function isValidUrl(url) {
  try {
    new URL(url)
    return true
  } catch {
    return false
  }
}

function isYoutubeUrl(url) {
  try {
    const parsedUrl = new URL(url)
    const host = parsedUrl.hostname.replace(/^www\./, "")

    return host === "youtube.com" || host === "youtu.be" || host === "m.youtube.com"
  } catch {
    return false
  }
}

export default defineCachedEventHandler(
  async (event) => {
    const body = await readBody(event).catch(() => null)

    if (!body || !Array.isArray(body.urls)) {
      throw createError({
        statusCode: 400,
        statusMessage: "Invalid payload. Expected { urls: string[] }",
      })
    }

    const urls = body.urls
      .map((url) => String(url).trim())
      .filter((url) => isValidUrl(url))
      .filter((url) => isYoutubeUrl(url))
      .slice(0, 50)

    if (urls.length === 0) {
      return { results: [] }
    }

    const results = await Promise.all(
      urls.map(async (url) => {
        const endpoint = new URL("https://www.youtube.com/oembed")
        endpoint.searchParams.set("url", url)
        endpoint.searchParams.set("format", "json")

        try {
          const data = await $fetch(endpoint.toString(), { timeout: 10000 })

          return {
            url,
            ok: true,
            title: data?.title ?? null,
            author_name: data?.author_name ?? null,
            thumbnail_url: data?.thumbnail_url ?? null,
          }
        } catch (error) {
          return {
            url,
            ok: false,
            error: error?.message || "Unknown oEmbed error",
          }
        }
      })
    )

    return { results }
  },
  {
    maxAge: 60 * 60 * 6,
    getKey: async (event) => {
      const body = await readBody(event).catch(() => null)
      const urls = Array.isArray(body?.urls) ? body.urls.join("|") : "none"
      return `youtube:oembed:${urls}`
    },
  }
)