var nameMapCache: [String: [Int: String]] = [:]
extension _NameMap {
    func protoNameFor(rawValue: Int, cacheKey: String) -> String? {
        if let cache = nameMapCache[cacheKey] {
            return cache[rawValue]
        }
        let selfMirror = Mirror(reflecting: self)
        
        guard let numberToNameMapChild = selfMirror.children.first(where: { (name, _) -> Bool in
            return name == "numberToNameMap"
        }), let numberToNameMap = numberToNameMapChild.value as? Dictionary<Int, Any> else {
                return nil
        }

        nameMapCache[cacheKey] = numberToNameMap.compactMapValues { value in
            let valueMirror = Mirror(reflecting: value)
            
            guard let protoChild = valueMirror.children.first(where: { (name, _) -> Bool in
                return name == "proto"
            }), let stringConvertible = protoChild.value as? CustomStringConvertible else {
                return nil
            }
            
            return stringConvertible.description
        }
        return protoNameFor(rawValue: rawValue, cacheKey: cacheKey)
    }
}

struct PBPayloadCommandNameReader: SwiftProtobuf.Visitor {
    let start: Int

    mutating func visitSingularDoubleField(value: Double, fieldNumber: Int) throws {
        try check(fieldNumber: fieldNumber)
    }

    mutating func visitSingularInt64Field(value: Int64, fieldNumber: Int) throws {
        try check(fieldNumber: fieldNumber)
    }

    mutating func visitSingularUInt64Field(value: UInt64, fieldNumber: Int) throws {
        try check(fieldNumber: fieldNumber)
    }

    mutating func visitSingularBoolField(value: Bool, fieldNumber: Int) throws {
        try check(fieldNumber: fieldNumber)
    }

    mutating func visitSingularStringField(value: String, fieldNumber: Int) throws {
        try check(fieldNumber: fieldNumber)
    }

    mutating func visitSingularBytesField(value: Data, fieldNumber: Int) throws {
        try check(fieldNumber: fieldNumber)
    }

    mutating func visitSingularEnumField<E>(value: E, fieldNumber: Int) throws where E : Enum {
        try check(fieldNumber: fieldNumber)
    }

    mutating func visitMapField<KeyType, ValueType>(fieldType: _ProtobufMap<KeyType, ValueType>.Type, value: _ProtobufMap<KeyType, ValueType>.BaseType, fieldNumber: Int) throws where KeyType : MapKeyType, ValueType : MapValueType {
        try check(fieldNumber: fieldNumber)
    }

    mutating func visitMapField<KeyType, ValueType>(fieldType: _ProtobufEnumMap<KeyType, ValueType>.Type, value: _ProtobufEnumMap<KeyType, ValueType>.BaseType, fieldNumber: Int) throws where KeyType : MapKeyType, ValueType : Enum, ValueType.RawValue == Int {
        try check(fieldNumber: fieldNumber)
    }

    mutating func visitMapField<KeyType, ValueType>(fieldType: _ProtobufMessageMap<KeyType, ValueType>.Type, value: _ProtobufMessageMap<KeyType, ValueType>.BaseType, fieldNumber: Int) throws where KeyType : MapKeyType, ValueType : Hashable, ValueType : SwiftProtobuf.Message {
        try check(fieldNumber: fieldNumber)
    }

    mutating func visitUnknown(bytes: Data) throws {
    }

    enum Found: Error { case found(String?) }
    mutating func visitSingularMessageField<M>(value: M, fieldNumber: Int) throws where M : SwiftProtobuf.Message {
        try check(fieldNumber: fieldNumber)
    }

    func check(fieldNumber: Int) throws {
        guard fieldNumber >= start else {
            return
        }
        throw Found.found(PBPayload._protobuf_nameMap.protoNameFor(rawValue: fieldNumber, cacheKey: "PBPayloadCommandReflection"))
    }
}

/// PBPayload { int64 ID = 1; bool IsResponse = 2; oneof Command { ... }; }
extension PBPayload {
    var commandName: String? {
        var reader = PBPayloadCommandNameReader(start: 3)
        do {
            try traverse(visitor: &reader)
        } catch {
            if case PBPayloadCommandNameReader.Found.found(let name) = error {
                return name
            }
            fatalError("Error while traversing: \(error)")
        }
        return nil
    }
}