using InnovEnergy.Lib.Protocols.DBus.Protocol.DataTypes;
using InnovEnergy.Lib.Protocols.DBus.Protocol.DataTypes.Signatures;

namespace InnovEnergy.Lib.Protocols.DBus.Protocol.Header;

using H = ValueTuple<Byte, Byte, Byte, Byte, UInt32, UInt32, IReadOnlyList<(Byte code, Variant variant)>>;
using Fields = IReadOnlyList<(Byte code, Variant variant)>;

internal static class HeaderExtensions
{
    public static Endian      Endian         (this H h) => (Endian)      h.Item1;
    public static MessageType MessageType    (this H h) => (MessageType) h.Item2;
    public static Byte        Flags          (this H h) => h.Item3;
    public static Byte        ProtocolVersion(this H h) => h.Item4;
    public static UInt32      PayloadLength  (this H h) => h.Item5;
    public static UInt32      Serial         (this H h) => h.Item6;
    public static Fields      Fields         (this H h) => h.Item7;

    public static Signature?  Signature      (this H h) => h.GetField<Signature> (FieldCode.Signature)   ;
    public static String?     Interface      (this H h) => h.GetField<String>    (FieldCode.Interface)   ;
    public static String?     Member         (this H h) => h.GetField<String>    (FieldCode.Member)      ;
    public static String?     Destination    (this H h) => h.GetField<String>    (FieldCode.Destination) ;
    public static String?     Sender         (this H h) => h.GetField<String>    (FieldCode.Sender)      ;
    public static String?     ErrorName      (this H h) => h.GetField<String>    (FieldCode.ErrorName)   ;
    public static UInt32?     ReplySerial    (this H h) => h.GetField<UInt32>    (FieldCode.ReplySerial);
    public static ObjectPath? ObjectPath     (this H h) => h.GetField<ObjectPath>(FieldCode.Path);

    public static Boolean ReplyExpected                (this H h) =>(h.Flags() & 1) == 0;
    public static Boolean AutoStart                    (this H h) =>(h.Flags() & 2) == 0;
    public static Boolean AllowInteractiveAuthorization(this H h) =>(h.Flags() & 4) != 0;

    private static T? GetField<T>(this H header, FieldCode fieldCode)
    {
        // not using a dictionary, list of header fields is always
        // small, so linear search is probably cheaper overall

        var fc = (Byte) fieldCode;

        return header
            .Fields()
            .Where(hf => hf.code == fc)
            .Select(hf => hf.variant.Value)
            .OfType<T>()
            .SingleOrDefault();
    }


    public static void AddField(this List<(Byte, Variant)> header,
        FieldCode fieldCode,
        Object? value)
    {
        if (value is null)
            return;

        header.Add(((Byte) fieldCode, value.Variant()));
    }


}