE_NAME
rm "$TEMP_SERVICE"
sudo chmod 644 /etc/systemd/system/$SERVICE_NAME
echo -e "${GREEN}✓ Service file installed${NC}"
echo ""

# Reload systemd
echo "Reloading systemd daemon..."
sudo systemctl daemon-reload
echo -e "${GREEN}✓ Systemd reloaded${NC}"
echo ""

# Enable and start service
echo "Enabling and starting $SERVICE_NAME..."
sudo systemctl enable "$SERVICE_NAME"
sudo systemctl start "$SERVICE_NAME"
echo -e "${GREEN}✓ Service enabled and started${NC}"
echo ""

# Show status
echo "======================================"
echo "Installation Complete!"
echo "======================================"
echo ""
echo "Service Status:"
sudo systemctl status "$SERVICE_NAME" --no-pager -l || true
echo ""

echo -e "${GREEN}email_tunnel is now running!${NC}"
echo ""
echo "Useful commands:"
echo "  View status:        systemctl status $SERVICE_NAME"
echo "  View logs:          ./logs_email_tunnel.sh -f"
echo "  Restart service:    sudo systemctl restart $SERVICE_NAME"
echo "  Stop service:       sudo systemctl stop $SERVICE_NAME"
echo "  Uninstall:          ./uninstall_email_tunnel.sh"
echo ""