page-helpers.ts

import type { Metadata } from 'next'
import { baseURL, defaultOGImage, defaultSEOConfig } from '@/app/metadata'
import { seo } from '@/config'

export interface PageMetadata {
  title?: string
  description?: string
  keywords?: string[]
  slug?: string
  featuredImage?: string
  focusKeyword?: string | string[]
  readingTimeMinutes?: number
  date?: string
  categories?: string[]
  publishDate?: string
  modifiedDate?: string
  alternates?: { canonical?: string }
  authors?: { name: string; url?: string }[]
  category?: string
  applicationName?: string
  referrer?: string
  /**
   * Per-page indexing override. Omit to inherit the site default (indexed).
   * Set `{ index: false }` on pages that must not reach search results.
   * e.g. unwritten legal placeholders.
   */
  robots?: { index?: boolean; follow?: boolean }
  openGraph?: {
    type?: 'website' | 'article'
    locale?: string
    url?: string
    siteName?: string
    title?: string
    description?: string
    image?: {
      url: string
      alt?: string
    }
  }
  twitter?: {
    card?: 'summary' | 'summary_large_image' | 'app' | 'player'
    site?: string
    creator?: string
    title?: string
    description?: string
    image?: string
  }
  other?: Record<string, string>
  structuredData?: object[]
}

export function generatePageMetadata(
  metadata: PageMetadata,
  slug?: string[]
): Metadata {
  return {
    title: metadata?.title || 'Page',
    description: metadata?.description || 'A page on our website',
    keywords: metadata?.keywords || undefined,
    other: {
      ...(metadata?.publishDate && {
        'article:published_time': metadata.publishDate,
      }),
      ...(metadata?.modifiedDate && {
        'article:modified_time': metadata.modifiedDate,
      }),
      ...metadata?.other,
    },
    alternates: metadata?.alternates?.canonical
      ? { canonical: `${baseURL}${metadata.alternates.canonical}` }
      : undefined,
    authors: metadata?.authors || undefined,
    creator: defaultSEOConfig.creator,
    publisher: defaultSEOConfig.publisher,
    category: metadata?.category || undefined,
    applicationName: metadata?.applicationName || undefined,
    referrer: 'origin-when-cross-origin',
    // A page-level `robots` override wins over the site default, so a single
    // page can be excluded from search without changing global config.
    robots: metadata?.robots
      ? { ...defaultSEOConfig.robots, ...metadata.robots }
      : defaultSEOConfig.robots,
    openGraph: {
      type: metadata?.openGraph?.type || 'website',
      locale: metadata?.openGraph?.locale || 'en_US',
      url:
        metadata?.openGraph?.url ||
        `${baseURL}${slug ? `/${slug.join('/')}` : ''}`,
      siteName: metadata?.openGraph?.siteName || seo.siteName,
      title: metadata?.openGraph?.title || metadata?.title || 'Page',
      description:
        metadata?.openGraph?.description ||
        metadata?.description ||
        'A page on our website',
      images: [
        {
          ...defaultOGImage,
          ...(metadata?.openGraph?.image?.alt && {
            alt: metadata.openGraph.image.alt,
          }),
        },
      ],
    },
    twitter: {
      card: metadata?.twitter?.card || 'summary_large_image',
      site: metadata?.twitter?.site || undefined,
      creator: metadata?.twitter?.creator || undefined,
      title:
        metadata?.twitter?.title ||
        metadata?.openGraph?.title ||
        metadata?.title ||
        'Page',
      description:
        metadata?.twitter?.description ||
        metadata?.openGraph?.description ||
        metadata?.description ||
        'A page on our website',
      images: defaultOGImage.url ? [defaultOGImage.url] : undefined,
    },
  }
}