Invoke-ATMCashDispenser.ps1

function Invoke-ATMCashDispenser {
    param([int]$AmountRequested)

    class UnitOfWork {
        hidden [int]$Amt
        [int]$Request
        [int]$NumberOf50
        [int]$NumberOf20
        [int]$NumberOf10
        [int]$NumberOf5

        UnitOfWork($amt) { $this.Request = $this.Amt = $amt }
    }

    class ATMHandler {
        [ATMHandler] $successor

        ATMHandler() {}
        ATMHandler($successor) { $this.successor = $successor }
        handleRequest([UnitOfWork]$request) {}
    }


    class ATM50Handler : ATMHandler {
        ATM50Handler() : base() {}
        ATM50Handler($successor) : base($successor) {}

        handleRequest([UnitOfWork]$request) {
            while ($request.Amt -ge 50) {
                $request.Amt -= 50
                $request.NumberOf50 += 1
            }

            if ([ATMHandler]$this.successor) {
                [ATMHandler]$this.successor.handleRequest($request)
            }
        }
    }

    class ATM20Handler : ATMHandler {
        ATM20Handler() : base() {}
        ATM20Handler($successor) : base($successor) {}

        handleRequest([UnitOfWork]$request) {
            while ($request.Amt -ge 20) {
                $request.Amt -= 20
                $request.NumberOf20 += 1
            }

            if ([ATMHandler]$this.successor) {
                [ATMHandler]$this.successor.handleRequest($request)
            }
        }
    }

    class ATM10Handler : ATMHandler {
        ATM10Handler() : base() {}
        ATM10Handler($successor) : base($successor) {}

        handleRequest([UnitOfWork]$request) {
            while ($request.Amt -ge 10) {
                $request.Amt -= 10
                $request.NumberOf10 += 1
            }

            if ([ATMHandler]$this.successor) {
                [ATMHandler]$this.successor.handleRequest($request)
            }
        }
    }

    class ATM5Handler : ATMHandler {
        ATM5Handler() : base() {}
        ATM5Handler($successor) : base($successor) {}

        handleRequest([UnitOfWork]$request) {
            while ($request.Amt -ge 5) {
                $request.Amt -= 5
                $request.NumberOf5 += 1
            }

            if ([ATMHandler]$this.successor) {
                [ATMHandler]$this.successor.handleRequest($request)
            }
        }
    }

    function Invoke-Withdrawal {
        param(
            [Parameter(Mandatory)]
            $Amt
        )

        $ATM5 = [ATM5Handler]::new()
        $ATM10 = [ATM10Handler]::new($ATM5)
        $ATM20 = [ATM20Handler]::new($ATM10)
        $ATM50 = [ATM50Handler]::new($ATM20)

        $request = [UnitOfWork]::new($amt)
        $ATM50.handleRequest($request)

        $request
    }

    Invoke-Withdrawal $AmountRequested
}