// The resolve call and the shared answer of the current page. On the server
// it takes the answer the Nitro middleware (server/middleware/seo.ts) already
// resolved for this request through its cache (event.context.seo), so a page
// costs one resolve call; for a request the middleware did not resolve (a
// path it skips, such as a dotted author slug) it calls the internal base (runtimeConfig.seo.apiBase) and forwards the
// visitor's x-forwarded-for plus the Nuxt peer, so the backend's per-IP
// throttle (seo-resolve, 600 a minute) keeps one bucket per visitor, also on
// route-cached renders. In the browser it calls the same-origin public base.
// Any failure (timeout, 4xx, 5xx, an unexpected body) answers null: the page
// then renders with its own head.

import { seoAnswer } from '../utils/seo.ts'
import type { SeoResolveAnswer } from '../utils/types.ts'

/** The resolve answer of the page being rendered, null when there is none. */
export function useSeoAnswer() {
  return useState<SeoResolveAnswer | null>('seo-layer:answer', () => null)
}

export async function resolveSeo(url: string): Promise<SeoResolveAnswer | null> {
  const config = useRuntimeConfig()
  const timeout = Number((config.seo as { timeoutMs?: number } | undefined)?.timeoutMs) || 1500
  try {
    if (import.meta.server) {
      const event = useRequestEvent()
      const resolved = event?.context.seoResolved as { url: string; answer: SeoResolveAnswer | null } | undefined
      if (resolved && resolved.url === url) return resolved.answer
      const base = (config.seo as { apiBase: string }).apiBase
      const recorded = event?.context.seoForwardedFor as string | undefined
      const headers: Record<string, string> = recorded ? { 'x-forwarded-for': recorded } : {}
      return seoAnswer(await $fetch('/resolve', { baseURL: base, query: { url }, headers, timeout }))
    }
    const base = (config.public.seo as { apiBase: string }).apiBase
    return seoAnswer(await $fetch('/resolve', { baseURL: base, query: { url }, timeout }))
  } catch {
    return null
  }
}