functions/Get-DbaAvailableCollation.ps1

function Get-DbaAvailableCollation {
    <#
        .SYNOPSIS
            Function to get available collations for a given SQL Server
 
        .DESCRIPTION
            The Get-DbaAvailableCollation function returns the list of collations available on each SQL Server.
            Only the connect permission is required to get this information.
 
        .PARAMETER SqlInstance
            The SQL Server instance, or instances. Only connect permission is required.
 
        .PARAMETER SqlCredential
            SqlCredential object to connect as. If not specified, current Windows login will be used.
 
        .PARAMETER Silent
            Use this switch to disable any kind of verbose messages
 
        .NOTES
            Author: Bryan Hamby (@galador)
 
            Website: https://dbatools.io
            Copyright: (C) Chrissy LeMaire, clemaire@gmail.com
            License: GNU GPL v3 https://opensource.org/licenses/GPL-3.0
 
        .LINK
            https://dbatools.io/Get-DbaAvailableCollation
 
        .EXAMPLE
            Get-DbaAvailableCollation -SqlInstance sql2016
 
            Gets all the collations from server sql2016 using NT authentication
 
    #>

    [CmdletBinding()]
    Param (
        [parameter(Position = 0, Mandatory = $true, ValueFromPipeline = $true)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [PSCredential]$SqlCredential,
        [switch]$Silent
    )

    begin {
        #Functions to get/cache the code page and language description.
        #It runs about 9x faster caching these (2 vs 18 seconds) in my test,
        #since there are so many duplicates

        #No longer supported by Windows, but still shows up in SQL Server
        #http://www.databaseteam.org/1-ms-sql-server/982faddda7a789a1.htm
        $locales = @{66577 = "Japanese_Unicode"}
        $codePages = @{}

        function Get-LocaleDescription ($LocaleId) {
            if ($locales.ContainsKey($LocaleId)) {
                $localeName = $locales.Get_Item($LocaleId)
            }
            else {
                try {
                    $localeName = (Get-Language $LocaleId).DisplayName    
                }
                catch {
                    $localeName = $null
                }
                $locales.Set_Item($LocaleId, $localeName)
            }
            return $localeName            
        }

        function Get-CodePageDescription ($codePageId) {
            if ($codePages.ContainsKey($codePageId)) {
                $codePageName = $codePages.Get_Item($codePageId)
            }
            else {
                try {
                    $codePageName = (Get-CodePage $codePageId).EncodingName    
                }
                catch {
                    $codePageName = $null
                }
                $codePages.Set_Item($codePageId, $codePageName)
            }
            return $codePageName            
        }
    }

    process {
        foreach ($Instance in $sqlInstance) {
            try {
                Write-Message -Level Verbose -Message "Connecting to $instance"
                $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $SqlCredential
            }
            catch {
                Stop-Function -Message "Failure" -Category ConnectionError -ErrorRecord $_ -Target $instance -Continue
            }

            $availableCollations = $server.EnumCollations()
            foreach ($collation in $availableCollations) {
                Add-Member -InputObject $collation -Force -MemberType NoteProperty -Name Instance -Value $Instance
                Add-Member -InputObject $collation -Force -MemberType NoteProperty -Name CodePageName -Value (Get-CodePageDescription $collation.CodePage)
                Add-Member -InputObject $collation -Force -MemberType NoteProperty -Name LocaleName -Value (Get-LocaleDescription $collation.LocaleID)
            }

            Select-DefaultView -InputObject $availableCollations -Property Instance, Name, CodePage, CodePageName, LocaleID, LocaleName, Description
        } 
    } 
}