silverbullet/packages/plugs/core/text.ts

import {
  getSelection,
  getText,
  insertAtCursor,
  moveCursor,
  replaceRange,
  setSelection,
} from "@silverbulletmd/plugos-silverbullet-syscall/editor";

export async function quoteSelection() {
  let text = await getText();
  const selection = await getSelection();
  let from = selection.from;
  while (from >= 0 && text[from] !== "\n") {
    from--;
  }
  from++;
  if (text[from] === ">" && text[from + 1] === " ") {
    // Already quoted, we have to unquote
    text = text.slice(from + 2, selection.to);
    text = text.replaceAll("\n> ", "\n");
  } else {
    text = text.slice(from, selection.to);
    text = `> ${text.replaceAll("\n", "\n> ")}`;
  }
  await replaceRange(from, selection.to, text);
}

export function boldCommand() {
  return insertMarker("**");
}

export function italicCommand() {
  return insertMarker("_");
}

async function insertMarker(marker: string) {
  let text = await getText();
  const selection = await getSelection();
  if (selection.from === selection.to) {
    // empty selection
    if (markerAt(selection.from)) {
      // Already there, skipping ahead
      await moveCursor(selection.from + marker.length);
    } else {
      // Not there, inserting
      await insertAtCursor(marker + marker);
      await moveCursor(selection.from + marker.length);
    }
  } else {
    let from = selection.from;
    let to = selection.to;
    let hasMarker = markerAt(from);
    if (!markerAt(from)) {
      // Maybe just before the cursor? We'll accept that
      from = selection.from - marker.length;
      to = selection.to + marker.length;
      hasMarker = markerAt(from);
    }

    if (!hasMarker) {
      // Adding
      await replaceRange(
        selection.from,
        selection.to,
        marker + text.slice(selection.from, selection.to) + marker
      );
      await setSelection(
        selection.from + marker.length,
        selection.to + marker.length
      );
    } else {
      // Removing
      await replaceRange(
        from,
        to,
        text.substring(from + marker.length, to - marker.length)
      );
      await setSelection(from, to - marker.length * 2);
    }
  }

  function markerAt(pos: number) {
    for (var i = 0; i < marker.length; i++) {
      if (text[pos + i] !== marker[i]) {
        return false;
      }
    }
    return true;
  }
}