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

async function checkSyntaxArgs (req, res) {
	return !!(
		(  // Проверка поля offset
			req.query.id === undefined ? true : Number.isInteger(+req.query.offset)
		) &&
		(  // Проверка поля offset
			req.query.offset === undefined ? true : Number.isInteger(+req.query.offset)
		) &&
		(  // Проверка поля count
			req.query.count === undefined ? true : Number.isInteger(+req.query.count)
		) &&
		(  // Проверка поля min_date
			req.query.min_date === undefined ? true : Number.isInteger(+req.query.min_date)
		) &&
		(  // Проверка поля max_date
			req.query.max_date === undefined ? true : Number.isInteger(+req.query.max_date)
		) &&
		(  // Проверка поля q. (Ключевые слова для поиска)
			true  // (Проверки нет, query всегда строка, необязательный параметр)
		)
	)
}

module.exports = async (req, res) => {
	if (req.method !== 'GET') {
		throw new ApiError("METHOD_MUST_BE_GET", {
			request_method : req.method
		});
	}
	if (!await checkSyntaxArgs(req, res)) {
		throw new ApiError("INVALID_OR_UNSYNTAX_PARAMS", {
			request_method : req.method,
			params         : {
				id     : req.query?.id === undefined ? null : req.query.id,
				q      : req.query?.q === undefined ? null : req.query.q,
				offset : req.query?.offset === undefined ? null : req.query.offset,
				count  : req.query?.count === undefined ? null : req.query.count,
				min_date  : req.query?.min_date === undefined ? null : req.query.min_date,
				max_date  : req.query?.max_date === undefined ? null : req.query.max_date
			}
		});
	}
	
	
	const offset = req.query.offset === undefined ? 0 : +req.query.offset;
	const countFromNull = req.query.count === undefined ? undefined : offset + (+req.query.count);
	
	let result = (await global.database.authors.promiseMode().get(
		req.query.id === undefined ? {} : {
			id : +req.query.id
		}
	)).map(i => ({
		id   : i.id,
		name : i.name,
		date : i.time
	}));
	// Если просят выборку по времени
	if (req.query.min_date || req.query.max_date) {
		const minDate = req.query.min_date === undefined ? 0 : +req.query.min_date;
		const maxDate = req.query.max_date === undefined ? 1e+32 : +req.query.max_date;
		
		result = result.filter((res) => minDate <= res.date && res.date <= maxDate);
	}
	
	if (req.query?.q !== undefined) {
		result = result.filter(i => {
			const search = req.query.q.toLowerCase();
			return i.name.toLowerCase().includes(search);
		});
	}
	
	result = result.slice(offset, countFromNull);
	return {
		count : result.length,
		items : result
	};
}