//
// Created by Selim Mustafaev on 09.08.2023.
//

#ifndef NES_CARTRIDGE_H
#define NES_CARTRIDGE_H

#include "Mapper/Mapper.h"

#include <filesystem>
#include <memory>
#include <span>

namespace nes {

    namespace fs = std::filesystem;

    constexpr uint8_t ROM_MAGIC[4] = { 'N', 'E', 'S', 0x1a };
    constexpr size_t PRG_CHUNK_SIZE = 16*1024;
    constexpr size_t CHR_CHUNK_SIZE = 8*1024;

    class Cartridge {
    public:
        enum Mirroring: uint8_t {
            Horizontal = 0,
            Vertical = 1
        };

        struct Flags {
            Mirroring mirroring: 1;
            uint8_t batteryBacked: 1;
            uint8_t trainer: 1;
            uint8_t nametableAltLayout: 1;
            uint8_t mapper: 4;
        };

        struct Flags2 {
            uint8_t reserved: 2;
            uint8_t version: 2;
            uint8_t upperMapper: 4;
        };

        struct RomHeader {
            uint8_t magic[4];
            uint8_t prgChunks;
            uint8_t chrChunks;
            Flags flags;
            Flags2 flags2;
            uint8_t prgRamSize;
            uint8_t reserved[7];
        };

    public:
        explicit Cartridge(const fs::path& path);

    public:
        uint8_t readPrg(uint16_t address);
        void writePrg(uint16_t address, uint8_t value);
        uint8_t readChr(uint16_t address);
        void writeChr(uint16_t address, uint8_t value);
        uint8_t readRam(uint16_t address);
        void writeRam(uint16_t address, uint8_t value);
        Mirroring mirroring() const;

    private:
        std::unique_ptr<uint8_t[]> _romData;
        std::unique_ptr<Mapper> _mapper;
        RomHeader* _header;
        std::span<uint8_t> _prgRom;
        std::span<uint8_t> _chrRom;
        std::unique_ptr<uint8_t[]> _ram;
        std::unique_ptr<uint8_t[]> _chrRam;
    };

}

#endif //NES_CARTRIDGE_H