Remember recent quarrels, fights and reprimands on the person.

Short offense list for the pupil card and save, capped by BehaviorDef — not a discipline score.

src/HSchool.People/OffenseMemory.cs

@@ -0,0 +1,103 @@
+using System.Text.Json.Serialization;
+using HSchool.Content;
+
+namespace HSchool.People;
+
+/// <summary>Stable kind ids written into <see cref="OffenseRecord.Kind"/> and listed on <see cref="BehaviorDef.OffenseMemoryKinds"/>.</summary>
+public static class OffenseKinds
+{
+    public const string Quarrel = "quarrel";
+
+    public const string Fight = "fight";
+
+    public const string Reprimand = "reprimand";
+
+    public static string LocaleKey(string kind) => kind switch
+    {
+        Quarrel => "OffenseQuarrel",
+        Fight => "OffenseFight",
+        Reprimand => "OffenseReprimand",
+        _ => "Offense" + char.ToUpperInvariant(kind[0]) + kind[1..],
+    };
+}
+
+/// <summary>One remembered misconduct. Sparse list on the person — not a discipline score.</summary>
+public sealed class OffenseRecord
+{
+    public required string Kind { get; init; }
+
+    public required DateTime Time { get; init; }
+
+    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+    public string? OtherPersonId { get; init; }
+}
+
+/// <summary>Appends recent offenses and drops the oldest when over the BehaviorDef ceiling.</summary>
+public static class OffenseMemory
+{
+    public static bool IsEnabled(string kind, BehaviorDef rules)
+    {
+        foreach (var allowed in rules.OffenseMemoryKinds)
+        {
+            if (allowed.Equals(kind, StringComparison.Ordinal))
+            {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    public static bool Record(Person person, string kind, DateTime time, string? otherPersonId, BehaviorDef rules)
+    {
+        ArgumentNullException.ThrowIfNull(person);
+        ArgumentNullException.ThrowIfNull(rules);
+        ArgumentException.ThrowIfNullOrWhiteSpace(kind);
+
+        if (rules.OffenseMemoryMax <= 0 || !IsEnabled(kind, rules))
+        {
+            return false;
+        }
+
+        var list = person.Offenses;
+        if (list is null)
+        {
+            list = [];
+            person.Offenses = list;
+        }
+
+        list.Add(new OffenseRecord
+        {
+            Kind = kind,
+            Time = DateTime.SpecifyKind(time, DateTimeKind.Utc),
+            OtherPersonId = string.IsNullOrWhiteSpace(otherPersonId) ? null : otherPersonId,
+        });
+
+        while (list.Count > rules.OffenseMemoryMax)
+        {
+            list.RemoveAt(0);
+        }
+
+        return true;
+    }
+
+    public static string? OtherParticipant(string personId, string? victimId, IReadOnlyList<string> members)
+    {
+        if (victimId is not null
+            && !victimId.Equals(personId, StringComparison.Ordinal)
+            && members.Contains(victimId, StringComparer.Ordinal))
+        {
+            return victimId;
+        }
+
+        foreach (var member in members)
+        {
+            if (!member.Equals(personId, StringComparison.Ordinal))
+            {
+                return member;
+            }
+        }
+
+        return null;
+    }
+}

src/HSchool.People/Roster.cs

@@ -69,6 +69,12 @@ public sealed record Person
     /// </summary>
     public string? BullyVictimId { get; set; }
 
+    /// <summary>
+    /// Recent misconduct (quarrel / fight / reprimand). Null when empty so people.json stays compact.
+    /// Ceiling and which kinds write live on <c>BehaviorDef</c>.
+    /// </summary>
+    public List<OffenseRecord>? Offenses { get; set; }
+
     public int AgeOn(DateTime asOf) => SchoolYears.AgeYears(BirthDate, asOf);
 }