#!/usr/bin/env python3
"""OPC UA client tool for ScadaLink test infrastructure."""

import argparse
import sys
import time

from opcua import Client, ua


DEFAULT_ENDPOINT = "opc.tcp://localhost:50000"


def cmd_check(args):
    """Connect and report server status."""
    client = Client(args.endpoint)
    try:
        client.connect()
        server_status = client.get_node(ua.ObjectIds.Server_ServerStatus).get_value()

        print(f"Connected to: {args.endpoint}")
        print(f"Server state: {server_status.State}")
        print(f"Start time:   {server_status.StartTime}")
        print(f"Current time: {server_status.CurrentTime}")
        print(f"Build info:   {server_status.BuildInfo.ProductName} {server_status.BuildInfo.SoftwareVersion}")

        ns = client.get_namespace_array()
        print(f"\nNamespaces:")
        for i, n in enumerate(ns):
            print(f"  {i}: {n}")

        endpoints = client.get_endpoints()
        print(f"\nEndpoints ({len(endpoints)}):")
        for ep in endpoints:
            print(f"  {ep.EndpointUrl} [{ep.SecurityPolicyUri.split('#')[-1]}]")
    except Exception as e:
        print(f"Error: {e}", file=sys.stderr)
        sys.exit(1)
    finally:
        client.disconnect()


def cmd_browse(args):
    """Browse server node tree."""
    client = Client(args.endpoint)
    try:
        client.connect()
        if args.path:
            root = client.get_objects_node()
            node = root.get_child(args.path.split("."))
        else:
            node = client.get_objects_node()

        browse_name = node.get_browse_name()
        print(f"Browsing: {browse_name.Name} ({node.nodeid})")
        print()

        children = node.get_children()
        for child in children:
            name = child.get_browse_name()
            node_class = child.get_node_class()
            class_name = node_class.name if hasattr(node_class, "name") else str(node_class)

            if node_class == ua.NodeClass.Variable:
                try:
                    value = child.get_value()
                    dtype = child.get_data_type_as_variant_type()
                    print(f"  {name.Name:<30} [{class_name}] {dtype.name} = {value}")
                except Exception:
                    print(f"  {name.Name:<30} [{class_name}]")
            else:
                print(f"  {name.Name:<30} [{class_name}]")
    except Exception as e:
        print(f"Error: {e}", file=sys.stderr)
        sys.exit(1)
    finally:
        client.disconnect()


def cmd_read(args):
    """Read a node value."""
    client = Client(args.endpoint)
    try:
        client.connect()
        node = client.get_node(args.node)
        data_value = node.get_data_value()
        value = data_value.Value.Value
        dtype = node.get_data_type_as_variant_type()
        ts = data_value.SourceTimestamp

        print(f"Node:      {args.node}")
        print(f"Value:     {value}")
        print(f"Data type: {dtype.name}")
        print(f"Timestamp: {ts}")
    except Exception as e:
        print(f"Error: {e}", file=sys.stderr)
        sys.exit(1)
    finally:
        client.disconnect()


def cmd_write(args):
    """Write a value to a node."""
    type_map = {
        "Double": (ua.VariantType.Double, float),
        "Boolean": (ua.VariantType.Boolean, lambda v: v.lower() in ("true", "1", "yes")),
        "UInt32": (ua.VariantType.UInt32, int),
        "Int32": (ua.VariantType.Int32, int),
        "String": (ua.VariantType.String, str),
    }

    if args.type not in type_map:
        print(f"Error: unsupported type '{args.type}'. Use one of: {', '.join(type_map)}", file=sys.stderr)
        sys.exit(1)

    variant_type, converter = type_map[args.type]
    converted_value = converter(args.value)

    client = Client(args.endpoint)
    try:
        client.connect()
        node = client.get_node(args.node)
        dv = ua.DataValue(ua.Variant(converted_value, variant_type))
        node.set_value(dv)
        print(f"Wrote {converted_value} ({args.type}) to {args.node}")
    except Exception as e:
        print(f"Error: {e}", file=sys.stderr)
        sys.exit(1)
    finally:
        client.disconnect()


def cmd_monitor(args):
    """Subscribe and print value changes."""
    nodes = [n.strip() for n in args.nodes.split(",")]

    client = Client(args.endpoint)
    try:
        client.connect()

        class Handler:
            def datachange_notification(self, node, val, data):
                print(f"  {node} = {val}")

        handler = Handler()
        sub = client.create_subscription(500, handler)

        handles = []
        for node_id in nodes:
            node = client.get_node(node_id)
            handle = sub.subscribe_data_change(node)
            handles.append(handle)
            name = node.get_browse_name()
            print(f"Monitoring: {name.Name} ({node_id})")

        print(f"\nListening for {args.duration}s...\n")
        time.sleep(args.duration)

        for handle in handles:
            sub.unsubscribe(handle)
        sub.delete()
        print("\nDone.")
    except Exception as e:
        print(f"Error: {e}", file=sys.stderr)
        sys.exit(1)
    finally:
        client.disconnect()


def main():
    parser = argparse.ArgumentParser(description="OPC UA client tool for ScadaLink test infrastructure")
    parser.add_argument("--endpoint", default=DEFAULT_ENDPOINT, help=f"OPC UA endpoint (default: {DEFAULT_ENDPOINT})")

    sub = parser.add_subparsers(dest="command", required=True)

    sub.add_parser("check", help="Connect and report server status")

    browse_p = sub.add_parser("browse", help="Browse server node tree")
    browse_p.add_argument("--path", help="Node path to browse (e.g. 3:OpcPlc.3:Telemetry)")

    read_p = sub.add_parser("read", help="Read a node value")
    read_p.add_argument("--node", required=True, help="Node ID (e.g. ns=3;s=Motor.Speed)")

    write_p = sub.add_parser("write", help="Write a value to a node")
    write_p.add_argument("--node", required=True, help="Node ID")
    write_p.add_argument("--value", required=True, help="Value to write")
    write_p.add_argument("--type", required=True, choices=["Double", "Boolean", "UInt32", "Int32", "String"],
                         help="Data type")

    monitor_p = sub.add_parser("monitor", help="Subscribe and print value changes")
    monitor_p.add_argument("--nodes", required=True, help="Comma-separated node IDs")
    monitor_p.add_argument("--duration", type=int, default=10, help="Duration in seconds (default: 10)")

    args = parser.parse_args()

    commands = {
        "check": cmd_check,
        "browse": cmd_browse,
        "read": cmd_read,
        "write": cmd_write,
        "monitor": cmd_monitor,
    }

    commands[args.command](args)


if __name__ == "__main__":
    main()