<#
    .SYNOPSIS
    Downloads and installs XPipe on the local machine.

    .DESCRIPTION
    Retrieves the XPipe msi for the latest or a specified version, and
    downloads and installs the application to the local machine.
#>
[CmdletBinding(DefaultParameterSetName = 'Default')]
param(
    # Specifies a target version of XPipe to install. By default, the latest
    # stable version is installed.
    [Parameter(Mandatory = $false)]
    [string]
    $XPipeVersion = $xpipeVersion,

    # If set, will download releases from the staging repository instead.
    [Parameter(Mandatory = $false)]
    [switch]
    $UseStageDownloads = $useStageDownloads
)

#region Functions

function Get-Downloader {
    <#
    .SYNOPSIS
    Gets a System.Net.WebClient that respects relevant proxies to be used for
    downloading data.

    .DESCRIPTION
    Retrieves a WebClient object that is pre-configured according to specified
    environment variables for any proxy and authentication for the proxy.
    Proxy information may be omitted if the target URL is considered to be
    bypassed by the proxy (originates from the local network.)

    .PARAMETER Url
    Target URL that the WebClient will be querying. This URL is not queried by
    the function, it is only a reference to determine if a proxy is needed.

    .EXAMPLE
    Get-Downloader -Url $fileUrl

    Verifies whether any proxy configuration is needed, and/or whether $fileUrl
    is a URL that would need to bypass the proxy, and then outputs the
    already-configured WebClient object.
    #>
    [CmdletBinding()]
    param(
        [Parameter(Mandatory = $false)]
        [string]
        $Url
    )

    $downloader = New-Object System.Net.WebClient

    $defaultCreds = [System.Net.CredentialCache]::DefaultCredentials
    if ($defaultCreds) {
        $downloader.Credentials = $defaultCreds
    }

    $downloader
}

function Request-File {
    <#
    .SYNOPSIS
    Downloads a file from a given URL.

    .DESCRIPTION
    Downloads a target file from a URL to the specified local path.
    Any existing proxy that may be in use will be utilised.

    .PARAMETER Url
    URL of the file to download from the remote host.

    .PARAMETER File
    Local path for the file to be downloaded to.

    Downloads the file to the path specified in $targetFile.
    #>
    [CmdletBinding()]
    param(
        [Parameter(Mandatory = $false)]
        [string]
        $Url,

        [Parameter(Mandatory = $false)]
        [string]
        $File
    )

    Write-Host "Downloading $url to $file"
    (Get-Downloader $url).DownloadFile($url, $file)
}


function Uninstall {
    [CmdletBinding()]
    param()

    # Quick heuristic to see whether is can be possibly installed
    if (-not ((Test-Path "$env:LOCALAPPDATA\$ProductName" -PathType Container) -or (Test-Path "$env:ProgramFiles\$ProductName" -PathType Container))) {
        return
    }

    Write-Host "Looking for previous $ProductName installations ..."

    $cim = Get-CimInstance Win32_Product | Where {$_.Name -eq "$ProductName" } | Select-Object -First 1
    if ($cim) {
        $message = @(
            "Uninstalling existing $ProductName $($cim.Version) installation ..."
        ) -join [Environment]::NewLine
        Write-Host $message
        $cimResult = Invoke-CimMethod -InputObject $cim -Name Uninstall
        if ($cimResult.ReturnValue) {
            Write-Host "Uninstallation failed: Code $($cimResult.ReturnValue)"
            exit
        }
    }
}

#endregion Functions

#region Pre-check

if ($UseStageDownloads) {
    $XPipeRepoUrl = "https://github.com/xpipe-io/xpipe-ptb"
    $ProductName = "XPipe PTB"
} else {
    $XPipeRepoUrl = "https://github.com/xpipe-io/xpipe"
    $ProductName = "XPipe"
}

if ($XPipeVersion) {
    $XPipeDownloadUrl = "$XPipeRepoUrl/releases/download/$XPipeVersion"
} else {
    $XPipeDownloadUrl = "$XPipeRepoUrl/releases/latest/download"
}

Uninstall

#endregion Pre-check

#region Setup

$XPipeDownloadUrl = "$XPipeDownloadUrl/xpipe-installer-windows-x86_64.msi"

if (-not $env:TEMP) {
    $env:TEMP = Join-Path $env:SystemDrive -ChildPath 'temp'
}

$tempDir = $env:TEMP

if (-not (Test-Path $tempDir -PathType Container)) {
    $null = New-Item -Path $tempDir -ItemType Directory
}

#endregion Setup

#region Download

$file = Join-Path $tempDir "xpipe-installer.msi"
Write-Host "Getting $ProductName from $XPipeRepoUrl."
Request-File -Url $XPipeDownloadUrl -File $file

#endregion Download

#region Install XPipe

Write-Host "Installing $ProductName ..."

# Wait for completion
# The file variable can contain spaces, so we have to accommodate for that
Start-Process -FilePath "msiexec" -Wait -ArgumentList "/i", "`"$file`"", "/quiet"

# Update current process PATH environment variable
$env:Path=(
    [System.Environment]::GetEnvironmentVariable("Path", "Machine"),
    [System.Environment]::GetEnvironmentVariable("Path", "User")
) -match '.' -join ';'

Write-Host
Write-Host "$ProductName has been successfully installed. You should be able to find it in your applications."
Write-Host

# Use absolute path as we can't assume that the user has selected to put XPipe into the Path
& "$env:LOCALAPPDATA\$ProductName\cli\bin\xpipe.exe" open

#endregion Install XPipe