Saxonite/Workspace/SaxoniteCoreWebAdmin/Admin/Controllers/OrganisationController-Ajax-Associations.cs

using Microsoft.AspNetCore.Mvc;
using Sarand.Net.Standard.Base.App;
using Sarand.Net.Standard.Base.Bus;
using Sarand.Net.Standard.Base.Core;
using Sarand.Net.Standard.Base.Dbas;
using Sarand.Net.Standard.Base.Utils;
using Saxonite.Net.Core.Web.Admin.Models;
using Saxonite.Net.Standard.Base.App;
using Saxonite.Net.Standard.Base.Bus;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading.Tasks;

namespace Saxonite.Net.Core.Web.Admin.Controllers
{
	//=======================================================================
	// Controller: Organisation - Ajax - Associations
	//=======================================================================
	partial class OrganisationController
	{
		//-------------------------------------------------------------------
		// Association type combinations.
		//-------------------------------------------------------------------
		private static readonly String optionLabel_AffiliatedTo = "Affiliated to";
		private static readonly String optionLabel_Affiliate = "Affiliation for";
		private static readonly String optionLabel_Partner = "Partner";
		// Associations are between two items (From & To) but in the context of
		// displaying associations for an organisation, the organisation may be
		// the 'From' item (normal) or the 'To' item (reversed).
		private class AssociationTypeData
		{
			public AssociationTypeData()
			{
				// No parameter construction - populating association details for individual item (see Populate()).
			}
			public AssociationTypeData(Sax.AssociationTypeOption associationTypeOption)
			{
				// Population on construction - generic association type definitions, eg. for drop down menu options.
				Populate(associationTypeOption);
			}
			public void Populate(Sax.AssociationTypeOption associationTypeOption)
			{
				// Default labels - option to select association etc.
				Type = ((int)associationTypeOption).ToString();
				Label = GetOptionLabel(associationTypeOption);
			}
			public void Populate(Sax.AssociationType associationType, bool reversed)
			{
				// Default labels - option to select association etc.
				Populate(GetAssociationTypeOption(associationType, reversed));
			}
			public void Populate(Sax.AssociationType associationType, bool reversed, String label)
			{
				// Populate for specific labels, eg. to identify nature of associated organisation.
				Sax.AssociationTypeOption associationTypeOption = GetAssociationTypeOption(associationType, reversed);
				Type = ((int)associationTypeOption).ToString();
				Label = label;
			}
			// Properties.
			public String Type { get; set; }
			public String Label { get; set; }
			// Utilities.
			public static Sax.AssociationTypeOption GetAssociationTypeOption(Sax.AssociationType associationType, bool reversed)
			{
				switch (associationType)
				{
					case Sax.AssociationType.Affiliate: return reversed ? Sax.AssociationTypeOption.AffiliateChild : Sax.AssociationTypeOption.AffiliateParent;
					case Sax.AssociationType.Partner: return Sax.AssociationTypeOption.Partner;
				}
				return Sax.AssociationTypeOption.Unknown;
			}
			public static String GetOptionLabel(Sax.AssociationTypeOption associationTypeOption)
			{
				switch (associationTypeOption)
				{
					case Sax.AssociationTypeOption.AffiliateParent: return optionLabel_AffiliatedTo;
					case Sax.AssociationTypeOption.AffiliateChild: return optionLabel_Affiliate;
					case Sax.AssociationTypeOption.Partner: return optionLabel_Partner;
				}
				return "";
			}
		}

		//-------------------------------------------------------------------
		// Association data.
		//-------------------------------------------------------------------
		private class AssociationListData : AjaxResponse_Data.ItemData_Base
		{
			public class OrganisationData
			{
				public String Id { get; set; }
				public String Name { get; set; }
				public String Sport { get; set; }
				public String Region { get; set; }
			}
			public OrganisationData Organisation { get; } = new OrganisationData();
			public OrganisationData OrganisationAssoc { get; } = new OrganisationData();
			public AssociationTypeData Assoc { get; } = new AssociationTypeData();
		}
		private class AssociationItemData : AssociationListData
		{
		}
		private void PopulateAssociationResponseListData(SaxModel_Admin model, AssociationListData data, SaxItemAssociation itemAssociation, SaxOrganisation organisation, SaxOrganisation organisationAssoc)
		{
			data.Id = SysId.ToString(itemAssociation.Id);
			// Organisation.
			data.Organisation.Id = SysId.ToString(organisation.Id);
			data.Organisation.Name = organisation.Name;
			// Associated Organisation.
			data.OrganisationAssoc.Id = SysId.ToString(organisationAssoc.Id);
			data.OrganisationAssoc.Name = organisationAssoc.Name;
			if (!organisation.SportIdPrimary.Equals(organisationAssoc.SportIdPrimary))
				data.OrganisationAssoc.Sport = model.GetSportName(organisationAssoc.SportIdPrimary);
			if (!organisation.RegionIdPrimary.Equals(organisationAssoc.RegionIdPrimary))
				data.OrganisationAssoc.Region = model.GetRegionName(organisationAssoc.RegionIdPrimary);
			// Association type.
			bool associationReversed = itemAssociation.ItemIdTo.Id.Equals(organisation.Id);
			String associationLabel = "";
			if (itemAssociation.AssociationType == Sax.AssociationType.Affiliate)
				associationLabel = associationReversed ? "Member organisation" : associationLabel = "Parent organisation";
			else if (itemAssociation.AssociationType == Sax.AssociationType.Partner)
				associationLabel = "Partner organisation";
			data.Assoc.Populate(itemAssociation.AssociationType, associationReversed, associationLabel);
			// Common properties.
			data.StatusCode = itemAssociation.StatusCode;
			data.StatusDesc = itemAssociation.StatusDesc;
		}
		private void PopulateAssociationResponseItemData(SaxModel_Admin model, AssociationItemData data, SaxItemAssociation itemAssociation, SaxOrganisation organisation, SaxOrganisation organisationAssoc)
		{
			PopulateAssociationResponseListData(model, data, itemAssociation, organisation, organisationAssoc);
		}

		//-------------------------------------------------------------------
		// Get Organisation Association List ajax request.
		//-------------------------------------------------------------------
		private class AjaxResponse_AssociationList : AjaxResponse_Data
		{
			// Construction.
			public AjaxResponse_AssociationList(SaxModel_Admin model) : base(model) { }
			// Association list.
			public List<AssociationListData> Associations { get; } = new List<AssociationListData>();
			// Reference data.
			public List<AssociationTypeData> AssociationTypes { get; } = new List<AssociationTypeData>();
			public List<CodeDesc> Statuses { get; } = new List<CodeDesc>();
			public String DefaultStatusCode { get; set; }
		}
		//-------------------------------------------------------------------
		[HttpPost]
		[Route("Organisation/Ajax/GetAssociationList")]
		[Route("Organisation/Ajax/GetAssociations")]
		public IActionResult Ajax_GetAssociationList(Model_OrganisationAssociations model)
		{
			String messageTitle = Localiser["caption.organisation.associations"];
			AjaxResponse_AssociationList responseData = new AjaxResponse_AssociationList(model);

			// Validate session.
			if (!ValidUserSession)
				return GetAjaxResult_InvalidSession(responseData);

			// Organisation Id is mandatory.
			SysId organisationId = SysId.ToSysId(model.Filter.OrganisationId);
			if (!SysId.IsValid(organisationId))
			{
				SaLogger.Warn($"{SysUtil.Fn} Request to retrieve associations without valid organisation Id.");
				return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.item.id.not.specified"]));
			}

			// Reference data - association types.
			// 'Label' is option caption to add new association of the specified type.
			responseData.AssociationTypes.Add(new AssociationTypeData(Sax.AssociationTypeOption.AffiliateParent));
			responseData.AssociationTypes.Add(new AssociationTypeData(Sax.AssociationTypeOption.AffiliateChild));
			responseData.AssociationTypes.Add(new AssociationTypeData(Sax.AssociationTypeOption.Partner));

			// Reference data - statuses.
			foreach (SaStatus status in SaxItemAssociation.ValidStatuses.FindAll(item => item != SaStatus.Deleted))
				responseData.Statuses.Add(SacsSystem.GetStatusCode(status), Localiser.GetStatusCaption(status));
			responseData.DefaultStatusCode = SacsSystem.GetStatusCode(SaxItemAssociation.DefaultStatus);

			// Get organisation associations.
			GetOrganisationAssociations(model, organisationId, responseData.Associations);

			if (model.Paging.IsPaged)
				model.Paging.ItemCount = (ushort)responseData.Associations.Count;

			// Complete response.
			responseData.SetPaging(model);
			responseData.Success = true;
			return Json(responseData);
		}
		private void GetOrganisationAssociations(SaxModel_Admin model, SysId organisationId, List<AssociationListData> associations)
		{
			// Record disposable items as they are created so all can be disposed when needed.
			using (DisposableCollection<IDisposable> disposableItems = new DisposableCollection<IDisposable>())
			{

				// Item filter.
				SaxItemAssociation.Params prmItemAssociation = new SaxItemAssociation.Params();
				prmItemAssociation.ItemIdsIncluded.Add(new ItemId((short)Sax.DataItemType.Organisation, organisationId));
				prmItemAssociation.StatusCat = SaxItemAssociation.StatusCat.NotDeleted;
				model.Paging.ItemTotal = (ulong)ItemDataMgr.GetItemAssociationCount(prmItemAssociation);
				model.PopulatePagingTo(prmItemAssociation.ResultsPaging);

				// Item columns.
				ColumnDfn colId = ItemDataMgr.GetItemAssociationColumnDfn(SaxItemAssociation.Column.Id);
				ColumnDfn colItemTypeFrom = ItemDataMgr.GetItemAssociationColumnDfn(SaxItemAssociation.Column.ItemTypeFrom);
				ColumnDfn colItemIdFrom = ItemDataMgr.GetItemAssociationColumnDfn(SaxItemAssociation.Column.ItemIdFrom);
				ColumnDfn colOrganisationFrom_Name = ItemDataMgr.GetItemAssociationColumnDfn(SaxItemAssociation.Column.OrganisationFrom_Name);
				ColumnDfn colOrganisationFrom_SportIdPrimary = ItemDataMgr.GetItemAssociationColumnDfn(SaxItemAssociation.Column.OrganisationFrom_SportIdPrimary);
				ColumnDfn colOrganisationFrom_RegionIdPrimary = ItemDataMgr.GetItemAssociationColumnDfn(SaxItemAssociation.Column.OrganisationFrom_RegionIdPrimary);
				ColumnDfn colItemTypeTo = ItemDataMgr.GetItemAssociationColumnDfn(SaxItemAssociation.Column.ItemTypeTo);
				ColumnDfn colItemIdTo = ItemDataMgr.GetItemAssociationColumnDfn(SaxItemAssociation.Column.ItemIdTo);
				ColumnDfn colOrganisationTo_Name = ItemDataMgr.GetItemAssociationColumnDfn(SaxItemAssociation.Column.OrganisationTo_Name);
				ColumnDfn colOrganisationTo_SportIdPrimary = ItemDataMgr.GetItemAssociationColumnDfn(SaxItemAssociation.Column.OrganisationTo_SportIdPrimary);
				ColumnDfn colOrganisationTo_RegionIdPrimary = ItemDataMgr.GetItemAssociationColumnDfn(SaxItemAssociation.Column.OrganisationTo_RegionIdPrimary);
				ColumnDfn colAssociationType = ItemDataMgr.GetItemAssociationColumnDfn(SaxItemAssociation.Column.AssociationType);
				ColumnDfn colStatus = ItemDataMgr.GetItemAssociationColumnDfn(SaxItemAssociation.Column.Status);
				List<ColumnDfn> columns = new List<ColumnDfn>()
				{
					colId,
					colItemTypeFrom, colItemIdFrom, colOrganisationFrom_Name, colOrganisationFrom_SportIdPrimary, colOrganisationFrom_RegionIdPrimary,
					colItemTypeTo, colItemIdTo, colOrganisationTo_Name, colOrganisationTo_SportIdPrimary, colOrganisationTo_RegionIdPrimary,
					colAssociationType,
					colStatus
				};

				// Query items.
				using (DbResultSet resultSet = ItemDataMgr.ExecuteItemAssociationQuery(columns, prmItemAssociation))
				{
					while (resultSet != null && resultSet.HasRows && resultSet.NextRecord())
					{
						NamedValue.Map values = resultSet.GetRecordValues();
						AssociationListData associationData = new AssociationListData()
						{
							Id = values.GetString(colId.DataName),
							StatusCode = values.GetString(colStatus.DataName),
							StatusDesc = SacsSystem.GetStatusDescForCode(values.GetString(colStatus.DataName)),
						};
						// Items.
						bool associationReversed = false;
						ItemId itemIdFrom = new ItemId((short)values.GetLong(colItemTypeFrom.DataName), new SysId(values.GetLong(colItemIdFrom.DataName)));
						String organisationNameFrom = values.GetString(colOrganisationFrom_Name.DataName);
						SysId sportIdFrom = new SysId(values.GetLong(colOrganisationFrom_SportIdPrimary.DataName));
						SysId regionIdFrom = new SysId(values.GetLong(colOrganisationFrom_RegionIdPrimary.DataName));
						ItemId itemIdTo = new ItemId((short)values.GetLong(colItemTypeTo.DataName), new SysId(values.GetLong(colItemIdTo.DataName)));
						String organisationNameTo = values.GetString(colOrganisationTo_Name.DataName);
						SysId sportIdTo = new SysId(values.GetLong(colOrganisationTo_SportIdPrimary.DataName));
						SysId regionIdTo = new SysId(values.GetLong(colOrganisationTo_RegionIdPrimary.DataName));
						if (ItemId.IsValid(itemIdFrom) && ItemId.IsValid(itemIdTo) && itemIdFrom.Type == (int)Sax.DataItemType.Organisation && itemIdTo.Type == (int)Sax.DataItemType.Organisation)
						{
							if (itemIdFrom.Id.Equals(organisationId))
							{
								associationData.Organisation.Id = SysId.ToString(itemIdFrom.Id);
								associationData.Organisation.Name = organisationNameFrom;
								associationData.OrganisationAssoc.Id = SysId.ToString(itemIdTo.Id);
								associationData.OrganisationAssoc.Name = organisationNameTo;
								if (!sportIdFrom.Equals(sportIdTo))
									associationData.OrganisationAssoc.Sport = model.GetSportName(sportIdTo);
								if (!regionIdFrom.Equals(regionIdTo))
									associationData.OrganisationAssoc.Sport = model.GetRegionName(regionIdTo);
							}
							else if (itemIdTo.Id.Equals(organisationId))
							{
								associationReversed = true;
								associationData.Organisation.Id = SysId.ToString(itemIdTo.Id);
								associationData.Organisation.Name = organisationNameTo;
								associationData.OrganisationAssoc.Id = SysId.ToString(itemIdFrom.Id);
								associationData.OrganisationAssoc.Name = organisationNameFrom;
								if (!sportIdFrom.Equals(sportIdTo))
									associationData.OrganisationAssoc.Sport = model.GetSportName(sportIdFrom);
								if (!regionIdFrom.Equals(regionIdTo))
									associationData.OrganisationAssoc.Sport = model.GetRegionName(regionIdFrom);
							}
							else if (SacsSystem.DebugMode)
								// Track invalid associations, ie. where neither item is this organisation.
								Debugger.Break();
						}
						else if (SacsSystem.DebugMode)
							// Track invalid associations, ie. where either item is not an organisation.
							Debugger.Break();
						// Association type.
						Sax.AssociationType associationType = (Sax.AssociationType)values.GetLong(colAssociationType.DataName);
						associationData.Assoc.Populate(associationType, associationReversed);
						// Add association to the list.
						associations.Add(associationData);
					}
				}
			}
		}

		//-------------------------------------------------------------------
		// Get Organisation Association ajax request.
		//-------------------------------------------------------------------
		private class AjaxResponse_Association : AjaxResponse_Data
		{
			// Construction.
			public AjaxResponse_Association(SaxModel_Admin model) : base(model) { }
			// Association details.
			public AssociationItemData Association { get; } = new AssociationItemData();
		}
		//-------------------------------------------------------------------
		[HttpPost]
		[Route("Organisation/Ajax/GetAssociation")]
		public IActionResult Ajax_GetAssociation(Model_OrganisationAssociations model)
		{
			String messageTitle = Localiser["caption.organisation.association"];
			AjaxResponse_Association responseData = new AjaxResponse_Association(model);

			// Validate session.
			if (!ValidUserSession)
				return GetAjaxResult_InvalidSession(responseData);

			// Record disposable items as they are created so all can be disposed when needed.
			using (DisposableCollection<IDisposable> disposableItems = new DisposableCollection<IDisposable>())
			{

				// Identify item.
				SysId itemAssociationId = SysId.ToSysId(model.ItemAssociationId);
				if (!SysId.IsValid(itemAssociationId))
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.item.id.not.specified"]));

				// Retrieve association.
				SaxItemAssociation itemAssociation = ItemDataMgr.GetItemAssociationById(itemAssociationId);
				disposableItems.Add(itemAssociation);
				if (itemAssociation == null)
				{
					SaLogger.Warn($"{SysUtil.Fn} Failed to retrieve Item Association for Id: '{model.ItemAssociationId}'");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.item.id.not.found"]));
				}

				// Identify organisations.
				SysId organisationId = SysId.ToSysId(model.OrganisationId);
				SysId organisationIdAssoc = null;
				if (!SysId.IsValid(organisationId))
				{
					SaLogger.Warn($"{SysUtil.Fn} Organisation Id must be supplied.");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.incomplete"]));
				}

				// Validate the association.
				if (itemAssociation.ItemIdFrom.Type != (int)Sax.DataItemType.Organisation)
				{
					SaLogger.Warn($"{SysUtil.Fn} Inconsistent association 'From' item type: {AssociationTypeCodes.GetCodeForType(itemAssociation.ItemIdFrom.Type)}. Expected: Organisation.");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.inconsistent"]));
				}
				if (itemAssociation.ItemIdTo.Type != (int)Sax.DataItemType.Organisation)
				{
					SaLogger.Warn($"{SysUtil.Fn} Inconsistent association 'To' item type: {AssociationTypeCodes.GetCodeForType(itemAssociation.ItemIdTo.Type)}. Expected: Organisation.");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.inconsistent"]));
				}

				// Identify organisations from association items.
				// The specified organisation must be one or other of the association's items.
				if (itemAssociation.ItemIdFrom.Id.Equals(organisationId))
					organisationIdAssoc = itemAssociation.ItemIdTo.Id;
				else if (itemAssociation.ItemIdTo.Id.Equals(organisationId))
					organisationIdAssoc = itemAssociation.ItemIdFrom.Id;
				else
				{
					SaLogger.Warn($"{SysUtil.Fn} Inconsistent association - Specified organisation is neither item.");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.inconsistent"]));
				}

				// Retrieve Organisation.
				SaxOrganisation organisation = AccountMgr.GetOrganisationById(organisationId);
				disposableItems.Add(organisation);
				if (organisation == null)
				{
					SaLogger.Warn($"{SysUtil.Fn} Failed to retrieve Organisation for Id: '{organisationId}'");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.system"]));
				}

				// Retrieve associated Organisation.
				SaxOrganisation organisationAssoc = AccountMgr.GetOrganisationById(organisationIdAssoc);
				disposableItems.Add(organisationAssoc);
				if (organisationAssoc == null)
				{
					SaLogger.Warn($"{SysUtil.Fn} Failed to retrieve associated Organisation for Id: '{organisationIdAssoc}'");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.system"]));
				}

				// Construct response.
				PopulateAssociationResponseItemData(model, responseData.Association, itemAssociation, organisation, organisationAssoc);
			}

			responseData.Success = true;
			return Json(responseData);
		}

		//-------------------------------------------------------------------
		// Store Organisation Association ajax request.
		//-------------------------------------------------------------------
		[HttpPost]
		[Route("Organisation/Ajax/StoreAssociation")]
		public IActionResult Ajax_StoreAssociation(Model_OrganisationAssociations model)
		{
			String messageTitle = Localiser["caption.organisation.association"];
			AjaxResponse_Association responseData = new AjaxResponse_Association(model);

			// Validate session.
			if (!ValidUserSession)
				return GetAjaxResult_InvalidSession(responseData);

			// Validate item properties.
			model.ValidateOrganisationAssociationData(responseData);
			if (responseData.HasControlErrors())
				return Json(responseData);

			// Record disposable items as they are created so all can be disposed when needed.
			using (DisposableCollection<IDisposable> disposableItems = new DisposableCollection<IDisposable>())
			{

				// Organisation.
				SysId organisationId = SysId.ToSysId(model.OrganisationId);
				SaxOrganisation organisation = AccountMgr.GetOrganisationById(organisationId);
				disposableItems.Add(organisation);
				if (organisation == null)
				{
					SaLogger.Warn($"{SysUtil.Fn} Failed to retrieve Organisation for Id: {model.OrganisationId}");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.incomplete"]));
				}

				// Associated Organisation.
				SysId organisationIdAssoc = SysId.ToSysId(model.OrganisationIdAssoc);
				SaxOrganisation organisationAssoc = AccountMgr.GetOrganisationById(organisationIdAssoc);
				disposableItems.Add(organisationAssoc);
				if (organisationAssoc == null)
				{
					SaLogger.Warn($"{SysUtil.Fn} Failed to retrieve associated Organisation for Id: {model.OrganisationIdAssoc}");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.incomplete"]));
				}
				if (organisationIdAssoc.Equals(organisationId))
				{
					SaLogger.Warn($"{SysUtil.Fn} Associated organisation must not be the same as the organisation.");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.inconsistent"]));
				}

				// Association type.
				Sax.AssociationType associationType = model.GetAssociationTypeForOption(model.Association.GetAssociationTypeOption());
				if ((int)associationType < 1)
				{
					SaLogger.Warn($"{SysUtil.Fn} Association Type must be specified.");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.inconsistent"]));
				}
				Sax.AssociationTypeOption associationTypeOption = model.Association.GetAssociationTypeOption();
				if ((int)associationTypeOption < 1)
				{
					SaLogger.Warn($"{SysUtil.Fn} Association Type Option must be specified.");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.inconsistent"]));
				}
				if (!model.IsConsistentWith(associationTypeOption, associationType))
				{
					SaLogger.Warn($"{SysUtil.Fn} Association Type Option ({associationTypeOption}) is inconsistent with Association Type ({associationType}).");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.inconsistent"]));
				}

				// Identify From/To items.
				ItemId itemIdFrom = organisation.GetItemId();
				ItemId itemIdTo = organisationAssoc.GetItemId();
				if (model.IsAssociationTypeDirectionReversed(associationTypeOption))
				{
					itemIdFrom = organisationAssoc.GetItemId();
					itemIdTo = organisation.GetItemId();
				}

				// Retrieve existing association.
				SysId itemAssociationId = SysId.ToSysId(model.ItemAssociationId);
				if (SysId.IsValid(itemAssociationId) == StringUtil.ToBool(model.NewItem))
				{
					// Inconsistentcy between the 'Existing' flag and whether the Item Association Id has been specified.
					SaLogger.Warn($"{SysUtil.Fn} Item Association Id " + (StringUtil.ToBool(model.NewItem) ? "specified for new item" : "not specified for existing item") + ".");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.inconsistent"]));
				}
				SaxItemAssociation itemAssociation = ItemDataMgr.GetItemAssociationById(itemAssociationId);
				if (itemAssociation == null && StringUtil.ToBool(model.NewItem))
				{
					// Check whether there's a matching association for the 'new' association with 'deleted' status.
					SaxItemAssociation.Params prmItemAsociation = new SaxItemAssociation.Params();
					prmItemAsociation.ItemIdsIncluded.Add(organisation.GetItemId());
					prmItemAsociation.AssociationTypesIncluded.Add(associationType);
					prmItemAsociation.StatusCat = SaxItemAssociation.StatusCat.DeletedOnly;
					foreach (SaxItemAssociation itemAssociationCandidate in ItemDataMgr.GetItemAssociationList(prmItemAsociation))
					{
						if (itemAssociationCandidate.ItemIdFrom.Equals(organisationAssoc.GetItemId()) || itemAssociationCandidate.ItemIdTo.Equals(organisationAssoc.GetItemId()))
						{
							itemAssociation = itemAssociationCandidate;
							itemAssociation.Status = SaxItemAssociation.DefaultStatus;
							break;
						}
						disposableItems.Add(itemAssociationCandidate);
					}
				}
				disposableItems.Add(itemAssociation);
				if (itemAssociation == null && SysId.IsValid(itemAssociationId))
				{
					SaLogger.Warn($"{SysUtil.Fn} Failed to retrieve item association for Id: '{itemAssociationId}'");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.item.id.not.found"]));
				}

				if (itemAssociation != null)
				{
					// Check if item relationship has been reversed, eg. from parent to child.
					bool associationReversed = itemAssociation.ItemIdTo.Id.Equals(organisation.Id);
					if (model.IsAssociationTypeDirectionReversed(associationTypeOption) != model.IsAssociationTypeDirectionReversed(AssociationTypeData.GetAssociationTypeOption(itemAssociation.AssociationType, associationReversed)))
					{
						// Logical direction has been reversed from that stored.
						// Items must be switched.
						ItemId itemAssociationItemIdFrom = itemAssociation.ItemIdFrom;
						itemAssociation.ItemIdFrom = itemAssociation.ItemIdTo;
						itemAssociation.ItemIdTo = itemAssociationItemIdFrom;
					}
					// Validate From/To items.
					if (!itemAssociation.ItemIdFrom.Equals(itemIdFrom))
					{
						SaLogger.Warn($"{SysUtil.Fn} Inconsistent association - expected 'From' Item Id: {SysId.ToString(itemIdFrom.Id)}. Found: {SysId.ToString(itemAssociation.ItemIdFrom.Id)}");
						return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.system"]));
					}
					if (!itemAssociation.ItemIdTo.Equals(itemIdTo))
					{
						SaLogger.Warn($"{SysUtil.Fn} Inconsistent association - expected 'To' Item Id: {SysId.ToString(itemIdTo.Id)}. Found: {SysId.ToString(itemAssociation.ItemIdTo.Id)}");
						return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.system"]));
					}
				}
				else
				{
					// Item Association not identified.

					// Check for deleted association that can be reused.
					SaxItemAssociation.Params itemAssociationParams = new SaxItemAssociation.Params();

					if (itemAssociation != null)
						itemAssociation.Status = SaxItemAssociation.DefaultStatus;
					else
					{
						// Association not found - create a new one.
						itemAssociation = ItemDataMgr.CreateItemAssociation(itemIdFrom, itemIdTo, associationType);
					}
					disposableItems.Add(itemAssociation);
				}

				// Populate item properties.
				if (model.Association.StatusCode != null)
					itemAssociation.Status = model.Association.GetStatus();

				// Store item.
				if (!SysId.IsValid(itemAssociation.Id))
				{
					if (!ItemDataMgr.InsertItemAssociation(itemAssociation, DbUpdateInfo))
					{
						SaLogger.Warn($"{SysUtil.Fn} Failed to insert item association: {ItemDataMgr.ErrorStateMessage}");
						return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.item.insert.failed"] + "\n\n" + ItemDataMgr.ErrorStateMessage));
					}
				}
				else
				{
					if (!ItemDataMgr.UpdateItemAssociation(itemAssociation, DbUpdateInfo))
					{
						SaLogger.Warn($"{SysUtil.Fn} Failed to update item association [Id:{SysId.ToString(itemAssociation.Id)}]: {ItemDataMgr.ErrorStateMessage}");
						return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.item.update.failed"] + "\n\n" + ItemDataMgr.ErrorStateMessage));
					}
				}

				// Construct response.
				PopulateAssociationResponseItemData(model, responseData.Association, itemAssociation, organisation, organisationAssoc);
			}

			responseData.Success = true;
			return Json(responseData);
		}

		//-------------------------------------------------------------------
		// Remove Organisation Association ajax request.
		//-------------------------------------------------------------------
		[HttpPost]
		[Route("Organisation/Ajax/RemoveAssociation")]
		public IActionResult Ajax_RemoveAssociation(Model_OrganisationAssociations model)
		{
			String messageTitle = Localiser["caption.organisation.association"];
			AjaxResponse_Association responseData = new AjaxResponse_Association(model);

			// Validate session.
			if (!ValidUserSession)
				return GetAjaxResult_InvalidSession(responseData);

			// Record disposable items as they are created so all can be disposed when needed.
			using (DisposableCollection<IDisposable> disposableItems = new DisposableCollection<IDisposable>())
			{

				// Organisation.
				SysId organisationId = SysId.ToSysId(model.OrganisationId);
				SaxOrganisation organisation = AccountMgr.GetOrganisationById(organisationId);
				disposableItems.Add(organisation);
				if (organisation == null)
				{
					SaLogger.Warn($"{SysUtil.Fn} Failed to retrieve Organisation for Id: '{model.OrganisationId}'");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.incomplete"]));
				}

				// Association Organisation.
				SysId organisationIdAssoc = SysId.ToSysId(model.OrganisationIdAssoc);
				SaxOrganisation organisationAssoc = AccountMgr.GetOrganisationById(organisationIdAssoc);
				disposableItems.Add(organisationAssoc);
				if (organisationAssoc == null)
				{
					SaLogger.Warn($"{SysUtil.Fn} Failed to retrieve associated Organisation for Id: '{model.OrganisationIdAssoc}'");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.incomplete"]));
				}
				if (organisationIdAssoc.Equals(organisationId))
				{
					SaLogger.Warn($"{SysUtil.Fn} Associated organisation must not be the same as the organisation.");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.inconsistent"]));
				}

				// Item Association.
				SysId itemAssociationId = SysId.ToSysId(model.ItemAssociationId);
				SaxItemAssociation itemAssociation = ItemDataMgr.GetItemAssociationById(itemAssociationId);
				disposableItems.Add(itemAssociation);
				if (itemAssociation == null)
				{
					SaLogger.Warn($"{SysUtil.Fn} Failed to retrieve Item Association for Id: '{itemAssociationId}'");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.item.id.not.found"]));
				}

				// Validate association Item Ids.
				if (!itemAssociation.ItemIdFrom.Id.Equals(organisation.Id) && !itemAssociation.ItemIdTo.Id.Equals(organisation.Id))
				{
					SaLogger.Warn($"{SysUtil.Fn} Inconsistent item association properties. Organisation must be 'From' or 'To' item");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.inconsistent"]));
				}
				if (!itemAssociation.ItemIdFrom.Id.Equals(organisationAssoc.Id) && !itemAssociation.ItemIdTo.Id.Equals(organisationAssoc.Id))
				{
					SaLogger.Warn($"{SysUtil.Fn} Inconsistent item association properties. Associated Organisation must be 'From' or 'To' item");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.data.inconsistent"]));
				}

				// Logically delete item.
				itemAssociation.Status = SaStatus.Deleted;
				if (!ItemDataMgr.UpdateItemAssociation(itemAssociation, DbUpdateInfo))
				{
					SaLogger.Warn($"{SysUtil.Fn} Failed to update Item Association [Id:{SysId.ToString(itemAssociation.Id)}]: {ItemDataMgr.ErrorStateMessage}");
					return Json(responseData.SetPopupMessage(messageTitle, Localiser["msg.error.item.update.failed"] + "\n\n" + ItemDataMgr.ErrorStateMessage));
				}

				// Construct response.
				PopulateAssociationResponseItemData(model, responseData.Association, itemAssociation, organisation, organisationAssoc);
			}

			responseData.Success = true;
			return Json(responseData);
		}

		//-------------------------------------------------------------------
	}
	//=======================================================================
}