const ApiError = require('../errorClass');

async function isAuthorExists (id) {
	if (!id || !Number.isInteger(id)) return false;
	return (await global.database.authors.promiseMode().get({ where : { id } })).length !== 0;
}

async function isMuzicExists (id) {
	if (!id || !Number.isInteger(id)) return false;
	let result = (await global.database.muzic.promiseMode().get({ where : { id } })).length !== 0;
	console.log('isMuzicExists', result);
	return result;
}

async function checkSyntaxArgs (req, res) {
	return !!(
		(  // Проверка поля type
			['author', 'muzic'].includes(req.json.type)
		) &&
		(  // Проверка поля name
			req.json.name === undefined ? true : (typeof req.json.name === 'string' && req.json.name.length >= 2)
		) &&
		(  // Проверка id
			req.json.type === 'author' ? await isAuthorExists(req.json.id) : await isMuzicExists(req.json.id)
		) &&
		(  // Проверка при type=muzic
			req.json.type === 'muzic' ? (
				(  // Проверка поля author_id
					req.json.author_id === undefined ? true : await isAuthorExists(req.json.author_id)
				) &&
				(  // Проверка поля data. (Передаётся либо ничего, либо строка с base64)
					req.json.data === undefined ? true : (
						typeof req.json.data === 'string'
					)
				)
			) : true
		)
	)
}

module.exports = async (req, res) => {
	if (req.method !== 'POST') {
		throw new ApiError("METHOD_MUST_BE_POST_JSON", {
			request_method : req.method
		});
	}
	console.log(await checkSyntaxArgs(req, res));
	if (!await checkSyntaxArgs(req, res)) {
		throw new ApiError("INVALID_OR_UNSYNTAX_PARAMS", {
			request_method : req.method,
			params         : {
				id   : req.json.id === undefined ? null : req.json.id,
				type : req.json.type === undefined ? null : req.json.type,
				name : req.json.name === undefined ? null : req.json.name,
				...(req.json.type === 'muzic' ? {
					author_id : req.json.author_id,
					data      : req.json.data
				} : {})
			}
		});
	}
	
	if (req.json.type === 'author') {
		await global.database.authors.promiseMode().edit({
			name : req.json.name
		}, {
			where : {
				id : req.json.id
			}
		});
	}
	else {
		await global.database.muzic.promiseMode().edit({
			name      : req.json.name,
			author_id : req.json.author_id,
			data      : !req.json.data ? undefined : Buffer.from(req.json.data, "base64")
		}, {
			where : {
				id : req.json.id
			}
		});
	}
	return 'ok';
}