import { WorkflowClientInterceptor, WorkflowStartInput, WorkflowStartOutput } from './interceptors';

export function adaptWorkflowClientInterceptor(i: WorkflowClientInterceptor): WorkflowClientInterceptor {
  return adaptLegacyStartInterceptor(i);
}

// Adapt legacy `start` interceptors to the new `startWithDetails` interceptor.
function adaptLegacyStartInterceptor(i: WorkflowClientInterceptor): WorkflowClientInterceptor {
  // If it already has the new method, or doesn't have the legacy one, no adaptation is needed.
  // eslint-disable-next-line @typescript-eslint/no-deprecated
  if (i.startWithDetails || !i.start) {
    return i;
  }

  // This interceptor has a legacy `start` but not `startWithDetails`. We'll adapt it.
  return {
    ...i,
    startWithDetails: async (input, next): Promise<WorkflowStartOutput> => {
      let downstreamOut: WorkflowStartOutput | undefined;

      // Patched `next` for legacy `start` interceptors.
      // Captures the full `WorkflowStartOutput` while returning `runId` as a string.
      const patchedNext = async (patchedInput: WorkflowStartInput): Promise<string> => {
        downstreamOut = await next(patchedInput);
        return downstreamOut.runId;
      };

      const runIdFromLegacyInterceptor = await i.start!(input, patchedNext); // eslint-disable-line @typescript-eslint/no-deprecated

      // If the interceptor short-circuited (didn't call `next`), `downstreamOut` will be undefined.
      // In that case, we can't have an eager start.
      if (downstreamOut === undefined) {
        return { runId: runIdFromLegacyInterceptor, eagerlyStarted: false };
      }

      // If `next` was called, honor the `runId` from the legacy interceptor but preserve
      // the `eagerlyStarted` status from the actual downstream call.
      return { ...downstreamOut, runId: runIdFromLegacyInterceptor };
    },
  };
}