// The list a participant actually gets to choose from., done-when 1.
//
// A browser's device list is NOT a menu. It carries entries with empty ids (what a browser reports
// before permission is granted - and `startAudioInput('')` is a silent no-op, i.e. a dead control),
// entries with empty LABELS for the same reason, and the duplicate `default` / `communications`
// aliases Windows adds for one physical microphone. On the machine that produced this card it also
// carried an OBS Virtual Camera and two DroidCam sources ahead of the real hardware.
//
// The product used to take `devices[0]` and never ask, which is how a patient ends up silent for a
// whole visit on a virtual microphone they did not know was selected. This is what makes asking
// possible; the picker is what asks.
import type { MediaKind } from './mediaFailure';

export interface DeviceChoice {
    deviceId: string;
    label: string;
}

const NOUN: Record<MediaKind, string> = { microphone: 'Microphone', camera: 'Camera' };

export function deviceChoices(
    devices: Array<{ deviceId?: string; label?: string }> | undefined,
    kind: MediaKind,
): DeviceChoice[] {
    const seen = new Set<string>();
    const choices: DeviceChoice[] = [];

    (devices ?? []).forEach((device) => {
        const deviceId = device?.deviceId;
        // An entry with no id cannot be selected. Rendering it is a control that does nothing.
        if (!deviceId || seen.has(deviceId)) return;
        seen.add(deviceId);
        choices.push({
            deviceId,
            // Positional, and numbered over the KEPT list rather than the raw one, so the names a user
            // sees are 1..n with no gaps where a dropped entry used to be.
            label: device.label?.trim() || `${NOUN[kind]} ${choices.length + 1}`,
        });
    });

    return choices;
}