const MsRest = require('ms-rest-azure');
var computeManagementClient = require('azure-arm-compute');
const SUBSCRIPTION_ID = "62ebff8f-c40b-41be-9239-252d6c0c8ad9";

var computeClient;
function auth(cb) {
    if ( computeClient ) {
        cb(computeClient);
    } else {
        MsRest.loginWithMSI({ port: 50342 }, function(err, credentials){
            if (err) {
                console.log("Could not authenticate with Azure", err);
                return;
            }
            computeClient = new computeManagementClient(credentials, SUBSCRIPTION_ID);
            cb(computeClient);
        });
    }
}

async function asyncForEach(array, callback) {
    for (let index = 0; index < array.length; index++) {
        await callback(array[index], index, array);
    }
}

function deallocate(resourceGroupName, cb) {
    try {
        console.log("Deallocating VMs for resource group: "+resourceGroupName);
        auth(async function(computeClient){
            let finalResult = await computeClient.virtualMachines.list(resourceGroupName);
            let out = [];
            await asyncForEach(finalResult, async function(vm)  {
                let res = await computeClient.virtualMachines.deallocate(resourceGroupName, vm.name);
                out.push(res);
            });
            console.log("All VMs DEALLOCATED for resource group: "+resourceGroupName);
            cb(null, out);
        })  
    } catch (err) {
        console.log("Error deallocating VMs for resource group: "+resourceGroupName);
        cb(err, null);
    }
    
}

function start(resourceGroupName, cb){
    try {
        console.log("Starting VMs for resource group: "+resourceGroupName);
        auth(async function(computeClient){
            let finalResult = await computeClient.virtualMachines.list(resourceGroupName);
            let out = [];
            await asyncForEach(finalResult, async function(vm)  {
                let res = await computeClient.virtualMachines.start(resourceGroupName, vm.name);
                out.push(res);
            });
            console.log("All VMs RUNNING for resource group: "+resourceGroupName);
            cb(null,out);
        });
    } catch (err) {
        console.log("Error starting VMs for resource group: "+resourceGroupName);
        cb(err, null);
    }
    
}

function getResourceGroupVms(resourceGroupName, cb){
    auth(function(computeClient){
        computeClient.virtualMachines.list(resourceGroupName, cb);
    });  
}

function getAllVms(cb){
    auth(function(computeClient){
        computeClient.virtualMachines.listAll(cb);
    });  
}

module.exports.start = start;
module.exports.deallocate = deallocate;
module.exports.getResourceGroupVms = getResourceGroupVms;
module.exports.getAllVms = getAllVms;