/*
    * Framebuffer.cpp
    * Framebuffer information storage
    * Copyright (c) 2025 Daniel Hammer
*/

#include "Framebuffer.hpp"
#include <Terminal/Terminal.hpp>
#include <Memory/HHDM.hpp>
#include <Memory/Paging.hpp>
#include <CppLib/Stream.hpp>

namespace Graphics::Framebuffer {

    // Framebuffer state
    static uint32_t* g_FbBase   = nullptr;
    static uint64_t  g_FbWidth  = 0;
    static uint64_t  g_FbHeight = 0;
    static uint64_t  g_FbPitch  = 0; // in bytes
    static uint8_t   g_Edid[256] = {};
    static uint64_t  g_EdidSize  = 0;

    void Initialize(const montauk::boot::Framebuffer& framebuffer) {
        g_FbBase   = reinterpret_cast<uint32_t*>(framebuffer.address);
        g_FbWidth  = framebuffer.width;
        g_FbHeight = framebuffer.height;
        g_FbPitch  = framebuffer.pitch;
        g_EdidSize = framebuffer.edidSize;
        if (g_EdidSize > sizeof(g_Edid)) g_EdidSize = sizeof(g_Edid);
        if (framebuffer.edid == nullptr) g_EdidSize = 0;
        for (uint64_t i = 0; i < g_EdidSize; i++) {
            g_Edid[i] = framebuffer.edid[i];
        }

        Kt::KernelLogStream(Kt::OK, "Graphics") << "Framebuffer initialized ("
            << (uint64_t)g_FbWidth << "x" << (uint64_t)g_FbHeight << ")";
    }

    uint32_t* GetBase()   { return g_FbBase; }
    uint64_t  GetWidth()  { return g_FbWidth; }
    uint64_t  GetHeight() { return g_FbHeight; }
    uint64_t  GetPitch()  { return g_FbPitch; }
    const uint8_t* GetEdid(uint64_t* size) {
        if (size) *size = g_EdidSize;
        return g_EdidSize ? g_Edid : nullptr;
    }

    void Set(uint32_t* base, uint64_t width, uint64_t height, uint64_t pitch) {
        g_FbBase = base;
        g_FbWidth = width;
        g_FbHeight = height;
        g_FbPitch = pitch;
        Kt::KernelLogStream(Kt::OK, "Graphics") << "Framebuffer switched ("
            << (uint64_t)g_FbWidth << "x" << (uint64_t)g_FbHeight << ")";
    }

    uint64_t GetPhysBase() {
        return Memory::SubHHDM((uint64_t)g_FbBase);
    }

    void MapWriteCombining() {
        uint64_t fbPhys = GetPhysBase();
        uint64_t fbSize = g_FbHeight * g_FbPitch;
        uint64_t numPages = (fbSize + 0xFFF) / 0x1000;

        for (uint64_t i = 0; i < numPages; i++) {
            uint64_t phys = fbPhys + i * 0x1000;
            Memory::VMM::g_paging->MapWC(phys, Memory::HHDM(phys));
        }

        Memory::VMM::FlushTLB();

        Kt::KernelLogStream(Kt::OK, "Graphics") << "Framebuffer mapped as Write-Combining ("
            << kcp::dec << numPages << " pages)";
    }

};