import {  PreviewAutomationControlInterruptedError,  PreviewAutomationExecutionError,  PreviewAutomationInvalidSelectorError,  PreviewAutomationNoFocusedOwnerError,  PreviewAutomationResultTooLargeError,  PreviewAutomationTabNotFoundError,  PreviewAutomationTimeoutError,  PreviewAutomationUnavailableError,  PreviewAutomationUnsupportedClientError,  type PreviewAutomationError,  type PreviewAutomationOperation,  type PreviewAutomationOwner,  type PreviewAutomationRequest,  type PreviewAutomationResponse,  type PreviewTabId,} from "@t3tools/contracts";import * as Context from "effect/Context";import * as Deferred from "effect/Deferred";import * as Effect from "effect/Effect";import * as Layer from "effect/Layer";import * as Option from "effect/Option";import * as Queue from "effect/Queue";import * as Stream from "effect/Stream";import * as SynchronizedRef from "effect/SynchronizedRef"; import * as McpInvocationContext from "./McpInvocationContext.ts"; export interface PreviewAutomationInvokeInput {  readonly scope: McpInvocationContext.McpInvocationScope;  readonly operation: PreviewAutomationOperation;  readonly input: unknown;  readonly tabId?: PreviewTabId;  readonly timeoutMs?: number;} export interface PreviewAutomationBrokerShape {  readonly connect: (clientId: string) => Effect.Effect<Stream.Stream<PreviewAutomationRequest>>;  readonly reportOwner: (    owner: PreviewAutomationOwner,  ) => Effect.Effect<void, PreviewAutomationError>;  readonly clearOwner: (clientId: string) => Effect.Effect<void>;  readonly respond: (    response: PreviewAutomationResponse,  ) => Effect.Effect<void, PreviewAutomationError>;  readonly invoke: <A = unknown>(    request: PreviewAutomationInvokeInput,  ) => Effect.Effect<A, PreviewAutomationError>;} export class PreviewAutomationBroker extends Context.Service<  PreviewAutomationBroker,  PreviewAutomationBrokerShape>()("t3/mcp/PreviewAutomationBroker") {} interface ClientConnection {  readonly clientId: string;  readonly queue: Queue.Queue<    Parameters<PreviewAutomationBrokerShape["respond"]>[0] extends never      ? never      : import("@t3tools/contracts").PreviewAutomationRequest  >;} interface PendingRequest {  readonly clientId: string;  readonly deferred: Deferred.Deferred<unknown, PreviewAutomationError>;} interface BrokerState {  readonly clients: ReadonlyMap<string, ClientConnection>;  readonly owners: ReadonlyMap<string, PreviewAutomationOwner>;  readonly pending: ReadonlyMap<string, PendingRequest>;  readonly requestSequence: number;} const makeResponseError = (  error: NonNullable<PreviewAutomationResponse["error"]>,): PreviewAutomationError => {  switch (error._tag) {    case "PreviewAutomationNoFocusedOwnerError":      return new PreviewAutomationNoFocusedOwnerError({ message: error.message });    case "PreviewAutomationUnsupportedClientError":      return new PreviewAutomationUnsupportedClientError({ message: error.message });    case "PreviewAutomationTabNotFoundError":      return new PreviewAutomationTabNotFoundError({ message: error.message });    case "PreviewAutomationTimeoutError":      return new PreviewAutomationTimeoutError({ message: error.message });    case "PreviewAutomationControlInterruptedError":      return new PreviewAutomationControlInterruptedError({ message: error.message });    case "PreviewAutomationInvalidSelectorError": {      const detail =        typeof error.detail === "object" && error.detail !== null ? error.detail : undefined;      return new PreviewAutomationInvalidSelectorError({        message: error.message,        selector:          detail && "selector" in detail && typeof detail.selector === "string"            ? detail.selector            : "",      });    }    case "PreviewAutomationResultTooLargeError": {      const detail =        typeof error.detail === "object" && error.detail !== null ? error.detail : undefined;      return new PreviewAutomationResultTooLargeError({        message: error.message,        maximumBytes:          detail && "maximumBytes" in detail && typeof detail.maximumBytes === "number"            ? detail.maximumBytes            : 64_000,      });    }    case "PreviewAutomationUnavailableError":      return new PreviewAutomationUnavailableError({ message: error.message });    default:      return new PreviewAutomationExecutionError({        message: error.message,        detail: error.detail,      });  }}; const make = Effect.gen(function* PreviewAutomationBrokerMake() {  const state = yield* SynchronizedRef.make<BrokerState>({    clients: new Map(),    owners: new Map(),    pending: new Map(),    requestSequence: 0,  });   const disconnect = Effect.fn("PreviewAutomationBroker.disconnect")(function* (    clientId: string,    queue: ClientConnection["queue"],  ) {    const toFail = yield* SynchronizedRef.modify(state, (current) => {      if (current.clients.get(clientId)?.queue !== queue) {        return [[] as ReadonlyArray<PendingRequest>, current] as const;      }      const clients = new Map(current.clients);      const owners = new Map(current.owners);      const pending = new Map(current.pending);      const disconnected: PendingRequest[] = [];      clients.delete(clientId);      owners.delete(clientId);      for (const [requestId, entry] of pending) {        if (entry.clientId === clientId) {          pending.delete(requestId);          disconnected.push(entry);        }      }      return [disconnected, { ...current, clients, owners, pending }] as const;    });    yield* Effect.forEach(      toFail,      ({ deferred }) =>        Deferred.fail(          deferred,          new PreviewAutomationUnavailableError({            message: "The preview automation client disconnected.",          }),        ),      { discard: true },    );    yield* Queue.shutdown(queue);  });   const connect: PreviewAutomationBrokerShape["connect"] = Effect.fn(    "PreviewAutomationBroker.connect",  )(function* (clientId) {    const queue = yield* Queue.unbounded<import("@t3tools/contracts").PreviewAutomationRequest>();    const previous = yield* SynchronizedRef.modify(state, (current) => {      const clients = new Map(current.clients);      clients.set(clientId, { clientId, queue });      return [current.clients.get(clientId), { ...current, clients }] as const;    });    if (previous) yield* disconnect(clientId, previous.queue);    return Stream.fromQueue(queue).pipe(Stream.ensuring(disconnect(clientId, queue)));  });   const reportOwner: PreviewAutomationBrokerShape["reportOwner"] = Effect.fn(    "PreviewAutomationBroker.reportOwner",  )(function* (owner) {    yield* SynchronizedRef.update(state, (current) => {      const owners = new Map(current.owners);      owners.set(owner.clientId, owner);      return { ...current, owners };    });  });   const clearOwner: PreviewAutomationBrokerShape["clearOwner"] = Effect.fn(    "PreviewAutomationBroker.clearOwner",  )(function* (clientId) {    yield* SynchronizedRef.update(state, (current) => {      const owners = new Map(current.owners);      owners.delete(clientId);      return { ...current, owners };    });  });   const respond: PreviewAutomationBrokerShape["respond"] = Effect.fn(    "PreviewAutomationBroker.respond",  )(function* (response) {    const pending = yield* SynchronizedRef.modify(state, (current) => {      const entry = current.pending.get(response.requestId);      if (!entry) return [undefined, current] as const;      const next = new Map(current.pending);      next.delete(response.requestId);      return [entry, { ...current, pending: next }] as const;    });    if (!pending) return;    if (response.ok) {      yield* Deferred.succeed(pending.deferred, response.result);    } else {      yield* Deferred.fail(        pending.deferred,        response.error          ? makeResponseError(response.error)          : new PreviewAutomationExecutionError({              message: "Preview automation failed without an error payload.",            }),      );    }  });   const invoke = Effect.fn("PreviewAutomationBroker.invoke")(function* <A = unknown>(    input: Parameters<PreviewAutomationBrokerShape["invoke"]>[0],  ): Effect.fn.Return<A, PreviewAutomationError> {    const current = yield* SynchronizedRef.get(state);    const candidates = Array.from(current.owners.values())      .filter(        (owner) =>          owner.environmentId === input.scope.environmentId &&          owner.threadId === input.scope.threadId &&          owner.supportsAutomation,      )      .sort((left, right) => right.focusedAt.localeCompare(left.focusedAt));    const owner = candidates[0];    if (!owner) {      return yield* new PreviewAutomationNoFocusedOwnerError({        message: "No desktop browser host is available for this thread.",      });    }    const connection = current.clients.get(owner.clientId);    if (!connection) {      return yield* new PreviewAutomationUnavailableError({        message: "The browser host is not connected.",      });    }    if (      input.operation !== "open" &&      input.operation !== "status" &&      !owner.tabId &&      !input.tabId    ) {      return yield* new PreviewAutomationTabNotFoundError({        message: "The browser host does not have an active tab.",      });    }    const timeoutMs = input.timeoutMs ?? 15_000;    const deferred = yield* Deferred.make<unknown, PreviewAutomationError>();    const requestId = yield* SynchronizedRef.modify(state, (next) => {      const requestId = `preview-${next.requestSequence}`;      const pending = new Map(next.pending);      pending.set(requestId, { clientId: owner.clientId, deferred });      return [requestId, { ...next, pending, requestSequence: next.requestSequence + 1 }] as const;    });    const removePending = SynchronizedRef.update(state, (next) => {      if (!next.pending.has(requestId)) return next;      const pending = new Map(next.pending);      pending.delete(requestId);      return { ...next, pending };    });    const awaitResponse = Effect.fn("PreviewAutomationBroker.awaitResponse")(function* () {      const offered = yield* Queue.offer(connection.queue, {        requestId,        threadId: input.scope.threadId,        tabId: input.tabId ?? owner.tabId ?? undefined,        operation: input.operation,        input: input.input,        timeoutMs,      });      if (!offered) {        return yield* new PreviewAutomationUnavailableError({          message: "The preview automation client is no longer accepting requests.",        });      }      const result = yield* Deferred.await(deferred).pipe(Effect.timeoutOption(timeoutMs));      return yield* Option.match(result, {        onNone: () =>          Effect.fail(            new PreviewAutomationTimeoutError({              message: `Preview automation timed out after ${timeoutMs}ms.`,            }),          ),        onSome: (value) => Effect.succeed(value as A),      });    });    return yield* awaitResponse().pipe(Effect.ensuring(removePending));  });   return PreviewAutomationBroker.of({ connect, reportOwner, clearOwner, respond, invoke });}).pipe(Effect.withSpan("PreviewAutomationBroker.make")); export const layer = Layer.effect(PreviewAutomationBroker, make); /** Exposed for tests. */export const __testing = {  make,};