#!/bin/bash

# Add Domain Helper Script
# Adds DKIM support and configuration for additional domains

set -euo pipefail

# Colors
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m'

# Check arguments
if [[ $# -ne 1 ]]; then
    echo "Usage: $0 <domain>"
    echo "Example: $0 newdomain.com"
    echo
    echo "This script will:"
    echo "  - Generate DKIM keys for the new domain"
    echo "  - Update OpenDKIM configuration"
    echo "  - Display DNS records to add"
    echo "  - Show PostfixAdmin setup instructions"
    exit 1
fi

DOMAIN=$1

# Logging
LOG_FILE="/var/log/email-server-setup.log"

log() {
    echo "$(date '+%Y-%m-%d %H:%M:%S') - $1" | tee -a "$LOG_FILE"
}

info() {
    echo -e "${BLUE}INFO: $1${NC}"
    log "INFO: $1"
}

success() {
    echo -e "${GREEN}SUCCESS: $1${NC}"
    log "SUCCESS: $1"
}

warning() {
    echo -e "${YELLOW}WARNING: $1${NC}"
    log "WARNING: $1"
}

error() {
    echo -e "${RED}ERROR: $1${NC}" >&2
    log "ERROR: $1"
    exit 1
}

# Check if running as root
check_root() {
    if [[ $EUID -ne 0 ]]; then
        error "This script must be run as root"
    fi
}

# Validate domain format
validate_domain() {
    if [[ ! "$DOMAIN" =~ ^[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9]*\.[a-zA-Z]{2,}$ ]]; then
        error "Invalid domain format: $DOMAIN"
    fi
}

# Check if domain already exists in DKIM
check_existing_domain() {
    if [[ -d "/etc/opendkim/keys/$DOMAIN" ]]; then
        warning "DKIM keys already exist for $DOMAIN"
        read -p "Do you want to regenerate them? (y/N): " -n 1 -r
        echo
        if [[ ! $REPLY =~ ^[Yy]$ ]]; then
            info "Keeping existing DKIM keys for $DOMAIN"
            return 1
        fi
    fi
    return 0
}

# Get main hostname from existing configuration
get_main_hostname() {
    if [[ -f "/etc/postfix/main.cf" ]]; then
        MAIN_HOSTNAME=$(grep "^myhostname" /etc/postfix/main.cf | cut -d= -f2 | tr -d ' ')
        if [[ -z "$MAIN_HOSTNAME" ]]; then
            error "Could not determine main hostname from Postfix configuration"
        fi
    else
        error "Postfix configuration not found. Run the main setup script first."
    fi
}

# Generate DKIM keys for the new domain
generate_dkim_keys() {
    info "Generating DKIM keys for domain: $DOMAIN"
    
    # Create directory
    mkdir -p /etc/opendkim/keys/$DOMAIN
    
    # Generate DKIM key
    opendkim-genkey -t -s mail -d $DOMAIN -D /etc/opendkim/keys/$DOMAIN
    
    # Set permissions
    chown -R opendkim:opendkim /etc/opendkim/keys/$DOMAIN
    chmod 600 /etc/opendkim/keys/$DOMAIN/mail.private
    
    success "DKIM keys generated for $DOMAIN"
}

# Update OpenDKIM configuration
update_opendkim_config() {
    info "Updating OpenDKIM configuration..."
    
    # Check if entry already exists in key.table
    if ! grep -q "mail._domainkey.$DOMAIN" /etc/opendkim/key.table 2>/dev/null; then
        echo "mail._domainkey.$DOMAIN $DOMAIN:mail:/etc/opendkim/keys/$DOMAIN/mail.private" >> /etc/opendkim/key.table
    fi
    
    # Check if entry already exists in signing.table
    if ! grep -q "*@$DOMAIN" /etc/opendkim/signing.table 2>/dev/null; then
        echo "*@$DOMAIN mail._domainkey.$DOMAIN" >> /etc/opendkim/signing.table
    fi
    
    # Check if domain already exists in trusted.hosts
    if ! grep -q "^$DOMAIN$" /etc/opendkim/trusted.hosts 2>/dev/null; then
        echo "$DOMAIN" >> /etc/opendkim/trusted.hosts
    fi
    
    success "OpenDKIM configuration updated"
}

# Restart OpenDKIM service
restart_opendkim() {
    info "Restarting OpenDKIM service..."
    if systemctl restart opendkim; then
        success "OpenDKIM service restarted"
    else
        error "Failed to restart OpenDKIM service"
    fi
}

# Test DKIM configuration
test_dkim() {
    info "Testing DKIM configuration..."
    sleep 2  # Give OpenDKIM time to start
    
    if opendkim-testkey -d $DOMAIN -s mail -vvv 2>&1 | grep -q "key OK"; then
        success "DKIM test passed for $DOMAIN"
    else
        warning "DKIM test failed. Check the DNS record below and try again later."
    fi
}

# Display DNS records to add
display_dns_records() {
    get_main_hostname
    
    echo
    echo -e "${YELLOW}=== DNS Records to Add for $DOMAIN ===${NC}"
    echo
    echo -e "${BLUE}1. MX Record:${NC}"
    echo "MX    $DOMAIN       $MAIN_HOSTNAME"
    echo
    echo -e "${BLUE}2. SPF Record:${NC}"
    echo "TXT   $DOMAIN       \"v=spf1 mx ~all\""
    echo
    echo -e "${BLUE}3. DMARC Record:${NC}"
    echo "TXT   _dmarc.$DOMAIN \"v=DMARC1; p=none; rua=mailto:dmarc@$DOMAIN\""
    echo
    echo -e "${BLUE}4. DKIM Record:${NC}"
    echo "Record name: mail._domainkey.$DOMAIN"
    echo "Record type: TXT"
    echo "Record value:"
    cat /etc/opendkim/keys/$DOMAIN/mail.txt 2>/dev/null || echo "Error: DKIM key file not found"
    echo
}

# Display PostfixAdmin instructions
display_postfixadmin_instructions() {
    get_main_hostname
    
    echo -e "${YELLOW}=== PostfixAdmin Setup Instructions ===${NC}"
    echo
    echo "1. Visit: https://$MAIN_HOSTNAME/postfixadmin/"
    echo "2. Login with your admin credentials"
    echo "3. Go to 'Domain List' → 'New Domain'"
    echo "4. Enter domain: $DOMAIN"
    echo "5. Set desired limits and quotas"
    echo "6. Click 'Add Domain'"
    echo "7. Create mailboxes under 'Virtual List' → 'Add Mailbox'"
    echo
    echo -e "${BLUE}Suggested mailboxes for $DOMAIN:${NC}"
    echo "  - admin@$DOMAIN"
    echo "  - info@$DOMAIN"
    echo "  - noreply@$DOMAIN"
    echo "  - support@$DOMAIN"
    echo
}

# Display application configuration
display_app_config() {
    get_main_hostname
    
    echo -e "${YELLOW}=== Application SMTP Configuration ===${NC}"
    echo
    echo "Your applications can now send email from $DOMAIN using these settings:"
    echo
    echo -e "${BLUE}SMTP Settings:${NC}"
    echo "  Host: $MAIN_HOSTNAME"
    echo "  Port: 587 (STARTTLS) or 465 (SSL/TLS)"
    echo "  Security: STARTTLS or SSL/TLS"
    echo "  Username: mailbox@$DOMAIN (full email address)"
    echo "  Password: [mailbox password from PostfixAdmin]"
    echo
    echo -e "${BLUE}Example Python code:${NC}"
    cat << 'EOF'
import smtplib
from email.mime.text import MIMEText

smtp_config = {
    'host': 'MAIN_HOSTNAME',
    'port': 587,
    'username': 'app@DOMAIN',
    'password': 'your_mailbox_password'
}

msg = MIMEText("Hello from DOMAIN!")
msg['Subject'] = "Test Email"
msg['From'] = smtp_config['username']
msg['To'] = "recipient@example.com"

with smtplib.SMTP(smtp_config['host'], smtp_config['port']) as server:
    server.starttls()
    server.login(smtp_config['username'], smtp_config['password'])
    server.send_message(msg)
EOF
    echo
}

# Verify email server is running
verify_email_server() {
    info "Verifying email server status..."
    
    services=("postfix" "dovecot" "opendkim" "postgresql")
    all_running=true
    
    for service in "${services[@]}"; do
        if ! systemctl is-active --quiet $service; then
            warning "$service is not running"
            all_running=false
        fi
    done
    
    if $all_running; then
        success "All required services are running"
    else
        warning "Some services are not running. You may need to restart them."
    fi
}

# Main function
main() {
    echo -e "${BLUE}Add Domain Script for Email Server${NC}"
    echo "=================================="
    echo "Adding domain: $DOMAIN"
    echo
    
    check_root
    validate_domain
    verify_email_server
    
    if check_existing_domain; then
        generate_dkim_keys
    fi
    
    update_opendkim_config
    restart_opendkim
    test_dkim
    display_dns_records
    display_postfixadmin_instructions
    display_app_config
    
    echo
    success "Domain $DOMAIN has been configured!"
    echo
    echo -e "${YELLOW}Next steps:${NC}"
    echo "1. Add the DNS records shown above"
    echo "2. Wait for DNS propagation (up to 24 hours)"
    echo "3. Add the domain in PostfixAdmin"
    echo "4. Create mailboxes for the domain"
    echo "5. Test email sending and receiving"
    echo
    echo -e "${BLUE}To test the configuration later, run:${NC}"
    echo "./test-email-server.sh"
}

# Show help if requested
if [[ "${1:-}" == "--help" || "${1:-}" == "-h" ]]; then
    echo "Add Domain Script for Email Server"
    echo "================================="
    echo
    echo "Usage: $0 <domain>"
    echo
    echo "This script adds DKIM support for additional domains to your email server."
    echo "It will generate DKIM keys, update OpenDKIM configuration, and provide"
    echo "DNS records and PostfixAdmin instructions."
    echo
    echo "Examples:"
    echo "  $0 newcompany.com"
    echo "  $0 mysite.org"
    echo
    echo "Prerequisites:"
    echo "  - Email server must be already set up with setup-email-server.sh"
    echo "  - Must be run as root"
    echo "  - Domain should point to your server"
    echo
    echo "After running this script:"
    echo "  1. Add the provided DNS records"
    echo "  2. Configure the domain in PostfixAdmin"
    echo "  3. Create mailboxes for the new domain"
    exit 0
fi

main "$@"