functions/configuration/Unregister-DbatoolsConfig.ps1

function Unregister-DbatoolsConfig
{
<#
    .SYNOPSIS
        Removes registered configuration settings.
     
    .DESCRIPTION
        Removes registered configuration settings.
        This function can be used to remove settings that have been persisted for either user or computer.
     
        Note: This command has no effect on configuration setings currently in memory.
     
    .PARAMETER ConfigurationItem
        A configuration object as returned by Get-DbatoolsConfig.
     
    .PARAMETER FullName
        The full name of the configuration setting to purge.
     
    .PARAMETER Module
        The module, amongst which settings should be unregistered.
     
    .PARAMETER Name
        The name of the setting to unregister.
        For use together with the module parameter, to limit the amount of settings that are unregistered.
     
    .PARAMETER Scope
        Settings can be set to either default or enforced, for user or the entire computer.
        By default, only DefaultSettings for the user are unregistered.
        Use this parameter to choose the actual scope for the command to process.
     
    .EXAMPLE
        PS C:\> Get-DbatoolsConfig | Unregister-DbatoolsConfig
     
        Completely removes all registered configurations currently loaded in memory.
        In most cases, this will mean removing all registered configurations.
     
    .EXAMPLE
        PS C:\> Unregister-DbatoolsConfig -Scope SystemDefault -FullName 'MyModule.Path.DefaultExport'
     
        Unregisters the setting 'MyModule.Path.DefaultExport' from the list of computer-wide defaults.
        Note: Changing system wide settings requires running the console with elevation.
     
    .EXAMPLE
        PS C:\> Unregister-DbatoolsConfig -Module MyModule
     
        Unregisters all configuration settings for the module MyModule.
#>

    [CmdletBinding(DefaultParameterSetName = 'Pipeline')]
    param (
        [Parameter(ValueFromPipeline = $true, ParameterSetName = 'Pipeline')]
        [Sqlcollaborative.Dbatools.Configuration.Config[]]
        $ConfigurationItem,
        
        [Parameter(ValueFromPipeline = $true, ParameterSetName = 'Pipeline')]
        [string[]]
        $FullName,
        
        [Parameter(Mandatory = $true, ParameterSetName = 'Module')]
        [string]
        $Module,
        
        [Parameter(ParameterSetName = 'Module')]
        [string]
        $Name = "*",
        
        [Sqlcollaborative.Dbatools.Configuration.ConfigScope]
        $Scope = "UserDefault"
    )
    
    begin
    {
        if (($PSVersionTable.PSVersion.Major -ge 6) -and ($PSVersionTable.OS -notlike "*Windows*") -and ($Scope -band 15))
        {
            Stop-Function -Message "Cannot unregister configurations from registry on non-windows machines." -Tag 'NotSupported' -Category ResourceUnavailable
            return
        }
        
        #region Initialize Collection
        $registryProperties = @()
        if ($Scope -band 1)
        {
            if (Test-Path $script:path_RegistryUserDefault) { $registryProperties += Get-ItemProperty -Path $script:path_RegistryUserDefault }
        }
        if ($Scope -band 2)
        {
            if (Test-Path $script:path_RegistryUserEnforced) { $registryProperties += Get-ItemProperty -Path $script:path_RegistryUserEnforced }
        }
        if ($Scope -band 4)
        {
            if (Test-Path $script:path_RegistryMachineDefault) { $registryProperties += Get-ItemProperty -Path $script:path_RegistryMachineDefault }
        }
        if ($Scope -band 8)
        {
            if (Test-Path $script:path_RegistryMachineEnforced) { $registryProperties += Get-ItemProperty -Path $script:path_RegistryMachineEnforced }
        }
        $pathProperties = @()
        if ($Scope -band 16)
        {
            $fileUserLocalSettings = @()
            if (Test-Path (Join-Path $script:path_FileUserLocal "psf_config.json")) { $fileUserLocalSettings = Get-Content (Join-Path $script:path_FileUserLocal "psf_config.json") -Encoding UTF8 | ConvertFrom-Json }
            if ($fileUserLocalSettings)
            {
                $pathProperties += [pscustomobject]@{
                    Path       = (Join-Path $script:path_FileUserLocal "psf_config.json")
                    Properties = $fileUserLocalSettings
                    Changed    = $false
                }
            }
        }
        if ($Scope -band 32)
        {
            $fileUserSharedSettings = @()
            if (Test-Path (Join-Path $script:path_FileUserShared "psf_config.json")) { $fileUserSharedSettings = Get-Content (Join-Path $script:path_FileUserShared "psf_config.json") -Encoding UTF8 | ConvertFrom-Json }
            if ($fileUserSharedSettings)
            {
                $pathProperties += [pscustomobject]@{
                    Path       = (Join-Path $script:path_FileUserShared "psf_config.json")
                    Properties = $fileUserSharedSettings
                    Changed    = $false
                }
            }
        }
        if ($Scope -band 64)
        {
            $fileSystemSettings = @()
            if (Test-Path (Join-Path $script:path_FileSystem "psf_config.json")) { $fileSystemSettings = Get-Content (Join-Path $script:path_FileSystem "psf_config.json") -Encoding UTF8 | ConvertFrom-Json }
            if ($fileSystemSettings)
            {
                $pathProperties += [pscustomobject]@{
                    Path       = (Join-Path $script:path_FileSystem "psf_config.json")
                    Properties = $fileSystemSettings
                    Changed    = $false
                }
            }
        }
        #endregion Initialize Collection
        
        $common = 'PSPath', 'PSParentPath', 'PSChildName', 'PSDrive', 'PSProvider'
    }
    process
    {
        if (Test-FunctionInterrupt) { return }
        # Silently skip since no action necessary
        if (-not ($pathProperties -or $registryProperties)) { return }
        
        foreach ($item in $ConfigurationItem)
        {
            # Registry
            foreach ($hive in ($registryProperties | Where-Object { $_.PSObject.Properties.Name -eq $item.FullName }))
            {
                Remove-ItemProperty -Path $hive.PSPath -Name $item.FullName
            }
            # Prepare file
            foreach ($fileConfig in ($pathProperties | Where-Object { $_.Properties.FullName -contains $item.FullName }))
            {
                $fileConfig.Properties = $fileConfig.Properties | Where-Object FullName -NE $item.FullName
                $fileConfig.Changed = $true
            }
        }
        
        foreach ($item in $FullName)
        {
            # Ignore string-casted configurations
            if ($item -ceq "Sqlcollaborative.Dbatools.Configuration.Config") { continue }
            
            # Registry
            foreach ($hive in ($registryProperties | Where-Object { $_.PSObject.Properties.Name -eq $item }))
            {
                Remove-ItemProperty -Path $hive.PSPath -Name $item
            }
            # Prepare file
            foreach ($fileConfig in ($pathProperties | Where-Object { $_.Properties.FullName -contains $item }))
            {
                $fileConfig.Properties = $fileConfig.Properties | Where-Object FullName -NE $item
                $fileConfig.Changed = $true
            }
        }
        
        if ($Module)
        {
            $compoundName = "{0}.{1}" -f $Module, $Name
            
            # Registry
            foreach ($hive in ($registryProperties | Where-Object { $_.PSObject.Properties.Name -like $compoundName }))
            {
                foreach ($propName in $hive.PSObject.Properties.Name)
                {
                    if ($propName -in $common) { continue }
                    
                    if ($propName -like $compoundName)
                    {
                        Remove-ItemProperty -Path $hive.PSPath -Name $propName
                    }
                }
            }
            # Prepare file
            foreach ($fileConfig in ($pathProperties | Where-Object { $_.Properties.FullName -like $compoundName }))
            {
                $fileConfig.Properties = $fileConfig.Properties | Where-Object FullName -NotLike $compoundName
                $fileConfig.Changed = $true
            }
        }
    }
    end
    {
        if (Test-FunctionInterrupt) { return }
        
        foreach ($fileConfig in $pathProperties)
        {
            if (-not $fileConfig.Changed) { continue }
            
            if ($fileConfig.Properties)
            {
                $fileConfig.Properties | ConvertTo-Json | Set-Content -Path $fileConfig.Path -Encoding UTF8
            }
            else
            {
                Remove-Item $fileConfig.Path
            }
        }
    }
}