SwiftLint/Source/SwiftLintBuiltInRules/Rules/RuleConfigurations/EmptyCountConfiguration.swift

private enum ConfigurationKey: String {
    case severity = "severity"
    case onlyAfterDot = "only_after_dot"
}

struct EmptyCountConfiguration: SeverityBasedRuleConfiguration, Equatable {
    typealias Parent = EmptyCountRule

    private(set) var severityConfiguration = SeverityConfiguration<Parent>(.error)
    private(set) var onlyAfterDot = false

    var consoleDescription: String {
        return ["severity: \(severityConfiguration.consoleDescription)",
                "\(ConfigurationKey.onlyAfterDot.rawValue): \(onlyAfterDot)"].joined(separator: ", ")
    }

    mutating func apply(configuration: Any) throws {
        guard let configuration = configuration as? [String: Any] else {
            throw Issue.unknownConfiguration(ruleID: Parent.identifier)
        }

        if let severityString = configuration[ConfigurationKey.severity.rawValue] as? String {
            try severityConfiguration.apply(configuration: severityString)
        }

        onlyAfterDot = configuration[ConfigurationKey.onlyAfterDot.rawValue] as? Bool ?? false
    }
}