using System;
using System.Runtime.InteropServices;
using ArchestrA.MxAccess;
using ZB.MOM.WW.OtOpcUa.Host.Domain;

namespace ZB.MOM.WW.OtOpcUa.Host.MxAccess
{
    /// <summary>
    ///     Wraps the real ArchestrA.MxAccess.LMXProxyServer COM object, forwarding calls to IMxProxy.
    ///     Uses strongly-typed interop — same pattern as the reference LmxProxy implementation. (MXA-001)
    /// </summary>
    public sealed class MxProxyAdapter : IMxProxy
    {
        private LMXProxyServer? _lmxProxy;

        /// <summary>
        ///     Occurs when the COM proxy publishes a live data-change callback for a subscribed Galaxy attribute.
        /// </summary>
        public event MxDataChangeHandler? OnDataChange;

        /// <summary>
        ///     Occurs when the COM proxy confirms completion of a write request.
        /// </summary>
        public event MxWriteCompleteHandler? OnWriteComplete;

        /// <summary>
        ///     Creates and registers the COM proxy session that backs live MXAccess operations.
        /// </summary>
        /// <param name="clientName">The client name reported to the Wonderware runtime.</param>
        /// <returns>The runtime connection handle assigned by the COM server.</returns>
        public int Register(string clientName)
        {
            _lmxProxy = new LMXProxyServer();

            _lmxProxy.OnDataChange += ProxyOnDataChange;
            _lmxProxy.OnWriteComplete += ProxyOnWriteComplete;

            var handle = _lmxProxy.Register(clientName);
            if (handle <= 0)
                throw new InvalidOperationException($"LMXProxyServer.Register returned invalid handle: {handle}");

            return handle;
        }

        /// <summary>
        ///     Unregisters the COM proxy session and releases the underlying COM object.
        /// </summary>
        /// <param name="handle">The runtime connection handle returned by <see cref="Register(string)" />.</param>
        public void Unregister(int handle)
        {
            if (_lmxProxy != null)
                try
                {
                    _lmxProxy.OnDataChange -= ProxyOnDataChange;
                    _lmxProxy.OnWriteComplete -= ProxyOnWriteComplete;
                    _lmxProxy.Unregister(handle);
                }
                finally
                {
                    Marshal.ReleaseComObject(_lmxProxy);
                    _lmxProxy = null;
                }
        }

        /// <summary>
        ///     Resolves a Galaxy attribute reference into a runtime item handle through the COM proxy.
        /// </summary>
        /// <param name="handle">The runtime connection handle.</param>
        /// <param name="address">The fully qualified Galaxy attribute reference.</param>
        /// <returns>The item handle assigned by the COM proxy.</returns>
        public int AddItem(int handle, string address)
        {
            return _lmxProxy!.AddItem(handle, address);
        }

        /// <summary>
        ///     Removes an item handle from the active COM proxy session.
        /// </summary>
        /// <param name="handle">The runtime connection handle.</param>
        /// <param name="itemHandle">The item handle to remove.</param>
        public void RemoveItem(int handle, int itemHandle)
        {
            _lmxProxy!.RemoveItem(handle, itemHandle);
        }

        /// <summary>
        ///     Enables supervisory callbacks for the specified runtime item.
        /// </summary>
        /// <param name="handle">The runtime connection handle.</param>
        /// <param name="itemHandle">The item handle to monitor.</param>
        public void AdviseSupervisory(int handle, int itemHandle)
        {
            _lmxProxy!.AdviseSupervisory(handle, itemHandle);
        }

        /// <summary>
        ///     Disables supervisory callbacks for the specified runtime item.
        /// </summary>
        /// <param name="handle">The runtime connection handle.</param>
        /// <param name="itemHandle">The item handle to stop monitoring.</param>
        public void UnAdviseSupervisory(int handle, int itemHandle)
        {
            _lmxProxy!.UnAdvise(handle, itemHandle);
        }

        /// <summary>
        ///     Writes a value to the specified runtime item through the COM proxy.
        /// </summary>
        /// <param name="handle">The runtime connection handle.</param>
        /// <param name="itemHandle">The item handle to write.</param>
        /// <param name="value">The value to send to the runtime.</param>
        /// <param name="securityClassification">The Wonderware security classification applied to the write.</param>
        public void Write(int handle, int itemHandle, object value, int securityClassification)
        {
            _lmxProxy!.Write(handle, itemHandle, value, securityClassification);
        }

        private void ProxyOnDataChange(int hLMXServerHandle, int phItemHandle, object pvItemValue,
            int pwItemQuality, object pftItemTimeStamp, ref MXSTATUS_PROXY[] ItemStatus)
        {
            OnDataChange?.Invoke(hLMXServerHandle, phItemHandle, pvItemValue, pwItemQuality, pftItemTimeStamp,
                ref ItemStatus);
        }

        private void ProxyOnWriteComplete(int hLMXServerHandle, int phItemHandle, ref MXSTATUS_PROXY[] ItemStatus)
        {
            OnWriteComplete?.Invoke(hLMXServerHandle, phItemHandle, ref ItemStatus);
        }
    }
}