Param(
  [Parameter(Mandatory=$true)][string]$buildId,
  [Parameter(Mandatory=$true)][string]$assemblyInfoPath
)

function Get-Version([string]$path)
{    
    if (!(Test-Path $assemblyInfoPath))
    {
        throw [System.IO.FileNotFoundException] "'$path' was not found."
    }

    $assemblyInfo = Get-Content -Path $path

    if (!$assemblyInfo)
    {
        throw [System.InvalidOperationException] "The file '$path' does not have any contents."
    }                

    # Attempt to get the version information from the AssemblyVersionAttribute first
    $versionMatches = [regex]::Match($assemblyInfo, "\[assembly\:\s*AssemblyVersion(Attribute)?\(`"(?<Major>\d+)\.(?<Minor>\d+)\.(?<Patch>\d+)(\.\d+)?`"\)\]")

    if ($versionMatches.Success)
    {
        # Parse out the AssemblyVersionAttribute value
        $major = $versionMatches.Groups["Major"]
        $minor = $versionMatches.Groups["Minor"]
        $patch = $versionMatches.Groups["Patch"]

        return "$major.$minor.$patch" 
    }
    
    # AssemblyVersionAttribute wasn't available, try for the AssemblyFileVersionAttribute
    $versionFileMatches = [regex]::Match($assemblyInfo, "\[assembly\:\s*AssemblyFileVersion(Attribute)?\(`"(?<Major>\d+)\.(?<Minor>\d+)\.(?<Patch>\d+)(\.\d+)?`"\)\]")
    
    if ($versionFileMatches.Success)
    {
        # Parse out the AssemblyVersionAttribute value
        $major = $versionFileMatches.Groups["Major"]
        $minor = $versionFileMatches.Groups["Minor"]
        $patch = $versionFileMatches.Groups["Patch"]

        return "$major.$minor.$patch" 
    }
    
    throw [System.InvalidOperationException] "Unable to load version information from '$path'."
}

function Get-FileEncoding
{
    [CmdletBinding()] Param (
     [Parameter(Mandatory = $True, ValueFromPipelineByPropertyName = $True)] [string]$Path
    )
 
    [byte[]]$byte = get-content -Encoding byte -ReadCount 4 -TotalCount 4 -Path $Path
    #Write-Host Bytes: $byte[0] $byte[1] $byte[2] $byte[3]

    # EF BB BF (UTF8)
    if ( $byte[0] -eq 0xef -and $byte[1] -eq 0xbb -and $byte[2] -eq 0xbf )
    { 
        return 'UTF8' 
    }

    # 00 00 FE FF (UTF32 Big-Endian)
    elseif ($byte[0] -eq 0 -and $byte[1] -eq 0 -and $byte[2] -eq 0xfe -and $byte[3] -eq 0xff)
    { 
        return 'BigEndianUTF32'
    }

    # 2B 2F 76 (38 | 38 | 2B | 2F)
    elseif ($byte[0] -eq 0x2b -and $byte[1] -eq 0x2f -and $byte[2] -eq 0x76 -and ($byte[3] -eq 0x38 -or $byte[3] -eq 0x39 -or $byte[3] -eq 0x2b -or $byte[3] -eq 0x2f) )
    { 
        return 'UTF7'
    }

    return 'ASCII'
}

function Set-Version([string]$path, [string]$newVersion)
{    
    if (!(Test-Path $assemblyInfoPath))
    {
        throw [System.IO.FileNotFoundException] "'$path' was not found."
    }

    $encoding = Get-FileEncoding $path
    $assemblyInfo = Get-Content -Path $path -Encoding $encoding | Out-String
    
    if (!$assemblyInfo)
    {
        throw [System.InvalidOperationException] "The file '$path' does not have any contents."
    }                
    
    $versionExpression = "\[assembly\:\s*AssemblyVersion(Attribute)?\(`"\d+(\.\d+){2,3}`"\)\]"
    $versionFileExpression = "\[assembly\:\s*AssemblyFileVersion(Attribute)?\(`"\d+(\.\d+){2,3}`"\)\]"
    
    $assemblyInfo = [regex]::Replace($assemblyInfo, $versionExpression, "[assembly: AssemblyVersion(`"$newVersion`")]")  
    $assemblyInfo = [regex]::Replace($assemblyInfo, $versionFileExpression, "[assembly: AssemblyFileVersion(`"$newVersion`")]")
    
    Set-Content $path $assemblyInfo -Encoding $encoding
}

Write-Host "Assigning version with BuildId $buildId"

$existingVersion = Get-Version $assemblyInfoPath

Write-Host "Found version from '$assemblyInfoPath' as $existingVersion"

$newVersion = "$existingVersion.$buildId"

Write-Host "Assigning new version as $newVersion"
Set-Version $assemblyInfoPath $newVersion

Write-Host "Setting build number to $newVersion."
Write-Host "##vso[build.updatebuildnumber]$newVersion"