#ifdef _WIN32
#include <Windows.h>
#endif
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <memory>
#include <cmath>
#include <unordered_map>
#include <fstream>
#include <iostream>
#include "recomp.h"
#include "../portultra/multilibultra.hpp"

#ifdef _WIN32
#define EXPORT __declspec(dllexport)
#else
#define EXPORT __attribute__((visibility("default")))
#endif

#ifdef _MSC_VER
inline uint32_t byteswap(uint32_t val) {
    return _byteswap_ulong(val);
}
#else
constexpr uint32_t byteswap(uint32_t val) {
    return __builtin_bswap32(val);
}
#endif

extern "C" void _bzero(uint8_t* rdram, recomp_context* ctx) {
    gpr start_addr = ctx->r4;
    gpr size = ctx->r5;

    for (uint32_t i = 0; i < size; i++) {
        MEM_B(start_addr, i) = 0;
    }
}

extern "C" void osGetMemSize_recomp(uint8_t * rdram, recomp_context * ctx) {
    ctx->r2 = 8 * 1024 * 1024;
}

enum class StatusReg {
    FR = 0x04000000,
};

extern "C" void cop0_status_write(recomp_context* ctx, gpr value) {
    uint32_t old_sr = ctx->status_reg;
    uint32_t new_sr = (uint32_t)value;
    uint32_t changed = old_sr ^ new_sr;

    // Check if the FR bit changed
    if (changed & (uint32_t)StatusReg::FR) {
        // Check if the FR bit was set
        if (new_sr & (uint32_t)StatusReg::FR) {
            // FR = 1, odd single floats point to their own registers
            ctx->f_odd = &ctx->f1.u32l;
            ctx->mips3_float_mode = true;
        }
        // Otherwise, it was cleared
        else {
            // FR = 0, odd single floats point to the upper half of the previous register
            ctx->f_odd = &ctx->f0.u32h;
            ctx->mips3_float_mode = false;
        }

        // Remove the FR bit from the changed bits as it's been handled
        changed &= ~(uint32_t)StatusReg::FR;
    }

    // If any other bits were changed, assert false as they're not handled currently
    if (changed) {
        printf("Unhandled status register bits changed: 0x%08X\n", changed);
        assert(false);
        exit(EXIT_FAILURE);
    }
    
    // Update the status register in the context
    ctx->status_reg = new_sr;
}

extern "C" gpr cop0_status_read(recomp_context* ctx) {
    return (gpr)(int32_t)ctx->status_reg;
}

extern "C" void switch_error(const char* func, uint32_t vram, uint32_t jtbl) {
    printf("Switch-case out of bounds in %s at 0x%08X for jump table at 0x%08X\n", func, vram, jtbl);
    assert(false);
    exit(EXIT_FAILURE);
}

extern "C" void do_break(uint32_t vram) {
    printf("Encountered break at original vram 0x%08X\n", vram);
    assert(false);
    exit(EXIT_FAILURE);
}

void run_thread_function(uint8_t* rdram, uint64_t addr, uint64_t sp, uint64_t arg) {
    recomp_context ctx{};
    ctx.r29 = sp;
    ctx.r4 = arg;
    ctx.mips3_float_mode = 0;
    ctx.f_odd = &ctx.f0.u32h;
    recomp_func_t* func = get_function(addr);
    func(rdram, &ctx);
}

void do_rom_read(uint8_t* rdram, gpr ram_address, uint32_t dev_address, size_t num_bytes);

std::unique_ptr<uint8_t[]> rom;
size_t rom_size;

// Recomp generation functions
extern "C" void recomp_entrypoint(uint8_t * rdram, recomp_context * ctx);
gpr get_entrypoint_address();
const char* get_rom_name();
void init_overlays();
extern "C" void load_overlays(uint32_t rom, int32_t ram_addr, uint32_t size);
extern "C" void unload_overlays(int32_t ram_addr, uint32_t size);

std::unique_ptr<uint8_t[]> rdram_buffer;
recomp_context context{};

EXPORT extern "C" void init() {
    {
        std::ifstream rom_file{ get_rom_name(), std::ios::binary };

        size_t iobuf_size = 0x100000;
        std::unique_ptr<char> iobuf = std::make_unique<char>(iobuf_size);
        rom_file.rdbuf()->pubsetbuf(iobuf.get(), iobuf_size);

        if (!rom_file) {
            fprintf(stderr, "Failed to open rom: %s\n", get_rom_name());
            exit(EXIT_FAILURE);
        }

        rom_file.seekg(0, std::ios::end);
        rom_size = rom_file.tellg();
        rom_file.seekg(0, std::ios::beg);

        rom = std::make_unique<uint8_t[]>(rom_size);

        rom_file.read(reinterpret_cast<char*>(rom.get()), rom_size);

        // TODO remove this
        // Modify the name in the rom header so RT64 doesn't find it
        rom[0x2F] = 'O';
    }

    // Initialize the overlays
    init_overlays();

    // Get entrypoint from recomp function
    gpr entrypoint = get_entrypoint_address();

    // Load overlays in the first 1MB
    load_overlays(0x1000, (int32_t)entrypoint, 1024 * 1024);

    // Allocate rdram_buffer (16MB to give room for any extra addressable data used by recomp)
    rdram_buffer = std::make_unique<uint8_t[]>(16 * 1024 * 1024);
    std::memset(rdram_buffer.get(), 0, 8 * 1024 * 1024);

    // Initial 1MB DMA (rom address 0x1000 = physical address 0x10001000)
    do_rom_read(rdram_buffer.get(), entrypoint, 0x10001000, 0x100000);

    // Set up stack pointer
    context.r29 = 0xFFFFFFFF803FFFF0u;

    // Set up context floats
    context.f_odd = &context.f0.u32h;
    context.mips3_float_mode = false;

    // Initialize variables normally set by IPL3
    constexpr int32_t osTvType = 0x80000300;
    constexpr int32_t osRomType = 0x80000304;
    constexpr int32_t osRomBase = 0x80000308;
    constexpr int32_t osResetType = 0x8000030c;
    constexpr int32_t osCicId = 0x80000310;
    constexpr int32_t osVersion = 0x80000314;
    constexpr int32_t osMemSize = 0x80000318;
    constexpr int32_t osAppNMIBuffer = 0x8000031c;
    uint8_t *rdram = rdram_buffer.get();
    MEM_W(osTvType, 0) = 1; // NTSC
    MEM_W(osRomBase, 0) = 0xB0000000u; // standard rom base
    MEM_W(osResetType, 0) = 0; // cold reset
    MEM_W(osMemSize, 0) = 8 * 1024 * 1024; // 8MB
}

// LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {
//     return DefWindowProc(hwnd, uMsg, wParam, lParam);
// }

/*EXPORT extern "C"*/ void start(Multilibultra::WindowHandle window_handle, const Multilibultra::audio_callbacks_t* audio_callbacks, const Multilibultra::input_callbacks_t* input_callbacks) {
    Multilibultra::set_audio_callbacks(audio_callbacks);
    Multilibultra::set_input_callbacks(input_callbacks);

    //// Register window class.
    //WNDCLASS wc;
    //memset(&wc, 0, sizeof(WNDCLASS));
    //wc.lpfnWndProc = WindowProc;
    //wc.hInstance = GetModuleHandle(0);
    //wc.hbrBackground = (HBRUSH)(COLOR_BACKGROUND);
    //wc.lpszClassName = "RT64Sample";
    //RegisterClass(&wc);

    //// Create window.
    //const int Width = 1280;
    //const int Height = 720;
    //RECT rect;
    //UINT dwStyle = WS_OVERLAPPEDWINDOW | WS_VISIBLE;
    //rect.left = (GetSystemMetrics(SM_CXSCREEN) - Width) / 2;
    //rect.top = (GetSystemMetrics(SM_CYSCREEN) - Height) / 2;
    //rect.right = rect.left + Width;
    //rect.bottom = rect.top + Height;
    //AdjustWindowRectEx(&rect, dwStyle, 0, 0);

    //HWND hwnd = CreateWindow(wc.lpszClassName, "Recomp", dwStyle, rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top, 0, 0, wc.hInstance, NULL);

    std::thread game_thread{[](Multilibultra::WindowHandle window_handle) {
        debug_printf("[Recomp] Starting\n");
        
        Multilibultra::set_native_thread_name("Game Start Thread");

        Multilibultra::preinit(rdram_buffer.get(), rom.get(), window_handle);

        recomp_entrypoint(rdram_buffer.get(), &context);
        
        debug_printf("[Recomp] Quitting\n");
    }, window_handle};

    game_thread.detach();
}