powerPing

# The variables in order of their appearence:
# $it = Main while loop interation number.
# $content = The entire contents of the hosts.txt as an array.
# $upperBound = The zero-based number of array objects in hosts.txt. i.e.: Five objects will return a value of 4.
# $selHost = The current line# of hosts.txt that the script is operating on.
# $alive = Did the test-connection work? Returns a boolean value.

function main(){ # Load a few initial variables and call secondary.
    clear
    $failures = @()
    $content = (GET-CONTENT .\hosts.txt)
    $upperBound = $content.getUpperBound(0)
    # Loads the config options as variables to be used later.
        $smtpServer = (get-content .\config.txt)[0]
        $alertSubject = (get-content .\config.txt)[1]
        $alertBody = (get-content .\config.txt)[2]
        $alertRecipient = (get-content .\config.txt)[3]
        $alertSender = (get-content .\config.txt)[4]
        #write-host "$smtpServer"
        #write-host "$alertSubject"
        #write-host "$alertBody"
        #write-host "$alertRecipient"
        #write-host "$alertSender"

    function secondary(){ # Contains the main loop and a few other misc things.
        while([int]$it -lt [int]$upperBound) { # Stops the loop if the iteration number exceeds the number of objects in $content.
            $it = [int]$it + [int]1 # Advances the value of $it by +1 every time it runs.
            $iteration = $it + 1
            write-host "Iteration $iteration"
            $selHost = (GET-CONTENT .\hosts.txt)[$it] # Grabs the line number $it from hosts.txt and wraps it in $selHost.
            write-host "Connecting to: $selHost"
            $alive = test-connection $selHost -count 2 -delay 1 -quiet
            $alertSubject
            start-sleep -s 1

            function testing(){ # Decides what to do with the results of the test-connection.
                if($alive){ # What to do if the test-connection returns "true".
                    if($failures -contains $selhost){
                        $temp = @()
                        foreach($computer in $failures){ # Removes $selhost from $failures if it was added previously, but has come back online.
                            if($computer -ne $selhost){
                                $temp += $computer
                            }
                        }
                        $failures = $temp

                        write-host "The connection to $selHost has succeded!"
                        start-sleep -s 1
                        secondary
                    }
                    elseif($failures -notcontains $selhost){
                        write-host "The connection to $selHost has succeded!"
                        start-sleep -s 1
                        secondary
                    }
                }
                elseif($alive = 'False'){ # What to do if the test-connection returns "false".
                        write-host "The connection to $selHost has failed!"
                    if($failures -notcontains $selhost){
                        write-host "Going in for failTesting..."
                        start-sleep -s 3
                        failTesting
                    }
                    elseif($failures -contains $selhost){
                        start-sleep -s 1
                        secondary
                    }
                }
            }
            start-sleep -s 1
            testing
        }
        # The following chunk of code runs at the end of every loop.
        $it = "-1"
        start-sleep -s 1
        write-host "Restarting loop in five seconds..."
        start-sleep -s 5
        clear
        secondary
    }
    function sendAlert(){ # Sends email alert using variables defined in config.txt and restarts the looping process.
        send-mailmessage -to "$alertRecipient" -from "$alertSender" -subject "$alertSubject" -body "$alertBody" -smtpServer "$smtpServer"
        secondary
    }
    function failTesting(){ # Tests the failed host three more times and then adds it to $failures and calls sendAlert if it doesn't pass.
        for ($i = 0; $i -lt 3; $i++){
            $alive = test-connection $selHost -count 2 -delay 1 -quiet
            if($alive){
                write-host "The connection to $selHost has succeded!"
                secondary
            }
            elseif($alive = 'False'){
                write-host "The connection to $selHost has failed!"
            }
        }
        start-sleep -s 1
        write-host "The connection to $selhost failed too many times."
        $failures += ,$selhost
        sendAlert
    }
    $it = "-1"
    secondary
}
main