#!/bin/bash

################################################################################
# BAIC Dashboard Deployment Script
#
# This script automates the deployment of the BAIC Dashboard application
# on an Ubuntu server with Apache and systemd.
#
# Prerequisites:
# - Repository cloned to /opt/baic_dashboard
# - .env file configured in repository root
# - Run this script from /opt/baic_dashboard directory
# - Execute with sudo/root privileges
#
# Usage: sudo bash deploy.sh
################################################################################

set -e  # Exit on any error

# Color codes for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# Expected deployment directory
EXPECTED_DIR="/opt/baic_dashboard"
SERVICE_NAME="baic-dashboard"
SERVICE_USER="www-data"

################################################################################
# Helper Functions
################################################################################

print_header() {
    echo -e "\n${BLUE}========================================${NC}"
    echo -e "${BLUE}$1${NC}"
    echo -e "${BLUE}========================================${NC}\n"
}

print_success() {
    echo -e "${GREEN}✓ $1${NC}"
}

print_error() {
    echo -e "${RED}✗ ERROR: $1${NC}"
}

print_warning() {
    echo -e "${YELLOW}⚠ WARNING: $1${NC}"
}

print_info() {
    echo -e "${BLUE}ℹ $1${NC}"
}

exit_with_error() {
    print_error "$1"
    exit 1
}

################################################################################
# Pre-flight Checks
################################################################################

print_header "Pre-flight Checks"

# Check if running as root
if [[ $EUID -ne 0 ]]; then
   exit_with_error "This script must be run as root (use sudo)"
fi
print_success "Running as root"

# Check if we're in the correct directory
CURRENT_DIR=$(pwd)
if [[ "$CURRENT_DIR" != "$EXPECTED_DIR" ]]; then
    exit_with_error "Script must be run from $EXPECTED_DIR (currently in $CURRENT_DIR)"
fi
print_success "Running from correct directory: $EXPECTED_DIR"

# Check for required commands
REQUIRED_COMMANDS=("python3" "npm" "systemctl")
for cmd in "${REQUIRED_COMMANDS[@]}"; do
    if ! command -v $cmd &> /dev/null; then
        exit_with_error "$cmd is not installed. Please install it first."
    fi
    print_success "$cmd is installed"
done

# Check if .env file exists
if [[ ! -f ".env" ]]; then
    exit_with_error ".env file not found in current directory. Please create it before running this script."
fi
print_success ".env file found"

# Check if apache2 is installed (warn if not, but don't fail)
if ! command -v apache2 &> /dev/null; then
    print_warning "apache2 is not installed. You'll need to install and configure it manually."
else
    print_success "apache2 is installed"
fi

################################################################################
# Backend Setup
################################################################################

print_header "Backend Setup"

# Create Python virtual environment
print_info "Creating Python virtual environment..."
if [[ -d "venv" ]]; then
    print_warning "Virtual environment already exists. Removing and recreating..."
    rm -rf venv
fi

python3 -m venv venv
if [[ $? -ne 0 ]]; then
    exit_with_error "Failed to create virtual environment"
fi
print_success "Virtual environment created"

# Activate virtual environment and install dependencies
print_info "Installing Python dependencies from requirements.txt..."
source venv/bin/activate

if [[ ! -f "backend/requirements.txt" ]]; then
    exit_with_error "backend/requirements.txt not found"
fi

pip install --upgrade pip > /dev/null 2>&1
pip install -r backend/requirements.txt
if [[ $? -ne 0 ]]; then
    exit_with_error "Failed to install Python dependencies"
fi
print_success "Python dependencies installed"

# Test that Flask can be imported
python3 -c "import flask" 2>/dev/null
if [[ $? -ne 0 ]]; then
    exit_with_error "Flask installation verification failed"
fi
print_success "Flask installation verified"

deactivate

# Set ownership to www-data
print_info "Setting ownership to $SERVICE_USER..."
chown -R $SERVICE_USER:$SERVICE_USER venv
chown -R $SERVICE_USER:$SERVICE_USER backend
print_success "Ownership set to $SERVICE_USER"

################################################################################
# Frontend Build
################################################################################

print_header "Frontend Build"

# Check if frontend directory exists
if [[ ! -d "frontend" ]]; then
    exit_with_error "frontend directory not found"
fi

cd frontend

# Install npm dependencies
print_info "Installing npm dependencies..."
npm install
if [[ $? -ne 0 ]]; then
    exit_with_error "Failed to install npm dependencies"
fi
print_success "npm dependencies installed"

# Copy .env file to frontend directory for Vite to read during build
print_info "Copying .env to frontend directory for build..."
cp ../.env ./.env
if [[ $? -ne 0 ]]; then
    exit_with_error "Failed to copy .env file"
fi
print_success ".env file copied"

# Build frontend
print_info "Building frontend for production (this may take a minute)..."
npm run build
if [[ $? -ne 0 ]]; then
    exit_with_error "Frontend build failed"
fi

# Remove .env from frontend directory (cleanup)
print_info "Cleaning up temporary .env file..."
rm -f ./.env
print_success "Cleanup complete"

# Verify dist directory was created
if [[ ! -d "dist" ]]; then
    exit_with_error "Build completed but dist/ directory not found"
fi
print_success "Frontend built successfully"

cd ..

################################################################################
# Frontend Deployment
################################################################################

print_header "Frontend Deployment"

# Prompt user for frontend deployment path
echo -e "${BLUE}Please enter the full path where the frontend files should be deployed${NC}"
echo -e "${BLUE}(e.g., /var/www/html/dashboard or /var/www/mysite.com/dashboard)${NC}"
read -p "Deployment path: " FRONTEND_DEPLOY_PATH

# Validate input
if [[ -z "$FRONTEND_DEPLOY_PATH" ]]; then
    exit_with_error "No deployment path provided"
fi

# Create directory if it doesn't exist
if [[ ! -d "$FRONTEND_DEPLOY_PATH" ]]; then
    print_info "Creating directory: $FRONTEND_DEPLOY_PATH"
    mkdir -p "$FRONTEND_DEPLOY_PATH"
    if [[ $? -ne 0 ]]; then
        exit_with_error "Failed to create deployment directory"
    fi
fi

# Copy frontend files
print_info "Copying frontend files to $FRONTEND_DEPLOY_PATH..."
cp -r frontend/dist/* "$FRONTEND_DEPLOY_PATH/"
if [[ $? -ne 0 ]]; then
    exit_with_error "Failed to copy frontend files"
fi
print_success "Frontend files copied"

# Set ownership and permissions
print_info "Setting ownership and permissions..."
chown -R $SERVICE_USER:$SERVICE_USER "$FRONTEND_DEPLOY_PATH"
find "$FRONTEND_DEPLOY_PATH" -type d -exec chmod 755 {} \;
find "$FRONTEND_DEPLOY_PATH" -type f -exec chmod 644 {} \;
print_success "Ownership and permissions set"

################################################################################
# Systemd Service Creation
################################################################################

print_header "Systemd Service Setup"

# Read BACKEND_PORT from .env or use default
BACKEND_PORT=$(grep "^BACKEND_PORT=" .env | cut -d'=' -f2 | tr -d ' ')
if [[ -z "$BACKEND_PORT" ]]; then
    BACKEND_PORT="5001"
    print_warning "BACKEND_PORT not found in .env, using default: 5001"
else
    print_info "Using BACKEND_PORT from .env: $BACKEND_PORT"
fi

SERVICE_FILE="/etc/systemd/system/${SERVICE_NAME}.service"

print_info "Creating systemd service file: $SERVICE_FILE"

cat > "$SERVICE_FILE" << EOF
[Unit]
Description=BAIC Dashboard Backend Service
After=network.target

[Service]
Type=simple
User=$SERVICE_USER
Group=$SERVICE_USER
WorkingDirectory=$EXPECTED_DIR/backend
EnvironmentFile=$EXPECTED_DIR/.env
ExecStart=$EXPECTED_DIR/venv/bin/python app.py

# Restart policy
Restart=always
RestartSec=10

# Security settings
NoNewPrivileges=true
PrivateTmp=true

# Logging
StandardOutput=journal
StandardError=journal
SyslogIdentifier=$SERVICE_NAME

[Install]
WantedBy=multi-user.target
EOF

if [[ $? -ne 0 ]]; then
    exit_with_error "Failed to create systemd service file"
fi
print_success "Systemd service file created"

################################################################################
# Service Management
################################################################################

print_header "Service Management"

# Reload systemd daemon
print_info "Reloading systemd daemon..."
systemctl daemon-reload
if [[ $? -ne 0 ]]; then
    exit_with_error "Failed to reload systemd daemon"
fi
print_success "Systemd daemon reloaded"

# Enable service
print_info "Enabling service to start on boot..."
systemctl enable $SERVICE_NAME
if [[ $? -ne 0 ]]; then
    exit_with_error "Failed to enable service"
fi
print_success "Service enabled"

# Restart service (to ensure code changes are picked up)
print_info "Restarting service..."
systemctl restart $SERVICE_NAME
if [[ $? -ne 0 ]]; then
    print_error "Failed to restart service. Check logs with: journalctl -u $SERVICE_NAME -n 50"
    exit 1
fi
print_success "Service restarted"

# Wait a moment for service to initialize
sleep 2

# Check service status
print_info "Checking service status..."
if systemctl is-active --quiet $SERVICE_NAME; then
    print_success "Service is running"
    echo ""
    systemctl status $SERVICE_NAME --no-pager -l
else
    print_error "Service failed to start properly"
    print_info "Showing recent logs:"
    journalctl -u $SERVICE_NAME -n 20 --no-pager
    exit 1
fi

################################################################################
# Apache Configuration Generation
################################################################################

print_header "Apache Configuration"

# Get domain and base path from .env
DOMAIN=$(grep "^DOMAIN=" .env | cut -d'=' -f2 | tr -d ' ')
BASE_PATH=$(grep "^BASE_PATH=" .env | cut -d'=' -f2 | tr -d ' ')

if [[ -z "$DOMAIN" ]]; then
    DOMAIN="yourdomain.com"
    print_warning "DOMAIN not found in .env, using placeholder in config"
fi

if [[ -z "$BASE_PATH" ]]; then
    BASE_PATH="/dashboard/"
    print_warning "BASE_PATH not found in .env, using default: /dashboard/"
fi

# Remove trailing slash from BASE_PATH for cleaner config
BASE_PATH_NO_SLASH=${BASE_PATH%/}

APACHE_CONFIG_FILE="$EXPECTED_DIR/apache-config.conf"

print_info "Generating Apache configuration: $APACHE_CONFIG_FILE"

cat > "$APACHE_CONFIG_FILE" << EOF
# Apache Configuration for BAIC Dashboard
#
# Add this configuration to your Apache virtual host file
# (e.g., /etc/apache2/sites-available/000-default.conf or your custom site config)
#
# Required Apache modules (enable with a2enmod):
# - proxy
# - proxy_http
# - headers
# - rewrite
#
# Enable modules:
#   sudo a2enmod proxy proxy_http headers rewrite
#   sudo systemctl restart apache2

<VirtualHost *:443>
    ServerName $DOMAIN

    # SSL Configuration (adjust paths to your certificates)
    # SSLEngine on
    # SSLCertificateFile /etc/letsencrypt/live/$DOMAIN/fullchain.pem
    # SSLCertificateKeyFile /etc/letsencrypt/live/$DOMAIN/privkey.pem

    # Frontend static files
    Alias $BASE_PATH_NO_SLASH $FRONTEND_DEPLOY_PATH
    <Directory $FRONTEND_DEPLOY_PATH>
        Options -Indexes +FollowSymLinks
        AllowOverride All
        Require all granted

        # Handle client-side routing (React Router)
        <IfModule mod_rewrite.c>
            RewriteEngine On
            RewriteBase $BASE_PATH_NO_SLASH/
            RewriteRule ^index\.html$ - [L]
            RewriteCond %{REQUEST_FILENAME} !-f
            RewriteCond %{REQUEST_FILENAME} !-d
            RewriteRule . $BASE_PATH_NO_SLASH/index.html [L]
        </IfModule>
    </Directory>

    # Backend API reverse proxy
    ProxyPreserveHost On
    ProxyTimeout 300

    <Location $BASE_PATH_NO_SLASH/back/api>
        ProxyPass http://localhost:$BACKEND_PORT/api
        ProxyPassReverse http://localhost:$BACKEND_PORT/api

        # Add headers for proper proxying
        RequestHeader set X-Forwarded-Proto "https"
        RequestHeader set X-Forwarded-Port "443"
    </Location>

    # Error and Access logs
    ErrorLog \${APACHE_LOG_DIR}/${SERVICE_NAME}-error.log
    CustomLog \${APACHE_LOG_DIR}/${SERVICE_NAME}-access.log combined
</VirtualHost>

# Optional: Redirect HTTP to HTTPS
<VirtualHost *:80>
    ServerName $DOMAIN
    Redirect permanent / https://$DOMAIN/
</VirtualHost>
EOF

if [[ $? -ne 0 ]]; then
    print_error "Failed to create Apache configuration file"
else
    print_success "Apache configuration file created"
fi

################################################################################
# Deployment Complete
################################################################################

print_header "Deployment Complete!"

echo -e "${GREEN}✓ Backend virtual environment created and dependencies installed${NC}"
echo -e "${GREEN}✓ Frontend built and deployed to: $FRONTEND_DEPLOY_PATH${NC}"
echo -e "${GREEN}✓ Systemd service created and restarted: $SERVICE_NAME${NC}"
echo -e "${GREEN}✓ Apache configuration generated: $APACHE_CONFIG_FILE${NC}"

echo ""
print_header "Next Steps"

echo -e "${YELLOW}1. Review the Apache configuration:${NC}"
echo -e "   cat $APACHE_CONFIG_FILE"
echo ""
echo -e "${YELLOW}2. Enable required Apache modules:${NC}"
echo -e "   sudo a2enmod proxy proxy_http headers rewrite"
echo ""
echo -e "${YELLOW}3. Add the configuration to your Apache virtual host:${NC}"
echo -e "   - Edit: /etc/apache2/sites-available/your-site.conf"
echo -e "   - Or copy: sudo cp $APACHE_CONFIG_FILE /etc/apache2/sites-available/${SERVICE_NAME}.conf"
echo -e "   - Enable: sudo a2ensite ${SERVICE_NAME}"
echo ""
echo -e "${YELLOW}4. Test Apache configuration:${NC}"
echo -e "   sudo apache2ctl configtest"
echo ""
echo -e "${YELLOW}5. Reload Apache:${NC}"
echo -e "   sudo systemctl reload apache2"
echo ""
echo -e "${YELLOW}6. Configure SSL/TLS certificates (if not already done):${NC}"
echo -e "   sudo apt install certbot python3-certbot-apache"
echo -e "   sudo certbot --apache -d $DOMAIN"
echo ""

print_header "Useful Commands"

echo -e "${BLUE}Service Management:${NC}"
echo -e "  sudo systemctl status $SERVICE_NAME      # Check service status"
echo -e "  sudo systemctl restart $SERVICE_NAME     # Restart service"
echo -e "  sudo systemctl stop $SERVICE_NAME        # Stop service"
echo -e "  sudo journalctl -u $SERVICE_NAME -f      # View live logs"
echo -e "  sudo journalctl -u $SERVICE_NAME -n 100  # View last 100 log lines"
echo ""

print_success "Deployment script completed successfully!"

exit 0