import { portDefOf, VARIABLES } from '../../nested';
import { type NodeDef, withInlineDefault } from '../../NodeRegistry';
import { writeTyped } from '../../values';
import { exec } from '../shared';

/**
 * Every variable picked is an output, read at the moment it is asked for. One switched to Set is an
 * input too; the flow pins exist only while at least one is.
 */
export const Variables: NodeDef = {
  type: VARIABLES,
  label: 'Variables',
  category: 'variable',
  description:
    "Reads this behavior's variables at any time. Those switched to Set are written together when " +
    'the flow arrives, and a read after that sees the new value.',
  inputs: [],
  outputs: [],
  params: [],
  declaresPorts: 'both',
  declaredPort: (port) => withInlineDefault(portDefOf(port)),
  derivePorts: ({ node }) => {
    const ports = node.ports ?? [];
    const only = ports.length === 1 ? ports[0]?.key : undefined;
    const shape = ports.some((p) => p.write) ? { inputs: [exec()], outputs: [exec()] } : {};
    return only ? { ...shape, label: only } : shape;
  },
  read: (ctx) => ctx.variables,
  run: (ctx, inputs, _params, def) => {
    for (const port of def.inputs)
      if (port.type !== 'exec') writeTyped(ctx.variables, port.key, inputs[port.key]);
    return { next: 'exec' };
  },
};