#region Copyright (c) 2011-2023 Technosoftware GmbH. All rights reserved
//-----------------------------------------------------------------------------
// Copyright (c) 2011-2023 Technosoftware GmbH. All rights reserved
// Web: https://www.technosoftware.com 
// 
// The source code in this file is covered under a dual-license scenario:
//   - Owner of a purchased license: SCLA 1.0
//   - GPL V3: everybody else
//
// SCLA license terms accompanied with this source code.
// See SCLA 1.0: https://technosoftware.com/license/Source_Code_License_Agreement.pdf
//
// GNU General Public License as published by the Free Software Foundation;
// version 3 of the License are accompanied with this source code.
// See https://technosoftware.com/license/GPLv3License.txt
//
// This source code is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE.
//-----------------------------------------------------------------------------
#endregion Copyright (c) 2011-2023 Technosoftware GmbH. All rights reserved

#region Using Directives

using System;
using System.Runtime.Serialization;
#endregion

namespace Technosoftware.DaAeHdaClient.Ae
{
    /// <summary>
    /// An in-process object which provides access to AE server objects.
    /// </summary>
    [Serializable]
    public class TsCAeServer : OpcServer, ITsCAeServer
    {
        #region SubscriptionCollection Class
        /// <summary>
        /// A read-only collection of subscriptions.
        /// </summary>
        public class SubscriptionCollection : OpcReadOnlyCollection
        {
            #region Constructors, Destructor, Initialization
            /// <summary>
            /// Creates an empty collection.
            /// </summary>
            internal SubscriptionCollection() : base(new TsCAeSubscription[0]) { }
            #endregion

            #region Public Methods
            /// <summary>
            /// An indexer for the collection.
            /// </summary>
            public new TsCAeSubscription this[int index] => (TsCAeSubscription)Array.GetValue(index);

            /// <summary>
			/// Returns a copy of the collection as an array.
			/// </summary>
			public new TsCAeSubscription[] ToArray()
            {
                return (TsCAeSubscription[])Array;
            }

            /// <summary>
            /// Adds a subscription to the end of the collection.
            /// </summary>
            internal void Add(TsCAeSubscription subscription)
            {
                var array = new TsCAeSubscription[Count + 1];

                Array.CopyTo(array, 0);
                array[Count] = subscription;

                Array = array;
            }

            /// <summary>
            /// Removes a subscription to the from the collection.
            /// </summary>
            internal void Remove(TsCAeSubscription subscription)
            {
                var array = new TsCAeSubscription[Count - 1];

                var index = 0;

                for (var ii = 0; ii < Array.Length; ii++)
                {
                    var element = (TsCAeSubscription)Array.GetValue(ii);

                    if (subscription != element)
                    {
                        array[index++] = element;
                    }
                }

                Array = array;
            }
            #endregion
        }
        #endregion

        #region Names Class
        /// <summary>
        /// A set of names for fields used in serialization.
        /// </summary>
        private class Names
        {
            internal const string Count = "CT";
            internal const string Subscription = "SU";
        }
        #endregion

        #region Fields
        private int filters_;
        private bool disposing_;
        private SubscriptionCollection subscriptions_ = new SubscriptionCollection();
        #endregion

        #region Constructors, Destructor, Initialization
        /// <summary>
        /// Initializes the object with a factory and a default OpcUrl.
        /// </summary>
        /// <param name="factory">The OpcFactory used to connect to remote servers.</param>
        /// <param name="url">The network address of a remote server.</param>
        public TsCAeServer(OpcFactory factory, OpcUrl url)
            : base(factory, url)
        {
        }

        /// <summary>
        /// Constructs a server by de-serializing its OpcUrl from the stream.
        /// </summary>
        protected TsCAeServer(SerializationInfo info, StreamingContext context)
            :
            base(info, context)
        {
            var count = (int)info.GetValue(Names.Count, typeof(int));

            subscriptions_ = new SubscriptionCollection();

            for (var ii = 0; ii < count; ii++)
            {
                var subscription = (TsCAeSubscription)info.GetValue(Names.Subscription + ii, typeof(TsCAeSubscription));
                subscriptions_.Add(subscription);
            }
        }
        #endregion

        #region Properties
        /// <summary>
        /// The filters supported by the server.
        /// </summary>
        // ReSharper disable once UnusedMember.Global
        public int AvailableFilters => filters_;

        /// <summary>
		/// The outstanding subscriptions for the server.
		/// </summary>
		public SubscriptionCollection Subscriptions => subscriptions_;
        #endregion

        #region Public Methods
        /// <summary>
        /// Connects to the server with the specified OpcUrl and credentials.
        /// </summary>
        public override void Connect(OpcUrl url, OpcConnectData connectData)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            // connect to server.
            base.Connect(url, connectData);

            // all done if no subscriptions.
            if (subscriptions_.Count == 0)
            {
                return;
            }

            // create subscriptions (should only happen if server has been deserialized).
            var subscriptions = new SubscriptionCollection();

            foreach (TsCAeSubscription template in subscriptions_)
            {
                // create subscription for template.
                try { subscriptions.Add(EstablishSubscription(template)); }
                catch
                {
                    // ignored
                }
            }

            // save new set of subscriptions.
            subscriptions_ = subscriptions;
        }

        /// <summary>
        /// Disconnects from the server and releases all network resources.
        /// </summary>
        public override void Disconnect()
        {
            if (Server == null) throw new NotConnectedException();

            // dispose of all subscriptions first.
            disposing_ = true;

            foreach (TsCAeSubscription subscription in subscriptions_)
            {
                subscription.Dispose();
            }

            disposing_ = false;

            // disconnect from server.
            base.Disconnect();
        }

        /// <summary>
        /// Returns the current server status.
        /// </summary>
        /// <returns>The current server status.</returns>
        public OpcServerStatus GetServerStatus()
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            var status = ((ITsCAeServer)Server).GetServerStatus();

            if (status != null)
            {
                if (status.StatusInfo == null)
                {
                    status.StatusInfo = GetString($"serverState.{status.ServerState}");
                }
            }
            else
            {
                if (Server == null) throw new NotConnectedException();
            }

            return status;
        }

        /// <summary>
        /// Creates a new event subscription.
        /// </summary>
        /// <param name="state">The initial state for the subscription.</param>
        /// <returns>The new subscription object.</returns>
        public ITsCAeSubscription CreateSubscription(TsCAeSubscriptionState state)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            // create remote object.
            var subscription = ((ITsCAeServer)Server).CreateSubscription(state);

            if (subscription != null)
            {
                // create wrapper.
                var wrapper = new TsCAeSubscription(this, subscription, state);
                subscriptions_.Add(wrapper);
                return wrapper;
            }

            // should never happen.
            return null;
        }

        /// <summary>
        /// Returns the event filters supported by the server.
        /// </summary>
        /// <returns>A bit mask of all event filters supported by the server.</returns>
        public int QueryAvailableFilters()
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            filters_ = ((ITsCAeServer)Server).QueryAvailableFilters();

            return filters_;
        }

        /// <summary>       
        /// Returns the event categories supported by the server for the specified event types.
        /// </summary>
        /// <param name="eventType">A bit mask for the event types of interest.</param>
        /// <returns>A collection of event categories.</returns>
        public TsCAeCategory[] QueryEventCategories(int eventType)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            // fetch categories from server.
            var categories = ((ITsCAeServer)Server).QueryEventCategories(eventType);

            // return result.
            return categories;
        }

        /// <summary>
        /// Returns the condition names supported by the server for the specified event categories.
        /// </summary>
        /// <param name="eventCategory">A bit mask for the event categories of interest.</param>
        /// <returns>A list of condition names.</returns>
        public string[] QueryConditionNames(int eventCategory)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            // fetch condition names from the server.
            var conditions = ((ITsCAeServer)Server).QueryConditionNames(eventCategory);

            // return result.
            return conditions;
        }

        /// <summary>
        /// Returns the sub-condition names supported by the server for the specified event condition.
        /// </summary>
        /// <param name="conditionName">The name of the condition.</param>
        /// <returns>A list of sub-condition names.</returns>
        public string[] QuerySubConditionNames(string conditionName)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            // fetch sub-condition names from the server.
            var subConditions = ((ITsCAeServer)Server).QuerySubConditionNames(conditionName);

            // return result.
            return subConditions;
        }

        /// <summary>
        /// Returns the condition names supported by the server for the specified event source.
        /// </summary>
        /// <param name="sourceName">The name of the event source.</param>
        /// <returns>A list of condition names.</returns>
        public string[] QueryConditionNames(string sourceName)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            // fetch condition names from the server.
            var conditions = ((ITsCAeServer)Server).QueryConditionNames(sourceName);

            // return result.
            return conditions;
        }

        /// <summary>       
        /// Returns the event attributes supported by the server for the specified event categories.
        /// </summary>
        /// <param name="eventCategory">A bit mask for the event categories of interest.</param>
        /// <returns>A collection of event attributes.</returns>
        public TsCAeAttribute[] QueryEventAttributes(int eventCategory)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            // fetch attributes from server.
            var attributes = ((ITsCAeServer)Server).QueryEventAttributes(eventCategory);

            // return result.
            return attributes;
        }

        /// <summary>
        /// Returns the DA item ids for a set of attribute ids belonging to events which meet the specified filter criteria.
        /// </summary>
        /// <param name="sourceName">The event source of interest.</param>
        /// <param name="eventCategory">The id of the event category for the events of interest.</param>
        /// <param name="conditionName">The name of a condition within the event category.</param>
        /// <param name="subConditionName">The name of a sub-condition within a multi-state condition.</param>
        /// <param name="attributeIDs">The ids of the attributes to return item ids for.</param>
        /// <returns>A list of item urls for each specified attribute.</returns>
        public TsCAeItemUrl[] TranslateToItemIDs(
          string sourceName,
          int eventCategory,
          string conditionName,
          string subConditionName,
          int[] attributeIDs)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            var itemUrls = ((ITsCAeServer)Server).TranslateToItemIDs(
                sourceName,
                eventCategory,
                conditionName,
                subConditionName,
                attributeIDs);

            return itemUrls;
        }

        /// <summary>
        /// Returns the current state information for the condition instance corresponding to the source and condition name.
        /// </summary>
        /// <param name="sourceName">The source name</param>
        /// <param name="conditionName">A condition name for the source.</param>
        /// <param name="attributeIDs">The list of attributes to return with the condition state.</param>
        /// <returns>The current state of the connection.</returns>
        public TsCAeCondition GetConditionState(
            string sourceName,
            string conditionName,
            int[] attributeIDs)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            var condition = ((ITsCAeServer)Server).GetConditionState(sourceName, conditionName, attributeIDs);

            return condition;
        }

        /// <summary>
        /// Places the specified process areas into the enabled state.
        /// </summary>
        /// <param name="areas">A list of fully qualified area names.</param>
        /// <returns>The results of the operation for each area.</returns>
        public OpcResult[] EnableConditionByArea(string[] areas)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            var results = ((ITsCAeServer)Server).EnableConditionByArea(areas);

            return results;
        }

        /// <summary>
        /// Places the specified process areas into the disabled state.
        /// </summary>
        /// <param name="areas">A list of fully qualified area names.</param>
        /// <returns>The results of the operation for each area.</returns>
        public OpcResult[] DisableConditionByArea(string[] areas)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            var results = ((ITsCAeServer)Server).DisableConditionByArea(areas);

            return results;
        }

        /// <summary>
        /// Places the specified process areas into the enabled state.
        /// </summary>
        /// <param name="sources">A list of fully qualified source names.</param>
        /// <returns>The results of the operation for each area.</returns>
        public OpcResult[] EnableConditionBySource(string[] sources)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            var results = ((ITsCAeServer)Server).EnableConditionBySource(sources);

            return results;
        }

        /// <summary>
        /// Places the specified process areas into the disabled state.
        /// </summary>
        /// <param name="sources">A list of fully qualified source names.</param>
        /// <returns>The results of the operation for each area.</returns>
        public OpcResult[] DisableConditionBySource(string[] sources)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            var results = ((ITsCAeServer)Server).DisableConditionBySource(sources);

            return results;
        }

        /// <summary>
        /// Returns the enabled state for the specified process areas. 
        /// </summary>
        /// <param name="areas">A list of fully qualified area names.</param>
        public TsCAeEnabledStateResult[] GetEnableStateByArea(string[] areas)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            var results = ((ITsCAeServer)Server).GetEnableStateByArea(areas);

            return results;
        }

        /// <summary>
        /// Returns the enabled state for the specified event sources. 
        /// </summary>
        /// <param name="sources">A list of fully qualified source names.</param>
        public TsCAeEnabledStateResult[] GetEnableStateBySource(string[] sources)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            var results = ((ITsCAeServer)Server).GetEnableStateBySource(sources);

            return results;
        }

        /// <summary>
        /// Used to acknowledge one or more conditions in the event server.
        /// </summary>
        /// <param name="acknowledgmentId">The identifier for who is acknowledging the condition.</param>
        /// <param name="comment">A comment associated with the acknowledgment.</param>
        /// <param name="conditions">The conditions being acknowledged.</param>
        /// <returns>A list of result id indicating whether each condition was successfully acknowledged.</returns>
        public OpcResult[] AcknowledgeCondition(
            string acknowledgmentId,
            string comment,
            TsCAeEventAcknowledgement[] conditions)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            return ((ITsCAeServer)Server).AcknowledgeCondition(acknowledgmentId, comment, conditions);
        }

        /// <summary>
        /// Browses for all children of the specified area that meet the filter criteria.
        /// </summary>
        /// <param name="areaId">The full-qualified id for the area.</param>
        /// <param name="browseType">The type of children to return.</param>
        /// <param name="browseFilter">The expression used to filter the names of children returned.</param>
        /// <returns>The set of elements that meet the filter criteria.</returns>
        public TsCAeBrowseElement[] Browse(
            string areaId,
            TsCAeBrowseType browseType,
            string browseFilter)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            return ((ITsCAeServer)Server).Browse(areaId, browseType, browseFilter);
        }

        /// <summary>
        /// Browses for all children of the specified area that meet the filter criteria.
        /// </summary>
        /// <param name="areaId">The full-qualified id for the area.</param>
        /// <param name="browseType">The type of children to return.</param>
        /// <param name="browseFilter">The expression used to filter the names of children returned.</param>
        /// <param name="maxElements">The maximum number of elements to return.</param>
        /// <param name="position">The object used to continue the browse if the number nodes exceeds the maximum specified.</param>
        /// <returns>The set of elements that meet the filter criteria.</returns>
        public TsCAeBrowseElement[] Browse(
            string areaId,
            TsCAeBrowseType browseType,
            string browseFilter,
            int maxElements,
            out IOpcBrowsePosition position)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            return ((ITsCAeServer)Server).Browse(areaId, browseType, browseFilter, maxElements, out position);
        }

        /// <summary>
        /// Continues browsing the server's address space at the specified position.
        /// </summary>
        /// <param name="maxElements">The maximum number of elements to return.</param>
        /// <param name="position">The position object used to continue a browse operation.</param>
        /// <returns>The set of elements that meet the filter criteria.</returns>
        public TsCAeBrowseElement[] BrowseNext(int maxElements, ref IOpcBrowsePosition position)
        {
            LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.AlarmsConditions);
            if (Server == null) throw new NotConnectedException();

            return ((ITsCAeServer)Server).BrowseNext(maxElements, ref position);
        }

        #endregion

        #region ISerializable Members

        /// <summary>
        /// Serializes a server into a stream.
        /// </summary>
        public override void GetObjectData(SerializationInfo info, StreamingContext context)
        {
            base.GetObjectData(info, context);

            info.AddValue(Names.Count, subscriptions_.Count);

            for (var ii = 0; ii < subscriptions_.Count; ii++)
            {
                info.AddValue(Names.Subscription + ii, subscriptions_[ii]);
            }
        }

        #endregion

        #region Private Methods

        /// <summary>
        /// Called when a subscription object is disposed.
        /// </summary>
        /// <param name="subscription"></param>
        internal void SubscriptionDisposed(TsCAeSubscription subscription)
        {
            if (!disposing_)
            {
                subscriptions_.Remove(subscription);
            }
        }

        /// <summary>
        /// Establishes a subscription based on the template provided.
        /// </summary>
        private TsCAeSubscription EstablishSubscription(TsCAeSubscription template)
        {
            ITsCAeSubscription remoteServer = null;

            try
            {
                // create remote object.
                remoteServer = ((ITsCAeServer)Server).CreateSubscription(template.State);

                if (remoteServer == null)
                {
                    return null;
                }

                // create wrapper.
                var subscription = new TsCAeSubscription(this, remoteServer, template.State);

                // set filters.
                subscription.SetFilters(template.Filters);

                // set attributes.
                var enumerator = template.Attributes.GetEnumerator();

                while (enumerator.MoveNext())
                {
                    if (enumerator.Key != null)
                        subscription.SelectReturnedAttributes(
                            (int)enumerator.Key,
                            ((TsCAeSubscription.AttributeCollection)enumerator.Value).ToArray());
                }

                // return new subscription
                return subscription;
            }
            catch
            {
                if (remoteServer != null)
                {
                    remoteServer.Dispose();
                }
            }

            // return null.
            return null;
        }
        #endregion
    }
}