Fix invalid liege entries in title history

ImperatorToCK3/CK3/Characters/CharacterCollection.cs

@@ -535,7 +535,7 @@ public void PurgeUnneededCharacters(Title.LandedTitles titles, DynastyCollection
 		dynasties.FlattenDynastiesWithNoFounders(this, houses, ck3BookmarkDate);
 
 		// Clean up title history.
-		titles.RemoveInvalidHoldersFromHistory(this);
+		titles.CleanUpHistory(this, ck3BookmarkDate);
 	}
 
 	public void RemoveEmployerIdFromLandedCharacters(Title.LandedTitles titles, Date conversionDate) {

ImperatorToCK3/CK3/Titles/LandedTitles.cs

@@ -257,7 +257,7 @@
 			return this.SelectMany(t => t.GetAllHolderIds()).ToImmutableHashSet();
 		}
 
-		public void RemoveInvalidHoldersFromHistory(CharacterCollection characters) {
+		public void CleanUpHistory(CharacterCollection characters, Date ck3BookmarkDate) {
 			Logger.Debug("Removing invalid holders from history...");
 
 			var validIds = characters.Select(c => c.Id).ToImmutableHashSet();
@@ -270,6 +270,31 @@
 					value => value.ToString() is string valStr && valStr != "0" && !validIds.Contains(valStr)
 				);
 			}
+
+			// Remove liege entries that are not valid (liege title is not held at the entry date).
+			foreach (var title in this) {
+				if (!title.History.Fields.TryGetValue("liege", out var liegeField)) {
+					continue;
+				}
+
+				foreach (var (date, entriesList) in liegeField.DateToEntriesDict.ToArray()) {
+					if (entriesList.Count == 0) {
+						continue;
+					}
+
+					var lastEntry = entriesList.Last();
+					var liegeTitleId = lastEntry.Value.ToString();
+					if (liegeTitleId is null || liegeTitleId == "0") {
+						continue;
+					}
+
+					if (!TryGetValue(liegeTitleId, out var liegeTitle)) {
+						liegeField.DateToEntriesDict.Remove(date);
+					} else if (liegeTitle.GetHolderId(date) == "0") {
+						liegeField.DateToEntriesDict.Remove(date);
+					}
+				}
+			}
 		}
 
 		public void ImportImperatorCountries(
@@ -532,168 +557,168 @@
 			}
 		}
 
 		public void ImportImperatorHoldings(ProvinceCollection ck3Provinces, Imperator.Characters.CharacterCollection irCharacters, Date conversionDate) {
 			Logger.Info("Importing Imperator holdings...");
 			var counter = 0;
 
 			var highLevelTitlesThatHaveHolders = this
 				.Where(t => t.Rank >= TitleRank.duchy && t.GetHolderId(conversionDate) != "0")
 				.ToImmutableList();
 			var highLevelTitleCapitalBaronyIds = highLevelTitlesThatHaveHolders
 				.Select(t=>t.CapitalCounty?.CapitalBaronyId ?? t.CapitalBaronyId)
 				.ToImmutableHashSet();
 
 			// Dukes and above should be excluded from having their holdings converted.
 			// Otherwise, governors with holdings would own parts of other governorships.
 			var dukeAndAboveIds = highLevelTitlesThatHaveHolders
 				.Where(t => t.Rank >= TitleRank.duchy)
 				.Select(t => t.GetHolderId(conversionDate))
 				.ToImmutableHashSet();
 
 			// We exclude baronies that are capitals of duchies and above.
 			var eligibleBaronies = this
 				.Where(t => t.Rank == TitleRank.barony)
 				.Where(b => !highLevelTitleCapitalBaronyIds.Contains(b.Id))
 				.ToArray();
 
 			var countyCapitalBaronies = eligibleBaronies
 				.Where(b => b.DeJureLiege?.CapitalBaronyId == b.Id)
 				.OrderBy(b => b.Id)
 				.ToArray();
 
 			var nonCapitalBaronies = eligibleBaronies.Except(countyCapitalBaronies).OrderBy(b => b.Id).ToArray();
 
 
 			// In CK3, a county holder shouldn't own baronies in counties that are not their own.
 			// This dictionary tracks what counties are held by what characters.
 			Dictionary<string, HashSet<string>> countiesPerCharacter = []; // characterId -> countyIds
 
 			// Evaluate all capital baronies first (we want to distribute counties first, then baronies).
 			foreach (var barony in countyCapitalBaronies) {
 				var ck3Province = GetBaronyProvince(barony);
 				if (ck3Province is null) {
 					continue;
 				}
 
 				// Skip none holdings and temple holdings.
 				if (ck3Province.GetHoldingType(conversionDate) is "church_holding" or "none") {
 					continue;
 				}
 
 				var irProvince = ck3Province.PrimaryImperatorProvince; // TODO: when the holding owner of the primary I:R province is not able to hold the CK3 equivalent, also check the holding owners from secondary source provinces
 				var ck3Owner = GetEligibleCK3OwnerForImperatorProvince(irProvince);
 				if (ck3Owner is null) {
 					continue;
 				}
 
 				var realm = ck3Owner.ImperatorCharacter?.HomeCountry?.CK3Title;
 				var deFactoLiege = realm;
 				if (realm is not null) {
 					var deJureDuchy = barony.DeJureLiege?.DeJureLiege;
 					if (deJureDuchy is not null && deJureDuchy.GetHolderId(conversionDate) != "0" && deJureDuchy.GetTopRealm(conversionDate) == realm) {
 						deFactoLiege = deJureDuchy;
 					} else {
 						var deJureKingdom = deJureDuchy?.DeJureLiege;
 						if (deJureKingdom is not null && deJureKingdom.GetHolderId(conversionDate) != "0" && deJureKingdom.GetTopRealm(conversionDate) == realm) {
 							deFactoLiege = deJureKingdom;
 						}
 					}
 				}
 
 				// Barony is a county capital, so set the county holder to the holding owner.
 				var county = barony.DeJureLiege;
 				if (county is null) {
 					Logger.Warn($"County capital barony {barony.Id} has no de jure county!");
 					continue;
 				}
 				county.SetHolder(ck3Owner, conversionDate);
 				county.SetDeFactoLiege(deFactoLiege, conversionDate);
 
 				if (!countiesPerCharacter.TryGetValue(ck3Owner.Id, out var countyIds)) {
 					countyIds = [];
 					countiesPerCharacter[ck3Owner.Id] = countyIds;
 				}
 				countyIds.Add(county.Id);
 
 				++counter;
 			}
 
 			// In CK3, a baron that doesn't own counties can only hold a single barony.
 			// This dictionary IDs of such barons that already hold a barony.
 			HashSet<string> baronyHolderIds = [];
 
 			// After all possible county capital baronies are distributed, distribute the rest of the eligible baronies.
 			foreach (var barony in nonCapitalBaronies) {
 				var ck3Province = GetBaronyProvince(barony);
 				if (ck3Province is null) {
 					continue;
 				}
 
 				// Skip none holdings and temple holdings.
 				if (ck3Province.GetHoldingType(conversionDate) is "church_holding" or "none") {
 					continue;
 				}
 
 				var irProvince = ck3Province.PrimaryImperatorProvince; // TODO: when the holding owner of the primary I:R province is not able to hold the CK3 equivalent, also check the holding owners from secondary source provinces
 				var ck3Owner = GetEligibleCK3OwnerForImperatorProvince(irProvince);
 				if (ck3Owner is null) {
 					continue;
 				}
 				if (baronyHolderIds.Contains(ck3Owner.Id)) {
 					continue;
 				}
 
 				var county = barony.DeJureLiege;
 				if (county is null) {
 					Logger.Warn($"Barony {barony.Id} has no de jure county!");
 					continue;
 				}
 				// A non-capital barony cannot be held by a character that owns a county but not the county the barony is in.
 				if (countiesPerCharacter.TryGetValue(ck3Owner.Id, out var countyIds) && !countyIds.Contains(county.Id)) {
 					continue;
 				}
 
 				barony.SetHolder(ck3Owner, conversionDate);
 				// No need to set de facto liege for baronies, they are tied to counties.
 
 				baronyHolderIds.Add(ck3Owner.Id);
 
 				++counter;
 			}
 			Logger.Info($"Imported {counter} holdings from I:R.");
 			Logger.IncrementProgress();
 			return;
 
 			Province? GetBaronyProvince(Title barony) {
 				var ck3ProvinceId = barony.ProvinceId;
 				if (ck3ProvinceId is null) {
 					return null;
 				}
 				if (!ck3Provinces.TryGetValue(ck3ProvinceId.Value, out var ck3Province)) {
 					return null;
 				}
 				return ck3Province;
 			}
 
 			Character? GetEligibleCK3OwnerForImperatorProvince(Imperator.Provinces.Province? irProvince) {
 				var holdingOwnerId = irProvince?.HoldingOwnerId;
 				if (holdingOwnerId is null) {
 					return null;
 				}
 
 				var irOwner = irCharacters[holdingOwnerId.Value];
 				var ck3Owner = irOwner.CK3Character;
 				if (ck3Owner is null) {
 					return null;
 				}
 				if (dukeAndAboveIds.Contains(ck3Owner.Id)) {
 					return null;
 				}
 
 				return ck3Owner;
 			}
 		}
 
 		public void RemoveInvalidLandlessTitles(Date ck3BookmarkDate) {
 			Logger.Info("Removing invalid landless titles...");
 			var removedGeneratedTitles = new HashSet<string>();