'use strict';
const fs = require('fs');
const Database = require('../.');

describe('Database#pragma(\'wal_checkpoint(RESTART)\')', function () {
	let db1, db2;
	before(function () {
		db1 = new Database(util.next());
		db2 = new Database(util.next());
		db1.pragma('journal_mode = WAL');
		db1.prepare('CREATE TABLE entries (a TEXT, b INTEGER)').run();
		db2.pragma('journal_mode = WAL');
		db2.prepare('CREATE TABLE entries (a TEXT, b INTEGER)').run();
	});
	after(function () {
		db1.close();
		db2.close();
	});

	function fillWall(count, expectation) {
		[db1, db2].forEach((db) => {
			let size1, size2;
			for (let i = 0; i < count; ++i) {
				size1 = fs.statSync(`${db.name}-wal`).size;
				db.prepare('INSERT INTO entries VALUES (?, ?)').run('bar', 999);
				size2 = fs.statSync(`${db.name}-wal`).size;
				expectation(size2, size1, db);
			}
		});
	}

	describe('when used without a specified database', function () {
		specify('every insert should increase the size of the WAL file', function () {
			fillWall(10, (b, a) => expect(b).to.be.above(a));
		});
		specify('inserts after a checkpoint should NOT increase the size of the WAL file', function () {
			db1.prepare(`ATTACH '${db2.name}' AS foobar`).run();
			db1.pragma('wal_checkpoint(RESTART)');
			fillWall(10, (b, a) => expect(b).to.equal(a));
		});
	});
	describe('when used on a specific database', function () {
		specify('every insert should increase the size of the WAL file', function () {
			db1.prepare('DETACH foobar').run();
			db1.close();
			db2.close();
			db1 = new Database(db1.name);
			db2 = new Database(db2.name);
			db1.prepare('CREATE TABLE _unused (a TEXT, b INTEGER)').run();
			db2.prepare('CREATE TABLE _unused (a TEXT, b INTEGER)').run();
			fillWall(10, (b, a) => expect(b).to.be.above(a));
		});
		specify('inserts after a checkpoint should NOT increase the size of the WAL file', function () {
			db1.prepare(`ATTACH '${db2.name}' AS bazqux`).run();
			db1.pragma('bazqux.wal_checkpoint(RESTART)');
			fillWall(10, (b, a, db) => {
				if (db === db1) expect(b).to.be.above(a);
				else expect(b).to.be.equal(a);
			});
		});
	});
});