import type { Article } from '@/types/nostr'

/**
 * Find similar articles based on category and title keywords
 */
export function findSimilarArticles(currentArticle: Article, allArticles: Article[], limit: number = 3): Article[] {
  if (!currentArticle.category) {
    return []
  }

  const currentTitleWords = extractKeywords(currentArticle.title)
  const similar = allArticles
    .filter((article) => {
      if (article.id === currentArticle.id || article.isPresentation) {
        return false
      }
      if (article.category !== currentArticle.category) {
        return false
      }
      const articleTitleWords = extractKeywords(article.title)
      return hasCommonKeywords(currentTitleWords, articleTitleWords)
    })
    .sort((a, b) => {
      const aWords = extractKeywords(a.title)
      const bWords = extractKeywords(b.title)
      const aScore = countCommonKeywords(currentTitleWords, aWords)
      const bScore = countCommonKeywords(currentTitleWords, bWords)
      return bScore - aScore
    })
    .slice(0, limit)

  return similar
}

/**
 * Find articles by the same author
 */
export function findAuthorArticles(currentArticle: Article, allArticles: Article[], limit: number = 3): Article[] {
  return allArticles
    .filter((article) => {
      if (article.id === currentArticle.id || article.isPresentation) {
        return false
      }
      return article.pubkey === currentArticle.pubkey
    })
    .sort((a, b) => b.createdAt - a.createdAt)
    .slice(0, limit)
}

/**
 * Find articles in the same category
 */
export function findCategoryArticles(currentArticle: Article, allArticles: Article[], limit: number = 3): Article[] {
  if (!currentArticle.category) {
    return []
  }

  return allArticles
    .filter((article) => {
      if (article.id === currentArticle.id || article.isPresentation) {
        return false
      }
      return article.category === currentArticle.category
    })
    .sort((a, b) => b.createdAt - a.createdAt)
    .slice(0, limit)
}

function extractKeywords(text: string): string[] {
  return text
    .toLowerCase()
    .split(/\s+/)
    .filter((word) => word.length > 3)
    .filter((word, index, array) => array.indexOf(word) === index)
}

function hasCommonKeywords(words1: string[], words2: string[]): boolean {
  return words1.some((word) => words2.includes(word))
}

function countCommonKeywords(words1: string[], words2: string[]): number {
  return words1.filter((word) => words2.includes(word)).length
}