// The server side of the resolve call: GET <apiBase>/resolve?url=<path and
// query>, forwarding the visitor's address so the backend's per-IP throttle
// (seo-resolve) keeps one bucket per visitor, also on route-cached renders
// (server/plugins/seo-client-address.ts records it). Any failure (timeout,
// 4xx, 5xx, an unexpected body) answers null and the page renders without
// CMS head tags (fail open); with the layer switched off nothing is called.
//
// Nitro auto-imports (useRuntimeConfig, $fetch) are used inside the
// functions only, so `node --test` can import this file.

import type { H3Event } from 'h3'
import { seoAnswer } from '../../app/utils/seo.ts'
import type { SeoResolveAnswer } from '../../app/utils/types.ts'
import { seoServerConfig, type SeoServerConfig } from './config.ts'

/** The x-forwarded-for value the SEO calls carry for this request. */
export function seoForwardedFor(event: H3Event): Record<string, string> {
  const recorded = event.context.seoForwardedFor as string | undefined
  return recorded ? { 'x-forwarded-for': recorded } : {}
}

async function fetchResolve(cfg: SeoServerConfig, url: string, headers: Record<string, string>): Promise<SeoResolveAnswer | null> {
  try {
    return seoAnswer(await $fetch('/resolve', { baseURL: cfg.apiBase, query: { url }, headers, timeout: cfg.timeoutMs }))
  } catch {
    return null
  }
}

/**
 * The resolve answer for `url` (path and query), or null on any failure or
 * when the layer is off (public.seo.enabled or seo.cms false).
 */
export async function resolveCached(event: H3Event, url: string): Promise<SeoResolveAnswer | null> {
  const cfg = seoServerConfig(useRuntimeConfig(event))
  if (!cfg.enabled) return null
  return fetchResolve(cfg, url, seoForwardedFor(event))
}