import { lift, wrapIn } from "prosemirror-commands";
import { Slice } from "prosemirror-model";
import { ReplaceAroundStep } from "prosemirror-transform";
import { compose } from "../compose";
import { UxCommand } from "../constants";
import { closest } from "../pquery";
import { schema } from "../schema";
import { Command } from "../types";

const { fragment, bq, p } = compose;

export const toggle: Command = (state, dispatch) => {
  const { $anchor } = state.selection;
  let match;
  if (closest($anchor, node => node.type === schema.nodes.bq) !== null) {
    return lift(state, dispatch);
  } else if (closest($anchor, node => node.type === schema.nodes.p) !== null) {
    return wrapIn(schema.nodes.bq)(state, dispatch);
  } else if ((match = closest($anchor, node => node.type === schema.nodes.h)) !== null) {
    if (dispatch !== undefined) {
      dispatch(
        state.tr.step(
          new ReplaceAroundStep(
            match.pos,
            match.pos + match.node.nodeSize,
            // We want to keep the content immediately inside the heading, so
            // the gap is set to that range.
            match.pos + 1, // h start
            match.pos + match.node.nodeSize - 1, // h end
            new Slice(fragment(bq(p())).fragment, 0, 0),
            2,
            /* structure */ true
          )
        )
      );
    }
    return true;
  }
  return false;
};

export const ux = {
  [UxCommand.ToggleBlockquote]: toggle
};