#!/usr/bin/env python3
"""Portscan — basic TCP port scanner."""
import argparse, socket, sys, concurrent.futures, time


def color(text, code):
    return f"\033[{code}m{text}\033[0m" if sys.stdout.isatty() else text


SERVICE_PORTS = {
    21: "FTP", 22: "SSH", 23: "Telnet", 25: "SMTP",
    53: "DNS", 80: "HTTP", 110: "POP3", 143: "IMAP",
    443: "HTTPS", 445: "SMB", 993: "IMAPS", 995: "POP3S",
    1433: "MSSQL", 1521: "Oracle", 3306: "MySQL",
    3389: "RDP", 5432: "PostgreSQL", 5900: "VNC",
    6379: "Redis", 8080: "HTTP-Alt", 8443: "HTTPS-Alt",
    27017: "MongoDB",
}


def get_service(port):
    try:
        name = socket.getservbyport(port)
        return name
    except OSError:
        return SERVICE_PORTS.get(port, "")


def scan_port(host, port, timeout=2):
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.settimeout(timeout)
        result = s.connect_ex((host, port))
        s.close()
        if result == 0:
            service = get_service(port)
            return (port, "open", service)
        return (port, "closed", "")
    except socket.gaierror:
        return (port, "error", "host not found")
    except OSError:
        return (port, "error", "connection error")


def main():
    parser = argparse.ArgumentParser(
        description="Portscan — basic TCP port scanner",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog=(
            "Examples:\n"
            "  portscan example.com               # Scan common ports\n"
            "  portscan 192.168.1.1 --range 1-100 # Scan port range\n"
            "  portscan example.com --ports 22,80,443  # Specific ports\n"
            "  portscan example.com --all         # Scan all 65535 ports\n"
        ),
    )
    parser.add_argument("host", help="Target hostname or IP")
    parser.add_argument("--range", help="Port range (e.g., 1-1000)")
    parser.add_argument("--ports", help="Comma-separated ports")
    parser.add_argument("--all", action="store_true",
                        help="Scan all 65535 ports")
    parser.add_argument("--timeout", type=float, default=2.0,
                        help="Connection timeout (default: 2s)")
    parser.add_argument("--threads", type=int, default=50,
                        help="Concurrent threads (default: 50)")
    parser.add_argument("--no-color", action="store_true",
                        help="Disable color output")
    parser.add_argument("--version", action="version",
                        version="portscan 1.0.0")
    
    args = parser.parse_args()
    
    # Build port list
    ports = []
    if args.all:
        ports = list(range(1, 65536))
    elif args.ports:
        try:
            ports = [int(p.strip()) for p in args.ports.split(",")]
        except ValueError:
            print("Error: Invalid port list", file=sys.stderr)
            sys.exit(1)
    elif args.range:
        try:
            parts = args.range.split("-")
            start, end = int(parts[0]), int(parts[1])
            ports = list(range(start, end + 1))
        except (ValueError, IndexError):
            print("Error: Invalid range format (use 1-1000)",
                  file=sys.stderr)
            sys.exit(1)
    else:
        # Default common ports
        ports = sorted(SERVICE_PORTS.keys())
    
    # Resolve hostname
    try:
        ip = socket.gethostbyname(args.host)
    except socket.gaierror:
        print(f"Error: Could not resolve '{args.host}'",
              file=sys.stderr)
        sys.exit(1)
    
    print(f"\n  {color('Portscan Results', '1')}")
    print(f"  Target:     {args.host} ({ip})")
    print(f"  Ports:      {len(ports)} to scan")
    print(f"  Timeout:    {args.timeout}s")
    print(f"  {color('─' * 45, '90')}")
    print()
    
    start_time = time.time()
    open_ports = []
    scanned = 0
    
    with concurrent.futures.ThreadPoolExecutor(max_workers=args.threads) as executor:
        futures = {executor.submit(scan_port, ip, p, args.timeout): p
                   for p in ports}
        
        for future in concurrent.futures.as_completed(futures):
            port, status, service = future.result()
            scanned += 1
            
            if status == "open":
                open_ports.append((port, service))
                svc = f" ({service})" if service else ""
                serv_color = "36" if service else ""
                print(f"  {color('OPEN', '32')}  {port:5d}/tcp  {color(svc, serv_color)}")
            
            # Progress every 100 ports
            if scanned % 100 == 0 and scanned < len(ports):
                pct = scanned * 100 // len(ports)
                print(f"  {color(f'... {scanned}/{len(ports)} ({pct}%)', '90')}")
    
    elapsed = time.time() - start_time
    
    print(f"\n  {color('─' * 45, '90')}")
    print(f"  Completed:  {len(ports)} ports in {elapsed:.1f}s")
    print(f"  Open:       {color(str(len(open_ports)), '32' if len(open_ports) < 10 else '31')}")
    
    if open_ports:
        print(f"\n  {color('Open Ports Summary:', '1')}")
        for port, service in sorted(open_ports):
            svc = f" ({service})" if service else ""
            print(f"    {port:5d}/tcp{svc}")
    print()


if __name__ == "__main__":
    main()