// Generated from types/*.ts — do not edit.
// Regenerate with: npm run generate:typescript

/**
 * Canvas Channel Reducer — Pure reducer for `CanvasState`.
 *
 * @module channels-canvas/reducer
 */

import { ActionType } from '../common/actions.js';
import type { CanvasAction } from '../action-origin.generated.js';
import type { CanvasState } from './state.js';

/**
 * Pure reducer for canvas state.
 *
 * The channel currently has one full-replacement action. The `if` form keeps
 * unknown future actions forward-compatible because TypeScript cannot narrow a
 * single-variant action union to `never` for the usual exhaustiveness helper.
 */
export function canvasReducer(state: CanvasState, action: CanvasAction, log?: (msg: string) => void): CanvasState {
  if (action.type === ActionType.CanvasStateChanged) {
    return action.canvas;
  }

  (log ?? console.warn)(`Unhandled action type: ${JSON.stringify(action)}`);
  return state;
}