import { Registry, Device } from 'azure-iothub';

async function getDevice(deviceId: string, registry: Registry): Promise<Device | undefined> {
    try {
        const response = await registry.get(deviceId);
        return response.responseBody;
    } catch {
        return undefined;
    }
}

async function getOrCreateDevice(i: number, registry: Registry): Promise<Device> {
    const deviceId = "simulated-device-" + (i + 1);
    let device = await getDevice(deviceId, registry);
    if (!device) {
        await registry.addDevices([{ deviceId }]);
        device = await getDevice(deviceId, registry);
        if (!device) {
            throw new Error("Creating a simulated device failed");
        }
    }
    return device;
}

async function getDevices(registry: Registry, count: number): Promise<Device[]> {
    const devices = [];
    for (let i = 0; i < count; i++) {
        const device = await getOrCreateDevice(i, registry);
        devices.push(device);
    }
    return devices;
}