// The SEO layer's settings as the server code reads them from runtime
// config. Pure TypeScript outside Nitro's auto-import directories, so
// `node --test`, the middleware and the routes import it directly.

import { seoEnabled } from '../../app/utils/seo.ts'

export interface SeoServerConfig {
  /** False when public.seo.enabled or its alias public.seo.cms is false: no CMS call at all. */
  enabled: boolean
  /** Server-only base of the plugin's API (NUXT_SEO_API_BASE), without a trailing slash. */
  apiBase: string
  /** Server-only origin of the Go binary for the root files (NUXT_SEO_BACKEND_BASE). */
  backendBase: string
  /** How long a call may take before the page renders without it (NUXT_SEO_TIMEOUT_MS). */
  timeoutMs: number
  /** Seconds a resolve answer stays cached (NUXT_SEO_RESOLVE_CACHE_TTL); 0 turns the cache off. */
  resolveCacheTtl: number
  /** Bearer token of POST /notfound (NUXT_SEO_NOTFOUND_TOKEN); empty: no reports. */
  notfoundToken: string
  /** Bearer token of the route report; falls back to notfoundToken. */
  routeReportToken: string
  /** Module option seo.routeReport (NUXT_PUBLIC_SEO_ROUTE_REPORT): report the static routes at start. */
  routeReport: boolean
  /** Module option seo.rootFiles: serve robots.txt, the sitemaps, llms.txt and the listed root files. */
  rootFiles: boolean
  /** Module option seo.resolveFiles: file extensions the middleware still resolves (['pdf']). */
  resolveFiles: string[]
}

export const DEFAULT_SEO_API_BASE = 'http://127.0.0.1:8096/_seo/api/v1'
export const DEFAULT_RESOLVE_CACHE_TTL = 60

const API_SUFFIX = /\/_seo\/api\/v1\/?$/

function section(config: unknown, name: string): Record<string, unknown> {
  if (config === null || typeof config !== 'object') return {}
  const value = (config as Record<string, unknown>)[name]
  return value !== null && typeof value === 'object' ? (value as Record<string, unknown>) : {}
}

const str = (v: unknown) => (typeof v === 'string' ? v.trim() : typeof v === 'number' ? String(v) : '')

function num(v: unknown, fallback: number): number {
  if (v === '' || v === null || v === undefined) return fallback
  const n = Number(v)
  return Number.isFinite(n) && n >= 0 ? n : fallback
}

/**
 * The backend origin for root files: backendBase when set, else apiBase
 * without its /_seo/api/v1 suffix (so an app that only sets
 * NUXT_SEO_API_BASE needs nothing else), else apiBase's origin.
 */
export function seoBackendBase(backendBase: string, apiBase: string): string {
  if (backendBase) return backendBase.replace(/\/+$/, '')
  if (API_SUFFIX.test(apiBase)) return apiBase.replace(API_SUFFIX, '')
  try {
    return new URL(apiBase).origin
  } catch {
    return ''
  }
}

/** Reads the layer's settings from a runtime config object (useRuntimeConfig(event)). */
export function seoServerConfig(config: unknown): SeoServerConfig {
  const seo = section(config, 'seo')
  const pub = section(section(config, 'public'), 'seo')
  const apiBase = (str(seo.apiBase) || DEFAULT_SEO_API_BASE).replace(/\/+$/, '')
  const notfoundToken = str(seo.notfoundToken)
  const resolveFiles = Array.isArray(pub.resolveFiles) ? pub.resolveFiles.filter((e): e is string => typeof e === 'string') : ['pdf']
  return {
    enabled: seoEnabled(pub),
    apiBase,
    backendBase: seoBackendBase(str(seo.backendBase), apiBase),
    timeoutMs: num(seo.timeoutMs, 1500) || 1500,
    resolveCacheTtl: num(seo.resolveCacheTtl, DEFAULT_RESOLVE_CACHE_TTL),
    notfoundToken,
    routeReportToken: str(seo.routeReportToken) || notfoundToken,
    routeReport: pub.routeReport !== false && pub.routeReport !== 'false',
    rootFiles: pub.rootFiles !== false && pub.rootFiles !== 'false',
    resolveFiles,
  }
}