Fixes #13 by adding new outliner commands

plugs/editor/editor.plug.yaml

@@ -227,6 +227,30 @@ functions:
     command:
       name: "Upload: File"
 
+  outlineMoveUp:
+    path: ./outline.ts:moveItemUp
+    command:
+      name: "Outline: Move Up"
+      key: "Alt-ArrowUp"
+
+  outlineMoveDown:
+    path: ./outline.ts:moveItemDown
+    command:
+      name: "Outline: Move Down"
+      key: "Alt-ArrowDown"
+
+  outlineIndent:
+    path: ./outline.ts:indentItem
+    command:
+      name: "Outline: Move Right"
+      key: "Alt-ArrowRight"
+
+  outlineOutdent:
+    path: ./outline.ts:outdentItem
+    command:
+      name: "Outline: Move Left"
+      key: "Alt-ArrowLeft"
+
   customFlashMessage:
     path: editor.ts:customFlashMessage
     command:

plugs/editor/outline.ts

@@ -0,0 +1,225 @@
+import { editor } from "$sb/syscalls.ts";
+
+export async function moveItemUp() {
+  const cursorPos = await editor.getCursor();
+  const text = await editor.getText();
+
+  try {
+    const currentItemBounds = determineItemBounds(text, cursorPos);
+    const previousItemBounds = determineItemBounds(
+      text,
+      currentItemBounds.from - 1,
+      currentItemBounds.indentLevel,
+    );
+
+    if (currentItemBounds.from === previousItemBounds.from) {
+      throw new Error("Already at the top");
+    }
+
+    const newText =
+      ensureNewLine(text.slice(currentItemBounds.from, currentItemBounds.to)) +
+      text.slice(previousItemBounds.from, previousItemBounds.to);
+    const newCursorPos = (cursorPos - currentItemBounds.from) +
+      previousItemBounds.from;
+
+    await editor.dispatch({
+      changes: [
+        {
+          from: previousItemBounds.from,
+          to: currentItemBounds.to,
+          insert: newText,
+        },
+      ],
+      selection: {
+        anchor: newCursorPos,
+      },
+    });
+  } catch (e: any) {
+    await editor.flashNotification(e.message, "error");
+  }
+}
+
+export async function moveItemDown() {
+  const cursorPos = await editor.getCursor();
+  const text = await editor.getText();
+
+  try {
+    const currentItemBounds = determineItemBounds(text, cursorPos);
+    const nextItemBounds = determineItemBounds(
+      text,
+      currentItemBounds.to + 1,
+      currentItemBounds.indentLevel,
+    );
+
+    if (currentItemBounds.from === nextItemBounds.from) {
+      throw new Error("Already at the bottom");
+    }
+
+    const nextItemText = ensureNewLine(
+      text.slice(nextItemBounds.from, nextItemBounds.to),
+    );
+    const newText = nextItemText +
+      text.slice(currentItemBounds.from, currentItemBounds.to);
+    const newCursorPos = (cursorPos - currentItemBounds.from) +
+      currentItemBounds.from + nextItemText.length;
+    await editor.dispatch({
+      changes: [
+        {
+          from: currentItemBounds.from,
+          to: nextItemBounds.to,
+          insert: newText,
+        },
+      ],
+      selection: {
+        anchor: newCursorPos,
+      },
+    });
+  } catch (e: any) {
+    await editor.flashNotification(e.message, "error");
+  }
+}
+
+export async function indentItem() {
+  const cursorPos = await editor.getCursor();
+  const text = await editor.getText();
+
+  try {
+    const currentItemBounds = determineItemBounds(text, cursorPos);
+    const itemText = text.slice(currentItemBounds.from, currentItemBounds.to);
+    const newText = itemText.split("\n").map((line) =>
+      line ? "  " + line : line
+    ).join("\n");
+    const preText = text.slice(currentItemBounds.from, cursorPos);
+    const newCursorPos = cursorPos + preText.split("\n").length * 2;
+    await editor.dispatch({
+      changes: [
+        {
+          from: currentItemBounds.from,
+          to: currentItemBounds.to,
+          insert: newText,
+        },
+      ],
+      selection: {
+        anchor: newCursorPos,
+      },
+    });
+  } catch (e: any) {
+    await editor.flashNotification(e.message, "error");
+  }
+}
+
+export async function outdentItem() {
+  const cursorPos = await editor.getCursor();
+  const text = await editor.getText();
+
+  try {
+    const currentItemBounds = determineItemBounds(text, cursorPos);
+    const itemText = text.slice(currentItemBounds.from, currentItemBounds.to);
+    if (!itemText.startsWith("  ")) {
+      throw new Error("Cannot outdent further");
+    }
+    const newText = itemText.split("\n").map((line) =>
+      line.startsWith("  ") ? line.substring(2) : line
+    ).join("\n");
+    const preText = text.slice(currentItemBounds.from, cursorPos);
+    const newCursorPos = cursorPos - preText.split("\n").length * 2;
+    await editor.dispatch({
+      changes: [
+        {
+          from: currentItemBounds.from,
+          to: currentItemBounds.to,
+          insert: newText,
+        },
+      ],
+      selection: {
+        anchor: newCursorPos,
+      },
+    });
+  } catch (e: any) {
+    await editor.flashNotification(e.message, "error");
+  }
+}
+
+function ensureNewLine(s: string) {
+  if (!s.endsWith("\n")) {
+    return s + "\n";
+  } else {
+    return s;
+  }
+}
+
+function determineItemBounds(
+  text: string,
+  pos: number,
+  minIndentLevel?: number,
+): { from: number; to: number; indentLevel: number } {
+  // Find the start of the item marked with a bullet
+  let currentItemStart = pos;
+  let indentLevel = 0;
+  while (true) {
+    while (currentItemStart > 0 && text[currentItemStart - 1] !== "\n") {
+      currentItemStart--;
+    }
+    // Check if the line is a bullet and determine the indent level
+    indentLevel = 0;
+    while (text[currentItemStart + indentLevel] === " ") {
+      indentLevel++;
+    }
+    if (minIndentLevel !== undefined && indentLevel < minIndentLevel) {
+      throw new Error("No item found at minimum indent level");
+    }
+    if (minIndentLevel !== undefined && indentLevel > minIndentLevel) {
+      // Not at the desired indent level yet, let's go up another line
+      currentItemStart--;
+      if (currentItemStart <= 0) {
+        // We've reached the top of the document, no bullet found
+        throw new Error("No item found");
+      }
+      continue;
+    }
+    if (["-", "*"].includes(text[currentItemStart + indentLevel])) {
+      // This is a bullet line, found it, let's break out of this loop
+      break;
+    } else {
+      // Not a bullet line, let's go up another line
+      currentItemStart--;
+      if (currentItemStart <= 0) {
+        // We've reached the top of the document, no bullet found
+        throw new Error("No item found");
+      }
+    }
+  }
+
+  // Ok, so at this point we have determine the starting point of our item
+  // Relevant variables are currentItemStart and indentLevel
+  // Now let's find the end point
+  let currentItemEnd = currentItemStart + 1;
+  while (true) {
+    // Let's traverse to the end of the line
+    while (currentItemEnd < text.length && text[currentItemEnd - 1] !== "\n") {
+      currentItemEnd++;
+    }
+    // Check the indent level of the next line
+    let nextIndentLevel = 0;
+    while (text[currentItemEnd + nextIndentLevel] === " ") {
+      nextIndentLevel++;
+    }
+    if (nextIndentLevel <= indentLevel) {
+      // This is a line indentend less than the current item, found it, let's break out of this loop
+      break;
+    } else {
+      // Not a bullet line, let's go up another line
+      currentItemEnd++;
+      if (currentItemEnd >= text.length) {
+        // End of the document, mark this as the end of the item
+        currentItemEnd = text.length - 1;
+        break;
+      }
+    }
+  }
+  return {
+    from: currentItemStart,
+    to: currentItemEnd,
+    indentLevel,
+  };
+}