using Qrakhen.Qamp.Core.Collections;
using System.Text;

namespace Qrakhen.Qamp.Core.Values.Objects;

public class String(string? value) : Obj(ValueType.String)
{
   // yea that's quite temporary
   private static readonly Register<uint, String> _strings = new();

   public string? Value = value;

   public override string ToString() => Value ?? "null";

   public Value SubString(Value start, Value length)
   {
      if (Value == null)
         throw new RuntimeException($"Can not call substring on an empty string.");

      int index = start.IsInteger ? 
         (int)start.Signed : 
         throw new RuntimeException($"{nameof(String)}.{nameof(SubString)} requires first parameter 'start' to be an integer.");

      if (index < 0 || index >= Value.Length)
         throw new RuntimeException($"Parameter 'start' {start} was out of bounds.");

      if (length.IsVoid)      
         return String.Make(Value.Substring(index));

      int _length = length.IsInteger ?
         (int)length.Signed :
         throw new RuntimeException($"{nameof(String)}.{nameof(SubString)} requires second parameter 'length' to be an integer.");

      return String.Make(Value.Substring(index, _length));
   }

   public Value IndexOf(Value needle)
   {
      if (!needle.IsString)
         throw new RuntimeException($"Parameter 'needle' is expected to be of type string, got {needle} instead.");

      return new Value(Value?.IndexOf(needle.Ptr.As<String>()!.Value!) ?? -1L);
   }

   public Value Split(Value delimiter)
   {
      return Values.Value.Void;
   }

   public Value Length()
   {
      return new Value(Value?.Length ?? 0L);
   }

   public uint GetHash()
   {
      if (string.IsNullOrEmpty(Value))
         return 0;

      return Value?.GetHash() ?? 0;
   }

   public static Value Make(string? value)
   {
      String? str;
      var hash = value?.GetHash() ?? 0;
      if (!_strings.TryGet(hash, out str)) {
         str = new String(value);
         _strings.Add(hash, str);
      }

      return Create(str);
   }

   public static byte[] SerializeStrings()
   {
      List<byte> result = new();
      foreach (var pair in _strings) {
         String str = pair.Value;
         if (str == null || str.__GC_Marked)
            continue;
         byte[] bytes;
         bytes = Encoding.ASCII.GetBytes(str.Value!);
         result.AddRange(pair.Key.GetBytes());
         result.AddRange(bytes.Length.GetBytes());
         result.AddRange(bytes);
         result.Add(0);
      }
      return result.ToArray();
   }
}