import { Node } from "prosemirror-model";
import { NodeSelection, Transaction } from "prosemirror-state";
import * as pquery from "../pquery";
import { EditorSchema, schema } from "../schema";
import { isTextSelection } from "../util";
import { WedgeSelection } from "../wedge/WedgeSelection";
import { AttachmentAttrs } from "./schema";

/**
 * Toggle whether an attachment preview is shown.
 */
export function toggleHidePreview(tr: Transaction<EditorSchema>, pos: number): void {
  const attachment = tr.doc.resolve(pos).nodeAfter!;
  const { hp, ...otherAttrs } = attachment.attrs as AttachmentAttrs;
  // Using `undefined` for "off" to serialise more efficiently to JSON.
  const newAttrs: AttachmentAttrs = { ...otherAttrs, hp: hp === true ? undefined : true };
  tr.setNodeMarkup(pos, undefined, newAttrs);
}

export function remove(tr: Transaction<EditorSchema>, pos: number): void {
  tr.delete(pos, pos + 1);
}

export function insertAttachment(tr: Transaction<EditorSchema>, nearPos: number, attachmentNode: Node): void {
  // Determine if, after inserting the attachment, the selection should be
  // changed to a node selection of the newly inserted attachment.
  const shouldSelectAttachment =
    (isTextSelection(tr.selection) && tr.selection.$cursor != null) || tr.selection instanceof WedgeSelection;
  let searchStart = nearPos;
  const $pos = tr.doc.resolve(nearPos);
  const { node: grandParentNode, index: grandParentIndex } = pquery.grandParent($pos);
  if (
    $pos.parent.type === schema.nodes.p &&
    grandParentNode.contentMatchAt(grandParentIndex).matchType(schema.nodes.at) != null
  ) {
    const p = $pos.parent;
    const pPos = $pos.before();
    const pStart = $pos.start();
    if (p.content.size === 0) {
      // Cursor in an empty paragraph.
      tr.replaceWith(pPos, pPos + p.nodeSize, attachmentNode);
      searchStart = pPos;
    } else if (nearPos === pStart) {
      // Cursor at the start of a paragraph.
      tr.insert(pPos, attachmentNode);
      searchStart = pPos;
    } else if (nearPos === pStart + p.content.size) {
      // Cursor at the end of a paragraph.
      tr.insert(pPos + p.nodeSize, attachmentNode);
    } else {
      // Cursor in the middle of a non-empty paragraph.
      tr.insert(nearPos, attachmentNode);
    }
  } else {
    tr.insert(nearPos, attachmentNode);
  }

  if (shouldSelectAttachment) {
    const found = pquery.findForward(tr.doc.resolve(searchStart), node => node === attachmentNode);
    if (found !== null) {
      tr.setSelection(new NodeSelection(found.$pos));
    }
  }
}