feat(*): one task editor, vim navigation and undo

src/ui/anchored-panel.svelte

@@ -0,0 +1,108 @@
+<script lang="ts">
+  import { Portal } from "bits-ui";
+  import type { Snippet } from "svelte";
+  import { onScreen, place } from "../lib/place";
+  import { cn } from "../lib/utils";
+  import { useView } from "./context";
+
+  interface Props {
+    /** CSS selector for whatever this should sit under. */
+    anchor: string;
+    /** Off when the panel's contents put the caret somewhere themselves. */
+    autofocus?: boolean;
+    children: Snippet;
+    class?: string;
+    onclose: () => void;
+    onkeydown?: (event: KeyboardEvent) => void;
+  }
+
+  let {
+    anchor,
+    autofocus = true,
+    children,
+    class: className,
+    onclose,
+    onkeydown,
+  }: Props = $props();
+
+  const view = useView();
+
+  let panel = $state<HTMLElement | null>(null);
+  let at = $state({ top: 0, left: 0 });
+  let placed = $state(false);
+
+  /**
+   * Placed by hand rather than by a floating layer: these panels are summoned
+   * by a key press, and a floating layer wants a trigger element to hang off.
+   */
+  function measure(): void {
+    const node = panel;
+    if (!node) return;
+
+    const boxes = [...document.querySelectorAll(anchor)].map((element) =>
+      element.getBoundingClientRect(),
+    );
+    at = place(onScreen(boxes), node.getBoundingClientRect(), {
+      width: window.innerWidth,
+      height: window.innerHeight,
+    });
+    placed = true;
+  }
+
+  function mount(node: HTMLElement) {
+    panel = node;
+    measure();
+    if (autofocus) {
+      (node.querySelector<HTMLElement>("input") ?? node).focus({
+        preventScroll: true,
+      });
+    }
+
+    const outside = (event: PointerEvent): void => {
+      if (!node.contains(event.target as Node)) onclose();
+    };
+    const reflow = (): void => measure();
+    document.addEventListener("pointerdown", outside, true);
+    window.addEventListener("resize", reflow);
+
+    return {
+      destroy() {
+        document.removeEventListener("pointerdown", outside, true);
+        window.removeEventListener("resize", reflow);
+        panel = null;
+      },
+    };
+  }
+
+  function keys(event: KeyboardEvent): void {
+    event.stopPropagation();
+    if (event.key === "Escape" && !event.defaultPrevented) {
+      event.preventDefault();
+      onclose();
+      return;
+    }
+    onkeydown?.(event);
+  }
+
+  /** Re-measures once the body has grown or shrunk under the cursor. */
+  export function reposition(): void {
+    measure();
+  }
+</script>
+
+<Portal to={view.portal()}>
+  <!-- svelte-ignore a11y_no_noninteractive_element_interactions -->
+  <div
+    class={cn(
+      "fixed z-50 overflow-hidden rounded-xl border border-border bg-popover text-popover-foreground shadow-[0_16px_40px_-12px_rgb(0_0_0/45%)] outline-none",
+      className,
+    )}
+    onkeydown={keys}
+    role="dialog"
+    style="top: {at.top}px; left: {at.left}px; opacity: {placed ? 1 : 0}"
+    tabindex="-1"
+    use:mount
+  >
+    {@render children()}
+  </div>
+</Portal>