import { EditorState, Fragment, liftTarget, TextSelection, Transaction, ReplaceAroundStep, NodeRange, Slice } from '../prosemirror';

/**
 * Function will lift list item following selection to level-1.
 */
export function liftFollowingList(
  state: EditorState<any>,
  from: number,
  to: number,
  rootListDepth: number,
  tr: Transaction
): Transaction {
  const { listItem } = state.schema.nodes;
  let lifted = false;
  tr.doc.nodesBetween(from, to, (node, pos) => {
    if (!lifted && node.type === listItem && pos > from) {
      lifted = true;
      let listDepth = rootListDepth + 3;
      while (listDepth > rootListDepth + 2) {
        const start = tr.doc.resolve(tr.mapping.map(pos));
        listDepth = start.depth;
        const end = tr.doc.resolve(tr.mapping.map(pos + node.textContent.length));
        const sel = new TextSelection(start, end);
        tr = liftListItem(state, sel, tr);
      }
    }
  });
  return tr;
}

/**
 * Lift list item.
 */
function liftListItem(state: EditorState<any>, selection, tr: Transaction): Transaction {
  let {$from, $to} = selection;
  const nodeType = state.schema.nodes.listItem;
  let range = $from.blockRange($to, node => node.childCount && node.firstChild.type === nodeType);
  if (!range || range.depth < 2 || $from.node(range.depth - 1).type !== nodeType) { return tr; }
  let end = range.end;
  let endOfList = $to.end(range.depth);
  if (end < endOfList) {
    tr.step(
      new ReplaceAroundStep(
        end - 1,
        endOfList,
        end,
        endOfList,
        new Slice(Fragment.from(nodeType.create(null, range.parent.copy())), 1, 0),
        1,
        true
      )
    );
    range = new NodeRange(tr.doc.resolve($from.pos), tr.doc.resolve(endOfList), range.depth);
  }
  return tr.lift(range, liftTarget(range)!).scrollIntoView();
}