#pragma once
#include <string>
#include <fstream>
#include <span>

struct MemoryBuffer;

//Class that can write binary data either from a file or from a fixed size buffer
//depending on the constructor used.
class BinaryWriter
{
public:
    //Writes binary data from file at path. If truncate == true any existing file contents will be cleared
    BinaryWriter(std::string_view inputPath, bool truncate = true);
    //Writes binary data from fixed size memory buffer
    BinaryWriter(char* buffer, uint32_t sizeInBytes);
    ~BinaryWriter();

    void Flush();

    void WriteUint8(uint8_t value);
    void WriteUint16(uint16_t value);
    void WriteUint32(uint32_t value);
    void WriteUint64(uint64_t value);

    void WriteInt8(int8_t value);
    void WriteInt16(int16_t value);
    void WriteInt32(int32_t value);
    void WriteInt64(int64_t value);

    void WriteChar(char value);
    //Write string to output with null terminator
    void WriteNullTerminatedString(const std::string& value);
    //Write string to output without null terminator
    void WriteFixedLengthString(const std::string& value);

    void WriteFloat(float value);
    void WriteDouble(double value);

    void WriteFromMemory(const void* data, size_t size);

    template<typename T>
    void Write(const T& data)
    {
        //Don't allow T to be a pointer to avoid accidentally writing the value of a pointer instead of what it points to.
        static_assert(!std::is_pointer<T>(), "BinaryWriter::Write<T> requires T to be a non pointer type.");
        WriteFromMemory(&data, sizeof(T));
    }

    template<typename T>
    void WriteSpan(std::span<T> data)
    {
        WriteFromMemory(data.data(), data.size_bytes());
    }
    
    void SeekBeg(size_t absoluteOffset);
    void SeekCur(size_t relativeOffset);
    void Skip(size_t bytesToSkip);
    void WriteNullBytes(size_t bytesToWrite);
    //Static method for calculating alignment pad from pos and alignment. Does not change position since static
    static size_t CalcAlign(size_t position, size_t alignmentValue = 2048);
    //Aligns stream to alignment value. Returns padding byte count
    size_t Align(size_t alignmentValue = 2048);

    size_t Position() const;
    size_t Length();

private:
    std::ostream* stream_ = nullptr;
    MemoryBuffer* buffer_ = nullptr;
};