InvokeAI/invokeai/frontend/web/src/common/hooks/useIsReadyToInvoke.ts

import { createSelector } from '@reduxjs/toolkit';
import { stateSelector } from 'app/store/store';
import { useAppSelector } from 'app/store/storeHooks';
import { defaultSelectorOptions } from 'app/store/util/defaultMemoizeOptions';
import { validateSeedWeights } from 'common/util/seedWeightPairs';
import { generationSelector } from 'features/parameters/store/generationSelectors';
import { systemSelector } from 'features/system/store/systemSelectors';
import { activeTabNameSelector } from 'features/ui/store/uiSelectors';
import {
  modelsApi,
  useGetMainModelsQuery,
} from '../../services/api/endpoints/models';

const readinessSelector = createSelector(
  [stateSelector, activeTabNameSelector],
  (state, activeTabName) => {
    const { generation, system, batch } = state;
    const { shouldGenerateVariations, seedWeights, initialImage, seed } =
      generation;

    const { isProcessing, isConnected } = system;
    const {
      isEnabled: isBatchEnabled,
      asInitialImage,
      imageNames: batchImageNames,
    } = batch;

    let isReady = true;
    const reasonsWhyNotReady: string[] = [];

    if (
      activeTabName === 'img2img' &&
      !initialImage &&
      !(asInitialImage && batchImageNames.length > 1)
    ) {
      isReady = false;
      reasonsWhyNotReady.push('No initial image selected');
    }

    const { isSuccess: mainModelsSuccessfullyLoaded } =
      modelsApi.endpoints.getMainModels.select()(state);
    if (!mainModelsSuccessfullyLoaded) {
      isReady = false;
      reasonsWhyNotReady.push('Models are not loaded');
    }

    // TODO: job queue
    // Cannot generate if already processing an image
    if (isProcessing) {
      isReady = false;
      reasonsWhyNotReady.push('System Busy');
    }

    // Cannot generate if not connected
    if (!isConnected) {
      isReady = false;
      reasonsWhyNotReady.push('System Disconnected');
    }

    // Cannot generate variations without valid seed weights
    if (
      shouldGenerateVariations &&
      (!(validateSeedWeights(seedWeights) || seedWeights === '') || seed === -1)
    ) {
      isReady = false;
      reasonsWhyNotReady.push('Seed-Weights badly formatted.');
    }

    // All good
    return { isReady, reasonsWhyNotReady };
  },
  defaultSelectorOptions
);

export const useIsReadyToInvoke = () => {
  const { isReady } = useAppSelector(readinessSelector);
  return isReady;
};