Add automatic project snapshots

src/domain/models/project-snapshot-policy.model.ts

@@ -0,0 +1,37 @@
+export const projectSnapshotKinds = ["named", "automatic"] as const;
+export type ProjectSnapshotKind =
+  (typeof projectSnapshotKinds)[number];
+
+export const automaticProjectSnapshotIntervalRevisions = 25;
+export const automaticProjectSnapshotRetentionCount = 12;
+
+export function shouldCaptureAutomaticProjectSnapshot(
+  currentRevision: number,
+  latestAutomaticRevision: number | null
+) {
+  assertRevision(currentRevision, "Current");
+  if (latestAutomaticRevision !== null) {
+    assertRevision(latestAutomaticRevision, "Latest automatic");
+    if (latestAutomaticRevision > currentRevision) {
+      throw new Error(
+        "Latest automatic snapshot revision exceeds current revision."
+      );
+    }
+  }
+  if (currentRevision < automaticProjectSnapshotIntervalRevisions) {
+    return false;
+  }
+  return (
+    latestAutomaticRevision === null ||
+    currentRevision - latestAutomaticRevision >=
+      automaticProjectSnapshotIntervalRevisions
+  );
+}
+
+function assertRevision(value: number, label: string) {
+  if (!Number.isSafeInteger(value) || value < 0) {
+    throw new Error(
+      `${label} snapshot revision must be a non-negative integer.`
+    );
+  }
+}

src/domain/ports/project-snapshot.store.ts

@@ -1,8 +1,12 @@
+import type { ProjectSnapshotKind } from "../models/project-snapshot-policy.model.js";
+import type { ProjectStateRestoreCommand } from "../models/project-state-restore-command.model.js";
+
 export interface ProjectSnapshotMetadata {
   id: string;
   projectId: string;
   sourceRevision: number;
   schemaVersion: number;
+  kind: ProjectSnapshotKind;
   name: string;
   description: string | null;
   payloadSha256: string;
@@ -33,4 +37,3 @@ export interface ProjectSnapshotStore {
     snapshotId: string
   ): PreparedProjectSnapshotRestore | null;
 }
-import type { ProjectStateRestoreCommand } from "../models/project-state-restore-command.model.js";