const assert = require("node:assert/strict");
const fs     = require("node:fs");

const sqlite = require("./napi-sqlite.node");
const { difference, log } = require("./utils");


const MIGRATIONS_DIR = __dirname + "/sql/migrations/";
const MIGRATION_FILENAMES = fs.readdirSync(MIGRATIONS_DIR, "UTF-8");

let db = null;
const init = async (dbName = process.env.PAPO_DB_PATH) => {
	assert(dbName);

	db = await sqlite.open(dbName);
	await db.exec(`
		BEGIN TRANSACTION;
		CREATE TABLE IF NOT EXISTS migrations (
			filename TEXT PRIMARY KEY
		);
		COMMIT TRANSACTION;
	`);

	const done = await db.all(`
		SELECT filename FROM migrations;
	`).map(row => row.filename);
	const pending = difference(
		new Set(MIGRATION_FILENAMES),
		new Set(done)
	);
	const sortedPending = [...pending].sort((a, b) => a.localeCompare(b));

	await db.exec("BEGIN TRANSACTION;");
	for (const filename of sortedPending) {
		log({
			log: "exec-migration",
			filename,
		});
		const sql = fs.readFileSync(MIGRATIONS_DIR + filename, "UTF-8");
		await db.exec(sql);
		await db.run(
			`INSERT INTO migrations (filename) VALUES ($filename);`,
			{ filename },
		);
	}
	await db.exec("COMMIT TRANSACTION;");
};

module.exports = {
	init,
};