feat: add youtube floating quick-download action

src/content/index.ts

@@ -140,3 +140,142 @@ function installProgrammaticInterceptors(): void {
 }
 
 installProgrammaticInterceptors()
+
+let ytOverlayRoot: HTMLDivElement | null = null
+let ytOverlayStatus: HTMLDivElement | null = null
+let ytOverlayBusy = false
+let ytUrlWatcherTimer: number | null = null
+let lastObservedUrl = window.location.href
+
+function isYoutubeWatchPage(url: string): boolean {
+  try {
+    const parsed = new URL(url)
+    if (parsed.hostname !== 'www.youtube.com' && parsed.hostname !== 'youtube.com') return false
+    return parsed.pathname === '/watch' && parsed.searchParams.has('v')
+  } catch {
+    return false
+  }
+}
+
+function setYtOverlayStatus(message: string, tone: 'ok' | 'error' | 'idle' = 'idle'): void {
+  if (!ytOverlayStatus) return
+  ytOverlayStatus.textContent = message
+  if (tone === 'ok') ytOverlayStatus.style.color = '#8ff0a4'
+  else if (tone === 'error') ytOverlayStatus.style.color = '#ff9b9b'
+  else ytOverlayStatus.style.color = '#aeb7d8'
+}
+
+async function enqueueCurrentYoutubePage(): Promise<void> {
+  if (ytOverlayBusy) return
+  ytOverlayBusy = true
+  setYtOverlayStatus('gdown으로 전송 중...')
+  try {
+    const result = (await browser.runtime.sendMessage({
+      type: 'page:enqueue-ytdlp-url',
+      url: window.location.href,
+      referer: window.location.href,
+    })) as { ok?: boolean; error?: string }
+    if (result?.ok) {
+      setYtOverlayStatus('다운로드 모달로 전송됨', 'ok')
+    } else {
+      setYtOverlayStatus(`전송 실패: ${result?.error || 'unknown error'}`, 'error')
+    }
+  } catch (error) {
+    setYtOverlayStatus(`전송 실패: ${String(error)}`, 'error')
+  } finally {
+    ytOverlayBusy = false
+  }
+}
+
+function removeYoutubeOverlay(): void {
+  if (ytOverlayRoot) {
+    ytOverlayRoot.remove()
+    ytOverlayRoot = null
+    ytOverlayStatus = null
+  }
+}
+
+function ensureYoutubeOverlay(): void {
+  if (window.top !== window.self) return
+  if (!isYoutubeWatchPage(window.location.href)) {
+    removeYoutubeOverlay()
+    return
+  }
+  if (ytOverlayRoot) return
+
+  const root = document.createElement('div')
+  root.id = 'gomdown-youtube-overlay'
+  root.style.position = 'fixed'
+  root.style.right = '20px'
+  root.style.bottom = '24px'
+  root.style.zIndex = '2147483647'
+  root.style.background = 'rgba(17, 21, 32, 0.94)'
+  root.style.border = '1px solid rgba(133, 148, 195, 0.35)'
+  root.style.borderRadius = '12px'
+  root.style.padding = '10px'
+  root.style.boxShadow = '0 8px 24px rgba(0, 0, 0, 0.28)'
+  root.style.backdropFilter = 'blur(6px)'
+  root.style.width = '220px'
+  root.style.fontFamily = 'ui-sans-serif, -apple-system, BlinkMacSystemFont, Segoe UI, sans-serif'
+  root.style.color = '#e8edff'
+
+  const title = document.createElement('div')
+  title.textContent = 'Gdown Helper'
+  title.style.fontSize = '12px'
+  title.style.fontWeight = '700'
+  title.style.marginBottom = '8px'
+
+  const action = document.createElement('button')
+  action.type = 'button'
+  action.textContent = '이 영상 다운로드'
+  action.style.width = '100%'
+  action.style.height = '34px'
+  action.style.border = '1px solid #5a69f0'
+  action.style.borderRadius = '8px'
+  action.style.background = '#5a69f0'
+  action.style.color = '#ffffff'
+  action.style.fontSize = '12px'
+  action.style.fontWeight = '700'
+  action.style.cursor = 'pointer'
+  action.addEventListener('click', () => {
+    void enqueueCurrentYoutubePage()
+  })
+
+  const status = document.createElement('div')
+  status.textContent = '클릭 시 gdown 다운로드 모달로 연결'
+  status.style.fontSize = '11px'
+  status.style.marginTop = '8px'
+  status.style.lineHeight = '1.35'
+  status.style.color = '#aeb7d8'
+
+  root.appendChild(title)
+  root.appendChild(action)
+  root.appendChild(status)
+  document.documentElement.appendChild(root)
+
+  ytOverlayRoot = root
+  ytOverlayStatus = status
+}
+
+function watchYoutubeRouteChanges(): void {
+  if (ytUrlWatcherTimer !== null) return
+  ytUrlWatcherTimer = window.setInterval(() => {
+    const current = window.location.href
+    if (current === lastObservedUrl) return
+    lastObservedUrl = current
+    ensureYoutubeOverlay()
+  }, 800)
+
+  window.addEventListener('popstate', () => {
+    lastObservedUrl = window.location.href
+    ensureYoutubeOverlay()
+  })
+
+  document.addEventListener('yt-navigate-finish', () => {
+    lastObservedUrl = window.location.href
+    ensureYoutubeOverlay()
+  })
+}
+
+ensureYoutubeOverlay()
+watchYoutubeRouteChanges()