import { useState, useEffect, useRef, useCallback } from 'react'

/**
 * useVoiceCommand — continuously listens for voice commands via SpeechRecognition.
 * Chrome/Edge only (webkit prefix).
 */
export function useVoiceCommand(onCommand: (transcript: string) => void, enabled: boolean = false) {
  const [listening, setListening] = useState(false)
  const [transcript, setTranscript] = useState('')
  const recRef = useRef<any>(null)

  useEffect(() => {
    if (!enabled) { recRef.current?.stop?.(); return }
    const SR = (window as any).SpeechRecognition || (window as any).webkitSpeechRecognition
    if (!SR) return
    const rec = new SR()
    rec.continuous = true
    rec.interimResults = true
    rec.lang = 'en-US'
    rec.onstart = () => setListening(true)
    rec.onend = () => setListening(false)
    rec.onresult = (e: any) => {
      const last = e.results[e.results.length - 1]
      const text = last[0].transcript
      setTranscript(text)
      if (last.isFinal) onCommand(text.trim())
    }
    rec.onerror = () => setListening(false)
    recRef.current = rec
    try { rec.start() } catch {}
    return () => { try { rec.stop() } catch {} }
  }, [enabled, onCommand])

  const start = useCallback(() => { try { recRef.current?.start() } catch {} }, [])
  const stop = useCallback(() => { try { recRef.current?.stop() } catch {} }, [])

  return { listening, transcript, start, stop }
}