"use client";

export const DEFAULT_AUDIO_INPUT_DEVICE_ID = "default";

export interface VoiceOverInputDevice {
	deviceId: string;
	label: string;
	isDefault: boolean;
}

export function buildVoiceOverAudioConstraints({
	deviceId,
}: {
	deviceId?: string | null;
}): MediaStreamConstraints {
	const audio: MediaTrackConstraints = {
		echoCancellation: true,
		noiseSuppression: true,
		autoGainControl: true,
	};

	if (deviceId && deviceId !== DEFAULT_AUDIO_INPUT_DEVICE_ID) {
		audio.deviceId = { exact: deviceId };
	}

	return { audio };
}

export function normalizeSelectedDeviceId({
	deviceId,
	devices,
}: {
	deviceId: string | null;
	devices: VoiceOverInputDevice[];
}): string | null {
	if (!deviceId) {
		return null;
	}

	if (deviceId === DEFAULT_AUDIO_INPUT_DEVICE_ID) {
		return deviceId;
	}

	return devices.some((device) => device.deviceId === deviceId)
		? deviceId
		: null;
}

export async function listVoiceOverInputDevices({
	requestPermission = false,
}: {
	requestPermission?: boolean;
} = {}): Promise<VoiceOverInputDevice[]> {
	const mediaDevices = navigator.mediaDevices;
	if (!mediaDevices?.enumerateDevices) {
		throw new Error("Microphone selection is not supported in this browser");
	}

	let permissionStream: MediaStream | null = null;
	if (requestPermission) {
		permissionStream = await mediaDevices.getUserMedia({
			audio: {
				echoCancellation: true,
				noiseSuppression: true,
				autoGainControl: true,
			},
		});
	}

	try {
		const devices = await mediaDevices.enumerateDevices();
		let inputIndex = 1;
		return devices
			.filter((device) => device.kind === "audioinput")
			.map((device) => {
				const isDefault = device.deviceId === DEFAULT_AUDIO_INPUT_DEVICE_ID;
				const fallbackLabel = isDefault
					? "System default microphone"
					: `Microphone ${inputIndex++}`;
				return {
					deviceId: device.deviceId,
					label: device.label || fallbackLabel,
					isDefault,
				};
			});
	} finally {
		if (permissionStream) {
			for (const track of permissionStream.getTracks()) {
				track.stop();
			}
		}
	}
}