Add related cases and duplicate review suggestions

src/lib/server/db/migrations.ts

@@ -32,7 +32,8 @@ import {
     migrateModeration,
     migrateModerationCases,
     migrateModerationCaseActions,
-    migrateModerationCaseAssessments
+    migrateModerationCaseAssessments,
+    migrateModerationCaseRelationships
 } from '../moderation/schema.js';
 import type { Migration } from './migration-runner.js';
 
@@ -185,6 +186,11 @@ export const migrations: readonly Migration[] = [
         version: 32,
         name: 'moderation case assessment revision history',
         run: migrateModerationCaseAssessments
+    },
+    {
+        version: 33,
+        name: 'moderation case relationships and duplicate review',
+        run: migrateModerationCaseRelationships
     }
 ];
 

src/lib/server/moderation/actions.ts

@@ -3,6 +3,7 @@ import { db } from '../db/index.js';
 import { archivedEvidenceSnapshots } from './evidence.js';
 import { caseActionReference, recordedCaseAction, isCaseActionLinked } from './case-actions.js';
 import { assessmentDraft } from './assessments.js';
+import { linkCases, unlinkCases } from './relationships.js';
 import { AuthError } from '../auth/index.js';
 import { moderatorMaximumRestrictionMs, type AuthUser } from '../../auth.js';
 import {
@@ -473,6 +474,21 @@ export function mutateModeration(actorId: string, input: Record<string, unknown>
         if (input.op === 'action') return liveAction(actor, input, now);
         if (input.op === 'create-case') return createCase(actor, input, now);
         if (input.op === 'update-case') return updateCase(actor, input, now);
+        if (input.op === 'link-case' || input.op === 'unlink-case') {
+            const row = caseRow(input.id);
+            checkCaseRevision(row, input.revision);
+            if (input.op === 'link-case')
+                linkCases(
+                    actor,
+                    row,
+                    caseRow(input.relatedCaseId),
+                    input.relation,
+                    input.reason,
+                    now
+                );
+            else unlinkCases(actor, row, input.relationshipId, input.reason, now);
+            return { id: row.id };
+        }
         if (input.op === 'assess-case') {
             const row = caseRow(input.id);
             checkCaseRevision(row, input.revision);

src/lib/server/moderation/cases.ts

@@ -4,6 +4,7 @@ import { moderationActor, textField } from './core.js';
 import { moderationOverview } from './overview.js';
 import { caseActionLists } from './case-actions.js';
 import { caseAssessmentHistory } from './assessments.js';
+import { relatedCases, candidateCases } from './relationships.js';
 import type {
     ModerationCase,
     ModerationCaseDetail,
@@ -86,6 +87,8 @@ export function moderationCaseDetail(actorId: string, id: string): ModerationCas
             ...caseActionLists(caseId, row, overview.checkedAt),
             assessment: assessmentHistory[0] ?? null,
             assessmentHistory,
+            relatedCases: relatedCases(caseId),
+            candidateCases: candidateCases(row),
             events,
             coverage: overview.coverage,
             assignees,

src/lib/server/moderation/relationships.ts

@@ -0,0 +1,212 @@
+import { randomUUID } from 'node:crypto';
+import type { AuthUser } from '../../auth.js';
+import {
+    moderationCaseRelations,
+    moderationGuid,
+    type ModerationCaseCandidate,
+    type ModerationCaseReference,
+    type ModerationCaseRelation,
+    type ModerationCaseRelationship
+} from '../../moderation.js';
+import { AuthError } from '../auth/index.js';
+import { db } from '../db/index.js';
+import { moderationEvent, textField } from './core.js';
+
+type RelationshipRow = {
+    id: string;
+    case_id: string;
+    target_case_id: string;
+    relation: ModerationCaseRelation;
+    removed_at: string | null;
+};
+
+function relationAudit(
+    actor: AuthUser,
+    relationship: RelationshipRow,
+    cases: ModerationCaseReference[],
+    action: 'case.linked' | 'case.unlinked',
+    reason: string,
+    now: string
+) {
+    db()
+        .prepare('UPDATE moderation_cases SET updated_at=?,revision=revision+1 WHERE id IN (?,?)')
+        .run(now, relationship.case_id, relationship.target_case_id);
+    for (const item of cases) {
+        const outgoing = item.id === relationship.case_id;
+        moderationEvent(
+            actor,
+            action,
+            item,
+            item.id,
+            JSON.stringify({
+                relationshipId: relationship.id,
+                relation: relationship.relation,
+                direction: outgoing ? 'outgoing' : 'incoming',
+                relatedCaseId: outgoing ? relationship.target_case_id : relationship.case_id,
+                reason
+            }),
+            now
+        );
+    }
+}
+
+export function linkCases(
+    actor: AuthUser,
+    source: ModerationCaseReference,
+    target: ModerationCaseReference,
+    value: unknown,
+    reasonValue: unknown,
+    now: string
+) {
+    const relation = moderationCaseRelations.find((relation) => relation === value);
+    if (!relation) throw new AuthError('Choose same incident, appeal of, or duplicate of.');
+    const reason = textField(reasonValue, 'Relationship reason', 4000);
+    if (source.id === target.id) throw new AuthError('A case cannot be related to itself.');
+    if (
+        relation !== 'same_incident' &&
+        (source.game !== target.game || source.guid !== target.guid)
+    )
+        throw new AuthError('Appeal and duplicate relationships require the same game and player.');
+    const [from, to] =
+        relation === 'same_incident' && source.id > target.id ? [target, source] : [source, target];
+    const handle = db();
+    if (
+        handle
+            .prepare(
+                `SELECT 1 FROM moderation_case_relationships
+        WHERE case_id=? AND target_case_id=? AND relation=? AND removed_at IS NULL`
+            )
+            .get(from.id, to.id, relation)
+    )
+        return;
+    if (
+        relation !== 'same_incident' &&
+        handle
+            .prepare(
+                `WITH RECURSIVE descendants(id) AS (
+        SELECT target_case_id FROM moderation_case_relationships
+            WHERE case_id=? AND relation=? AND removed_at IS NULL
+        UNION
+        SELECT r.target_case_id FROM moderation_case_relationships r
+            JOIN descendants d ON r.case_id=d.id WHERE r.relation=? AND r.removed_at IS NULL
+        ) SELECT 1 FROM descendants WHERE id=? LIMIT 1`
+            )
+            .get(to.id, relation, relation, from.id)
+    )
+        throw new AuthError(
+            'This relationship would create a cycle. Review the linked cases.',
+            409
+        );
+    const relationship: RelationshipRow = {
+        id: randomUUID(),
+        case_id: from.id,
+        target_case_id: to.id,
+        relation,
+        removed_at: null
+    };
+    handle
+        .prepare('INSERT INTO moderation_case_relationships VALUES(?,?,?,?,?,?,?,NULL)')
+        .run(relationship.id, from.id, to.id, relation, actor.id, actor.username, now);
+    relationAudit(actor, relationship, [from, to], 'case.linked', reason, now);
+}
+
+export function unlinkCases(
+    actor: AuthUser,
+    source: ModerationCaseReference,
+    value: unknown,
+    reasonValue: unknown,
+    now: string
+) {
+    const id = textField(value, 'Relationship ID', 128);
+    const reason = textField(reasonValue, 'Removal reason', 4000);
+    const handle = db();
+    const relationship = handle
+        .prepare(
+            `SELECT id,case_id,target_case_id,relation,removed_at
+        FROM moderation_case_relationships WHERE id=? AND (case_id=? OR target_case_id=?)`
+        )
+        .get(id, source.id, source.id) as RelationshipRow | undefined;
+    if (!relationship) throw new AuthError('The case relationship is unavailable.', 404);
+    if (relationship.removed_at) return;
+    const otherId =
+        relationship.case_id === source.id ? relationship.target_case_id : relationship.case_id;
+    const other = handle
+        .prepare('SELECT id,title,status,game,guid FROM moderation_cases WHERE id=?')
+        .get(otherId) as ModerationCaseReference;
+    handle.prepare('UPDATE moderation_case_relationships SET removed_at=? WHERE id=?').run(now, id);
+    relationAudit(actor, relationship, [source, other], 'case.unlinked', reason, now);
+}
+
+/** Relationships remain readable from both endpoints, with the original direction intact. */
+export function relatedCases(caseId: string): ModerationCaseRelationship[] {
+    const rows = db()
+        .prepare(
+            `SELECT r.id,r.relation,r.actor,r.created_at AS createdAt,
+        CASE WHEN r.case_id=? THEN 'outgoing' ELSE 'incoming' END AS direction,
+        c.id AS otherId,c.title,c.status,c.game,c.guid
+        FROM moderation_case_relationships r JOIN moderation_cases c
+            ON c.id=CASE WHEN r.case_id=? THEN r.target_case_id ELSE r.case_id END
+        WHERE (r.case_id=? OR r.target_case_id=?) AND r.removed_at IS NULL
+        ORDER BY r.created_at DESC,r.id`
+        )
+        .all(caseId, caseId, caseId, caseId) as Array<
+        Omit<ModerationCaseRelationship, 'case'> &
+            Omit<ModerationCaseReference, 'id'> & { otherId: string }
+    >;
+    return rows.map(({ otherId, title, status, game, guid, ...relationship }) => ({
+        ...relationship,
+        case: { id: otherId, title, status, game, guid }
+    }));
+}
+
+function archivedMatch(value: string, subject: ModerationCaseReference): number | null {
+    try {
+        const snapshot = JSON.parse(value);
+        if (
+            !Number.isSafeInteger(snapshot?.matchId) ||
+            snapshot.matchId < 1 ||
+            snapshot.match?.game !== subject.game ||
+            typeof snapshot.match?.server !== 'string' ||
+            typeof snapshot.match?.started_at !== 'string' ||
+            snapshot.entry?.type !== 'message' ||
+            typeof snapshot.entry.message?.guid !== 'string' ||
+            typeof snapshot.entry.message?.message !== 'string' ||
+            moderationGuid(subject.game, snapshot.entry.message.guid) !== subject.guid
+        )
+            return null;
+        return snapshot.matchId;
+    } catch {
+        return null;
+    }
+}
+
+/** Sharing archived match context is a review hint, never a duplicate decision. */
+export function candidateCases(subject: ModerationCaseReference): ModerationCaseCandidate[] {
+    const handle = db();
+    const candidates = handle
+        .prepare(
+            `SELECT id,title,status,game,guid FROM moderation_cases
+        WHERE game=? AND guid=? AND id<>? ORDER BY updated_at DESC,id LIMIT 25`
+        )
+        .all(subject.game, subject.guid, subject.id) as ModerationCaseReference[];
+    const ids = [subject.id, ...candidates.map((candidate) => candidate.id)];
+    const snapshots = handle
+        .prepare(
+            `SELECT case_id,snapshot FROM moderation_evidence
+        WHERE case_id IN (${ids.map(() => '?').join(',')}) AND snapshot IS NOT NULL`
+        )
+        .all(...ids) as { case_id: string; snapshot: string }[];
+    const matches = new Map<string, Set<number>>();
+    for (const snapshot of snapshots) {
+        const match = archivedMatch(snapshot.snapshot, subject);
+        if (match === null) continue;
+        const set = matches.get(snapshot.case_id) ?? new Set<number>();
+        set.add(match);
+        matches.set(snapshot.case_id, set);
+    }
+    const current = matches.get(subject.id) ?? new Set<number>();
+    return candidates.map((candidate) => ({
+        ...candidate,
+        sharedMatch: [...(matches.get(candidate.id) ?? [])].some((match) => current.has(match))
+    }));
+}

src/lib/server/moderation/schema.ts

@@ -179,3 +179,26 @@ export function migrateModerationCaseAssessments(handle: Database.Database): voi
         );
     `);
 }
+
+export function migrateModerationCaseRelationships(handle: Database.Database): void {
+    handle.exec(`
+        CREATE TABLE IF NOT EXISTS moderation_case_relationships (
+            id TEXT PRIMARY KEY,
+            case_id TEXT NOT NULL REFERENCES moderation_cases(id),
+            target_case_id TEXT NOT NULL REFERENCES moderation_cases(id),
+            relation TEXT NOT NULL CHECK(relation IN ('same_incident','appeal_of','duplicate_of')),
+            actor_id TEXT NOT NULL,
+            actor TEXT NOT NULL,
+            created_at TEXT NOT NULL,
+            removed_at TEXT,
+            CHECK(case_id != target_case_id),
+            CHECK(relation != 'same_incident' OR case_id < target_case_id)
+        );
+        CREATE UNIQUE INDEX IF NOT EXISTS moderation_case_relationship_active
+            ON moderation_case_relationships(case_id,target_case_id,relation) WHERE removed_at IS NULL;
+        CREATE INDEX IF NOT EXISTS moderation_case_relationship_target
+            ON moderation_case_relationships(target_case_id,removed_at);
+        CREATE INDEX IF NOT EXISTS moderation_case_subject_recent
+            ON moderation_cases(game,guid,updated_at DESC,id);
+    `);
+}