import { ref, onMounted, onUnmounted } from 'vue'

export function useExtension() {
  const isExtensionReady = ref(false)
  const isListening = ref(false)
  const lastClipboardText = ref('')
  let extensionCheckInterval = null
  let lastPongTime = Date.now()

  const PING_INTERVAL = 200
  const TIMEOUT_THRESHOLD = 1000

  const handleMessage = (event) => {
    if (event.source !== window) return

    if (event.data.type === 'TOOLS_APP_EXTENSION_READY' || event.data.type === 'TOOLS_APP_PONG') {
      isExtensionReady.value = true
      lastPongTime = Date.now()
    }

    if (event.data.type === 'TOOLS_APP_CLIPBOARD_UPDATE') {
      const text = event.data.content
      // Only update if listening
      if (isListening.value && text) {
        lastClipboardText.value = text
      }
    }
  }

  const startWatchdog = () => {
    extensionCheckInterval = setInterval(() => {
      window.postMessage({ type: 'TOOLS_APP_PING' }, '*')
      if (Date.now() - lastPongTime > TIMEOUT_THRESHOLD) {
         isExtensionReady.value = false
      }
    }, PING_INTERVAL)
  }

  const startListening = () => {
    window.postMessage({ type: 'TOOLS_APP_START_SNIFFING' }, '*')
    isListening.value = true
  }

  const stopListening = () => {
    window.postMessage({ type: 'TOOLS_APP_STOP_SNIFFING' }, '*')
    isListening.value = false
  }

  const writeClipboard = (text) => {
    // Send to extension (background -> offscreen -> clipboard)
    window.postMessage({ type: 'TOOLS_APP_CLIPBOARD_WRITE', content: text }, '*')
    // Update local state to avoid echo loop if we are listening
    lastClipboardText.value = text
  }

  onMounted(() => {
    window.addEventListener('message', handleMessage)
    // Initial check
    window.postMessage({ type: 'TOOLS_APP_INIT' }, '*')
    startWatchdog()
  })

  onUnmounted(() => {
    if (isListening.value) {
      stopListening()
    }
    if (extensionCheckInterval) clearInterval(extensionCheckInterval)
    window.removeEventListener('message', handleMessage)
  })

  return {
    isExtensionReady,
    isListening,
    lastClipboardText,
    startListening,
    stopListening,
    writeClipboard
  }
}