import { db } from './db';
import { getOrCreateTag } from './tags';
import { getPostTags } from './tags';

// Load the blog post into a SQLite database
// This allows us to index and make queries against the metadata
// to support functions like search, filtering, and sorting
// as well as return either the post or the full AppShell with the post content
export function addToDatabase(filePath: string, data: { [key: string]: any }, content: string) {
  if (!data) return;

  // Use a transaction to ensure data consistency
  const transaction = db.transaction(() => {
    try {
      // Extract common fields
      const { title, date, readingTime, tags, excerpt } = data;

      // Convert all values to strings or null explicitly (except tags)
      // Ensure date is stored in ISO format for consistent sorting
      const values = [
        filePath ? String(filePath) : null,
        title ? String(title) : null,
        date ? (date instanceof Date ? date.toISOString().split('T')[0] : String(date)) : null,
        readingTime ? String(readingTime) : null,
        excerpt ? String(excerpt) : null,
        content ? String(content) : null
      ];

      // Query to insert or replace metadata (without tags)
      const insertPost = db.query(`
        INSERT OR REPLACE INTO posts
        (path, title, date, reading_time, summary, content)
        VALUES (?, ?, ?, ?, ?, ?)
      `);

      insertPost.run(...values);

      // Get the post ID
      const getPostId = db.query('SELECT id FROM posts WHERE path = ?');
      const postResult = getPostId.get(filePath) as { id: number } | undefined;
      if (!postResult) {
        throw new Error(`Failed to retrieve post ID for ${filePath}`);
      }

      // Delete existing tag associations for this post
      const deleteExistingTags = db.query('DELETE FROM post_tags WHERE post_id = ?');
      deleteExistingTags.run(postResult.id);

      // If tags exist, process them
      if (tags && Array.isArray(tags)) {
        // Insert into junction table
        const insertPostTag = db.query('INSERT OR IGNORE INTO post_tags (post_id, tag_id) VALUES (?, ?)');

        for (const tag of tags) {
          const tagId = getOrCreateTag(String(tag));
          insertPostTag.run(postResult.id, tagId);
        }
      }

    } catch (error) {
      console.error(`Failed to store ${filePath}:`, error);
      throw error; // Re-throw to make the transaction fail
    }
  });

  // Execute the transaction
  try {
    transaction();
  } catch (error) {
    console.error(`Transaction failed for ${filePath}:`, error);
  }
}

// Returns the total number of posts

export function getNumOfPosts() {
  const queryCount = db.query('SELECT COUNT(*) AS count FROM posts');
  const numPosts = queryCount.get() as { count: number };

  return numPosts.count;
}

// Helper function to get post data with tags
export function getPostWithTags(postPath: string) {
  const getPost = db.query(`
    SELECT * FROM posts WHERE path = ?
  `);

  const post = getPost.get(postPath) as any;
  if (!post) return null;

  // Get tags for this post
  if (post.id) {
    post.tags = getPostTags(post.id);
  }

  return post;
}

// Get recent posts
export function getRecentPosts(limit: number = 10, offset: number = 0) {
  const query = db.query(`
    SELECT * FROM posts
    WHERE path NOT LIKE '%.md'
    ORDER BY date DESC
    LIMIT ? OFFSET ?
  `);

  const posts = query.all(limit, offset) as any[];

  // Add tags to each post and clean up paths
  return posts.map(post => ({
    ...post,
    tags: getPostTags(post.id),
    path: post.path.replace(/^.*\/content\//, '/').replace(/\.md$/, '')
  }));
}

// Get all posts
export function getAllPosts() {
  const query = db.query(`
    SELECT * FROM posts
    ORDER BY date DESC
  `);

  const posts = query.all() as any[];

  // Add tags to each post
  return posts.map(post => ({
    ...post,
    tags: getPostTags(post.id)
  }));
}

// Helper function to get a post by its path
export function getPostByPath(path: string) {
  const query = db.query(`
    SELECT * FROM posts
    WHERE path = ?
  `);

  const post = query.get(path) as any;
  if (!post) return null;

  // Get tags for this post
  post.tags = getPostTags(post.id);

  return post;
}

// Helper function to calculate read time
export function calculateReadTime(content: string): number {
  const wordsPerMinute = 200;
  const words = content.split(/\s+/).length;
  return Math.max(1, Math.ceil(words / wordsPerMinute));
}

// Helper function to format date for display
export function formatDate(dateString: string): string {
  // Parse ISO date string (YYYY-MM-DD)
  const date = new Date(dateString + 'T00:00:00');
  
  return date.toLocaleDateString('en-US', {
    year: 'numeric',
    month: 'long',
    day: 'numeric'
  });
}

// Get adjacent posts (previous and next) chronologically for a given post
export function getAdjacentPosts(currentPostPath: string) {
  const allPostsQuery = db.query(`
    SELECT path, title, date
    FROM posts
    WHERE path NOT LIKE '%.md'
    ORDER BY date DESC
  `);

  const allPosts = allPostsQuery.all() as any[];
  
  // Find the current post index
  const currentIndex = allPosts.findIndex(post => post.path === currentPostPath);
  
  // If not found, return empty navigation
  if (currentIndex === -1) {
    return { previousPost: null, nextPost: null };
  }

  // Get previous post (newer post, which comes before current in reverse chronological order)
  let previousPost = null;
  if (currentIndex > 0) {
    const prevPost = allPosts[currentIndex - 1];
    // Clean up the path to match the URL structure
    const cleanPath = prevPost.path.replace(/^.*\/content\//, '/').replace(/\.md$/, '');
    previousPost = {
      title: prevPost.title,
      path: cleanPath
    };
  }

  // Get next post (older post, which comes after current in reverse chronological order)
  let nextPost = null;
  if (currentIndex < allPosts.length - 1) {
    const post = allPosts[currentIndex + 1];
    // Clean up the path to match the URL structure
    const cleanPath = post.path.replace(/^.*\/content\//, '/').replace(/\.md$/, '');
    nextPost = {
      title: post.title,
      path: cleanPath
    };
  }

  return { previousPost, nextPost };
}