Public/Edit-PowerShellProfileToImportTiPS.ps1

function Edit-PowerShellProfileToImportTiPS
{
    [CmdletBinding(SupportsShouldProcess = $true)]
    [OutputType([void])]
    Param()

    Process
    {
        [bool] $moduleIsAlreadyInProfile = Test-PowerShellProfileImportsTiPS
        if ($moduleIsAlreadyInProfile)
        {
            Write-Verbose "PowerShell profile already imports the tiPS module."
            return
        }

        [string] $profileFilePath = GetPowerShellProfileFilePath
        [string] $contentToAddToProfile = 'Import-Module -Name tiPS # Added by tiPS.'

        if ([string]::IsNullOrWhiteSpace($profileFilePath))
        {
            Write-Error "Could not determine the PowerShell profile file path."
            return
        }

        if (-not (Test-Path -Path $profileFilePath -PathType Leaf))
        {
            if ($PSCmdlet.ShouldProcess("PowerShell profile '$profileFilePath'", 'Create'))
            {
                Write-Verbose "Creating PowerShell profile '$profileFilePath'."
                New-Item -Path $profileFilePath -ItemType File -Force > $null
            }
        }

        if ($PSCmdlet.ShouldProcess("PowerShell profile '$profileFilePath'", 'Update'))
        {
            Write-Verbose "Adding '$contentToAddToProfile' to PowerShell profile '$profileFilePath'."
            Add-Content -Path $profileFilePath -Value $contentToAddToProfile -Force
        }
    }
}

# Use a function to get the file path so we can mock this function for testing.
function GetPowerShellProfileFilePath
{
    [string] $profileFilePath = [string]::Empty

    # The $PROFILE variable may not exist depending on the host or the context in which PowerShell was started.
    if (Test-Path -Path variable:PROFILE)
    {
        $profileFilePath = $PROFILE.CurrentUserAllHosts
    }

    return $profileFilePath
}