// @vitest-environment jsdom

import {
  act,
  renderHook,
  waitFor,
} from "@testing-library/react";
import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
import type { ReactNode } from "react";
import { describe, expect, it, vi } from "vitest";

import {
  type ApplicationResult,
  useApplicationMutation,
  useApplicationQuery,
} from "../../src/presentation/adapters/query/application-query.ts";
import type { MutationIntentFactory } from "../../src/application/ports/mutation-intent-factory.ts";
import { MutationIntentProvider } from "../../src/presentation/adapters/query/mutation-intent-provider.tsx";
import { QueryInvalidationProvider } from "../../src/presentation/adapters/query/query-invalidation-provider.tsx";
import {
  defineQueryInvalidationTopic,
  type QueryInvalidationCoordinator,
} from "../../src/contracts/query-invalidation.ts";
import { createFailure } from "../../src/contracts/errors.ts";
import {
  createQueryInvalidationPrefix,
  createRuntimeIdentityRegistry,
  defineQueryNamespaceIdentity,
} from "../../src/contracts/query-keys.ts";
import {
  bindQuery,
  type QueryResultMeasure,
} from "../../src/contracts/server-state.ts";
import type { CacheScopeSnapshot } from "../../src/contracts/server-state-scope.ts";

const RESOURCE_INVALIDATION_TOPIC =
  defineQueryInvalidationTopic("resource");

/**
 * §24.12: the scope-bound commit fence is common runtime, so it is verified
 * here with a local scope fixture rather than through the removable sample
 * feature.
 */
function scopeSnapshot(): CacheScopeSnapshot & { fence(): void } {
  let current = true;
  const lifetime = new AbortController();
  const identities = createRuntimeIdentityRegistry({
    tokenFactory: () => "scope-identity-token-0001",
  });
  return {
    generation: 1,
    fingerprint: "scope-fingerprint-0001",
    identities,
    signal: lifetime.signal,
    isCurrent: () => current,
    fence() {
      current = false;
      lifetime.abort();
    },
  };
}

function measureOne(): QueryResultMeasure {
  return { itemCount: 1, estimatedBytes: 8 };
}

function queryClient() {
  return new QueryClient({
    defaultOptions: {
      queries: { retry: false, staleTime: 0, gcTime: Infinity },
      mutations: { retry: false },
    },
  });
}

function deterministicMutationIntentFactory(): MutationIntentFactory {
  let sequence = 0;
  return Object.freeze({
    create(input) {
      sequence += 1;
      return Object.freeze({
        intentId: `intent-${sequence}`,
        operationId: input.operationId,
        canonicalInputIdentity: input.canonicalInputIdentity,
        ...(input.requiresIdempotencyKey
          ? { idempotencyKey: `key-${sequence}` }
          : {}),
        createdAtMonotonicMs: sequence,
      });
    },
  });
}

function wrapper(
  client: QueryClient,
  mutationIntentFactory = deterministicMutationIntentFactory(),
) {
  const coordinator: QueryInvalidationCoordinator = {
    async invalidate(topics) {
      for (const topic of topics) {
        await client.invalidateQueries({
          queryKey: [topic],
          exact: false,
          refetchType: "active",
        });
      }
    },
    beginMutation() {
      return { release: async () => {} };
    },
    async resetLocal() {
      await client.cancelQueries();
      client.clear();
    },
    dispose() {},
  };
  return function QueryWrapper({ children }: { children: ReactNode }) {
    return (
      <MutationIntentProvider factory={mutationIntentFactory}>
        <QueryClientProvider client={client}>
          <QueryInvalidationProvider coordinator={coordinator}>
            {children}
          </QueryInvalidationProvider>
        </QueryClientProvider>
      </MutationIntentProvider>
    );
  };
}

describe("application query inbound bridge", () => {
  it("latches a background failure over stale data and clears it on retry success", async () => {
    const client = queryClient();
    const responses: ApplicationResult<string[]>[] = [
      { ok: true, value: ["first"] },
      {
        ok: false,
        error: createFailure("SERVER_FAILURE", "LIST", 0),
      },
      { ok: true, value: ["recovered"] },
    ];
    const execute = vi.fn(async () => responses.shift() ?? responses[0]);
    const hook = renderHook(
      () =>
        useApplicationQuery({
          queryKey: ["resource", "list"],
          execute,
        }),
      { wrapper: wrapper(client) },
    );

    await waitFor(() => expect(hook.result.current.data).toEqual(["first"]));
    await act(() => hook.result.current.retry());
    await waitFor(() =>
      expect(hook.result.current.state.indicator).toBe("stale-degraded"),
    );
    expect(hook.result.current.state.base).toBe("success");
    expect(hook.result.current.data).toEqual(["first"]);

    await act(() => hook.result.current.retry());
    await waitFor(() =>
      expect(hook.result.current.data).toEqual(["recovered"]),
    );
    expect(hook.result.current.state.indicator).toBeNull();
    expect(execute).toHaveBeenCalledTimes(3);
  });

  it("projects an initial application failure into terminal state", async () => {
    const client = queryClient();
    const failure = createFailure("FORBIDDEN", "LIST", 0);
    const hook = renderHook(
      () =>
        useApplicationQuery({
          queryKey: ["forbidden"],
          execute: async () => ({ ok: false, error: failure }),
        }),
      { wrapper: wrapper(client) },
    );

    await waitFor(() =>
      expect(hook.result.current.state.base).toBe("terminal-error"),
    );
    expect(hook.result.current.state.failure).toBe(failure);
  });

  it("normalizes an unexpected execute rejection into a safe terminal failure", async () => {
    const client = queryClient();
    const hook = renderHook(
      () =>
        useApplicationQuery({
          queryKey: ["unexpected-rejection"],
          execute: async () => {
            throw new Error("private upstream detail");
          },
        }),
      { wrapper: wrapper(client) },
    );

    await waitFor(() =>
      expect(hook.result.current.state.base).toBe("terminal-error"),
    );
    expect(hook.result.current.state.failure).toMatchObject({
      kind: "UNKNOWN_FAILURE",
      operationId: "APPLICATION_QUERY",
      userMessageKey: "error.unknown_failure",
      action: "contact-support",
    });
    expect(JSON.stringify(hook.result.current.state.failure)).not.toContain(
      "private upstream detail",
    );
  });

  it("passes cancellation to the application and does not retain an unmounted error", async () => {
    const client = queryClient();
    let aborted = false;
    const execute = vi.fn(
      ({ signal }: { signal: AbortSignal }) =>
        new Promise<ApplicationResult<unknown>>((resolve) => {
          signal.addEventListener(
            "abort",
            () => {
              aborted = true;
              resolve({
                ok: false,
                error: createFailure("REQUEST_ABORTED", "LIST", 0),
              });
            },
            { once: true },
          );
        }),
    );
    const hook = renderHook(
      () =>
        useApplicationQuery({
          queryKey: ["cancelled"],
          execute,
        }),
      { wrapper: wrapper(client) },
    );

    await waitFor(() => expect(execute).toHaveBeenCalledOnce());
    hook.unmount();
    await waitFor(() => expect(aborted).toBe(true));
    expect(client.getQueryState(["cancelled"])?.status).not.toBe("error");
  });
});

describe("scope-bound query commit fence", () => {
  it("binds the namespace-first V2 query key", () => {
    const scope = scopeSnapshot();
    const definition = {
      definitionId: "resource-detail-v1",
      definitionVersion: 1,
      owner: "platform-test",
      namespace: "resource",
      namespaceVersion: 1,
      operationId: "GET_RESOURCE",
      profileId: "DETAIL_STANDARD" as const,
      measureResult: measureOne,
      execute: async () => ({ ok: true as const, value: "value" }),
    };

    const bound = bindQuery(definition, "resource-1", scope);

    expect(bound.queryKey).toEqual([
      "query",
      2,
      "resource",
      1,
      "scope-fingerprint-0001",
      1,
      "scope-identity-token-0001",
    ]);
    expect(bound.queryKey.slice(0, 4)).toEqual(
      createQueryInvalidationPrefix(
        defineQueryNamespaceIdentity("resource", 1),
      ),
    );
  });

  it("discards a successful result whose scope was fenced during execution", async () => {
    const client = queryClient();
    const scope = scopeSnapshot();
    let complete: (value: ApplicationResult<string>) => void = () => {};
    const hook = renderHook(
      () =>
        useApplicationQuery(
          bindQuery(
            {
              definitionId: "fenced-detail-v1",
              definitionVersion: 1,
              owner: "platform-test",
              namespace: "fenced",
              namespaceVersion: 1,
              operationId: "GET_FENCED",
              profileId: "DETAIL_STANDARD",
              measureResult: measureOne,
              execute: () =>
                new Promise<ApplicationResult<string>>((resolve) => {
                  complete = resolve;
                }),
            },
            "input",
            scope,
          ),
        ),
      { wrapper: wrapper(client) },
    );

    // §10.8: the scope goes stale after dispatch but before commit.
    scope.fence();
    await act(async () => {
      complete({ ok: true, value: "late" });
    });

    await waitFor(() =>
      expect(hook.result.current.state.failure?.kind).toBe(
        "SCOPE_GENERATION_CHANGED",
      ),
    );
    expect(hook.result.current.data).toBeUndefined();
  });

  it("refuses to start when the captured scope is already stale", async () => {
    const client = queryClient();
    const scope = scopeSnapshot();
    const execute = vi.fn(async () => ({ ok: true as const, value: "v" }));
    scope.fence();

    const hook = renderHook(
      () =>
        useApplicationQuery(
          bindQuery(
            {
              definitionId: "stale-detail-v1",
              definitionVersion: 1,
              owner: "platform-test",
              namespace: "stale",
              namespaceVersion: 1,
              operationId: "GET_STALE",
              profileId: "DETAIL_STANDARD",
              measureResult: measureOne,
              execute,
            },
            "input",
            scope,
          ),
        ),
      { wrapper: wrapper(client) },
    );

    await waitFor(() =>
      expect(hook.result.current.state.failure?.kind).toBe(
        "SCOPE_GENERATION_CHANGED",
      ),
    );
    expect(execute).not.toHaveBeenCalled();
  });

  it("rejects a result that exceeds the profile budget instead of caching it", async () => {
    const client = queryClient();
    const scope = scopeSnapshot();
    const hook = renderHook(
      () =>
        useApplicationQuery(
          bindQuery(
            {
              definitionId: "oversized-list-v1",
              definitionVersion: 1,
              owner: "platform-test",
              namespace: "oversized",
              namespaceVersion: 1,
              operationId: "LIST_OVERSIZED",
              profileId: "VOLATILE_STATUS",
              // §10.4: VOLATILE_STATUS admits 1 item and 64KiB.
              measureResult: (): QueryResultMeasure => ({
                itemCount: 2,
                estimatedBytes: 8,
              }),
              execute: async () => ({ ok: true as const, value: "value" }),
            },
            "input",
            scope,
          ),
        ),
      { wrapper: wrapper(client) },
    );

    await waitFor(() =>
      expect(hook.result.current.state.failure?.kind).toBe(
        "RESULT_LIMIT_EXCEEDED",
      ),
    );
    expect(hook.result.current.data).toBeUndefined();
  });

  it("treats a throwing measurement as a measurement failure, not a cache commit", async () => {
    const client = queryClient();
    const scope = scopeSnapshot();
    const hook = renderHook(
      () =>
        useApplicationQuery(
          bindQuery(
            {
              definitionId: "unmeasurable-v1",
              definitionVersion: 1,
              owner: "platform-test",
              namespace: "unmeasurable",
              namespaceVersion: 1,
              operationId: "GET_UNMEASURABLE",
              profileId: "DETAIL_STANDARD",
              measureResult: (): QueryResultMeasure => {
                throw new Error("estimator defect");
              },
              execute: async () => ({ ok: true as const, value: "value" }),
            },
            "input",
            scope,
          ),
        ),
      { wrapper: wrapper(client) },
    );

    await waitFor(() =>
      expect(hook.result.current.state.failure?.kind).toBe(
        "RESULT_LIMIT_EXCEEDED",
      ),
    );
    expect(hook.result.current.data).toBeUndefined();
  });
});

describe("scope-bound mutation fence", () => {
  it("rejects a submit whose scope is already fenced", async () => {
    const client = queryClient();
    const scope = scopeSnapshot();
    const execute = vi.fn(async () => ({ ok: true as const, value: "v" }));
    const hook = renderHook(
      () =>
        useApplicationMutation<string, string>({
          definitionId: "fenced-mutation-v1",
          definitionVersion: 1,
          operationId: "CREATE_FENCED",
          requiresIdempotencyKey: false,
          owner: "platform-test",
          duplicatePolicy: "REJECT_WHILE_ACTIVE",
          scope,
          execute,
          invalidate: [],
        }),
      { wrapper: wrapper(client) },
    );

    scope.fence();
    const outcome = await hook.result.current.submit("value");
    expect(outcome).toMatchObject({
      ok: false,
      error: { kind: "SCOPE_GENERATION_CHANGED" },
    });
    expect(execute).not.toHaveBeenCalled();
  });

  it("discards a mutation result whose scope was fenced after dispatch", async () => {
    const client = queryClient();
    const scope = scopeSnapshot();
    const execute = vi.fn(async () => {
      scope.fence();
      return { ok: true as const, value: "committed" };
    });
    const hook = renderHook(
      () =>
        useApplicationMutation<string, string>({
          definitionId: "late-mutation-v1",
          definitionVersion: 1,
          operationId: "CREATE_LATE",
          requiresIdempotencyKey: false,
          owner: "platform-test",
          duplicatePolicy: "ALLOW_PARALLEL",
          scope,
          execute,
          invalidate: [],
        }),
      { wrapper: wrapper(client) },
    );

    const outcome = await hook.result.current.submit("value");
    expect(outcome).toMatchObject({
      ok: false,
      error: { kind: "SCOPE_GENERATION_CHANGED" },
    });
    expect(execute).toHaveBeenCalledOnce();
  });

  it("aborts a hung mutation when its captured scope is fenced", async () => {
    const client = queryClient();
    const scope = scopeSnapshot();
    let observedSignal: AbortSignal | undefined;
    const execute = vi.fn(
      (_input: string, context: Readonly<{ signal: AbortSignal }>) =>
        new Promise<ApplicationResult<string>>((resolve) => {
          observedSignal = context.signal;
          context.signal.addEventListener(
            "abort",
            () =>
              resolve({
                ok: false,
                error: createFailure("REQUEST_ABORTED", "CREATE_HUNG", 0),
              }),
            { once: true },
          );
        }),
    );
    const hook = renderHook(
      () =>
        useApplicationMutation<string, string>({
          definitionId: "hung-mutation-v1",
          definitionVersion: 1,
          operationId: "CREATE_HUNG",
          requiresIdempotencyKey: false,
          owner: "platform-test",
          duplicatePolicy: "REJECT_WHILE_ACTIVE",
          scope,
          execute,
          invalidate: [],
        }),
      { wrapper: wrapper(client) },
    );

    const outcome = hook.result.current.submit("value");
    await waitFor(() => expect(observedSignal).toBe(scope.signal));

    scope.fence();

    expect(observedSignal?.aborted).toBe(true);
    await expect(outcome).resolves.toMatchObject({
      ok: false,
      error: {
        kind: "SCOPE_GENERATION_CHANGED",
        effect: "MAYBE_APPLIED",
        retryable: false,
        action: "contact-support",
      },
    });
  });
});

describe("application mutation inbound bridge", () => {
  it("creates a distinct logical intent for each independently admitted submit", async () => {
    const client = queryClient();
    const scope = scopeSnapshot();
    const observedIntents: unknown[] = [];
    const execute = vi.fn(
      async (
        input: string,
        context: Readonly<{ signal: AbortSignal; intent?: unknown }>,
      ) => {
        observedIntents.push(context.intent);
        return { ok: true as const, value: input };
      },
    );
    const hook = renderHook(
      () =>
        useApplicationMutation<string, string>({
          definitionId: "independent-intent-v1",
          definitionVersion: 1,
          operationId: "CREATE_WITH_INTENT",
          requiresIdempotencyKey: true,
          owner: "platform-test",
          duplicatePolicy: "ALLOW_PARALLEL",
          scope,
          execute,
          invalidate: [],
        }),
      { wrapper: wrapper(client) },
    );

    await act(async () => {
      await hook.result.current.submit("same-input");
      await hook.result.current.submit("same-input");
    });

    expect(observedIntents).toHaveLength(2);
    expect(observedIntents[0]).toMatchObject({
      intentId: "intent-1",
      operationId: "CREATE_WITH_INTENT",
      idempotencyKey: "key-1",
    });
    expect(observedIntents[1]).toMatchObject({
      intentId: "intent-2",
      operationId: "CREATE_WITH_INTENT",
      idempotencyKey: "key-2",
    });
    expect(observedIntents[0]).not.toEqual(observedIntents[1]);
  });

  it("creates no second intent when JOIN_IDENTICAL shares an admitted submit", async () => {
    const client = queryClient();
    const scope = scopeSnapshot();
    const deterministicFactory = deterministicMutationIntentFactory();
    const createIntent = vi.fn(deterministicFactory.create);
    const factory: MutationIntentFactory = Object.freeze({
      create: createIntent,
    });
    let complete: (value: ApplicationResult<string>) => void = () => {};
    const execute = vi.fn(
      () =>
        new Promise<ApplicationResult<string>>((resolve) => {
          complete = resolve;
        }),
    );
    const hook = renderHook(
      () =>
        useApplicationMutation<string, string>({
          definitionId: "joined-intent-v1",
          definitionVersion: 1,
          operationId: "CREATE_JOINED",
          requiresIdempotencyKey: true,
          owner: "platform-test",
          duplicatePolicy: "JOIN_IDENTICAL",
          scope,
          execute,
          invalidate: [],
        }),
      { wrapper: wrapper(client, factory) },
    );

    let first: Promise<ApplicationResult<string>> | null = null;
    let joined: Promise<ApplicationResult<string>> | null = null;
    act(() => {
      first = hook.result.current.submit("same-input");
      joined = hook.result.current.submit("same-input");
    });

    expect(first).toBe(joined);
    await waitFor(() => expect(execute).toHaveBeenCalledOnce());
    expect(createIntent).toHaveBeenCalledOnce();
    expect(createIntent).toHaveBeenCalledWith({
      operationId: "CREATE_JOINED",
      canonicalInputIdentity:
        "scope-fingerprint-0001:joined-intent-v1:scope-identity-token-0001",
      requiresIdempotencyKey: true,
    });

    complete({ ok: true, value: "same-input" });
    if (!first) throw new Error("expected admitted mutation");
    await act(() => first);
  });

  it("keeps the legacy raw mutation path outside the intent factory", async () => {
    const client = queryClient();
    const createIntent = vi.fn<MutationIntentFactory["create"]>();
    const factory: MutationIntentFactory = Object.freeze({
      create: createIntent,
    });
    const execute = vi.fn(async (input: string) => ({
      ok: true as const,
      value: input,
    }));
    const hook = renderHook(
      () => useApplicationMutation<string, string>({ execute }),
      { wrapper: wrapper(client, factory) },
    );

    await act(() => hook.result.current.submit("legacy-input"));

    expect(execute).toHaveBeenCalledOnce();
    expect(createIntent).not.toHaveBeenCalled();
  });

  it("rejects a duplicate submit by default while one is active", async () => {
    const client = queryClient();
    let complete: (value: ApplicationResult<string>) => void = () => {};
    const execute = vi.fn(
      () =>
        new Promise<ApplicationResult<string>>((resolve) => {
          complete = resolve;
        }),
    );
    const hook = renderHook(
      () => useApplicationMutation<string, string>({ execute }),
      { wrapper: wrapper(client) },
    );

    let first: Promise<ApplicationResult<string>> | null = null;
    let duplicate: Promise<ApplicationResult<string>> | null = null;
    act(() => {
      first = hook.result.current.submit("created");
      duplicate = hook.result.current.submit("created");
    });

    if (!first || !duplicate) throw new Error("expected two submissions");
    await expect(duplicate).resolves.toMatchObject({
      ok: false,
      error: { kind: "DUPLICATE_IN_FLIGHT" },
    });
    expect(execute).toHaveBeenCalledOnce();

    complete({ ok: true, value: "created" });
    await act(() => first as Promise<ApplicationResult<string>>);
  });

  it("deduplicates submit and commits one optimistic mutation", async () => {
    const client = queryClient();
    const key = ["resource", "list"];
    client.setQueryData(key, ["existing"]);
    let complete: (value: ApplicationResult<string>) => void = () => {};
    const execute = vi.fn(
      () =>
        new Promise<ApplicationResult<string>>((resolve) => {
          complete = resolve;
        }),
    );
    const hook = renderHook(
      () =>
        useApplicationMutation<string, string>({
          // §11.2: joining is opt-in. The default is REJECT_WHILE_ACTIVE.
          duplicatePolicy: "JOIN_IDENTICAL",
          execute,
          invalidate: [RESOURCE_INVALIDATION_TOPIC],
          currentData: client.getQueryData(key),
          optimistic: {
            queryKey: key,
            update: (previous, input) => [
              ...(previous as string[]),
              input,
            ],
          },
        }),
      { wrapper: wrapper(client) },
    );

    let first: Promise<ApplicationResult<string>> | null = null;
    let duplicate: Promise<ApplicationResult<string>> | null = null;
    act(() => {
      first = hook.result.current.submit("created");
      duplicate = hook.result.current.submit("created");
    });
    expect(first).toBe(duplicate);
    await waitFor(() =>
      expect(client.getQueryData(key)).toEqual(["existing", "created"]),
    );
    await waitFor(() => expect(execute).toHaveBeenCalledOnce());
    await waitFor(() =>
      expect(hook.result.current.state.indicator).toBe("mutation-pending"),
    );

    complete({ ok: true, value: "created" });
    if (!first) throw new Error("expected pending mutation");
    await act(() => first);
    expect(client.getQueryState(key)?.isInvalidated).toBe(true);
    await waitFor(() =>
      expect(hook.result.current.state.indicator).toBeNull(),
    );
  });

  it("never joins distinct mutation inputs to the same runtime promise", async () => {
    const client = queryClient();
    const resolvers = new Map<
      string,
      (value: ApplicationResult<string>) => void
    >();
    const execute = vi.fn(
      (input: string) =>
        new Promise<ApplicationResult<string>>((resolve) => {
          resolvers.set(input, resolve);
        }),
    );
    const hook = renderHook(
      () =>
        useApplicationMutation<string, string>({
          execute,
          currentData: true,
        }),
      { wrapper: wrapper(client) },
    );

    let first: Promise<ApplicationResult<string>> | undefined;
    let second: Promise<ApplicationResult<string>> | undefined;
    act(() => {
      first = hook.result.current.submit("first");
      second = hook.result.current.submit("second");
    });
    expect(first).not.toBe(second);
    await waitFor(() => expect(execute).toHaveBeenCalledTimes(2));

    resolvers.get("first")?.({ ok: true, value: "first" });
    resolvers.get("second")?.({ ok: true, value: "second" });
    if (!first || !second) throw new Error("expected pending mutations");
    await act(async () => {
      await Promise.all([first, second]);
    });
  });

  it("cancels an in-flight query before taking the optimistic snapshot", async () => {
    const client = queryClient();
    const key = ["resource", "ordered-update"];
    client.setQueryData(key, ["existing"]);
    let finishCancellation: () => void = () => {};
    const cancellation = new Promise<void>((resolve) => {
      finishCancellation = resolve;
    });
    const cancelQueries = vi
      .spyOn(client, "cancelQueries")
      .mockImplementation(async () => cancellation);
    const getQueryData = vi.spyOn(client, "getQueryData");
    const update = vi.fn((previous, input) => [
      ...(previous as string[]),
      input,
    ]);
    const execute = vi.fn(async () => ({
      ok: true as const,
      value: "created",
    }));
    const hook = renderHook(
      () =>
        useApplicationMutation<string, string>({
          execute,
          currentData: ["existing"],
          optimistic: { queryKey: key, update },
        }),
      { wrapper: wrapper(client) },
    );

    let pending: Promise<ApplicationResult<string>> | undefined;
    act(() => {
      pending = hook.result.current.submit("created");
    });
    expect(cancelQueries).toHaveBeenCalledWith({
      queryKey: key,
      exact: true,
    });
    expect(getQueryData).not.toHaveBeenCalled();
    expect(update).not.toHaveBeenCalled();
    expect(execute).not.toHaveBeenCalled();

    finishCancellation();
    if (!pending) throw new Error("expected pending mutation");
    await act(() => pending);

    expect(getQueryData).toHaveBeenCalledWith(key);
    expect(update).toHaveBeenCalledWith(["existing"], "created");
    expect(execute).toHaveBeenCalledOnce();
    expect(client.getQueryData(key)).toEqual(["existing", "created"]);
  });

  it("keeps a committed optimistic update when invalidation fails", async () => {
    const client = queryClient();
    const key = ["resource", "committed-update"];
    client.setQueryData(key, ["existing"]);
    vi.spyOn(client, "invalidateQueries").mockRejectedValue(
      new Error("cache refresh failed"),
    );
    const hook = renderHook(
      () =>
        useApplicationMutation<string, string>({
          execute: async () => ({ ok: true, value: "created" }),
          invalidate: [RESOURCE_INVALIDATION_TOPIC],
          currentData: ["existing"],
          optimistic: {
            queryKey: key,
            update: (previous, input) => [
              ...(previous as string[]),
              input,
            ],
          },
        }),
      { wrapper: wrapper(client) },
    );

    let outcome;
    await act(async () => {
      outcome = await hook.result.current.submit("created");
    });

    expect(outcome).toEqual({ ok: true, value: "created" });
    expect(client.getQueryData(key)).toEqual(["existing", "created"]);
  });

  it("normalizes an optimistic preparation defect without running the command", async () => {
    const client = queryClient();
    const key = ["resource", "invalid-optimistic-update"];
    client.setQueryData(key, ["existing"]);
    const execute = vi.fn(async () => ({
      ok: true as const,
      value: "created",
    }));
    const hook = renderHook(
      () =>
        useApplicationMutation<string, string>({
          execute,
          currentData: ["existing"],
          optimistic: {
            queryKey: key,
            update: () => {
              throw new Error("private optimistic detail");
            },
          },
        }),
      { wrapper: wrapper(client) },
    );

    let outcome;
    await act(async () => {
      outcome = await hook.result.current.submit("created");
    });

    expect(outcome).toMatchObject({
      ok: false,
      error: {
        kind: "UNKNOWN_FAILURE",
        operationId: "APPLICATION_MUTATION",
        userMessageKey: "error.unknown_failure",
      },
    });
    expect(JSON.stringify(outcome)).not.toContain("private optimistic detail");
    expect(execute).not.toHaveBeenCalled();
    expect(client.getQueryData(key)).toEqual(["existing"]);
  });

  it("removes an optimistic cache entry when no prior data existed", async () => {
    const client = queryClient();
    const key = ["resource", "new-optimistic-entry"];
    const failure = createFailure("SERVER_FAILURE", "CREATE", 0);
    const hook = renderHook(
      () =>
        useApplicationMutation<string, string>({
          execute: async () => ({ ok: false, error: failure }),
          currentData: true,
          optimistic: {
            queryKey: key,
            update: (_previous, input) => [input],
          },
        }),
      { wrapper: wrapper(client) },
    );

    let outcome;
    await act(async () => {
      outcome = await hook.result.current.submit("temporary");
    });

    expect(outcome).toEqual({ ok: false, error: failure });
    expect(client.getQueryData(key)).toBeUndefined();
    expect(client.getQueryState(key)).toBeUndefined();
  });

  it("rolls optimistic data back and exposes a resolvable conflict", async () => {
    const client = queryClient();
    const key = ["resource", "list"];
    client.setQueryData(key, ["existing"]);
    const conflict = createFailure("CONFLICT", "CREATE", 0);
    const hook = renderHook(
      () =>
        useApplicationMutation<string, string>({
          execute: async () => ({ ok: false, error: conflict }),
          invalidate: [RESOURCE_INVALIDATION_TOPIC],
          currentData: client.getQueryData(key),
          optimistic: {
            queryKey: key,
            update: (previous, input) => [
              ...(previous as string[]),
              input,
            ],
          },
        }),
      { wrapper: wrapper(client) },
    );

    let outcome;
    await act(async () => {
      outcome = await hook.result.current.submit("conflicting");
    });
    expect(outcome).toEqual({ ok: false, error: conflict });
    expect(client.getQueryData(key)).toEqual(["existing"]);
    expect(hook.result.current.state.indicator).toBe("mutation-conflict");
    expect(hook.result.current.state.overlay).toMatchObject({
      mutationPending: false,
      mutationConflict: true,
    });

    await act(() => hook.result.current.resolveConflict());
    expect(hook.result.current.state.indicator).toBeNull();
    expect(client.getQueryState(key)?.isInvalidated).toBe(true);
  });
});