import { Operation } from 'slate';
import invariant from 'tiny-invariant';
import { SharedType } from '../model';
import { YjsEditor } from '../plugin';
import node from './node';
import text from './text';
import { ApplyFunc, OpMapper } from './types';

const nullOp: ApplyFunc = (doc: SharedType) => doc;

const opMappers: OpMapper = {
  ...text,
  ...node,

  // SetSelection is currently a null op since we don't support cursors
  set_selection: nullOp
};

/**
 * Applies a slate operation to a SharedType
 *
 * @param sharedType
 * @param op
 */
export function applySlateOp(
  sharedType: SharedType,
  op: Operation
): SharedType {
  const apply = opMappers[op.type] as ApplyFunc<typeof op>;
  if (!apply) {
    throw new Error(`Unknown operation: ${op.type}`);
  }

  return apply(sharedType, op);
}

/**
 * Applies slate operations to a SharedType
 *
 * @param sharedType
 * @param op
 */
export default function applySlateOps(
  sharedType: SharedType,
  ops: Operation[],
  editor: YjsEditor
): SharedType {
  invariant(sharedType.doc, 'Shared type without attached document');

  if (ops.length > 0) {
    sharedType.doc.transact(() => {
      ops.forEach((op) => applySlateOp(sharedType, op));
    }, editor);
  }

  return sharedType;
}