using StgSharp.Data;

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Numerics;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;

namespace StgSharp.Data
{
    public static class CodeSeparator
    {
        public static unsafe T[] SeparateCode<T>(string filePath) where T : struct
        {
            byte[] allByte = File.ReadAllBytes(filePath);
            List<T> rawList = new List<T>();

            fixed (byte* allBytePtr = allByte)
            {
                for (int i = 0; i < allByte.Length; i += Marshal.SizeOf<T>()) 
                {
                    T t = new T();
                    t= *(T*)(allBytePtr + i);
                    rawList.Add(t);
                }
            }
            return rawList.ToArray();
        }

        public static unsafe T[] SeparateCode<T>(byte[] stream) where T : struct
        {
            List<T> rawList = new List<T>();

            fixed (byte* allBytePtr = stream)
            {
                for (int i = 0; i < stream.Length; i += Marshal.SizeOf<T>())
                {
                    T t = new T();
                    t = *(T*)(allBytePtr + i);
                    rawList.Add(t);
                }
            }
            return rawList.ToArray();
        }

        public static List<(T, ulong)> CountCodeFrequency<T>(T[] rawArray) where T : struct
        {
            Dictionary<T, ulong> frequencyCollection = new Dictionary<T, ulong>();

            foreach (var item in rawArray)
            {
                if (frequencyCollection.ContainsKey(item))
                {
                    frequencyCollection[item] += 1;
                }
                else 
                {
                    frequencyCollection.Add(item, 1);
                }
            }

            return frequencyCollection.OrderByDescending(pair=>pair.Value)
                .Select(pair=>(pair.Key, pair.Value)).ToList();
        }

    }
}