import { describe, expect, it } from "vitest";

import type { ResumableUploadCheckpoint } from "../../src/application/ports/browser-transfer/resumable-upload.ts";
import { RESUMABLE_UPLOAD_PROTOCOL } from "../../src/application/ports/browser-transfer/resumable-upload.ts";
import {
  createIndexedDbResumableUploadCheckpointRuntime,
  createIndexedDbResumableUploadCheckpointStore,
  uploadCheckpointDatabaseName,
} from "../../src/adapters/browser-transfer/resumable-upload/indexeddb-checkpoint-store.ts";
import { MemoryIndexedDbFactory } from "../helpers/memory-indexeddb.ts";

const scope = Object.freeze({
  authorityToken: "authority_token_01",
  namespaceToken: "namespace_token_01",
  partitionToken: "partition_token_01",
});

function checkpoint(
  revision: number,
  overrides: Partial<ResumableUploadCheckpoint> = {},
): ResumableUploadCheckpoint {
  return {
    schemaVersion: 1,
    protocol: RESUMABLE_UPLOAD_PROTOCOL,
    revision,
    state: "ACTIVE",
    uploadKey: "upload_key_01",
    requestBindingSha256: "a".repeat(64),
    fingerprint: {
      algorithm: "SHA-256-PARTS-V1",
      digestHex: "b".repeat(64),
      byteLength: 4,
      partSizeBytes: 4,
      partCount: 1,
    },
    sessionId: "session_01",
    sessionExpiresAtEpochMs: 5_000,
    sessionMaxConcurrency: 1,
    acceptedParts: [],
    updatedAtEpochMs: 1_000,
    ...overrides,
  };
}

function deletingFactory(
  memory: MemoryIndexedDbFactory,
  mode: "SUCCESS" | "BLOCKED",
): IDBFactory {
  return {
    open: memory.factory.open.bind(memory.factory),
    cmp: memory.factory.cmp.bind(memory.factory),
    deleteDatabase: () => {
      const request = {
        result: undefined,
        error: null,
        transaction: null,
        source: null,
        readyState: "pending",
        onsuccess: null,
        onerror: null,
        onblocked: null,
        onupgradeneeded: null,
        addEventListener() {},
        removeEventListener() {},
        dispatchEvent: () => true,
      } as unknown as IDBOpenDBRequest;
      queueMicrotask(() => {
        if (mode === "SUCCESS") {
          request.onsuccess?.(new Event("success"));
        } else {
          request.onblocked?.({
            oldVersion: 1,
            newVersion: null,
          } as IDBVersionChangeEvent);
        }
      });
      return request;
    },
    databases: async () => [],
  } as IDBFactory;
}

/**
 * A database the test drives by hand. The memory fake commits or aborts on its
 * own, so the three places the checkpoint store deliberately disagrees with the
 * other IndexedDB adapters — a commit that produced no value, a request error
 * that must abort, and an `abort()` that throws — are only observable here.
 *
 * The scope-binding transaction is driven automatically because no test below
 * is about it; only checkpoint transactions are handed to the test.
 */
type ScriptedRequest = {
  result: unknown;
  error: DOMException | null;
  onsuccess: ((event: Event) => unknown) | null;
  onerror: ((event: Event) => unknown) | null;
};

type ScriptedTransaction = {
  abortCalls: number;
  error: DOMException | null;
  oncomplete: ((event: Event) => unknown) | null;
  onerror: ((event: Event) => unknown) | null;
  onabort: ((event: Event) => unknown) | null;
  readonly requests: ScriptedRequest[];
  objectStore(name: string): IDBObjectStore;
  abort(): void;
  complete(): void;
};

function scriptedFactory(
  options: Readonly<{ abortThrows?: boolean }> = {},
): Readonly<{
  factory: IDBFactory;
  /** One entry per `database.transaction(...)` call, holding its argument count. */
  transactionArguments: number[];
  checkpoints: ScriptedTransaction[];
}> {
  const transactionArguments: number[] = [];
  const checkpoints: ScriptedTransaction[] = [];

  const scriptedRequest = (): ScriptedRequest => ({
    result: undefined,
    error: null,
    onsuccess: null,
    onerror: null,
  });

  const makeTransaction = (): ScriptedTransaction => {
    const requests: ScriptedRequest[] = [];
    const transaction: ScriptedTransaction = {
      abortCalls: 0,
      error: null,
      oncomplete: null,
      onerror: null,
      onabort: null,
      requests,
      objectStore: () => {
        const queue = () => {
          const request = scriptedRequest();
          requests.push(request);
          return request as unknown as IDBRequest;
        };
        return {
          get: queue,
          add: queue,
          put: queue,
          delete: queue,
        } as unknown as IDBObjectStore;
      },
      abort() {
        transaction.abortCalls += 1;
        if (options.abortThrows === true) {
          throw new DOMException("Transaction is finished.", "InvalidStateError");
        }
        transaction.error = new DOMException("Transaction aborted.", "AbortError");
        transaction.onerror?.(new Event("error"));
        transaction.onabort?.(new Event("abort"));
      },
      complete() {
        transaction.oncomplete?.(new Event("complete"));
      },
    };
    return transaction;
  };

  const database = {
    close() {},
    transaction: (...args: unknown[]) => {
      transactionArguments.push(args.length);
      const requested = args[0];
      const names =
        typeof requested === "string"
          ? [requested]
          : [...(requested as Iterable<string>)];
      const transaction = makeTransaction();
      if (names.includes("governance")) {
        queueMicrotask(() => {
          transaction.requests[0]?.onsuccess?.(new Event("success"));
          queueMicrotask(() => {
            transaction.requests[1]?.onsuccess?.(new Event("success"));
            queueMicrotask(() => {
              transaction.complete();
            });
          });
        });
      } else {
        checkpoints.push(transaction);
      }
      return transaction as unknown as IDBTransaction;
    },
  } as unknown as IDBDatabase;

  const factory = {
    open: () => {
      const request = {
        result: database,
        error: null,
        transaction: null,
        onsuccess: null,
        onerror: null,
        onblocked: null,
        onupgradeneeded: null,
      } as unknown as IDBOpenDBRequest;
      queueMicrotask(() => request.onsuccess?.(new Event("success")));
      return request;
    },
    cmp: () => 0,
    databases: async () => [],
  } as unknown as IDBFactory;

  return { factory, transactionArguments, checkpoints };
}

async function flushTasks(): Promise<void> {
  for (let tick = 0; tick < 5; tick += 1) {
    await new Promise<void>((resolve) => {
      setTimeout(resolve, 0);
    });
  }
}

async function openedCheckpointTransaction(
  scripted: ReturnType<typeof scriptedFactory>,
): Promise<ScriptedTransaction> {
  await flushTasks();
  const transaction = scripted.checkpoints[0];
  if (!transaction) throw new Error("no checkpoint transaction was opened");
  return transaction;
}

describe("IndexedDB resumable upload checkpoint", () => {
  it("length-prefixes scope tuples so delimiter placement cannot collide", () => {
    const first = uploadCheckpointDatabaseName({
      authorityToken: "aaaaaaaa-bbbbbbbb",
      namespaceToken: "cccccccc",
      partitionToken: "dddddddd",
    });
    const second = uploadCheckpointDatabaseName({
      authorityToken: "aaaaaaaa",
      namespaceToken: "bbbbbbbb-cccccccc",
      partitionToken: "dddddddd",
    });

    expect(first).not.toBe(second);
    expect(first).toContain("17:aaaaaaaa-bbbbbbbb");
    expect(second).toContain("8:aaaaaaaa");
  });

  it("commits CAS only at transaction completion and rejects stale revisions", async () => {
    const memory = new MemoryIndexedDbFactory();
    const store = createIndexedDbResumableUploadCheckpointStore({
      scope,
      factory: memory.factory,
    });
    const first = checkpoint(1);
    expect(
      await store.compareAndSwap({
        expectedRevision: null,
        checkpoint: first,
      }),
    ).toEqual({ ok: true, value: first });
    expect(await store.read(first.uploadKey)).toEqual({
      ok: true,
      value: first,
    });

    memory.failNextWriteCommit(
      new DOMException("commit failed", "UnknownError"),
    );
    const failed = await store.compareAndSwap({
      expectedRevision: 1,
      checkpoint: checkpoint(2, { state: "ABORT_PENDING" }),
    });
    expect(failed).toMatchObject({
      ok: false,
      error: { code: "UNAVAILABLE" },
    });
    expect(await store.read(first.uploadKey)).toEqual({
      ok: true,
      value: first,
    });

    expect(
      await store.compareAndSwap({
        expectedRevision: 2,
        checkpoint: checkpoint(3),
      }),
    ).toMatchObject({
      ok: false,
      error: { code: "CONFLICT", recovery: "RECONCILE" },
    });
  });

  it("rejects unknown persisted fields so URLs and credentials cannot enter a checkpoint", async () => {
    const memory = new MemoryIndexedDbFactory();
    const store = createIndexedDbResumableUploadCheckpointStore({
      scope,
      factory: memory.factory,
    });
    const smuggled = {
      ...checkpoint(1),
      signedUrl: "https://object.invalid/secret?signature=value",
    } as unknown as ResumableUploadCheckpoint;
    expect(
      await store.compareAndSwap({
        expectedRevision: null,
        checkpoint: smuggled,
      }),
    ).toMatchObject({
      ok: false,
      error: { code: "INVALID_INPUT" },
    });
    expect(await store.read("upload_key_01")).toEqual({
      ok: true,
      value: null,
    });
  });

  it("closes the bound partition before successful lifecycle deletion", async () => {
    const memory = new MemoryIndexedDbFactory();
    const runtime = createIndexedDbResumableUploadCheckpointRuntime({
      scope,
      factory: deletingFactory(memory, "SUCCESS"),
      blockedTimeoutMs: 10,
    });
    expect(
      await runtime.store.compareAndSwap({
        expectedRevision: null,
        checkpoint: checkpoint(1),
      }),
    ).toMatchObject({ ok: true });
    expect(await runtime.admin.deletePartition()).toEqual({
      ok: true,
      value: { state: "DELETED", effect: "APPLIED" },
    });
    expect(await runtime.store.read("upload_key_01")).toMatchObject({
      ok: false,
      error: { code: "UNAVAILABLE", recovery: "RESUME" },
    });
  });

  it("returns PENDING UNKNOWN when deleteDatabase is still blocked", async () => {
    const memory = new MemoryIndexedDbFactory();
    const factory = deletingFactory(memory, "BLOCKED");
    const runtime = createIndexedDbResumableUploadCheckpointRuntime({
      scope,
      factory,
      blockedTimeoutMs: 1,
    });
    // BT-UP-03. The native request is still live, so the deadline is not
    // evidence that nothing happened.
    expect(await runtime.admin.deletePartition()).toEqual({
      ok: true,
      value: {
        state: "PENDING",
        effect: "UNKNOWN",
        reason: "BLOCKED_DEADLINE",
      },
    });
  });

  it("keeps the checkpoint store closed until a pending delete is resolved externally", async () => {
    const memory = new MemoryIndexedDbFactory();
    const factory = deletingFactory(memory, "BLOCKED");
    const runtime = createIndexedDbResumableUploadCheckpointRuntime({
      scope,
      factory,
      blockedTimeoutMs: 1,
    });
    expect(await runtime.admin.deletePartition()).toMatchObject({
      ok: true,
      value: { state: "PENDING" },
    });

    // A second runtime over the same realm and database would race an unknown
    // native effect.
    expect(() =>
      createIndexedDbResumableUploadCheckpointRuntime({
        scope,
        factory,
        blockedTimeoutMs: 1,
      }),
    ).toThrow(TypeError);
  });

  it("never reports a false abort after irreversible deleteDatabase dispatch", async () => {
    const memory = new MemoryIndexedDbFactory();
    const runtime = createIndexedDbResumableUploadCheckpointRuntime({
      scope,
      factory: deletingFactory(memory, "SUCCESS"),
    });
    const controller = new AbortController();
    const deletion = runtime.admin.deletePartition(controller.signal);
    controller.abort();
    expect(await deletion).toEqual({
      ok: true,
      value: { state: "DELETED", effect: "APPLIED" },
    });

    const preAborted = new AbortController();
    preAborted.abort();
    const second = createIndexedDbResumableUploadCheckpointRuntime({
      scope: { ...scope, partitionToken: "partition_token_02" },
      factory: deletingFactory(new MemoryIndexedDbFactory(), "SUCCESS"),
    });
    expect(
      await second.admin.deletePartition(preAborted.signal),
    ).toMatchObject({
      ok: false,
      error: { code: "ABORTED" },
    });
  });

  // CP-1. Three IndexedDB adapters report a value-less commit as UNAVAILABLE;
  // this one reports CORRUPT_DATA/RECONCILE because a checkpoint read that
  // committed while producing nothing means the stored row could not be turned
  // into a checkpoint, and the caller has to reconcile rather than retry.
  it("reports a checkpoint commit that produced no value as CORRUPT_DATA", async () => {
    const scripted = scriptedFactory();
    const store = createIndexedDbResumableUploadCheckpointStore({
      scope,
      factory: scripted.factory,
    });
    const pending = store.read("upload_key_01");
    const transaction = await openedCheckpointTransaction(scripted);

    transaction.complete();

    expect(await pending).toMatchObject({
      ok: false,
      error: {
        code: "CORRUPT_DATA",
        operation: "UPLOAD_RECONCILE",
        recovery: "RECONCILE",
      },
    });
  });

  // CP-2. A third argument would be a `{durability}` options bag. An engine
  // that has never seen the bag treats it differently from no bag at all, so
  // checkpoint writes stay on whatever the engine defaults to.
  it("opens checkpoint transactions without a durability options bag", async () => {
    const scripted = scriptedFactory();
    const store = createIndexedDbResumableUploadCheckpointStore({
      scope,
      factory: scripted.factory,
    });
    const pending = store.read("upload_key_01");
    const transaction = await openedCheckpointTransaction(scripted);
    transaction.complete();
    await pending;

    expect(scripted.transactionArguments).toEqual([2, 2]);
  });

  // CP-3. Recording the error and letting the transaction run on would let
  // `compareAndSwap`'s put commit after its get had already failed.
  it("aborts the checkpoint transaction as soon as a request fails", async () => {
    const scripted = scriptedFactory();
    const store = createIndexedDbResumableUploadCheckpointStore({
      scope,
      factory: scripted.factory,
    });
    const pending = store.read("upload_key_01");
    const transaction = await openedCheckpointTransaction(scripted);
    const read = transaction.requests[0];
    if (!read) throw new Error("the checkpoint read queued no request");

    read.error = new DOMException("disk is unreadable", "NotReadableError");
    read.onerror?.(new Event("error"));

    expect(transaction.abortCalls).toBe(1);
    expect(await pending).toMatchObject({
      ok: false,
      error: { code: "NOT_READABLE", retryable: true, recovery: "REOPEN" },
    });
  });

  // CP-4. The transaction can already be durably committed while its completion
  // event is still queued, which is when `abort()` throws. Claiming the abort
  // would report a committed checkpoint as ABORTED.
  it("keeps a committed checkpoint when the abort call itself throws", async () => {
    const scripted = scriptedFactory({ abortThrows: true });
    const store = createIndexedDbResumableUploadCheckpointStore({
      scope,
      factory: scripted.factory,
    });
    const controller = new AbortController();
    const stored = checkpoint(1);
    const pending = store.read(stored.uploadKey, controller.signal);
    const transaction = await openedCheckpointTransaction(scripted);
    const read = transaction.requests[0];
    if (!read) throw new Error("the checkpoint read queued no request");

    read.result = stored;
    read.onsuccess?.(new Event("success"));
    controller.abort();
    expect(transaction.abortCalls).toBe(1);
    transaction.complete();

    expect(await pending).toEqual({ ok: true, value: stored });
  });

  // CP-5. The blocked deadline is the only bound on an open that another
  // context is holding up, so it has to fire from the scheduler the store was
  // built with rather than leave the read pending forever.
  it("bounds a blocked open with the configured deadline", async () => {
    const memory = new MemoryIndexedDbFactory();
    const store = createIndexedDbResumableUploadCheckpointStore({
      scope,
      factory: memory.factory,
      blockedTimeoutMs: 1,
    });
    memory.blockNextOpen();

    expect(await store.read("upload_key_01")).toMatchObject({
      ok: false,
      error: { code: "BLOCKED", retryable: true, recovery: "RESUME" },
    });
  });
});