import type { Metadata } from "next"
import { businessConfig } from "@/lib/seo-config"
import { buildAbsoluteUrl, ogImagePath } from "@/lib/seo-registry"

/**
 * Clean HTML entities from text (e.g., & -> &, " -> ")
 */
function cleanHtmlEntities(text: string): string {
  if (!text) return ""
  return text
    .replace(/&/g, "&")
    .replace(/"/g, '"')
    .replace(/'/g, "'")
    .replace(/&lt;/g, "<")
    .replace(/&gt;/g, ">")
    .replace(/&nbsp;/g, " ")
    .trim()
}

export interface SEOData {
  title: string
  description: string
  excerpt?: string
  date?: string
  modified?: string
  image?: string
  robots?: Metadata["robots"]
  path?: string
  keywords?: string[]
}

/**
 * Generate SEO metadata for a WordPress page/post
 */
export function generateSEOMetadata(data: SEOData): Metadata {
  const {
    title,
    description,
    excerpt,
    date,
    modified,
    image,
    robots,
    path,
    keywords,
  } = data

  const cleanTitle = cleanHtmlEntities(title)
  const fullTitle = cleanTitle.includes(`| ${businessConfig.name}`)
    ? cleanTitle
    : `${cleanTitle} | ${businessConfig.name}`
  let seoDescription = cleanHtmlEntities(description || excerpt || "")
    .replace(/\s+/g, " ")
    .trim()

  if (!seoDescription) {
    seoDescription =
      "Rocky Mountain Vending provides vending machine placement, service, repairs, and support across Utah."
  } else if (seoDescription.length > 165) {
    seoDescription = `${seoDescription.slice(0, 162).trim()}...`
  }

  const ogImage = image || ogImagePath
  const canonicalUrl = path ? buildAbsoluteUrl(path) : undefined

  const openGraph: NonNullable<Metadata["openGraph"]> = {
    title: fullTitle,
    description: seoDescription,
    type: date || modified ? "article" : "website",
    ...(canonicalUrl ? { url: canonicalUrl } : {}),
    images: [
      {
        url: ogImage,
        width: 1200,
        height: 630,
        alt: cleanTitle,
      },
    ],
    siteName: businessConfig.name,
    ...(date && { publishedTime: date }),
    ...(modified && { modifiedTime: modified }),
  }

  const metadata: Metadata = {
    title: fullTitle,
    description: seoDescription,
    keywords,
    openGraph,
    twitter: {
      card: "summary_large_image",
      title: fullTitle,
      description: seoDescription,
      images: [ogImage],
    },
    alternates: canonicalUrl ? { canonical: canonicalUrl } : undefined,
    robots,
  }

  return metadata
}

/**
 * Generate structured data (JSON-LD) for a page
 */
export function generateStructuredData(data: {
  title: string
  description: string
  url: string
  datePublished?: string
  dateModified?: string
  type?: "Article" | "WebPage"
}) {
  const {
    title,
    description,
    url,
    datePublished,
    dateModified,
    type = "WebPage",
  } = data

  const structuredData: Record<string, unknown> = {
    "@context": "https://schema.org",
    "@type": type,
    headline: cleanHtmlEntities(title),
    description: cleanHtmlEntities(description),
    url: url,
  }

  if (datePublished) {
    structuredData.datePublished = datePublished
  }
  if (dateModified) {
    structuredData.dateModified = dateModified
  }

  if (type === "Article") {
    structuredData.author = {
      "@type": "Organization",
      name: businessConfig.name,
      url: businessConfig.website,
    }
    structuredData.publisher = {
      "@type": "Organization",
      name: businessConfig.name,
      legalName: businessConfig.legalName,
      url: businessConfig.website,
      logo: {
        "@type": "ImageObject",
        url: `${businessConfig.website}/rmv-logo.png`,
        width: 180,
        height: 45,
      },
    }
    structuredData.mainEntityOfPage = {
      "@type": "WebPage",
      "@id": url,
    }
  }

  return structuredData
}