function Get-AuthHeader {
    <#
.SYNOPSIS
    Returns an HTTP Authentication/Authorization Header

.PARAMETER ApiUserUsername
    TeamCity User Username to use for building a Basic Auth HTTP Header

.PARAMETER ApiUserPassword
    TeamCity User Password to use for building a Basic Auth HTTP Header

.PARAMETER BearerToken
    A Bearer Token to use for building a Bearer Token Auth HTTP Header

.PARAMETER GetBearerToken
    Call Get-BearerToken function

.PARAMETER TokenFilePath
    Path(optional) to file containing the bearer token to use when calling Get-BearerToken

#>
    [CmdletBinding()]
    [OutputType([string])]
    param(
        [Parameter(Mandatory = $false)]
        [string]$ApiUserUsername = $null,
        [Parameter(Mandatory = $false)]
        [string]$ApiUserPassword = $null,
        [Parameter(Mandatory = $false)]
        [string]$BearerToken = $null,
        [Parameter(Mandatory = $false)]
        [switch]$GetBearerToken,
        [Parameter(Mandatory = $false)]
        [Alias("Path")]
        [string]$TokenFilePath = $null
    )
    $logLead = Get-LogLeadName

    $authHeaderPatternBearer = "Bearer {0}"
    if ($GetBearerToken) {
        Write-Host "$logLead : Getting token"
        $splat = @{}
        if ($null -ne $TokenFilePath) {
            Write-Host "$logLead : Passing user supplied path - $TokenFilePath"
            $splat.TokenFilePath = $TokenFilePath
        }
        $gotBearerToken = Get-BearerToken @splat
        $authHeaderValue = ($authHeaderPatternBearer -f $gotBearerToken)

    } elseif ([string]::IsNullOrEmpty($ApiUserUsername) -or [string]::IsNullOrEmpty($ApiUserPassword)) {
        Write-Host "$logLead : Using supplied token"
        $authHeaderValue = ($authHeaderPatternBearer -f $BearerToken)

    } else {
        Write-Host "$logLead : Using auth pair"
        $authorizationPair = "$($apiUserUsername):$($apiUserPassword)"
        $encodedCredentials = [System.Convert]::ToBase64String([System.Text.Encoding]::ASCII.GetBytes($authorizationPair))
        $authHeaderValue = "Basic $encodedCredentials"

    }

    $headers = @{
        Authorization = $authHeaderValue
        Accept        = "application/json"
    }
    Write-Host "$logLead : Header creation complete"
    return $headers
}