#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>

#include <glad/glad.h>
#include <windows.h>

#include "XCEngine/RHI/OpenGL/OpenGLDevice.h"
#include "XCEngine/RHI/OpenGL/OpenGLSwapChain.h"
#include "XCEngine/RHI/OpenGL/OpenGLCommandList.h"
#include "XCEngine/Debug/Logger.h"
#include "XCEngine/Debug/ConsoleLogSink.h"
#include "XCEngine/Containers/String.h"

#pragma comment(lib, "opengl32.lib")

using namespace XCEngine::RHI;
using namespace XCEngine::Debug;
using namespace XCEngine::Containers;

static const int gWidth = 1280;
static const int gHeight = 720;

void Log(const char* format, ...) {
    char buffer[1024];
    va_list args;
    va_start(args, format);
    vsnprintf(buffer, sizeof(buffer), format, args);
    va_end(args);
    Logger::Get().Debug(LogCategory::Rendering, String(buffer));
}

void SaveScreenshotPPM(const char* filename, int width, int height) {
    unsigned char* pixels = (unsigned char*)malloc(width * height * 3);
    if (!pixels) {
        Log("[ERROR] Failed to allocate pixel buffer");
        return;
    }

    glFinish();
    glReadBuffer(GL_BACK);
    glPixelStorei(GL_PACK_ALIGNMENT, 1);
    glPixelStorei(GL_PACK_ROW_LENGTH, 0);
    glPixelStorei(GL_PACK_SKIP_PIXELS, 0);
    glPixelStorei(GL_PACK_SKIP_ROWS, 0);
    glReadPixels(0, 0, width, height, GL_RGB, GL_UNSIGNED_BYTE, pixels);

    FILE* f = fopen(filename, "wb");
    if (!f) {
        Log("[ERROR] Failed to open file for screenshot: %s", filename);
        free(pixels);
        return;
    }

    fprintf(f, "P6\n%d %d\n255\n", width, height);

    unsigned char* row = (unsigned char*)malloc(width * 3);
    for (int y = height - 1; y >= 0; y--) {
        memcpy(row, pixels + y * width * 3, width * 3);
        fwrite(row, 1, width * 3, f);
    }

    free(row);
    free(pixels);
    fclose(f);

    Log("[INFO] Screenshot saved to %s", filename);
}

LRESULT CALLBACK WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
    switch (msg) {
    case WM_CLOSE:
        PostQuitMessage(0);
        break;
    }
    return DefWindowProc(hwnd, msg, wParam, lParam);
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd) {
    // Initialize logger
    Logger::Get().Initialize();
    Logger::Get().AddSink(std::make_unique<ConsoleLogSink>());
    Logger::Get().SetMinimumLevel(LogLevel::Debug);

    Log("[INFO] OpenGL Integration Test Starting");

    // Register window class
    WNDCLASSEXW wc = {};
    wc.cbSize = sizeof(WNDCLASSEXW);
    wc.style = CS_HREDRAW | CS_VREDRAW;
    wc.lpfnWndProc = WindowProc;
    wc.hInstance = hInstance;
    wc.lpszClassName = L"XCEngine_OpenGL_Test";

    if (!RegisterClassExW(&wc)) {
        Log("[ERROR] Failed to register window class");
        return -1;
    }

    // Calculate full window size from client area size
    RECT rect = { 0, 0, gWidth, gHeight };
    AdjustWindowRect(&rect, WS_OVERLAPPEDWINDOW, FALSE);

    // Create window
    HWND hwnd = CreateWindowExW(
        0,
        L"XCEngine_OpenGL_Test",
        L"OpenGL Integration Test",
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT,
        rect.right - rect.left, rect.bottom - rect.top,
        NULL, NULL, hInstance, NULL
    );

    if (!hwnd) {
        Log("[ERROR] Failed to create window");
        return -1;
    }

    // Initialize OpenGL device with existing window
    OpenGLDevice device;
    if (!device.InitializeWithExistingWindow(hwnd)) {
        Log("[ERROR] Failed to initialize OpenGL device");
        return -1;
    }

    ShowWindow(hwnd, nShowCmd);
    UpdateWindow(hwnd);

    // Log OpenGL device info
    Log("[INFO] OpenGL Device: %S", device.GetDeviceInfo().renderer.c_str());
    Log("[INFO] OpenGL Version: %S", device.GetDeviceInfo().version.c_str());

    // Create swap chain for rendering
    OpenGLSwapChain swapChain;
    swapChain.Initialize(hwnd, gWidth, gHeight);

    // Create command list for rendering commands
    OpenGLCommandList commandList;

    // Main render loop
    MSG msg = {};
    int frameCount = 0;
    const int targetFrameCount = 30;

    while (frameCount < targetFrameCount) {
        if (PeekMessageW(&msg, NULL, 0, 0, PM_REMOVE)) {
            if (msg.message == WM_QUIT) {
                break;
            }
            TranslateMessage(&msg);
            DispatchMessageW(&msg);
        } else {
            // Set viewport and clear color using encapsulated command list
            commandList.SetViewport(0, 0, gWidth, gHeight);
            commandList.Clear(1.0f, 0.0f, 0.0f, 1.0f, 1 | 2);

            // Present the rendered frame
            swapChain.Present(0, 0);
            frameCount++;
        }
    }

    // Take screenshot after target frame count is reached
    // glFinish ensures all OpenGL commands are completed before reading pixels
    Log("[INFO] Reached target frame count %d - taking screenshot!", targetFrameCount);
    SaveScreenshotPPM("minimal.ppm", gWidth, gHeight);

    // Shutdown in reverse order of initialization
    swapChain.Shutdown();
    device.Shutdown();
    Logger::Get().Shutdown();

    Log("[INFO] OpenGL Integration Test Finished");
    return 0;
}