Param(
    [int]$bufferSize=100,
    [int]$numThreads=4,
    [string]$sampleFileLocation="c:\users\1530983\desktop\ass2-20000.txt"
);
set-strictmode -version 2.0;

[int]$global:threadBufferSize = ($bufferSize / $numThreads);

$global:jobSubTotals = @{};

$global:threadScript = {
    Param($subThreads, [int[]]$items, $threadName);

    #Checks if number is prime
    function isPrime([int]$num) {
        if ($num % 2 -eq 0) {
            return $false;
        }

        for ($i = 3; $i * $i -lt $num; $i += 2) {
            if ($num % $i -eq 0) {
                return $false;
            }
        }
        return $true;
    }

    #Calculate subtotal value for this thread
    [int]$subTotal = 0;
    foreach($item in $items) {
        if ((isPrime $item)) {
            $subTotal += $item;
        }
    }

    Add-Content ("c:\users\1530983\desktop\thread_" + $threadName + ".txt") $subTotal;
    Add-Content ("c:\users\1530983\desktop\threadWait_" + $threadName + ".txt") "\n";

    $subThreads.Reverse();#Reverse sub threads to start by getting oldest thread first
    foreach($job in $subThreads) {
        Add-Content ("c:\users\1530983\desktop\threadWait_" + $threadName + ".txt") ("Waiting on " + $job.Name);
        Wait-Job -Job $job;
        Add-Content ("c:\users\1530983\desktop\threadWait_" + $threadName + ".txt") ("Got job " + $subThreadName + " " + $job.Name);

        $subTotal += Receive-Job -Job $job;
    }
    Add-Content ("c:\users\1530983\desktop\thread_" + $threadName + ".txt") "Done";
    return $subTotal;
};

function StartThreads {
    Param([int[]]$items, $threadName);
    [int]$subThreadCount = 0;
    $subThreads = New-Object System.Collections.ArrayList;

    while ($items.Count -gt $threadBufferSize + 1) {#Loop until this thread has proper buffer size
        [int]$subThreadSize = $items.Count / 2;

        #Start thread using first have of $items
        [int[]]$subItems = @(0) * $subThreadSize;
        [int]$subItemIndex = 0;
        foreach ($subItemIndex in 0..($subThreadSize - 1)) {
            $subItems[$subItemIndex] = $items[$subItemIndex];
        }

        #Start sub thread
        StartThreads -items $subItems -threadName ($threadName + "-" + $subThreadCount);
        $job = Get-Job -Name ($threadName + "-" + $subThreadCount);
        $subThreads.Add($job);
        $subThreadCount++;

        #Get new $items using second have of current $items
        [int[]]$subItems = @(0) * ($items.Count - $subThreadSize);
        $subItemIndex++;
        $newItemIndex = 0;
        foreach ($subItemIndex in $subItemIndex..($items.Count - 1)) {
            $subItems[$newItemIndex] = $items[$subItemIndex];
            $newItemIndex++;
        }
        $items = $subItems;
    }

    Start-Job -ScriptBlock $threadScript -ArgumentList @($subThreads, $items, $threadName) -Name $threadName;
}

$file = New-Object System.IO.StreamReader -Arg $sampleFileLocation;
[int[]]$arr = @();
[int]$index = 0;
[int]$total = 0;

while ($line = $file.ReadLine()) {
    $arr += $line;
    $index++;

    if ($index -eq $bufferSize) {#Buffer full, time to process
        $mainThreadName = "MainJob";
        StartThreads -items $arr -threadName $mainThreadName;

        $job = Get-Job -Name $mainThreadName;
        Wait-Job -Job $job;

        $total += Receive-Job -Job $job;
        Remove-Job *;


        #Reset buffer
        $index = 0;
        $arr = @();
    }
}
echo $total;

$file.close();