/// <summary>
/// Performs the validation of this configuration object.
/// Returns empty list if no problems found, otherwise list contains validation problems.
/// </summary>
public IEnumerable <ConfigurationValidationItem> Validate()
{
// Helper to collect and perform validations
var validations = new ConfigurationValidationCollector <SampleConfig>(this);
// Here are validations
validations.ValidateNotZero(c => c.SomeValue, "Configuration should not contain default value (=0).");
validations.ValidateNotNullOrEmpty(c => c.SomeName, "Configuration should specify value for Name.");
validations.ValidateUri(c => c.SomeEndpoint, "External API endpoint is incorrect");
validations.ValidateEmail(c => c.SomeEmail, "E-mail address is wrong.");
validations.ValidateIpV4Address(c => c.SomeIp, "IP address is not valid.");
validations.ValidatePublicIpV4Address(c => c.SomeIp, "IP address is not a public IP address.");
// Generic methods, expecting boolean outcome of Linq expression
validations.ValidateMust(c => c.SomeEndpoint.StartsWith("https", StringComparison.OrdinalIgnoreCase), nameof(this.SomeEndpoint), "Enpoint is no SSL secured.");
validations.ValidateMust(c => c.SomeEndpoint.EndsWith("/", StringComparison.OrdinalIgnoreCase), nameof(this.SomeEndpoint), "Enpoint should end with shash /.");
validations.ValidateMust(c =>
c.SomeName.Contains("sparta", StringComparison.OrdinalIgnoreCase) &&
c.SomeValue > 10,
$"{nameof(this.SomeName)} and {nameof(this.SomeValue)}",
"Combined validations failed.");
// Syntactic sugar
validations.ValidateStartsWith(c => c.SomeEndpoint, "https", "Enpoint is no SSL secured.");
validations.ValidateEndsWith(c => c.SomeEndpoint, "/", "Enpoint should end in slash /.");
// Returning all found validation problems
return(validations.Result);
}