/* SPDX-License-Identifier: Unlicense
 */

#pragma once

#include "bus.hpp"

#include <cstddef>
#include <cstring>

class VDP {
    public:
        VDP(const uint32_t base_address_a = VDP_START): base_address(base_address_a) {}
        uint32_t Read(uint32_t offset, enum bitness);
        void Write(uint32_t offset, enum bitness, uint32_t value);
        bool Scanline(); // Returns true if display disabled or vblank happened
        void Reset();

        const uint32_t base_address;

    private:
        struct StatusRegister {
            bool fifo_not_empty{};
            bool fifo_full{};
            bool v_irq{};
            bool sprites_overflow{};
            bool sprites_collision{};
            bool odd_frame{};
            bool vblank{};
            bool hblank{};
            bool dma_busy{};
            bool pal_mode{};
        };

        enum class AddressMode: uint8_t {
            kVRAMWrite = 1,
            kCRAMWrite = 3,
            kVSRAMWrite = 5,
            kVRAMRead = 0,
            kCRAMRead = 8,
            kVSRAMRead = 4,
        };

        enum class RegID: size_t {
            kModeSet1 = 0,
            kModeSet2 = 1,
            kScrollAAddress = 2,
            kWindowAddress = 3,
            kScrollBAddress = 4,
            kSpritesTableAddress = 5,
            kBackgroundColor = 7,
            kHint = 10,
            kModeSet3 = 11,
            kModeSet4 = 12,
            kHScrollTableAddress = 13,
            kAutoIncrement = 15,
            kScrollSize = 16,
            kWindowHorizontalPosition = 17,
            kWindowVertialPosition = 18,
            kDMACounterLow = 19,
            kDMACounterHigh = 20,
            kDMASourceAddressLow = 21,
            kDMASourceAddressMid = 22,
            kDMASourceAddressHigh = 23,
            kRegistersCount, ///< Keep it last
        };

        void writeData(uint8_t address_mode, uint16_t address, uint16_t value);
        void writeControl(uint16_t value);
        uint16_t readData(uint8_t address_mode, uint16_t address);
        uint16_t readStatusRegister() const;

        const char* addressModeToString(uint8_t address_mode);
        const char* regIDToString(RegID);

        static constexpr size_t kRegistersCount = static_cast<size_t>(RegID::kRegistersCount);
        static constexpr size_t kVRAMSize = 64*1024;
        static constexpr size_t kCRAMSize = 64*2;
        static constexpr size_t kVSRAMSize = 40*2;
        static constexpr uint16_t kLinesPerScreenNTSC = 262;
        static constexpr uint16_t kLinesPerScreenPAL = 312;

        StatusRegister _status{};
        bool _control_write_second_word{};
        uint16_t _lines_counter{};
        uint8_t _address_mode{};
        uint16_t _address{};
        uint8_t _reg[kRegistersCount]{};
        uint8_t _vram[kVRAMSize]{};
        uint8_t _cram[kCRAMSize]{};
        uint8_t _vsram[kVSRAMSize]{};
};