feat: initialize gomdown-helper with yt-dlp transfer flow

src/content/index.ts

@@ -0,0 +1,142 @@
+import browser from 'webextension-polyfill'
+import { isLikelyDownloadUrl, normalizeUrl } from '../lib/downloadIntent'
+
+const CAPTURE_TTL_MS = 8000
+const captureInFlight = new Map<string, number>()
+
+function pruneCaptureInFlight(): void {
+  const now = Date.now()
+  for (const [url, expiresAt] of captureInFlight.entries()) {
+    if (expiresAt <= now) captureInFlight.delete(url)
+  }
+}
+
+async function sendCapture(url: string, referer: string): Promise<boolean> {
+  const normalized = normalizeUrl(url, window.location.href)
+  if (!normalized) return false
+
+  pruneCaptureInFlight()
+  if (captureInFlight.has(normalized)) return true
+  captureInFlight.set(normalized, Date.now() + CAPTURE_TTL_MS)
+
+  try {
+    const result = (await browser.runtime.sendMessage({
+      type: 'capture-link-download',
+      url: normalized,
+      referer: referer || document.referrer || window.location.href,
+    })) as { ok?: boolean }
+    if (result?.ok) return true
+  } catch {
+    // ignored
+  }
+
+  captureInFlight.delete(normalized)
+  return false
+}
+
+function findAnchor(target: EventTarget | null): HTMLAnchorElement | null {
+  if (!target) return null
+  if (target instanceof HTMLAnchorElement) return target
+  if (target instanceof Element) return target.closest('a[href]') as HTMLAnchorElement | null
+  return null
+}
+
+function shouldIgnoreHotkey(event: MouseEvent | KeyboardEvent): boolean {
+  return !!(event.metaKey || event.ctrlKey || event.shiftKey || event.altKey)
+}
+
+async function interceptAnchorEvent(event: MouseEvent): Promise<void> {
+  if (event.defaultPrevented) return
+  if (shouldIgnoreHotkey(event)) return
+
+  const anchor = findAnchor(event.target)
+  if (!anchor) return
+  const href = anchor.href || ''
+  if (!href || !isLikelyDownloadUrl(href, window.location.href)) return
+
+  event.preventDefault()
+  event.stopImmediatePropagation()
+  event.stopPropagation()
+  await sendCapture(href, document.referrer || window.location.href)
+}
+
+function interceptMouseLike(event: MouseEvent): void {
+  const anchor = findAnchor(event.target)
+  if (!anchor) return
+  const href = anchor.href || ''
+  if (!href || !isLikelyDownloadUrl(href, window.location.href)) return
+  if (shouldIgnoreHotkey(event)) return
+
+  event.preventDefault()
+  event.stopImmediatePropagation()
+  event.stopPropagation()
+  void sendCapture(href, document.referrer || window.location.href)
+}
+
+document.addEventListener('pointerdown', (event: PointerEvent) => {
+  if (event.button !== 0) return
+  interceptMouseLike(event)
+}, true)
+
+document.addEventListener('mousedown', (event: MouseEvent) => {
+  if (event.button !== 0) return
+  interceptMouseLike(event)
+}, true)
+
+document.addEventListener('click', (event: MouseEvent) => {
+  if (event.button !== 0) return
+  void interceptAnchorEvent(event)
+}, true)
+
+document.addEventListener('keydown', (event: KeyboardEvent) => {
+  if (event.key !== 'Enter') return
+  if (event.defaultPrevented) return
+  if (shouldIgnoreHotkey(event)) return
+
+  const anchor = findAnchor(event.target)
+  if (!anchor) return
+  const href = anchor.href || ''
+  if (!href || !isLikelyDownloadUrl(href, window.location.href)) return
+
+  event.preventDefault()
+  event.stopImmediatePropagation()
+  event.stopPropagation()
+  void sendCapture(href, document.referrer || window.location.href)
+}, true)
+
+document.addEventListener('auxclick', (event: MouseEvent) => {
+  if (event.button !== 1) return
+  void interceptAnchorEvent(event)
+}, true)
+
+function installProgrammaticInterceptors(): void {
+  try {
+    const originalOpen = window.open.bind(window)
+    window.open = function gomdownInterceptOpen(url?: string | URL, target?: string, features?: string): Window | null {
+      const raw = String(url || '').trim()
+      if (raw && isLikelyDownloadUrl(raw, window.location.href)) {
+        void sendCapture(raw, window.location.href)
+        return null
+      }
+      return originalOpen(url as string, target, features)
+    }
+  } catch {
+    // ignored
+  }
+
+  try {
+    const originalAnchorClick = HTMLAnchorElement.prototype.click
+    HTMLAnchorElement.prototype.click = function gomdownInterceptAnchorClick(): void {
+      const href = this.href || this.getAttribute('href') || ''
+      if (href && isLikelyDownloadUrl(href, window.location.href)) {
+        void sendCapture(href, document.referrer || window.location.href)
+        return
+      }
+      originalAnchorClick.call(this)
+    }
+  } catch {
+    // ignored
+  }
+}
+
+installProgrammaticInterceptors()