const db = require('../db');
const {
  findArticlesByEmbedding,
  findSimilarArticles,
  getEmbeddingBuffer,
  getOrCreateQueryEmbedding,
} = require('../embeddings');

function buildArticlesQuery(query) {
  const conditions = [];
  const params = [];
  const includeEmbedding = String(query.include_embedding || '').toLowerCase() === 'true';

  if (query.keyword) {
    conditions.push('(title LIKE ? OR description LIKE ? OR content LIKE ?)');
    const keyword = `%${query.keyword}%`;
    params.push(keyword, keyword, keyword);
  }

  if (query.source) {
    conditions.push('source = ?');
    params.push(query.source);
  }

  if (query.from) {
    conditions.push('pub_date >= ?');
    params.push(query.from);
  }

  if (query.to) {
    conditions.push('pub_date <= ?');
    params.push(query.to);
  }

  const whereClause = conditions.length > 0 ? `WHERE ${conditions.join(' AND ')}` : '';
  const limit = Number.parseInt(query.limit, 10);
  const offset = Number.parseInt(query.offset, 10);

  params.push(Number.isFinite(limit) && limit > 0 ? Math.min(limit, 100) : 20);
  params.push(Number.isFinite(offset) && offset >= 0 ? offset : 0);

  return {
    sql: `
      SELECT id, title, description, content, image, ${includeEmbedding ? 'embedding,' : ''} url, normalized_title, source, pub_date, ingested_at
      FROM articles
      ${whereClause}
      ORDER BY COALESCE(pub_date, ingested_at) DESC, id DESC
      LIMIT ? OFFSET ?
    `,
    params,
  };
}

async function articleRoutes(fastify) {
  fastify.get('/articles', async (request, reply) => {
    const query = request.query || {};
    if (query.include_embedding) {
      reply.code(400);
      return { error: 'Embeddings are not returned directly. Use similar_to_article for vector search.' };
    }

    if (query.semantic !== undefined) {
      const limit = Number.parseInt(query.limit, 10);
      const embedding = await getOrCreateQueryEmbedding(query.semantic);

      if (!embedding) {
        reply.code(400);
        return { error: 'Semantic query must not be empty' };
      }

      const neighbors = findArticlesByEmbedding(
        embedding,
        Number.isFinite(limit) && limit > 0 ? Math.min(limit, 100) : 20
      );
      const ids = neighbors.map((row) => row.articleId);
      if (ids.length === 0) {
        return [];
      }

      const placeholders = ids.map(() => '?').join(', ');
      const articles = db.prepare(`
        SELECT id, title, description, content, image, url, normalized_title, source, pub_date, ingested_at
        FROM articles
        WHERE id IN (${placeholders})
      `).all(...ids);
      const byId = new Map(articles.map((article) => [article.id, article]));

      return neighbors
        .map((row) => {
          const article = byId.get(row.articleId);
          return article ? { ...article, distance: row.distance } : null;
        })
        .filter(Boolean);
    }

    if (query.similar_to_article) {
      const limit = Number.parseInt(query.limit, 10);
      const articleId = Number.parseInt(query.similar_to_article, 10);
      const neighbors = findSimilarArticles(
        articleId,
        Number.isFinite(limit) && limit > 0 ? Math.min(limit, 100) : 20
      );

      if (neighbors.length === 0 && !getEmbeddingBuffer(articleId)) {
        reply.code(404);
        return { error: 'Embedding not found for article' };
      }

      const ids = neighbors.map((row) => row.articleId);
      if (ids.length === 0) {
        return [];
      }

      const placeholders = ids.map(() => '?').join(', ');
      const articles = db.prepare(`
        SELECT id, title, description, content, image, url, normalized_title, source, pub_date, ingested_at
        FROM articles
        WHERE id IN (${placeholders})
      `).all(...ids);
      const byId = new Map(articles.map((article) => [article.id, article]));

      return neighbors
        .map((row) => {
          const article = byId.get(row.articleId);
          return article ? { ...article, distance: row.distance } : null;
        })
        .filter(Boolean);
    }

    const { sql, params } = buildArticlesQuery(query);
    return db.prepare(sql).all(...params);
  });

  fastify.get('/articles/:id', async (request, reply) => {
    if (String((request.query || {}).include_embedding || '').toLowerCase() === 'true') {
      reply.code(400);
      return { error: 'Embeddings are not returned directly. Use similar_to_article for vector search.' };
    }

    const article = db.prepare(`
      SELECT id, title, description, content, image, url, normalized_title, source, pub_date, ingested_at
      FROM articles
      WHERE id = ?
    `).get(request.params.id);

    if (!article) {
      reply.code(404);
      return { error: 'Article not found' };
    }

    return article;
  });
}

module.exports = articleRoutes;