feat: version 2 beta

adapters/mongo/providers/snapshots.ts

@@ -0,0 +1,50 @@
+import type { Collection } from "mongodb";
+
+import { SnapshotsProvider } from "../../../types/adapter.ts";
+import { schema, type SnapshotSchema } from "../collections/snapshots.ts";
+import { DatabaseAccessor } from "../types.ts";
+import { toParsedRecord } from "../utilities.ts";
+
+export class MongoSnapshotsProvider implements SnapshotsProvider {
+  readonly #accessor: DatabaseAccessor;
+
+  constructor(accessor: DatabaseAccessor) {
+    this.#accessor = accessor;
+  }
+
+  get collection(): Collection<SnapshotSchema> {
+    return this.#accessor.db.collection<SnapshotSchema>("snapshots");
+  }
+
+  /**
+   * Add snapshot state under given reducer stream.
+   *
+   * @param name   - Name of the reducer the snapshot is attached to.
+   * @param stream - Stream the snapshot is attached to.
+   * @param cursor - Cursor timestamp for the last event used in the snapshot.
+   * @param state  - State of the reduced events.
+   */
+  async insert(name: string, stream: string, cursor: string, state: Record<string, unknown>): Promise<void> {
+    await this.collection.updateOne({ name }, { $set: { stream, cursor, state } }, { upsert: true });
+  }
+
+  /**
+   * Get snapshot state by stream.
+   *
+   * @param name   - Name of the reducer which the state was created.
+   * @param stream - Stream the state was reduced for.
+   */
+  async getByStream(name: string, stream: string): Promise<SnapshotSchema | undefined> {
+    return this.collection.findOne({ name, stream }).then(toParsedRecord(schema));
+  }
+
+  /**
+   * Removes a snapshot for the given reducer stream.
+   *
+   * @param name   - Name of the reducer the snapshot is attached to.
+   * @param stream - Stream to remove from snapshots.
+   */
+  async remove(name: string, stream: string): Promise<void> {
+    await this.collection.deleteOne({ name, stream });
+  }
+}