const PROTOCOL_PACKAGE_NAME = '@vela/protocol';

const SESSION_STATES = Object.freeze(['idle', 'listening', 'thinking', 'speaking']);

const CLIENT_EVENT_TYPES = Object.freeze([
	'session.start',
	'input_audio.append',
	'input_audio.commit',
	'response.cancel'
]);

const SERVER_EVENT_TYPES = Object.freeze([
	'session.ready',
	'session.state',
	'transcript.partial',
	'transcript.final',
	'response.text.delta',
	'response.completed',
	'error'
]);

function createMessageEnvelope(type, payload) {
	return { type, payload };
}

function isMessageEnvelope(value) {
	return Boolean(
		value &&
		typeof value === 'object' &&
		typeof value.type === 'string' &&
		'payload' in value
	);
}

function isClientEventType(type) {
	return CLIENT_EVENT_TYPES.includes(type);
}

function isServerEventType(type) {
	return SERVER_EVENT_TYPES.includes(type);
}

module.exports = {
	PROTOCOL_PACKAGE_NAME,
	SESSION_STATES,
	CLIENT_EVENT_TYPES,
	SERVER_EVENT_TYPES,
	createMessageEnvelope,
	isMessageEnvelope,
	isClientEventType,
	isServerEventType
};