New-SymFS.ps1

New-SymFS.ps1

$StartTime = Get-Date

# Setup initial parameters
try {
    $UserDirName = $(Get-Item $HOME).Name
    $GoogleDrivePath = "$HOME\Google Drive"
    $GDUserPath = "$GoogleDrivePath\$UserDirName"
    $LogFileName = "NewSymFS_Log_" + $(Get-Date -Format MMddyy_hhmmss) + '.log'
    $LogFileDir = "E:\"
    $LogFilePath = $LogFileDir + $LogFileName
    $FileAgeInMonths = 12

    $FileAgeInDays = $FileAgeInMonths*30.5
    $FileTimeSpan = New-Timespan -Days $FileAgeInDays

    $HomeDirFoldersToExclude = @(
        "Google Drive"
        #"AppData"
    )
    $HomeDirItems = Get-ChildItem -Path $HOME -Directory -Force | Where-Object {$HomeDirFoldersToExclude -notcontains $_.Name}
}
catch {
    Write-Error $_
    if ($LogFileName) {
        $_ >> "$HOME\$LogFileName"
    }
    $global:FunctionResult = "1"
    return
}

# Make sure the $LogFileDir exists
try {
    if (!$(Test-Path $LogFileDir)) {
        $null = New-Item -ItemType Directory -Path $LogFileDir -Force -ErrorAction Stop
    }
}
catch {
    Write-Error $_
    $_ >> "$HOME\$LogFileName"
    $global:FunctionResult = "1"
    return
}

# Make sure we're running PowerShell 7
if ($PSVersionTable.PSVersion.Major -lt 7) {
    $ErrMsg = "This script must be run using PowerShell Core version 7 or greater! Halting!"
    Write-Error $ErrMsg
    $ErrMsg >> $LogFilePath
    $global:FunctionResult = 1
    return
}

# Make sure $HOME\Google Drive exists
if (!$(Test-Path $GoogleDrivePath)) {
    $ErrMsg = "The path $GoogleDrivePath was not found! Halting!"
    Write-Error $ErrMsg
    $ErrMsg >> $LogFilePath
    $global:FunctionResult = "1"
    return
}

# Make sure $GDUserPath exists
if (!$(Test-Path $GDUserPath)) {
    try {
        $null = New-Item -ItemType Directory -Path $GDUserPath -ErrorAction Stop
        if (!$(Test-Path $GDUserPath)) {
            throw "The path $GDUserPath still wasn't created eventhough New-Item didn't throw an error!"
        }
    }
    catch {
        Write-Error $_
        $_ >> $LogFilePath
        $global:FunctionResult = "1"
        return
    }
}

# First, get all directories recursively under $HOME and recreate them (for real) under $GDUserPath so that
# they actually appear in Google Drive
$(Get-Date).ToString() >> $LogFilePath
"`n##### CREATING DIRECTORIES #####`n" >> $LogFilePath
foreach ($HDI in $HomeDirItems) {
    try {
        $ParentNewPath = $HDI.FullName -replace [regex]::Escape($HOME),$GDUserPath
        if (!$(Test-Path $ParentNewPath)) {
            $null = New-Item -ItemType Directory -Path $ParentNewPath -ErrorAction Stop
        }

        Get-ChildItem -Recurse -Path $HDI.FullName -Directory -Force -ErrorAction SilentlyContinue | foreach {
            $NewPath = $_.FullName -replace [regex]::Escape($HOME),$GDUserPath
            if (!$(Test-Path $NewPath)) {
                $null = New-Item -ItemType Directory -Path $NewPath -ErrorAction Stop
            }
        }
    }
    catch {
        $_ >> $LogFilePath
    }
}

# Next, iterate over all files under $HOME.
# If the file is too old, create a symlink under the Google Drive folder so that Google Backup and Sync does NOT actually sync it to Google Drive
# If the file is recent enough, move it to the Google Drive folder and create a hard link from where it was to where it is now (under Google Drive folder)
# Creating a hard link should prevent any problems with programs not expecting a symlink and also not take up any additional space on the HDD
$(Get-Date).ToString() >> $LogFilePath
"`n##### CREATING SYMLINKS AND HARDLINKS #####`n" >> $LogFilePath
foreach ($HDI in $HomeDirItems) {
    Get-ChildItem -Recurse -Path $HDI.FullName -File -Force -ErrorAction SilentlyContinue | foreach {
        $NewPath = $_.FullName -replace [regex]::Escape($HOME),$GDUserPath
        $TestPathCheck = Test-Path $NewPath

        try {
            if ($_.LastWriteTime -le $(Get-Date).Subtract($FileTimeSpan)) {
                # Then the file is too old and should NOT be synced to Google Drive
                # If the path doesn't exist, or if it is does exist but is *not* a symlink, create a symlink
                
                if (!$TestPathCheck) {
                    #Write-Host "$($_.FullName) is too old!"
                    #Write-Host "LastWriteTime is $($_.LastWriteTime)"
                    $null = New-Item -ItemType SymbolicLink -Path $NewPath -Target $_.FullName -ErrorAction Stop
                }
                elseif ($TestPathCheck) {
                    if ($(Get-Item $NewPath -ErrorAction SilentlyContinue).LinkType -ne 'SymbolicLink') {
                        $null = Remove-Item $NewPath -Force -ErrorAction SilentlyContinue
                        $null = New-Item -ItemType SymbolicLink -Path $NewPath -Target $_.FullName -ErrorAction Stop
                    }
                }
            }
            else {
                # The file is recent enough that it SHOULD be synced to Google Drive
                # If the path doesn't exist, or if it is does exist but is *not* a hardlink, create a symlink
                if (!$TestPathCheck) {
                    #Write-Host "$($_.FullName) is recent enough!"
                    #Write-Host "LastWriteTime is $($_.LastWriteTime)"
                    #$null = Move-Item -Path $_.FullName -Destination $NewPath
                    #$null = Invoke-Expression "cmd /c mklink /h `"$NewPath`" `"$($_.FullName)`"" -ErrorAction SilentlyContinue >> $LogFilePath
                    $null = New-Item -ItemType HardLink -Path $NewPath -Target $_.FullName -ErrorAction Stop
                }
                elseif ($TestPathCheck) {
                    if ($(Get-Item $NewPath -ErrorAction SilentlyContinue).LinkType -ne 'HardLink') {
                        $null = Remove-Item $NewPath -Force -ErrorAction SilentlyContinue
                        $null = New-Item -ItemType HardLink -Path $NewPath -Target $_.FullName -ErrorAction Stop
                    }
                }
            }
        }
        catch {
            $_ >> $LogFilePath
        }
    }
}

$EndTime = Get-Date

"`n##### TOTAL RUNTIME #####`n" >> $LogFilePath
$TotalTime = $EndTime - $StartTime
$TotalTime >> $LogFilePath