var PassThrough = require('stream').PassThrough;
var objectAssign = require('object-assign');

module.exports = function (opts) {
	opts = objectAssign({}, opts);

	var array = opts.array;
	var encoding = opts.encoding;

	var buffer = encoding === 'buffer';
	var objectMode = false;

	if (array) {
		objectMode = !(encoding || buffer);
	} else {
		encoding = encoding || 'utf8';
	}

	if (buffer) {
		encoding = null;
	}

	var len = 0;
	var ret = [];

	var stream = new PassThrough({objectMode: objectMode});

	if (encoding) {
		stream.setEncoding(encoding);
	}

	stream.on('data', function (chunk) {
		ret.push(chunk);

		if (objectMode) {
			len = ret.length;
		} else {
			len += chunk.length;
		}
	});

	stream.getBufferedValue = function () {
		if (array) {
			return ret;
		}
		return buffer ? Buffer.concat(ret, len) : ret.join('');
	};

	stream.getBufferedLength = function () {
		return len;
	};

	return stream;
};