function send-teamsmessage( $message ) {
    $message
    $splat = @{
        uri         = $uri
        method      = 'Post'
        body        = ConvertTo-Json -Compress @{ text = $message }
        erroraction = 'Ignore'
    }
    Invoke-RestMethod @splat | Out-Null
}

function compare-time( $actual ) {
    if ( $actual -match ',' ) {
        $result = $actual.Split(',').Trim() | ForEach-Object { parse-time $_ }
    }
    else {
        $result = parse-time $actual
    }
    if ($result) { $true }
}

function parse-time( $inputillo ) {
    try {
        $inputillo = (Get-Date $inputillo).DayOfYear
    } 
    catch {
        "Not Datetime" | Out-Null
    }
    if ( $inputillo -eq $timeDate.week -or $inputillo -eq $timeDate.day -or $inputillo -eq $timeDate.year ) {
        $true
    }
    if ( $inputillo -eq 'start') {
        $global:entityStart = $false
    }
    if ( $inputillo -eq 'stop') {
        $global:entityStop = $false
    }
}

function parse-entity( $inputillo ) {
    try {
        $action = $null; $global:entityStop = $global:entityStart = $true
        $schedule = $inputillo.schedule | ConvertFrom-Json -ErrorAction Stop
        if ( compare-time $schedule.ignore ) {
            "Skipped: {0}." -f $inputillo.Id
            continue
        }
        $data = $schedule.($timeDate.week)
        [int]$start, [int]$stop = $data.Split("-")
        $currentHour = $timeDate.hour + [int]$schedule.UTC
        if ( $currentHour -lt 0 ) { # there is possibly a better way of doing this, but this works
            $currentHour = $currentHour + 24
        }
        if ( $currentHour -gt 23 ) {
            $currentHour = $currentHour - 24
        }
        if ( ( $start - $stop ) -eq 0 -or ( $start - $stop ) -ge 20 ) {
            $global:messages += "Error: Malformed Start\Stop at {0}" -f $inputillo.Id
            continue
        }
        if ( $currentHour -eq $stop -and $global:entityStop ) {
            $action = $mapper[$inputillo.Type].action
        }
        elseif ( $currentHour -eq $start -and $global:entityStart ) {
            $action = "Start"
        }
        if ( $action ) { 
            $global:processed += New-Object -TypeName psobject -Property @{
                action = $action
                apiVer = $mapper[$inputillo.Type].apiver
                delay  = $( if ( $schedule.delayed ) { $true } else { $false } )
                id     = $inputillo.id
            }
        }
    }
    catch {
        $global:messages += "Error: Malformed JSON at {0}" -f $inputillo.Id
    }
}

function process-entity( $inputillo, $header ) {
    try {
        "Performing action {0} on {1}" -f $inputillo.action, $inputillo.Id
        $uri = "https://management.azure.com{0}/{1}?api-version={2}" -f $inputillo.Id, $inputillo.action, $inputillo.apiVer
        $global:requests += Invoke-WebRequest -Headers $header -Method Post -Uri $uri -UseBasicParsing | Add-Member @{ id = $inputillo.Id } -PassThru
    }
    catch {
        Write-Error $_
        $global:messages += "Error: start\stop operation failed at {0}" -f $inputillo.id
        $retries += $inputillo
    }
}

# Initialize variables 
$uri = Get-AutomationVariable -Name 'teamsWebhookUri' # this is needed to send notification to teams
$all = $processed = $requests = $messages = $retries = @(); $startTime = Get-Date; [Int32]$maxRetry = 5; [Int32]$retry = 0
$mapper = @{
    'Microsoft.Network/applicationGateways'     = @{
        action = 'stop'
        apiver = '2017-04-01'
    }
    'Microsoft.Compute/virtualMachines'         = @{
        action = 'deallocate'
        apiver = '2017-03-30'
    }
    'Microsoft.Compute/virtualMachineScaleSets' = @{
        action = 'deallocate'
        apiver = '2017-03-30'
    }
    'Microsoft.ClassicCompute/virtualMachines'  = @{
        action = 'shutdown'
        apiver = '2017-04-01'
    }
}
$timeDate = New-Object psobject -Property @{
    hour = $startTime.ToUniversalTime().Hour
    day  = $startTime.DayOfWeek
    week = if ($startTime.DayOfWeek -notin "Sunday", "Saturday") { "weekdays" } else { "weekends" }
    year = $startTime.DayOfYear
}

do { # Connect to Azure
    $Error.Clear(); $retry++;
    $servicePrincipalConnection = Get-AutomationConnection -Name "vm-start-stop"
    Add-AzureRmAccount -ServicePrincipal -TenantId $servicePrincipalConnection.TenantId `
        -CertificateThumbprint $servicePrincipalConnection.CertificateThumbprint `
        -ApplicationId $servicePrincipalConnection.ApplicationId | Out-Null
    $token = (Get-AzureRmContext).TokenCache.ReadItems() | Select-Object -First 1 -ExpandProperty AccessToken
    $header = @{ Authorization = "Bearer $token" }

    (Get-AzureRmSubscription).Where{ $_.name -notmatch 'prd|prod' }.foreach{ # Get resources except production\stale subs
        Select-AzureRmSubscription $PSItem | Out-Null
        $resources = Get-AzureRmResource -ODataQuery "`$filter=tagname eq 'schedule'" -ExpandProperties
        $cvms = (Get-AzureRmResourceGroup).Where{ $_.tags.classicSchedule }.foreach{
            $schedule = $_.tags.classicSchedule
            Get-AzureRmResource -ResourceType Microsoft.ClassicCompute/virtualMachines -ResourceGroupName $_.ResourceGroupName |
                Add-Member @{ Tags = @{ schedule = $schedule } } -PassThru -Force
        }
        $all += ($resources, $cvms).foreach{ # Build array of resources to iterate over
            $PSItem | ForEach-Object {
                [psobject]@{
                    Type     = $_.ResourceType
                    Id       = $_.ResourceId
                    Schedule = $_.Tags.schedule
                }   
            }
        }
    }
} while ( $Error.Count -gt 0 -and $maxRetry -ge $retry)

if ( $Error.Count -gt 0 ) { send-teamsmessage ( "{0} FATAL: runbook failed. {1}" -f (Get-Date), $Error[0] ) } # possibly exit here

try {
    "Parsing {0} resource entities" -f $all.Count
    # Runbook payload begins here
    foreach ( $entity in $all ) { parse-entity $entity }
    $processed.where{ $_.Delay -ne $true -or $_.Action -ne 'Start' }.foreach{ process-entity $PSItem $header}
    if ( $processed.where{ $_.Delay -eq $true -and $_.Action -eq 'Start' } ) {
        # Waiting before processing delayed resources
        Start-Sleep -Seconds 600
        $processed.where{ $_.Delay -eq $true -and $_.Action -eq 'Start' }.foreach{ process-entity $PSItem $header }
    }
}
catch {
    # Possibly restart runbook and\or determine state and restart failed
    Write-Error $_
    send-teamsmessage ( "{0} FATAL: runbook failed. {1}" -f (Get-Date), $PSItem )
}

if ( $retries ) {
    $retries.foreach{ process-entity $PSItem $header }
}

if ( $messages ) {
    $messages
    send-teamsmessage ("examine start\stop job state at {1}" -f (Get-Date))
}

$subs = Get-AzureRmSubscription

# Resource start\stop role
$role = Get-AzureRmRoleDefinition "Virtual Machine Contributor"
$role.Id = $null
$role.Name = "Resource Start/Stop (Scheduled)"
$role.Description = "Can read\start\stop VMs, VMSSs, Application Gateways, and read resource groups"
$role.Actions.Clear()
$role.Actions.Add("Microsoft.ClassicCompute/virtualMachines/read")
$role.Actions.Add("Microsoft.ClassicCompute/virtualMachines/start/action")
$role.Actions.Add("Microsoft.ClassicCompute/virtualMachines/shutdown/action")
$role.Actions.Add("Microsoft.ClassicCompute/virtualMachines/operationStatuses/read")
$role.Actions.Add("Microsoft.Compute/virtualMachines/deallocate/action")
$role.Actions.Add("Microsoft.Compute/virtualMachines/read")
$role.Actions.Add("Microsoft.Compute/virtualMachines/restart/action")
$role.Actions.Add("Microsoft.Compute/virtualMachines/start/action")
$role.Actions.Add("Microsoft.Compute/virtualMachineScaleSets/read")
$role.Actions.Add("Microsoft.Compute/virtualMachineScaleSets/start/action")
$role.Actions.Add("Microsoft.Compute/virtualMachineScaleSets/deallocate/action")
$role.Actions.Add("Microsoft.Network/applicationGateways/read")
$role.Actions.Add("Microsoft.Network/applicationGateways/start/action")
$role.Actions.Add("Microsoft.Network/applicationGateways/stop/action")
$role.Actions.Add("Microsoft.Resources/subscriptions/resourceGroups/read")
$role.AssignableScopes.Clear()
$subs | ForEach-Object {
    $scope = "/subscriptions/{0}" -f $_.Id
    $role.AssignableScopes.Add($scope)
}
$def = New-AzureRmRoleDefinition -Role $role

$subs | ForEach-Object {
    $_ | Select-AzureRmSubscription
    New-AzureRmRoleAssignment -ObjectId your_runbook_service_principal_object_id -RoleDefinitionId $def.id -Scope "/subscriptions/$($_.id)"
}