; =============================================================================
; Display Service - Auto-resize on window change
; =============================================================================

align 4
kos_display_ptr dd ?

proc display_change uses ebx ecx edx esi edi
    DEBUGF 2, "display_change\n"

    ; Request display change information
    mov eax, [vbox_device.display_phys]
    stdcall vmmdev_request_perform, eax

    mov ebx, [vbox_device.display_virt]
    mov edi, [ebx + VMMDEV_DISPLAY_CHANGE.x_res]
    mov esi, [ebx + VMMDEV_DISPLAY_CHANGE.y_res]
    mov ecx, [ebx + VMMDEV_DISPLAY_CHANGE.bpp]

    DEBUGF 2, "[display] Requested resolution: %dx%d %dbpp\n", edi, esi, ecx

    ; Validate minimum
    cmp edi, DISP_W_MIN
    jb .skip
    cmp esi, DISP_H_MIN
    jb .skip

    ; Validate maximum
    cmp edi, DISP_W_MAX
    ja .skip
    cmp esi, DISP_H_MAX
    ja .skip

    ; Validate BPP
    cmp ecx, 32
    je .valid
    cmp ecx, 24
    je .valid
    cmp ecx, 16
    je .valid
    cmp ecx, 8
    jne .skip

.valid:
    DEBUGF 2, "[display] Setting resolution %dx%d %dbpp\n", edi, esi, ecx

    ; Set video mode using VGA
    cli
    vga_set_mode edi, esi, ecx
    sti

    ; Update KolibriOS display structure
    mov eax, [kos_display_ptr]
    mov [eax + DISPLAY.width], edi
    mov [eax + DISPLAY.height], esi
    mov [eax + DISPLAY.bits_per_pixel], ecx

    ; Calculate pitch
    push ebx
    mov ebx, ecx
    shr ecx, 3
    imul ecx, edi
    mov [eax + DISPLAY.pitch], ecx
    pop ebx

    ; Apply changes
    mov eax, edi
    mov edx, esi
    dec eax
    dec edx
    invoke SetScreen

    DEBUGF 2, "[display] Resolution set successfully\n"

.skip:
    DEBUGF 2, "[trace] <<< display_change\n"
    ret
endp