Function Install-WebExtension {
<#
.SYNOPSIS
	Install a WebExtension to the appropriate place (generally C:\orb\)

.DESCRIPTION
    Install a WebExtension to the appropriate place. (generally C:\orb\)
	Will make certain assumptions based on best practices, such as locations to install to based on flags.

.PARAMETER ExtensionName
    [string] The name of the extension. Will be used to build a dynamic path. Typically the package id.

.PARAMETER SourcePath
    [string] The folder that contains the files. Typically a chocolatey path.

.PARAMETER IsAdmin
    [switch] Is this package installed to admin?

.PARAMETER RemoveLogs
    [switch] Remove logs if the service was running?

.PARAMETER NoSymlink
	[switch] Override the machine settings for handling Symlinks?

.INPUTS
    ExtensionName and SourcePath are required.

.OUTPUTS
    Various diagnostic information about the install process

.EXAMPLE
    Install-WebExtension -ExtensionName Alkami.Client.WebExtension.Example -SourcePath C:\ProgramData\chocolatey\lib\Alkami.Client.WebExtension.Example

Various diagnostic information about the install process.

#>
    [CmdletBinding()]
    Param(
        [Parameter(Mandatory=$true, Position=0)]
        [string]$ExtensionName,
        [Parameter(Mandatory=$true, Position=1)]
        [string]$SourcePath,
        [switch]$isAdmin,
        [switch]$RemoveLogs,
        [Parameter(Mandatory = $false)]
        [switch]$NoSymlink
    )
    process {
		$loglead = (Get-LogLeadName)

		if (!(Test-IsDeveloperMachine) -and !(Test-IsWebServer)) {
			Write-Warning "$loglead : Can not install WebExtensions on the app tier"
			return
		}

		if (!(Test-IsAdmin)){
			throw "You are not running as administrator. Can not continue."
		}

        $usingSymlinkStrategy = $false

		# See if there is an override
		if($NoSymlink) {
			Write-Host "$loglead : Override provided! Skipping Symlink strategy."
		} else {
			$usingSymlinkStrategy = Test-InstallerUseSymlinkStrategy

			if($usingSymlinkStrategy) {
				Write-Host "$loglead : Using Symlink Installer Strategy."
			} else {
				Write-Host "$loglead : Using Legacy non-Symlink Installer Strategy"
			}
		}

        Write-Host "$loglead : $ExtensionName being installed by $($env:username) on $($env:computername) at $(Get-Date)"

        # Build the Source Path
        if (!(Test-Path $SourcePath)) {
            throw "Could not find the source path specified at $SourcePath"
        }

        # Append lib to the chocolatey directory
        # ex: c:\ProgramData\chocolatey\lib\Alkami.Sample.Service\lib
        $libSourcePath = (Join-Path $SourcePath 'lib')

        if (!(Test-Path $libSourcePath)) {
            throw "Could not find the lib folder path specified at $libSourcePath"
        }

		## Write warning that more than one lib folder was detected
        # Go into the first subfolder.
        # ex: c:\ProgramData\chocolatey\lib\Alkami.Sample.Service\lib\net472
        $libSourceFolderName = (Get-ChildItem $libSourcePath -Directory) | Sort-Object -Descending | Select-Object -First 1

		$libSourceFolder = (Join-Path $libSourcePath $libSourceFolderName)

        if ((Get-ChildItem (Join-Path $libSourceFolder "*.dll")).Count -eq 0) {
            throw "Could not find any dll files under $libSourceFolder"
        }

        Write-Host "$loglead : Looks like we are ready to install $ExtensionName"

        $appName = 'WebClient'

        if ($isAdmin) {
			$appName = 'WebClientAdmin'
		}

        # Build the target path
        # ex: c:\orb\WebClient\Modules
        $moduleRootPath = Join-Path (Join-Path (Get-OrbPath) $appName) 'Modules'
        # ex: c:\orb\WebClient\Modules\Alkami.Sample.Service
        $orbExtensionPath = (Join-Path -Path $moduleRootPath -ChildPath $ExtensionName)

        $isRunning = (Test-IISAppPoolByName $appName)
        if ($isRunning) {
            Write-Host "$loglead : Stopping $appName"
            Stop-WebAppPool $appName
			Do
			{
				Start-Sleep -Milliseconds 100
			}
			Until ((Get-WebAppPoolState -Name $appName).Value -eq "Stopped" )
        }

        # Check if we're Removing logs and it was running (because there should be no new logs if it isn't running)
        if ($RemoveLogs -and $isRunning) {
            $logfiles = Get-LogPathsForOrbApplication $appName

            # Delete each log file.
            foreach($logPath in $logfiles) {
                if (Test-Path $logPath) {
                    Remove-FileSystemItem $logPath -ErrorAction Stop
                }
            }
        }

		## Clear .NET Temp files associated with the site
		$tempFilePath = (Get-SiteTempDirectoryPath $appName)
		if ($isRunning -and !([string]::IsNullOrWhiteSpace($tempFilePath)) -and (Test-Path $tempFilePath)) {
			Remove-FileSystemItem $tempFilePath -Recurse -ErrorAction Stop
		}

        # Always delete the target folder as we'll recreate it or symlink it below
        if (Test-Path $orbExtensionPath) {
            ## Update OrbCore manifest if it exists to say that I've removed these files from the folder
            Remove-FileSystemItem $orbExtensionPath -Recurse -ErrorAction Stop
        }

        ## This is because we are changing the way we path our extensions
        ## Originally people got to choose their own folder name, ex: Signalr
        ## We are changing the pattern to Alkami.Modules.SignalR for the folder name
        ## Therefore, if the old folder exists at the last part of the split, then we remove that folder too
        ## That way there's only one version of the module, assuming reasonable assumptions from developer discussions
        $badOldFolderName = ($ExtensionName -split '\.')[-1]
        $badOldFolderPath = (Join-Path (Join-Path (Join-Path (Get-OrbPath) $appName) 'Modules') $badOldFolderName)

        if (Test-Path $badOldFolderPath) {
			## Update OrbCore manifest if it exists to say that I've removed these files from the folder
            Write-Host "I am removing all files from $badOldFolderPath because it is an old path."
            Remove-FileSystemItem $badOldFolderPath -Recurse -ErrorAction Stop
        }

        if($usingSymlinkStrategy) {
            # Setup Symlinks
            Write-Host "$loglead : In the block to do Symlinking"
            Write-Host "$loglead : Symlinking files from $libSourceFolder into Destination $moduleRootPath"

            New-Symlink -path $libSourceFolder -Destination $moduleRootPath -TargetName $ExtensionName
        } else {
            Write-Host "$loglead : In the block to do Copying."
            ## It should never exist because we deleted it but let's make sure it doesn't ...
            if (!(Test-Path $orbExtensionPath)) {
                (New-Item $orbExtensionPath -ItemType Directory) | Out-Null
            }

            Write-Host "$loglead : Copying contents of $libSourceFolder into Destination $orbExtensionPath"
            (Copy-Item -Path (Join-Path $libSourceFolder '*') -Destination $orbExtensionPath -Recurse -Force) | Out-Null
        }

        if ($isRunning) {
            Write-Host "$loglead : Starting $appName"
            Start-WebAppPool $appName
        }
    }
}