#pragma once

#include "endian.hpp"
#include "types.hpp"
#include "../utils.hpp"
#include <cstring>
#include <stdexcept>

namespace sibs
{
    class DeserializeException : public std::runtime_error
    {
    public:
        DeserializeException(const std::string &errMsg) : std::runtime_error(errMsg) {}
    };
    
    /**
     * Endian independent deserializer
     */
    class SafeDeserializer
    {
    public:
        SafeDeserializer(const u8 *_data, usize _size) : 
            data(_data),
            size(_size)
        {
            
        }
        
        /*
         * Throws DeserializeException on failure
         */
        template <typename T>
        T extract()
        {
            constexpr usize typeSize = sizeof(T);
            verifyExtractSize(typeSize);
            size -= typeSize;
            T result;
            #if BYTE_ORDER == BIG_ENDIAN
            switch(typeSize)
            {
                case 1:
                    result = *(T*)data;
                    break;
                case 2:
                    *(u16*)&result = byteswap(*(u16*)data);
                    break;
                case 4:
                    *(u32*)&result = byteswap(*(u32*)data);
                    break;
                case 8:
                    *(u64*)&result = byteswap(*(u64*)data);
                    break;
                default:
                {
                    for(int i = 0; i < typeSize; ++i)
                    {
                        ((char*)&result)[i] = data[typeSize - 1 - i];
                    }
                    break;
                }
            }
            #else
            result = *(T*)data;
            #endif
            data += typeSize;
            return result;
        }
        
        /*
         * Throws DeserializeException on failure
         */
        void extract(u8 *destination, usize destinationSize)
        {
            if(destinationSize > 0)
            {
                verifyExtractSize(destinationSize);
                size -= destinationSize;
                memcpy(destination, data, destinationSize);
                data += destinationSize;
            }
        }
        
        bool empty() const
        {
            return size == 0;
        }
        
        const u8* getBuffer()
        {
            return data;
        }
        
        usize getSize() const
        {
            return size;
        }

        void skip(usize bytesToSkip)
        {
            bytesToSkip = bytesToSkip < size ? bytesToSkip : size;
            size -= bytesToSkip;
            data += bytesToSkip;
        }
    private:
        void verifyExtractSize(usize typeSize) const
        {
            if(typeSize > size)
            {
                std::string errMsg = "Unable to extract ";
                errMsg += std::to_string(typeSize);
                errMsg += " bytes, only ";
                errMsg += std::to_string(size);
                errMsg += " bytes left in buffer";
                throw DeserializeException(errMsg);
            }
        }
    private:
        const u8 *data;
        usize size;
    };
}