import { textOf } from '../../../model/Properties';
import type { NodeDef } from '../../NodeRegistry';
import { type EmptyMode, isEmptyValue } from '../../values';
import { any } from '../shared';

const MODES: Record<string, EmptyMode> = {
  any: 'any',
  nothing: 'nothing',
  null: 'null',
};

export const FirstNotEmpty: NodeDef = {
  type: 'FirstNotEmpty',
  label: 'First not empty',
  category: 'data',
  description: 'a, unless it is empty, then b. The setting says what is empty.',
  inputs: [any('a'), any('b')],
  outputs: [any('value')],
  // Whatever goes in comes out: with both inputs on the same type, `value` is that type too (#207).
  sharedType: { inputs: ['a', 'b'], outputs: ['value'] },
  params: [
    {
      key: 'empty',
      label: 'Empty means',
      kind: 'enum',
      default: 'any',
      options: [
        { value: 'any', label: 'Any empty value' },
        { value: 'nothing', label: 'Nothing there (0 and false count)' },
        { value: 'null', label: 'Only a missing value' },
      ],
    },
  ],
  run: (_ctx, inputs, params) => {
    // The fallback matches the param's declared default, so a node with no setting behaves
    // like a freshly created one.
    const mode = MODES[textOf(params.empty)] ?? 'any';
    return { outputs: { value: (isEmptyValue(inputs.a, mode) ? inputs.b : inputs.a) ?? null } };
  },
};