// about.c — "About DVX Shell" sample DXE application (callback-only)
//
// Demonstrates a simple callback-only app: creates a window with widgets,
// registers callbacks, and returns.  The shell event loop handles the rest.

#include "dvxApp.h"
#include "dvxWidget.h"
#include "shellApp.h"

#include <stdint.h>
#include <stdbool.h>

// ============================================================
// Prototypes
// ============================================================

int32_t appMain(DxeAppContextT *ctx);
static void onClose(WindowT *win);
static void onOkClick(WidgetT *w);

// ============================================================
// App state
// ============================================================

static DxeAppContextT *sCtx = NULL;
static WindowT        *sWin = NULL;

// ============================================================
// App descriptor (required DXE export)
// ============================================================

AppDescriptorT appDescriptor = {
    .name        = "About",
    .hasMainLoop = false,
    .stackSize   = 0,
    .priority    = TS_PRIORITY_NORMAL
};

// ============================================================
// Callbacks
// ============================================================

static void onClose(WindowT *win) {
    dvxDestroyWindow(sCtx->shellCtx, win);
    sWin = NULL;
}


static void onOkClick(WidgetT *w) {
    (void)w;

    if (sWin) {
        dvxDestroyWindow(sCtx->shellCtx, sWin);
        sWin = NULL;
    }
}

// ============================================================
// Entry point
// ============================================================

int32_t appMain(DxeAppContextT *ctx) {
    sCtx = ctx;

    AppContextT *ac = ctx->shellCtx;
    int32_t screenW = ac->display.width;
    int32_t screenH = ac->display.height;
    int32_t winW    = 280;
    int32_t winH    = 200;
    int32_t winX    = (screenW - winW) / 2;
    int32_t winY    = (screenH - winH) / 3;

    sWin = dvxCreateWindow(ac, "About DVX Shell", winX, winY, winW, winH, false);

    if (!sWin) {
        return -1;
    }

    sWin->onClose = onClose;

    WidgetT *root = wgtInitWindow(ac, sWin);

    wgtLabel(root, "DVX Shell 1.0");
    wgtHSeparator(root);
    wgtLabel(root, "A DOS Visual eXecutive desktop shell for DJGPP/DPMI.");
    wgtLabel(root, "Using DXE3 dynamic loading for application modules.");
    wgtSpacer(root);

    WidgetT *btnRow = wgtHBox(root);
    btnRow->align = AlignCenterE;

    WidgetT *okBtn = wgtButton(btnRow, "OK");
    okBtn->onClick = onOkClick;
    okBtn->prefW   = wgtPixels(80);

    dvxFitWindow(ac, sWin);
    wgtInvalidate(root);
    return 0;
}