[cmdletbinding()]
param(
    [Parameter(
            Mandatory = $true, 
            ValueFromPipeline = $true,
            Position = 0
    )]
    [string[]]$hostnames,
    [string]$domain = "home.johnhgaunt.com",
    [System.IO.FileInfo]$Path = [Environment]::GetFolderPath("Desktop"),
    [ValidateSet("RSA2048", "RSA4096","ECC-256", "ECC-384")]
    [string]$algorithm = "ECC-384",
    [string]$server = "gauntonlineca.home.johnhgaunt.com\GauntOnlineCA-CA"
)

begin {
    $subCA = "-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----"
}

process {

    foreach ($hostname in $hostnames) {

        # create a working directory in the temp folder
        $configFile = "$env:TEMP\$hostname.$domain.csr.conf"
        $csrFile = "$path\$hostname.$domain.csr"
        $keyFile = "$path\$hostname.$domain.key"
        $crtFile = "$path\$hostname.$domain.crt"

        $config = "[ req ]
prompt = no
default_md = sha512
req_extensions = req_ext
distinguished_name = req_distinguished_name

[ req_distinguished_name ]
C=US
ST=PA
L=Pittsburgh
O=Gaunt
OU=Gaunt
CN=$hostname.$domain

[ req_ext ]
subjectAltName = @alt_names

[ alt_names ]
DNS.1 = $hostname.$domain
DNS.2 = $hostname"

        # convert to unix file
        # https://stackoverflow.com/questions/5102115/unix-format-files-with-powershell
        Set-Content "$configFile" ([byte[]][char[]] "$config") -Encoding Byte -Force

        switch ($algorithm) {
            "RSA2048" { $privateKeyGenerateArguments = "genrsa -out `"$keyFile`" 2048" }
            "RSA4096" { $privateKeyGenerateArguments = "genrsa -out `"$keyFile`" 4096" }
            "ECC-256" { $privateKeyGenerateArguments = "ecparam -name prime256v1 -genkey -noout -out `"$keyFile`"" }
            "ECC-384" { $privateKeyGenerateArguments = "ecparam -name secp384r1 -genkey -noout -out `"$keyFile`"" }
        }
        switch -regex ($algorithm) {
            "RSA.*" { $certReqAttrib = "CertificateTemplate:ServerandClient(RSA)" }
            "ECC.*" { $certReqAttrib = "CertificateTemplate:ServerandClient(ECC)" }
        }

        Start-Process openssl.exe `
            -ArgumentList $privateKeyGenerateArguments `
            -Wait

        Start-Process openssl.exe `
            -ArgumentList "req -new -key `"$keyFile`" -nodes -out `"$csrFile`" -config `"$configFile`"" `
            -Wait

        Start-Process certreq.exe `
            -ArgumentList "-submit -config `"$server`" -attrib `"$certReqAttrib`" `"$csrFile`" `"$crtFile`"" `
            -Wait

        # add the sub CA to the end of the cert
        add-content $crtFile $subCA
        
        Remove-Item -Path "$path\$hostname.$domain.rsp"
        Remove-Item -Path "$csrFile"
    }
}

end {

}