/**
 * Touch-gesture primitives for Phase 3 mobile specs.
 *
 * The app uses two custom Svelte actions:
 *
 *   1. `longpress` — listens for `pointerdown`, starts a 500 ms timer,
 *      cancels on pointerup / pointermove > 10 px / pointercancel.
 *      [frontend/src/lib/actions/longpress.ts]
 *
 *   2. `doubletap` — listens for `pointerup` and times consecutive
 *      releases within 300 ms on roughly the same coordinate.
 *      [frontend/src/lib/actions/doubletap.ts]
 *
 * Both listen to pointer events, which fire from mouse, touch, and pen
 * input. We drive them with `page.mouse` because it works identically
 * across all Playwright engines and respects the project's mobile
 * viewport — the action doesn't care whether the underlying device was
 * touch or mouse.
 */
import type { Locator, Page } from '@playwright/test';

async function centerOf(locator: Locator): Promise<{ x: number; y: number }> {
  const box = await locator.boundingBox();
  if (!box) throw new Error(`Cannot get bounding box for locator (not visible?)`);
  return { x: box.x + box.width / 2, y: box.y + box.height / 2 };
}

/** Hold the pointer down on `locator` for `durationMs`. Default 600 ms beats the 500 ms long-press threshold. */
export async function longPress(page: Page, locator: Locator, durationMs = 600) {
  const { x, y } = await centerOf(locator);
  await page.mouse.move(x, y);
  await page.mouse.down();
  await page.waitForTimeout(durationMs);
  await page.mouse.up();
}

/**
 * Two rapid pointer-event pairs within the doubletap action's 300 ms window.
 *
 * Dispatches synthetic `pointerdown`/`pointerup` directly on the element via
 * `page.evaluate` (not via `page.mouse`). Why: with real mouse events, the
 * first tap fires the element's `onclick` synchronously — which on a
 * FeedListCard image button means the lightbox opens *before* the second tap
 * lands. That makes mouse-driven double-tap impossible to test in headless
 * Chromium. Dispatching pointer events bypasses the synthetic click pipeline
 * entirely, so we can exercise the `doubletap` action's contract directly.
 */
export async function doubleTap(page: Page, locator: Locator) {
  await locator.evaluate((el: HTMLElement) => {
    const rect = el.getBoundingClientRect();
    const x = rect.left + rect.width / 2;
    const y = rect.top + rect.height / 2;
    const mk = (type: string) =>
      new PointerEvent(type, {
        bubbles: true,
        cancelable: true,
        clientX: x,
        clientY: y,
        pointerType: 'touch',
        isPrimary: true,
      });
    el.dispatchEvent(mk('pointerdown'));
    el.dispatchEvent(mk('pointerup'));
    // Second tap < 300 ms later.
    return new Promise<void>((resolve) =>
      setTimeout(() => {
        el.dispatchEvent(mk('pointerdown'));
        el.dispatchEvent(mk('pointerup'));
        resolve();
      }, 50)
    );
  });
}

/** Touch swipe from start to end coordinates via the touchscreen API (mobile viewports). */
export async function swipe(
  page: Page,
  from: { x: number; y: number },
  to: { x: number; y: number },
  steps = 10
) {
  // page.touchscreen.tap exists but doesn't expose move; fall back to dispatching
  // raw touch events via page.evaluate when needed. For now, mouse-based pointer
  // events are equivalent because the app's planned swipe handlers (when they
  // land) will use pointer events too.
  await page.mouse.move(from.x, from.y);
  await page.mouse.down();
  for (let i = 1; i <= steps; i++) {
    const t = i / steps;
    await page.mouse.move(from.x + (to.x - from.x) * t, from.y + (to.y - from.y) * t);
  }
  await page.mouse.up();
}

/** Read computed style on a locator. Useful for asserting `padding-bottom` includes env(safe-area-inset-bottom). */
export async function computedStyle(locator: Locator, prop: string): Promise<string> {
  return locator.evaluate((el, p) => getComputedStyle(el).getPropertyValue(p), prop);
}

/** Read the raw inline `style` attribute (env() vars expand only inside computed style, not here). */
export async function inlineStyle(locator: Locator): Promise<string> {
  return locator.evaluate((el) => (el as HTMLElement).getAttribute('style') ?? '');
}