tech-log-frontend/tests/helpers/fake-push-control-repository.ts

import type {
  IndexedDbCompareAndSwapInput,
  IndexedDbDeleteInput,
  IndexedDbWriteReceipt,
} from "../../src/application/ports/browser-file-storage/indexeddb-port.ts";
import type {
  BrowserDataResult,
} from "../../src/application/ports/browser-file-storage/shared.ts";
import type {
  PushControlV1,
} from "../../src/contracts/web-push.ts";
import type {
  PushControlRepository,
} from "../../src/adapters/web-push/push-association-fence-store.ts";
import {
  browserDataFailure,
  browserDataSuccess,
} from "../../src/adapters/browser-file-storage/result.ts";

type StoredControl = Readonly<{
  value: unknown;
  revision: number;
}>;

type Deferred = Readonly<{
  promise: Promise<void>;
  resolve(): void;
}>;

export type PausedPushControlWrite = Readonly<{
  reached: Promise<void>;
  release(): void;
}>;

export class FakePushControlRepository
  implements PushControlRepository
{
  #stored: StoredControl | null = null;
  #closed = false;
  #pause:
    | Readonly<{
        predicate(value: PushControlV1): boolean;
        reached: Deferred;
        released: Deferred;
      }>
    | null = null;
  #pausedRemove:
    | Readonly<{
        reached: Deferred;
        released: Deferred;
      }>
    | null = null;

  open(
    signal?: AbortSignal,
  ): Promise<BrowserDataResult<void>> {
    return Promise.resolve(this.#available(signal, undefined));
  }

  read(
    _key: string,
    signal?: AbortSignal,
  ): Promise<
    BrowserDataResult<
      Readonly<{ value: PushControlV1; revision: number }> | null
    >
  > {
    const unavailable = this.#unavailable(signal);
    if (unavailable) return Promise.resolve(unavailable);
    if (!this.#stored) return Promise.resolve(browserDataSuccess(null));
    return Promise.resolve(
      browserDataSuccess(
        Object.freeze({
          value: this.#stored.value as PushControlV1,
          revision: this.#stored.revision,
        }),
      ),
    );
  }

  async compareAndSwap(
    input: IndexedDbCompareAndSwapInput<PushControlV1>,
  ): Promise<BrowserDataResult<IndexedDbWriteReceipt>> {
    const unavailable = this.#unavailable(input.signal);
    if (unavailable) return unavailable;
    const pause = this.#pause;
    if (pause?.predicate(input.value)) {
      this.#pause = null;
      pause.reached.resolve();
      await pause.released.promise;
    }
    const lateUnavailable = this.#unavailable(input.signal);
    if (lateUnavailable) return lateUnavailable;
    const currentRevision = this.#stored?.revision ?? null;
    if (currentRevision !== input.expectedRevision) {
      return browserDataFailure("CONFLICT", "INDEXEDDB_WRITE");
    }
    const revision = (currentRevision ?? 0) + 1;
    this.#stored = Object.freeze({
      value: structuredClone(input.value),
      revision,
    });
    return browserDataSuccess(
      Object.freeze({
        key: input.key,
        revision,
        replayed: false,
      }),
    );
  }

  async remove(
    input: IndexedDbDeleteInput,
  ): Promise<BrowserDataResult<IndexedDbWriteReceipt>> {
    const unavailable = this.#unavailable(input.signal);
    if (unavailable) return unavailable;
    const pause = this.#pausedRemove;
    if (pause) {
      this.#pausedRemove = null;
      pause.reached.resolve();
      await pause.released.promise;
    }
    const lateUnavailable = this.#unavailable(input.signal);
    if (lateUnavailable) return lateUnavailable;
    if (
      !this.#stored ||
      this.#stored.revision !== input.expectedRevision
    ) {
      return browserDataFailure("CONFLICT", "INDEXEDDB_WRITE");
    }
    const revision = input.expectedRevision + 1;
    this.#stored = null;
    return browserDataSuccess(
      Object.freeze({
        key: input.key,
        revision,
        replayed: false,
      }),
    );
  }

  close(): void {
    this.#closed = true;
  }

  seedRaw(value: unknown, revision = 1): void {
    this.#stored = Object.freeze({ value, revision });
  }

  pauseNextWrite(
    predicate: (value: PushControlV1) => boolean,
  ): PausedPushControlWrite {
    if (this.#pause) {
      throw new Error("A push-control write is already paused.");
    }
    const reached = deferred();
    const released = deferred();
    this.#pause = Object.freeze({ predicate, reached, released });
    return Object.freeze({
      reached: reached.promise,
      release: released.resolve,
    });
  }

  pauseNextRemove(): PausedPushControlWrite {
    if (this.#pausedRemove) {
      throw new Error("A push-control remove is already paused.");
    }
    const reached = deferred();
    const released = deferred();
    this.#pausedRemove = Object.freeze({ reached, released });
    return Object.freeze({
      reached: reached.promise,
      release: released.resolve,
    });
  }

  #available<Value>(
    signal: AbortSignal | undefined,
    value: Value,
  ): BrowserDataResult<Value> {
    return (
      this.#unavailable(signal) ?? browserDataSuccess(value)
    );
  }

  #unavailable(
    signal: AbortSignal | undefined,
  ): BrowserDataResult<never> | null {
    if (signal?.aborted) {
      return browserDataFailure("ABORTED", "INDEXEDDB_READ");
    }
    return this.#closed
      ? browserDataFailure("UNAVAILABLE", "INDEXEDDB_OPEN", {
          retryable: true,
          recovery: "REOPEN",
        })
      : null;
  }
}

export function createFakePushControlStoreDependencies(): Readonly<{
  repository: FakePushControlRepository;
  idempotencyKeyFactory(): string;
}> {
  const repository = new FakePushControlRepository();
  let sequence = 0;
  return Object.freeze({
    repository,
    idempotencyKeyFactory() {
      sequence += 1;
      return `push-control-test-${sequence}`;
    },
  });
}

function deferred(): Deferred {
  let resolvePromise: (() => void) | undefined;
  const promise = new Promise<void>((resolve) => {
    resolvePromise = resolve;
  });
  return Object.freeze({
    promise,
    resolve() {
      resolvePromise?.();
    },
  });
}