import Database from 'better-sqlite3';
import path from 'path';
import fs from 'fs';

const DATA_DIR = process.env.DATA_DIR ?? '/data';
const DB_DIR = path.join(DATA_DIR, 'db');
const DB_PATH = path.join(DB_DIR, 'memer.db');

fs.mkdirSync(DB_DIR, { recursive: true });

const db = new Database(DB_PATH);

// Enable WAL mode for better concurrent read performance
db.pragma('journal_mode = WAL');
db.pragma('foreign_keys = ON');

db.exec(`
  CREATE TABLE IF NOT EXISTS memes (
    id          TEXT PRIMARY KEY,
    title       TEXT NOT NULL,
    description TEXT,
    file_path   TEXT NOT NULL,
    file_name   TEXT NOT NULL,
    file_size   INTEGER NOT NULL,
    mime_type   TEXT NOT NULL,
    width       INTEGER NOT NULL,
    height      INTEGER NOT NULL,
    parent_id   TEXT REFERENCES memes(id) ON DELETE CASCADE,
    created_at  TEXT NOT NULL DEFAULT (datetime('now'))
  );

  CREATE TABLE IF NOT EXISTS tags (
    id   INTEGER PRIMARY KEY AUTOINCREMENT,
    name TEXT UNIQUE NOT NULL COLLATE NOCASE
  );

  CREATE TABLE IF NOT EXISTS meme_tags (
    meme_id TEXT NOT NULL REFERENCES memes(id) ON DELETE CASCADE,
    tag_id  INTEGER NOT NULL REFERENCES tags(id) ON DELETE CASCADE,
    PRIMARY KEY (meme_id, tag_id)
  );

  CREATE INDEX IF NOT EXISTS idx_memes_parent_id ON memes(parent_id);
  CREATE INDEX IF NOT EXISTS idx_memes_created_at ON memes(created_at DESC);
  CREATE INDEX IF NOT EXISTS idx_meme_tags_meme_id ON meme_tags(meme_id);
  CREATE INDEX IF NOT EXISTS idx_meme_tags_tag_id ON meme_tags(tag_id);
`);

export default db;