import { useEffect, useMemo, useRef, useState } from "react"

let apiPromise: Promise<void> | null = null

/** Charge l'API IFrame YouTube une seule fois. */
function loadYoutubeApi(): Promise<void> {
  if (window.YT?.Player) {
    return Promise.resolve()
  }
  if (apiPromise) {
    return apiPromise
  }
  apiPromise = new Promise((resolve) => {
    const previous = window.onYouTubeIframeAPIReady
    window.onYouTubeIframeAPIReady = () => {
      previous?.()
      resolve()
    }
    const tag = document.createElement("script")
    tag.src = "https://www.youtube.com/iframe_api"
    document.head.appendChild(tag)
  })
  return apiPromise
}

export interface YoutubeApi {
  play: () => void
  pause: () => void
  seek: (seconds: number) => void
  time: () => number
  duration: () => number
}

/**
 * Crée un lecteur YouTube pour `youtubeId`. Renvoie un ref à poser sur un div
 * hôte, l'état "prêt", et une API impérative (play/pause/seek/time).
 */
export function useYoutube(youtubeId: string) {
  const hostRef = useRef<HTMLDivElement>(null)
  const playerRef = useRef<YT.Player | null>(null)
  const [ready, setReady] = useState(false)

  useEffect(() => {
    let cancelled = false
    const host = hostRef.current
    if (!host) {
      return
    }
    setReady(false)
    // YT remplace l'élément fourni par une iframe → on lui donne un enfant jetable
    // pour que React ne gère jamais ce nœud.
    const inner = document.createElement("div")
    host.appendChild(inner)

    loadYoutubeApi().then(() => {
      if (cancelled || !window.YT) {
        return
      }
      playerRef.current = new window.YT.Player(inner, {
        videoId: youtubeId,
        playerVars: {
          autoplay: 0,
          controls: 0,
          disablekb: 1,
          modestbranding: 1,
          rel: 0,
          playsinline: 1,
        },
        events: {
          onReady: () => {
            if (!cancelled) {
              setReady(true)
            }
          },
        },
      })
    })

    return () => {
      cancelled = true
      playerRef.current?.destroy()
      playerRef.current = null
      host.replaceChildren()
    }
  }, [youtubeId])

  const api = useMemo<YoutubeApi>(
    () => ({
      play: () => playerRef.current?.playVideo(),
      pause: () => playerRef.current?.pauseVideo(),
      seek: (seconds) => playerRef.current?.seekTo(seconds, true),
      time: () => playerRef.current?.getCurrentTime() ?? 0,
      duration: () => playerRef.current?.getDuration() ?? 0,
    }),
    []
  )

  return { hostRef, ready, api }
}