import fs from "node:fs";
import path from "node:path";
import matter from "gray-matter";

export type DevblogPost = {
  slug: string;
  title: string;
  date: string;
  excerpt: string;
  author?: string;
  tags?: string[];
  game?: string;
  content: string;
};

const POSTS_DIR = path.join(process.cwd(), "content", "devblog");

function ensureDir() {
  if (!fs.existsSync(POSTS_DIR)) {
    fs.mkdirSync(POSTS_DIR, { recursive: true });
  }
}

export function getAllPosts(): DevblogPost[] {
  ensureDir();
  const files = fs
    .readdirSync(POSTS_DIR)
    .filter((f) => f.endsWith(".mdx") || f.endsWith(".md"));

  const posts = files.map((file) => {
    const slug = file.replace(/\.(mdx|md)$/, "");
    const raw = fs.readFileSync(path.join(POSTS_DIR, file), "utf8");
    const { data, content } = matter(raw);
    return {
      slug,
      title: data.title ?? slug,
      date: data.date ?? new Date().toISOString().slice(0, 10),
      excerpt: data.excerpt ?? "",
      author: data.author,
      tags: data.tags ?? [],
      game: data.game,
      content,
    } as DevblogPost;
  });

  return posts.sort((a, b) => (a.date < b.date ? 1 : -1));
}

export function getPost(slug: string): DevblogPost | undefined {
  return getAllPosts().find((p) => p.slug === slug);
}

export function getPostsByGame(gameSlug: string): DevblogPost[] {
  return getAllPosts().filter(
    (p) => p.game === gameSlug || p.tags?.includes(gameSlug),
  );
}

export function getAdjacentPosts(slug: string): {
  newer?: DevblogPost;
  older?: DevblogPost;
} {
  const posts = getAllPosts();
  const idx = posts.findIndex((p) => p.slug === slug);
  if (idx === -1) return {};
  return {
    newer: idx > 0 ? posts[idx - 1] : undefined,
    older: idx < posts.length - 1 ? posts[idx + 1] : undefined,
  };
}