Explanation for php code with if statement

I have code like this can some one help me figure out how the condition logic work in this

$environment = ( $this->environment == "yes" ) ? 'TRUE' : 'FALSE';
    // Decide which URL to post to
      $environment_url = ( "FALSE" == $environment )
                               ? 'https://api.ewaypayments.com/AccessCodes'
               : 'https://api.sandbox.ewaypayments.com/AccessCodes';