format PE64
entry main 

include 'fasm\INCLUDE\win64a.inc'
; include '.\main_data.asm'

//@start This here is the section I wanted to store in main_data.asm
section '.data' data readable writeable 

        GlobalRunning db 0


struc draw_buffer BmpInfoHeader, PixelPtr, Width, Height
{
        .BitmapInfoHeader dq BmpInfoHeader
        .PixelPointer dq PixelPtr
        .Width dq Width
        .Height dq Height
}

        DrawBufferBMPInfoHeader BITMAPINFOHEADER
        GlobalDrawBuffer draw_buffer DrawBufferBMPInfoHeader,0,0,0
        
        WindowClassName db "win32app",0
        WindowTitle db "win32 Apllication",0
        WindowRegErrorMessage db "Error encountered when registering window class: closing",0
        WindowCreateErrorMessage db "Error encountered when creating window: closing",0

  WindowClass WNDCLASSEX sizeof.WNDCLASSEX,0,Win32CallbackProc,0,0,0,0,0,COLOR_WINDOW,0,WindowClassName,0
        Message MSG
        WindowHandle dq 0


//@end 

section '.text' code readable executable 
main:

        sub     rsp,8
        invoke  GetModuleHandle,0
        mov     [WindowClass.hInstance], rax

        invoke LoadIcon,0,IDI_APPLICATION
        mov     [WindowClass.hIcon],rax
        mov     [WindowClass.hIconSm],rax
        invoke LoadCursor,0,IDC_ARROW
        mov     [WindowClass.hCursor],rax
        
        invoke RegisterClassExA,WindowClass
        test rax, rax
        jz registration_error 

        invoke CreateWindowExA,0,WindowClassName,WindowTitle, WS_VISIBLE+WS_OVERLAPPEDWINDOW,\
                        CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, 0,0,[WindowClass.hInstance],0
        mov [WindowHandle], rax

        test rax, rax
        jz creation_error

        
        stdcall InitDrawBuffer,GlobalDrawBuffer

        mov [GlobalRunning], 1
.loop:
        cmp [GlobalRunning], 0
        je exit

        call Win32MessagePump
        jmp .loop


registration_error:
        invoke MessageBoxA,0,WindowRegErrorMessage,WindowTitle,MB_ICONERROR+MB_OK
        jmp exit

creation_error:
        invoke MessageBoxA,0,WindowCreateErrorMessage,WindowTitle,MB_ICONERROR+MB_OK
        ;jmp exit

exit:
invoke  ExitProcess,[Message.wParam]

;---

proc InitDrawBuffer uses BitmapInfo, Pixels, Width, Height

int3
;TODO lea? whats a better way to do this... this is **** 
        mov [BitmapInfo], rcx
        mov rax, [rcx+8]
        mov [Pixels], rax
        mov rax, [rcx+16]
        mov [Width], rax
        mov rax, [rcx+24]
        mov [Height], rax

        mov [bmiHeader.biSize], sizeof.BitmapInfo.bmiHeader
        ;mov [bmiHeader.biWidth], [Width]
        ;mov [bmiHeader.biHeight], [Height]
        mov [bmiHeader.biWidth], 500
        mov [bmiHeader.biHeight], 900
        mov [bmiHeader.biPlanes], 1
        mov [bmiHeader.biBitCount], 32
        mov [bmiHeader.biCompression], BI_RGB

        ret
endp


proc Win32DisplayBuffer 

        
        invoke GetDC,WindowHandle 
        ;invoke StretchDIBits,rax,0,0,Width,Height,0,0,Width,Height,Pixels,BitmapInfo,DIB_RGB_COLORS, SRCCOPY

        ret
endp

proc Win32MessagePump; uses WindowHandle

.while_message: 

        ;invoke PeekMessageA, Message, WindowHandle,0,0, PM_REMOVE   ;TODO why does this freeze up?
        invoke GetMessage,Message,0,0,0 ;TODO replace with peekmessage

        cmp eax, 0
        je .end
        
        cmp [Message.message], WM_QUIT
        mov [GlobalRunning], 0
        je .end

        cmp [Message.message], WM_PAINT
        je .paint

        cmp [Message.message], WM_KEYDOWN
        je .keydown

        invoke TranslateMessage,Message
        invoke DispatchMessage,Message

        jmp .while_message

.paint:
        push rax
        call Win32DisplayBuffer 
        pop rax
        jmp .while_message

.keydown:
        call Win32DisplayBuffer
        jmp .while_message

.end:
        
        ret
endp

proc Win32CallbackProc ;proc WndProc uses rbx rsi rdi, hwnd,wmsg,wparam,lparam
        cmp edx, WM_DESTROY 
        je .destroy

  .default:
                                invoke  DefWindowProcA,rcx,rdx,r8,r9
        jmp .end
  .destroy:
        invoke PostQuitMessage,0
        xor rax,rax
  .end:
        ret
endp


section '.idata' import data readable writeable

  library kernel,'KERNEL32.DLL',\
          user,'USER32.DLL',\
                gdi, 'GDI32.DLL',\

  import kernel,\
         GetModuleHandle,'GetModuleHandleA',\
         ExitProcess,'ExitProcess'

  import user,\
         RegisterClassExA,'RegisterClassExA',\
         CreateWindowExA,'CreateWindowExA',\
         ShowWindow,'ShowWindow',\
         UpdateWindow,'UpdateWindow',\
         DefWindowProcA,'DefWindowProcA',\
         GetMessage,'GetMessageA',\
         TranslateMessage,'TranslateMessage',\
         DispatchMessage,'DispatchMessageA',\
         LoadCursor,'LoadCursorA',\
         LoadIcon,'LoadIconA',\
         GetClientRect,'GetClientRect',\
         GetDC,'GetDC',\
         ReleaseDC,'ReleaseDC',\
         BeginPaint,'BeginPaint',\
         EndPaint,'EndPaint',\
         PostQuitMessage,'PostQuitMessage',\
         MessageBoxA, 'MessageBoxA',\
         PeekMessageA, 'PeekMessageA'

        import gdi,\
                StretchDIBits, 'StretchDIBits'    

                gdi, 'GDI32.DLL',\ ; <--- extra trailing comma    

proc InitDrawBuffer uses BitmapInfo, Pixels, Width, Height    

ps. are the code blocks markdown?