#include "framework.h"
#include "WindowsProject3.h"
#include <string>
#include <sstream>
#include <iomanip>

#define MAX_LOADSTRING 100

// Global Variables:
HINSTANCE hInst;                                // current instance
WCHAR szTitle[MAX_LOADSTRING];                  // The title bar text
WCHAR szWindowClass[MAX_LOADSTRING];            // the main window class name

// Hex editor globals
HWND hHexEdit = NULL;
WNDPROC oldEditProc = NULL;
const int BYTES_PER_LINE = 16;
const int TOTAL_LINES = 100;  // Total lines of hex data
int currentScrollPos = 0;

// Sample hex data
BYTE hexData[BYTES_PER_LINE * TOTAL_LINES];

// Forward declarations of functions included in this code module:
ATOM                MyRegisterClass(HINSTANCE hInstance);
BOOL                InitInstance(HINSTANCE, int);
LRESULT CALLBACK    WndProc(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK    About(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK    HexEditProc(HWND, UINT, WPARAM, LPARAM);
void                UpdateHexDisplay(HWND hEdit, int scrollPos);
void                InitializeHexData();

int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
                     _In_opt_ HINSTANCE hPrevInstance,
                     _In_ LPWSTR    lpCmdLine,
                     _In_ int       nCmdShow)
{
    UNREFERENCED_PARAMETER(hPrevInstance);
    UNREFERENCED_PARAMETER(lpCmdLine);

    // TODO: Place code here.

    // Initialize global strings
    LoadStringW(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
    LoadStringW(hInstance, IDC_WINDOWSPROJECT3, szWindowClass, MAX_LOADSTRING);
    MyRegisterClass(hInstance);

    // Perform application initialization:
    if (!InitInstance (hInstance, nCmdShow))
    {
        return FALSE;
    }

    HACCEL hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_WINDOWSPROJECT3));

    MSG msg;

    // Main message loop:
    while (GetMessage(&msg, nullptr, 0, 0))
    {
        if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }

    return (int) msg.wParam;
}



//
//  FUNCTION: MyRegisterClass()
//
//  PURPOSE: Registers the window class.
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
    WNDCLASSEXW wcex;

    wcex.cbSize = sizeof(WNDCLASSEX);

    wcex.style          = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc    = WndProc;
    wcex.cbClsExtra     = 0;
    wcex.cbWndExtra     = 0;
    wcex.hInstance      = hInstance;
    wcex.hIcon          = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_WINDOWSPROJECT3));
    wcex.hCursor        = LoadCursor(nullptr, IDC_ARROW);
    wcex.hbrBackground  = (HBRUSH)(COLOR_WINDOW+1);
    wcex.lpszMenuName   = MAKEINTRESOURCEW(IDC_WINDOWSPROJECT3);
    wcex.lpszClassName  = szWindowClass;
    wcex.hIconSm        = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));

    return RegisterClassExW(&wcex);
}

//
//   FUNCTION: InitInstance(HINSTANCE, int)
//
//   PURPOSE: Saves instance handle and creates main window
//
//   COMMENTS:
//
//        In this function, we save the instance handle in a global variable and
//        create and display the main program window.
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
   hInst = hInstance; // Store instance handle in our global variable

   HWND hWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, 800, 600, nullptr, nullptr, hInstance, nullptr);

   if (!hWnd)
   {
      return FALSE;
   }

   ShowWindow(hWnd, nCmdShow);
   UpdateWindow(hWnd);

   return TRUE;
}

//
//  FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
//
//  PURPOSE: Processes messages for the main window.
//
//  WM_COMMAND  - process the application menu
//  WM_PAINT    - Paint the main window
//  WM_DESTROY  - post a quit message and return
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
    case WM_CREATE:
        {
            // Initialize hex data
            InitializeHexData();

            // Create the edit control with vertical scrollbar
            hHexEdit = CreateWindowExW(
                0,
                L"EDIT",
                L"",
                WS_CHILD | WS_VISIBLE | WS_VSCROLL | WS_BORDER | 
                ES_MULTILINE | ES_READONLY | ES_AUTOVSCROLL,
                10, 10, 760, 500,
                hWnd,
                (HMENU)1001,
                hInst,
                NULL
            );

            if (hHexEdit)
            {
                // Set a fixed-width font for better hex display
                HFONT hFont = CreateFontW(
                    16, 0, 0, 0, FW_NORMAL, FALSE, FALSE, FALSE,
                    DEFAULT_CHARSET, OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS,
                    DEFAULT_QUALITY, FIXED_PITCH | FF_MODERN, L"Courier New"
                );
                SendMessage(hHexEdit, WM_SETFONT, (WPARAM)hFont, TRUE);

                // Subclass the edit control
                oldEditProc = (WNDPROC)SetWindowLongPtr(hHexEdit, GWLP_WNDPROC, (LONG_PTR)HexEditProc);

                // Set up scrollbar info
                SCROLLINFO si = { 0 };
                si.cbSize = sizeof(SCROLLINFO);
                si.fMask = SIF_RANGE | SIF_PAGE | SIF_POS;
                si.nMin = 0;
                si.nMax = TOTAL_LINES - 1;
                si.nPage = 20;  // Visible lines
                si.nPos = 0;
                SetScrollInfo(hHexEdit, SB_VERT, &si, TRUE);

                // Initial display
                UpdateHexDisplay(hHexEdit, 0);
            }
        }
        break;
    case WM_COMMAND:
        {
            int wmId = LOWORD(wParam);
            // Parse the menu selections:
            switch (wmId)
            {
            case IDM_ABOUT:
                DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
                break;
            case IDM_EXIT:
                DestroyWindow(hWnd);
                break;
            default:
                return DefWindowProc(hWnd, message, wParam, lParam);
            }
        }
        break;
    case WM_VSCROLL:
        {
            // Handle scrollbar messages
            SCROLLINFO si = { 0 };
            si.cbSize = sizeof(SCROLLINFO);
            si.fMask = SIF_ALL;
            GetScrollInfo(hHexEdit, SB_VERT, &si);

            int newPos = si.nPos;

            switch (LOWORD(wParam))
            {
            case SB_LINEUP:
                newPos -= 1;
                break;
            case SB_LINEDOWN:
                newPos += 1;
                break;
            case SB_PAGEUP:
                newPos -= si.nPage;
                break;
            case SB_PAGEDOWN:
                newPos += si.nPage;
                break;
            case SB_THUMBTRACK:
            case SB_THUMBPOSITION:
                newPos = HIWORD(wParam);
                break;
            }

            // Clamp the position
            newPos = max(0, min(newPos, si.nMax - (int)si.nPage + 1));

            if (newPos != si.nPos)
            {
                currentScrollPos = newPos;
                si.nPos = newPos;
                si.fMask = SIF_POS;
                SetScrollInfo(hHexEdit, SB_VERT, &si, TRUE);
                UpdateHexDisplay(hHexEdit, newPos);
            }
        }
        break;
    case WM_SIZE:
        {
            // Resize the edit control when window is resized
            if (hHexEdit)
            {
                RECT rect;
                GetClientRect(hWnd, &rect);
                MoveWindow(hHexEdit, 10, 10, rect.right - 20, rect.bottom - 20, TRUE);
            }
        }
        break;
    case WM_PAINT:
        {
            PAINTSTRUCT ps;
            HDC hdc = BeginPaint(hWnd, &ps);
            // TODO: Add any drawing code that uses hdc here...
            EndPaint(hWnd, &ps);
        }
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}

// Message handler for about box.
INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
    UNREFERENCED_PARAMETER(lParam);
    switch (message)
    {
    case WM_INITDIALOG:
        return (INT_PTR)TRUE;

    case WM_COMMAND:
        if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
        {
            EndDialog(hDlg, LOWORD(wParam));
            return (INT_PTR)TRUE;
        }
        break;
    }
    return (INT_PTR)FALSE;
}

//
// FUNCTION: HexEditProc(HWND, UINT, WPARAM, LPARAM)
//
// PURPOSE: Subclassed window procedure for the hex edit control
//
LRESULT CALLBACK HexEditProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
    case WM_VSCROLL:
        // Forward scroll messages to parent
        return SendMessage(GetParent(hWnd), WM_VSCROLL, wParam, lParam);

    case WM_MOUSEWHEEL:
        {
            // Handle mouse wheel scrolling
            int delta = GET_WHEEL_DELTA_WPARAM(wParam);
            int scrollAmount = delta / WHEEL_DELTA;

            if (scrollAmount > 0)
            {
                SendMessage(GetParent(hWnd), WM_VSCROLL, SB_LINEUP, 0);
            }
            else if (scrollAmount < 0)
            {
                SendMessage(GetParent(hWnd), WM_VSCROLL, SB_LINEDOWN, 0);
            }
            return 0;
        }
    }

    return CallWindowProc(oldEditProc, hWnd, message, wParam, lParam);
}

//
// FUNCTION: InitializeHexData()
//
// PURPOSE: Initialize sample hex data
//
void InitializeHexData()
{
    for (int i = 0; i < BYTES_PER_LINE * TOTAL_LINES; i++)
    {
        hexData[i] = (BYTE)(i % 256);
    }
}

//
// FUNCTION: UpdateHexDisplay(HWND, int)
//
// PURPOSE: Update the hex editor display based on scroll position
//
void UpdateHexDisplay(HWND hEdit, int scrollPos)
{
    std::wstringstream ss;

    // Display 20 lines at a time
    int startLine = scrollPos;
    int endLine = min(startLine + 20, TOTAL_LINES);

    for (int line = startLine; line < endLine; line++)
    {
        // Address
        ss << std::hex << std::uppercase << std::setfill(L'0') << std::setw(8) << (line * BYTES_PER_LINE) << L"  ";

        // Hex bytes
        for (int col = 0; col < BYTES_PER_LINE; col++)
        {
            int index = line * BYTES_PER_LINE + col;
            ss << std::setw(2) << (int)hexData[index] << L" ";
            if (col == 7) ss << L" ";  // Extra space in the middle
        }

        ss << L" ";

        // ASCII representation
        for (int col = 0; col < BYTES_PER_LINE; col++)
        {
            int index = line * BYTES_PER_LINE + col;
            BYTE b = hexData[index];
            if (b >= 32 && b <= 126)
                ss << (wchar_t)b;
            else
                ss << L".";
        }

        ss << L"\r\n";
    }

    SetWindowTextW(hEdit, ss.str().c_str());
}