Reveiw #1

gistfile1.ps1

#How it works:
    #switch to p4 branch
    #get changes from p4
        ## gets changelist number workspace is synced to
        ## gets list of changelists that is present on server and don't at my workspace
    #commit change-by-change to p4 branch on behalf of corresponding users
    #switch back the to previous branch

Param(
    [Switch]$Preview,
    [Switch]$ShortPreview,
)
$Env:P4CHARSET = "utf8"

# You do not need parse arguments, I added construction that will work for you
# also PowerShell does not require full argument, you can type first letters
# just to ensure that first letter are not clash with other arguments
#if ($args[0] -eq "-preview" -or $args[0] -eq "-p") {$preview = $TRUE } 
#else { 
#   $shortPreview = $FALSE
#   $preview = $FALSE 
#}

#if ($args[1] -eq "-preview-short" -or $args[1] -eq "-ph") {
#   $preview = $TRUE
#   $shortPreview = $TRUE 
#} 
#else { $shortPreview = $FALSE }

if ($ShortPreview){
   $Preview = $True
}

Function ExitIfPreviousCommandFailed() {
    if ($LastExitCode -ne 0){
        Write-Host "Command failed." -ForegroundColor Red
        Exit 1
    }
}
#getting current branch from the list of branches
Function GetCurrentBranch() {
    $currentBranch = git br --contains HEAD

    $currentBranch | foreach { 
        if ($_.Contains("* ")) {
            $currentBranch = $_.Replace("* ", "")
        }
    }

    return $currentBranch
}
# get list of p4 users
Function GetAllP4Users() {  
    $p4Users = @{}
    p4 users | foreach {
        if ($_ -Match "(?<name>(\w|\S)*) <(?<email>.*)> \((?<wellformedName>.*)\)") {

            # NOTE: Just use hashtables
            # $p4User = @{}
            # $p4User.Name = $matches["name"]
            # Or even
            # $p4User = @{"Name" = $matches["name"], "Email" = $matches["email"],}

            $p4User = New-Object PsObject |            
                Add-Member NoteProperty Name $matches["name"] -PassThru |             
                Add-Member NoteProperty Email $matches["email"] -PassThru |
                Add-Member NoteProperty WellformedName $matches["wellformedName"] -PassThru 

            $p4Users.Add($p4User.Name, $p4User)
        }
    }

    return $p4Users
}
#get current changelist workspace is updted to
Function GetCurrentWorkspaceChangelist($currentDirectory) {
    if (p4 changes -m 1 "$currentDirectory...#have" | Where-Object {$_ -Match "Change (?<changesetId>\d+) on"} ) {
        Return $matches["changesetId"]  
    }
}

$currentDir = Get-Location
$currentBranch = GetCurrentBranch

if ($currentBranch -ne "p4") {
    #Write-Host "Stashing changes..." -ForegroundColor DarkYellow
    #git stash
    Write-Host "Checking out p4 branch..." -ForegroundColor DarkYellow
    git checkout p4
    ExitIfPreviousCommandFailed
}

$currentChangelist = GetCurrentWorkspaceChangelist($currentDir)
Write-Host "p4 workspace is updated to: " -ForegroundColor DarkYellow -NoNewLine
Write-Host ("@" + $currentChangelist) -ForegroundColor Yellow


$p4Users = GetAllP4Users

#get list of changes that is in between current changelist and #head
[Array]$aggregatedOutput = @()
$changeList = ""
$firstIteration = $TRUE

p4 changes -t -l -s submitted "$currentDir...@$currentChangelist,#head" | 
    foreach {
        if ($_ -Match "Change \d+" -and -not $firstIteration) {
            #add combined changelist to array
            $aggregatedOutput = $aggregatedOutput + $changeList 
            $changeList = ""
        }

        $changeList = $changeList + $_.Trim() + "`r`n"

        if ($firstIteration) { $firstIteration = $FALSE }
    }

if ($aggregatedOutput.length -eq 0) { 
    Write-Host "Git is okay with that =)" -ForegroundColor Green
}
else {
    Write-Host "Changelist that are not in the workspace yet [" -ForegroundColor Yellow -NoNewLine
    Write-Host $aggregatedOutput.length -ForegroundColor Cyan -NoNewLine
    Write-Host "]:" -ForegroundColor Yellow
}

#get list of changelist objects
[Array]$p4Changelists = @()
$aggregatedOutput | foreach {
    if ($_ -Match "Change (?<changelistId>\d+) on (?<date>\d\d\d\d/\d\d/\d\d \d\d:\d\d:\d\d) by (?<author>[\w._]+)@.*\r\n\r\n(?<comments>(.*[\r\n]?)*)" ) {
        
        if ($preview -and -not $shortPreview) {
            Write-Host $matches["changelistId"]  -ForegroundColor White -NoNewLine
            Write-Host ""$matches["date"] -ForegroundColor DarkGray -NoNewLine
            Write-Host ""$matches["author"]  -ForegroundColor Blue -NoNewLine
            Write-Host `n $matches["comments"].Trim() -ForegroundColor DarkCyan
        }
        $author = $matches["author"]

        if (-not $p4Users.ContainsKey($author)) {
            # Write-Host "Commit author: '$author' was not recognized. Check what is wrong using 'p4 users' command."  -ForegroundColor Red
             $p4User = New-Object PsObject |            
                Add-Member NoteProperty Name $author -PassThru |             
                Add-Member NoteProperty Email ($author + "@fake-email.com") -PassThru |
                Add-Member NoteProperty WellformedName $author -PassThru 
        }
        else {
            $p4User = $p4Users[$author]
        }
    
        $p4Changelist = New-Object PsObject |            
            Add-Member NoteProperty Id $matches["changelistId"] -PassThru |             
            Add-Member NoteProperty Date $matches["date"] -PassThru |
            Add-Member NoteProperty Comments $matches["comments"] -PassThru |
            Add-Member NoteProperty Author ($p4User.WellformedName + " <" + $p4User.Email + ">") -PassThru

        $p4Changelists += $p4Changelist
    }
}

#update workspace to changelists one by one and commit changes to git
if (-not $preview) {
    $p4Changelists | sort Id | foreach {

        Write-Host "Updating workspace to changelist @$($_.Id)" -ForegroundColor DarkYellow
        p4 sync -q ("$currentDir...@" + $_.Id) 
        ExitIfPreviousCommandFailed

        Write-Host "Committing changes to git..." -ForegroundColor DarkYellow
        git add -A

        #write git commits to a temp file to allow multiline comments, I was unable to get them working in other way
        #NOTE You do not need System
        $tempFile = [IO.Path]::GetTempFileName()
        # NOTE you can use Add-Content instead of WriteAllLines
        # ac $tempFile  $_.Comments
        [System.IO.File]::WriteAllLines($tempFile, $_.Comments)

        #Write-Host "git commit -m `"$($comments)`" --author `"$($_.Author)`" --date `"$($_.Date)`""
        git commit -F "$tempFile" --author "`"$($_.Author)`"" --date "`"$($_.Date)`"" --allow-empty --allow-empty-message
        #todo: sync workspace to previous changelist if something failed on git side
        ExitIfPreviousCommandFailed
        #tag git commit with changelist id
        git tag ("@" + $_.Id) -f
    }
}

#switch back to previous branch and un-stash changes
if ($currentBranch -ne "p4") {
    git checkout $currentBranch
    #Write-Host "un-stashing changes..." -ForegroundColor DarkYellow
    #git stash pop
}