import socket
import time


# Assume a basic SIP2 client library is available or you build one
# This is a conceptual example of how a library might be used.
class SIP2Client:
    def __init__(self, host, port):
        self.host = host
        self.port = port
        self.sock = None
        self.sequence_number = 0

    def connect(self):
        try:
            self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            self.sock.connect((self.host, self.port))
            print(f"Connected to SIP2 server at {self.host}:{self.port}")
            return True
        except socket.error as e:
            print(f"Error connecting to SIP2 server: {e}")
            return False

    def disconnect(self):
        if self.sock:
            self.sock.close()
            print("Disconnected from SIP2 server.")
        self.sock = None

    def send_message(self, message_code, fields):
        # This is highly simplified. A real library would handle checksums,
        # sequence numbers, field formatting (e.g., 'AOusername|')
        # and message framing (length prefix).
        self.sequence_number = (self.sequence_number + 1) % 10  # 0-9
        seq_str = str(self.sequence_number)

        # Build the message string (example for a Login message)
        # 9300BNusername|COpassword|
        # A proper library would handle escape characters, etc.
        sip_message = f"{message_code}"
        for key, value in fields.items():
            sip_message += f"{key}{value}|"

        # Add sequence number and checksum (crucial for SIP2)
        # This is a placeholder for actual SIP2 checksum calculation
        checksum = "0000"  # Placeholder
        full_message = f"{sip_message}{seq_str}{checksum}\r"  # CR terminator

        print(f"Sending: {full_message.strip()}")
        try:
            self.sock.sendall(full_message.encode("ascii"))
            response = self.sock.recv(4096).decode("ascii")
            print(f"Received: {response.strip()}")
            return response
        except socket.error as e:
            print(f"Error sending/receiving SIP2 message: {e}")
            return None

    def login(self, username, password):
        # Example of a common SIP2 operation: Login (93)
        fields = {"BN": username, "CO": password}
        return self.send_message("93", fields)

    def patron_status(self, patron_id):
        # Example: Patron Status Request (23)
        # This needs proper formatting with 'AA' for patron ID
        fields = {"AA": patron_id}
        return self.send_message("23", fields)

    # ... other SIP2 commands like check-out (11), check-in (09), etc.


# --- Usage Example ---
if __name__ == "__main__":
    sip2_host = "192.168.1.100"  # Replace with your SIP2 server IP
    sip2_port = 6000  # Replace with your SIP2 server port

    client = SIP2Client(sip2_host, sip2_port)
    if client.connect():
        # Perform a login (essential for most SIP2 operations)
        login_response = client.login("mylibuser", "mypassword")
        if login_response and login_response.startswith("94"):  # 94 is Login Response
            print("Login successful!")

            # Example: Get patron status
            patron_response = client.patron_status("12345")
            # You'd parse patron_response based on SIP2 spec (e.g., 24 message)
            if patron_response and patron_response.startswith("24"):
                print("Patron status received.")
        else:
            print("Login failed or unexpected response.")

        client.disconnect()
    else:
        print("Failed to connect to SIP2 server.")
