PATH.psm1

[CmdletBinding()]
param()

if ($PSVersionTable.PSVersion -lt '6.0') {
    [Diagnostics.CodeAnalysis.SuppressMessageAttribute(
        'PSAvoidAssignmentToAutomaticVariable', '', Justification = 'Compatibility with PowerShell 6.0 and newer.'
    )]
    $IsWindows = [System.Environment]::OSVersion.Platform -eq 'Win32NT'
}

$scriptName = 'PATH'
Write-Verbose "[$scriptName] - Importing module"

#region - From [public]
Write-Verbose "[$scriptName] - [public] - Processing folder"

#region - From [public] - [Add-EnvironmentPath]
Write-Verbose "[$scriptName] - [public] - [Add-EnvironmentPath] - Importing"

#Requires -Modules Admin

function Add-EnvironmentPath {
    <#
    .SYNOPSIS
    Add a path to the PATH environment variable.

    .DESCRIPTION
    Add a path to the PATH environment variable. This command will normalize the path separators.

    .EXAMPLE
    Add-EnvironmentPath -Scope CurrentUser -Path 'C:\Program Files\Git\cmd'

    Add the path 'C:\Program Files\Git\cmd' to the PATH environment variable for the current user.

    .EXAMPLE
    Add-EnvironmentPath -Scope AllUsers -Path 'C:\Program Files\Git\cmd'

    Add the path 'C:\Program Files\Git\cmd' to the PATH environment variable for all users.

    .EXAMPLE
    Add-EnvironmentPath -Scope CurrentUser -Path 'C:\Program Files\Git\cmd', 'C:\Program Files\Git\bin'

    Add the paths 'C:\Program Files\Git\cmd' and 'C:\Program Files\Git\bin' to the PATH environment variable for the current user.

    .EXAMPLE
    Add-EnvironmentPath -Scope CurrentUser -Path 'C:\Program Files\Git\cmd', 'C:\Program Files\Git\bin' -Force

    Add the paths 'C:\Program Files\Git\cmd' and 'C:\Program Files\Git\bin' to the PATH environment variable for the current user.
    Any invalid paths will be removed.

    .EXAMPLE
    'C:\Program Files\Git\cmd', 'C:\Program Files\Git\bin' | Add-EnvironmentPath -Scope CurrentUser

    Add the paths 'C:\Program Files\Git\cmd' and 'C:\Program Files\Git\bin' to the PATH environment variable for the current user.
    #>

    [CmdletBinding()]
    param(
        # The scope of the environment variable.
        [Parameter()]
        [ValidateSet('AllUsers', 'CurrentUser')]
        [string] $Scope = 'CurrentUser',

        # The path to add to the environment variable.
        [Parameter(
            Mandatory,
            ValueFromPipeline,
            ValueFromPipelineByPropertyName
        )]
        [ValidateNotNullOrEmpty()]
        [Alias('FullName')]
        [string[]] $Path,

        # Remove any invalid paths.
        [Parameter()]
        [switch] $Force
    )

    begin {
        $separatorChar = [System.IO.Path]::DirectorySeparatorChar

        $target = if ($Scope -eq 'CurrentUser') {
            [System.EnvironmentVariableTarget]::User
        } else {
            [System.EnvironmentVariableTarget]::Machine
            if (-not (IsAdmin)) {
                $errorMessage = @'
Administrator rights are required to modify machine PATH.
Please run the command again with elevated rights (Run as Administrator) or provide '-Scope CurrentUser' to your command.
'@

                throw $errorMessage
            }
        }
        $environmentPath = Get-EnvironmentPath -Scope $Scope -AsArray
        Write-Verbose "Add PATH - [$target]"
    }

    process {
        foreach ($envPath in $Path) {
            Write-Verbose "Add PATH - [$target] - [$envPath]"

            $envPathExists = Test-Path $envPath
            if ($envPathExists) {
                Write-Verbose "Add PATH - [$target] - [$envPath] - Path exists - Yes"

                $envPathObject = Get-Item -Path $envPath -ErrorAction SilentlyContinue
                if ($envPath -ceq $envPathObject.FullName) {
                    Write-Verbose "Add PATH - [$target] - [$envPath] - Verify path - Ok"
                } else {
                    $envPath = $envPathObject.FullName
                    Write-Verbose "Add PATH - [$target] - [$envPath] - Verify path - Updated"
                }
            } else {
                if ($Force) {
                    Write-Verbose "Add PATH - [$target] - [$envPath] - Path exists - No - Continuing (Force)"
                } else {
                    Write-Warning "Add PATH - [$target] - [$envPath] - Path exists - No - Skipping (Use -Force to add)"
                    continue
                }
            }

            Write-Verbose "Add PATH - [$target] - [$envPath] - Normalize path"
            $envPath = $envPath.Replace('\', $separatorChar)
            $envPath = $envPath.Replace('/', $separatorChar)
            $envPath = $envPath.TrimEnd($separatorChar)

            $environmentPath += $envPath
            Write-Verbose "Add PATH - [$target] - [$envPath] - Added"
        }
    }

    end {
        $pathSeparator = [System.IO.Path]::PathSeparator
        $environmentPath = $environmentPath -join $pathSeparator
        $environmentPath = $environmentPath.Trim($pathSeparator)
        $environmentPath = $environmentPath + $pathSeparator

        [System.Environment]::SetEnvironmentVariable('PATH', $environmentPath, [System.EnvironmentVariableTarget]::$target)
        Write-Verbose "Add PATH - [$target] - Done"
    }
}

Write-Verbose "[$scriptName] - [public] - [Add-EnvironmentPath] - Done"
#endregion - From [public] - [Add-EnvironmentPath]
#region - From [public] - [Get-EnvironmentPath]
Write-Verbose "[$scriptName] - [public] - [Get-EnvironmentPath] - Importing"

function Get-EnvironmentPath {
    <#
    .SYNOPSIS
    Get the PATH environment variable.

    .DESCRIPTION
    Get the PATH environment variable for the current user or all users.

    .EXAMPLE
    Get-EnvironmentPath -Scope CurrentUser

    Get the PATH environment variable for the current user.

    .EXAMPLE
    Get-EnvironmentPath -Scope AllUsers -AsArray

    Get the PATH environment variable for the current user as an array.
    #>

    [OutputType([string[]], ParameterSetName = 'AsArray')]
    [OutputType([string], ParameterSetName = 'AsString')]
    [CmdletBinding(DefaultParameterSetName = 'AsString')]
    param(
        # The scope of the environment variable.
        [Parameter()]
        [ValidateSet('AllUsers', 'CurrentUser')]
        [string] $Scope = 'CurrentUser',

        # Return the environment variable as an array.
        [Parameter(ParameterSetName = 'AsArray')]
        [switch] $AsArray
    )

    $target = if ($Scope -eq 'CurrentUser') {
        [System.EnvironmentVariableTarget]::User
    } else {
        [System.EnvironmentVariableTarget]::Machine
    }

    $environmentPath = [System.Environment]::GetEnvironmentVariable('PATH', [System.EnvironmentVariableTarget]::$target)
    if (-not $AsArray) {
        return $environmentPath
    }
    $pathSeparator = [System.IO.Path]::PathSeparator
    $environmentPath = $environmentPath.Trim($pathSeparator)
    $environmentPath = $environmentPath.Split($pathSeparator)
    $environmentPath = $environmentPath | Sort-Object

    return $environmentPath
}

Write-Verbose "[$scriptName] - [public] - [Get-EnvironmentPath] - Done"
#endregion - From [public] - [Get-EnvironmentPath]
#region - From [public] - [Remove-EnvironmentPath]
Write-Verbose "[$scriptName] - [public] - [Remove-EnvironmentPath] - Importing"

#Requires -Modules Admin, DynamicParams

function Remove-EnvironmentPath {
    <#
    .SYNOPSIS
    Remove a path from the PATH environment variable.

    .DESCRIPTION
    Remove a path from the PATH environment variable. This command will normalize the path separators.

    .EXAMPLE
    Remove-EnvironmentPath -Scope CurrentUser -Path 'C:\Program Files\Git\cmd'

    Remove the path 'C:\Program Files\Git\cmd' from the PATH environment variable for the current user.

    .EXAMPLE
    Remove-EnvironmentPath -Scope AllUsers -Path 'C:\Program Files\Git\cmd'

    Remove the path 'C:\Program Files\Git\cmd' from the PATH environment variable for all users.

    .EXAMPLE
    Remove-EnvironmentPath -Scope CurrentUser -Path 'C:\Program Files\Git\cmd', 'C:\Program Files\Git\bin'

    Remove the paths 'C:\Program Files\Git\cmd' and 'C:\Program Files\Git\bin' from the PATH environment variable for the current user.

    .EXAMPLE
    'C:\Program Files\Git\cmd', 'C:\Program Files\Git\bin' | Remove-EnvironmentPath -Scope CurrentUser

    Remove the paths 'C:\Program Files\Git\cmd' and 'C:\Program Files\Git\bin' from the PATH environment variable for the current user.

    .EXAMPLE
    (Get-EnvironmentPath -Scope AllUsers -AsArray) | where {$_ -like "$env:USERPROFILE*"} | Remove-EnvironmentPath -Scope AllUsers

    Remove all paths from the PATH environment variable for all users that start with the current user's profile path.

    .EXAMPLE
    (Get-EnvironmentPath -Scope CurrentUser -AsArray) |
        where {$_ -like "$env:windir*" -or $_ -like "$env:ProgramFiles*" -or $_ -like "${env:ProgramFiles(x86)}*"} |
        Remove-EnvironmentPath -Scope CurrentUser

    Remove all paths from the PATH environment variable for the current user that start with the Windows directory,
    Program Files directory or Program Files (x86) directory.

    #>

    [CmdletBinding(SupportsShouldProcess)]
    param(
        # The scope of the environment variable.
        [Parameter()]
        [ValidateSet('AllUsers', 'CurrentUser')]
        [string] $Scope = 'CurrentUser'
    )

    dynamicparam {
        $DynamicParamDictionary = New-DynamicParamDictionary

        $dynPath = @{
            Name                            = 'Path'
            Alias                           = 'FullName'
            Type                            = [string[]]
            Mandatory                       = $true
            HelpMessage                     = 'Name of the font to uninstall.'
            ValueFromPipeline               = $true
            ValueFromPipelineByPropertyName = $true
            ValidateSet                     = if ([string]::IsNullOrEmpty($Scope)) {
                Get-EnvironmentPath -Scope 'CurrentUser' -AsArray
            } else {
                Get-EnvironmentPath -Scope $Scope -AsArray
            }
            DynamicParamDictionary          = $DynamicParamDictionary
        }
        New-DynamicParam @dynPath

        return $DynamicParamDictionary
    }

    begin {
        $target = if ($Scope -eq 'CurrentUser') {
            [System.EnvironmentVariableTarget]::User
        } else {
            [System.EnvironmentVariableTarget]::Machine
            if (-not (IsAdmin)) {
                $errorMessage = @'
Administrator rights are required to modify machine PATH.
Please run the command again with elevated rights (Run as Administrator) or provide '-Scope CurrentUser' to your command.
'@

                throw $errorMessage
            }
        }
        $environmentPath = Get-EnvironmentPath -Scope $Scope -AsArray
        Write-Verbose "Remove PATH - [$target]"
    }

    process {
        $Path = $PSBoundParameters['Path']
        foreach ($envPath in $Path) {
            Write-Verbose "Remove PATH - [$target] - [$envPath]"
            $environmentPath = $environmentPath | Where-Object { $_ -ne $envPath }
            Write-Warning "Remove PATH - [$target] - [$envPath] - Removed"
        }
    }

    end {
        $pathSeparator = [System.IO.Path]::PathSeparator
        $environmentPath = $environmentPath -join $pathSeparator
        $environmentPath = $environmentPath.Trim($pathSeparator)
        $environmentPath = $environmentPath + $pathSeparator

        if ($PSCmdlet.ShouldProcess($environmentPath, 'Remove')) {
            [System.Environment]::SetEnvironmentVariable('PATH', $environmentPath, [System.EnvironmentVariableTarget]::$target)
        }
        Write-Verbose "Remove PATH - [$target] - Done"
    }
}

Write-Verbose "[$scriptName] - [public] - [Remove-EnvironmentPath] - Done"
#endregion - From [public] - [Remove-EnvironmentPath]
#region - From [public] - [Repair-EnvironmentPath]
Write-Verbose "[$scriptName] - [public] - [Repair-EnvironmentPath] - Importing"

#Requires -Modules Admin

function Repair-EnvironmentPath {
    <#
    .SYNOPSIS
    Repair the PATH environment variable.

    .DESCRIPTION
    Repair the PATH environment variable. This command will remove any invalid paths and normalize the path separators.

    .EXAMPLE
    Repair-EnvironmentPath -Scope CurrentUser

    Repair the PATH environment variable for the current user.

    .EXAMPLE
    Repair-EnvironmentPath -Scope AllUsers

    Repair the PATH environment variable for all users.

    .EXAMPLE

    Repair-EnvironmentPath -Scope CurrentUser -Force

    Repair the PATH environment variable for the current user. Any invalid paths will be removed.

    .EXAMPLE

    Repair-EnvironmentPath -Scope AllUsers -Force

    Repair the PATH environment variable for all users. Any invalid paths will be removed.

    .NOTES
    General notes
    #>

    [CmdletBinding()]
    param(
        # The scope of the environment variable.
        [Parameter()]
        [ValidateSet('AllUsers', 'CurrentUser')]
        [string] $Scope = 'CurrentUser',

        # Remove any invalid paths.
        [switch] $Force
    )

    begin {
        $separatorChar = [System.IO.Path]::DirectorySeparatorChar

        $target = if ($Scope -eq 'CurrentUser') {
            [System.EnvironmentVariableTarget]::User
        } else {
            [System.EnvironmentVariableTarget]::Machine
            if (-not (IsAdmin)) {
                $errorMessage = @'
Administrator rights are required to modify machine PATH.
Please run the command again with elevated rights (Run as Administrator) or provide '-Scope CurrentUser' to your command.
'@

                throw $errorMessage
            }
        }
        $environmentPaths = Get-EnvironmentPath -Scope $Scope -AsArray
        Write-Verbose "Repair PATH - [$target]"
        $repairedEnvironmentPaths = @()
    }

    process {
        foreach ($envPath in $environmentPaths) {
            Write-Verbose "Repair PATH - [$target] - [$envPath]"
            $environmentPathExists = Test-Path $envPath

            if ($environmentPathExists) {
                Write-Verbose "Repair PATH - [$target] - [$envPath] - Path exists - Yes"
                $envPathObject = Get-Item -Path $envPath -ErrorAction SilentlyContinue
                if ($envPath -ceq $envPathObject.FullName) {
                    Write-Verbose "Repair PATH - [$target] - [$envPath] - Verify path - Ok"
                } else {
                    $envPath = $envPathObject.FullName
                    Write-Verbose "Repair PATH - [$target] - [$envPath] - Verify path - Updated"
                }
            } else {
                if ($Force) {
                    Write-Warning "Repair PATH - [$target] - [$envPath] - Path exists - No - Removeing (Force)"
                    continue
                } else {
                    Write-Warning "Repair PATH - [$target] - [$envPath] - Path exists - No - Continuing (Use -Force to remove))"
                }
            }

            Write-Verbose "Repair PATH - [$target] - [$envPath] - Normalize path"
            $envPath = $envPath.Replace('\', $separatorChar)
            $envPath = $envPath.Replace('/', $separatorChar)
            $envPath = $envPath.TrimEnd($separatorChar)

            $repairedEnvironmentPaths += $envPath
            Write-Verbose "Repair PATH - [$target] - [$envPath] - Repaired"
        }
    }

    end {

        $pathSeparator = [System.IO.Path]::PathSeparator
        $repairedEnvironmentPaths = $repairedEnvironmentPaths | Sort-Object -Unique
        $repairedEnvironmentPaths = $repairedEnvironmentPaths -join $pathSeparator
        $repairedEnvironmentPaths = $repairedEnvironmentPaths.Trim($pathSeparator)
        $repairedEnvironmentPaths = $repairedEnvironmentPaths + $pathSeparator

        [System.Environment]::SetEnvironmentVariable('PATH', $repairedEnvironmentPaths, [System.EnvironmentVariableTarget]::$target)
        Write-Verbose "Repair PATH - [$target] - Done"
    }
}

Write-Verbose "[$scriptName] - [public] - [Repair-EnvironmentPath] - Done"
#endregion - From [public] - [Repair-EnvironmentPath]

Write-Verbose "[$scriptName] - [public] - Done"
#endregion - From [public]


$exports = @{
    Alias    = '*'
    Cmdlet   = ''
    Function = @(
        'Add-EnvironmentPath'
        'Get-EnvironmentPath'
        'Remove-EnvironmentPath'
        'Repair-EnvironmentPath'
    )
    Variable = ''
}
Export-ModuleMember @exports