// shellExport.c -- DXE wrapper overrides for resource tracking
//
// Registers three wrapper functions via dlregsym that override the
// real dvxCreateWindow, dvxCreateWindowCentered, and dvxDestroyWindow
// for all subsequently loaded app DXEs.
//
// The key mechanic: dlregsym takes precedence over RTLD_GLOBAL exports.
// Since libdvx.dxe (which has the real functions) was loaded before
// shellExportInit() registers these wrappers, libdvx.dxe keeps the
// real implementations.  But any app DXE loaded afterward gets the
// wrappers, which add resource tracking (appId stamping, last-window
// reaping) transparently.
//
// All other symbol exports (dvx*, wgt*, platform*, libc) are handled
// by the DXE modules and the loader's dlregsym table -- they no longer
// need to be listed here.

#include "shellApp.h"
#include "dvxApp.h"
#include "dvxWm.h"

#include <sys/dxe.h>

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

static WindowT *shellWrapCreateWindow(AppContextT *ctx, const char *title, int32_t x, int32_t y, int32_t w, int32_t h, bool resizable);
static WindowT *shellWrapCreateWindowCentered(AppContextT *ctx, const char *title, int32_t w, int32_t h, bool resizable);
static void shellWrapDestroyWindow(AppContextT *ctx, WindowT *win);

// ============================================================
// Wrapper: dvxCreateWindow -- stamps win->appId
// ============================================================

// The wrapper calls the real dvxCreateWindow (resolved from libdvx.dxe
// at shellcore load time), then tags the result with sCurrentAppId.
// This is how the shell knows which app owns which window, enabling
// per-app window cleanup on crash/termination.
static WindowT *shellWrapCreateWindow(AppContextT *ctx, const char *title, int32_t x, int32_t y, int32_t w, int32_t h, bool resizable) {
    WindowT *win = dvxCreateWindow(ctx, title, x, y, w, h, resizable);

    if (win) {
        win->appId = sCurrentAppId;
    }

    return win;
}


// ============================================================
// Wrapper: dvxCreateWindowCentered -- stamps win->appId
// ============================================================

static WindowT *shellWrapCreateWindowCentered(AppContextT *ctx, const char *title, int32_t w, int32_t h, bool resizable) {
    WindowT *win = dvxCreateWindowCentered(ctx, title, w, h, resizable);

    if (win) {
        win->appId = sCurrentAppId;
    }

    return win;
}


// ============================================================
// Wrapper: dvxDestroyWindow -- checks for last-window reap
// ============================================================

// Beyond just destroying the window, this wrapper implements the lifecycle
// rule for callback-only apps: when their last window closes, they're done.
// Main-loop apps manage their own lifetime (their task returns from
// appMain), so this check only applies to callback-only apps.
// The appId is captured before destruction because the window struct is
// freed by dvxDestroyWindow.
static void shellWrapDestroyWindow(AppContextT *ctx, WindowT *win) {
    int32_t appId = win->appId;

    dvxDestroyWindow(ctx, win);

    // If this was a callback-only app's last window, mark for reaping
    if (appId > 0) {
        ShellAppT *app = shellGetApp(appId);

        if (app && !app->hasMainLoop && app->state == AppStateRunningE) {
            // Check if app still has any windows
            bool hasWindows = false;

            for (int32_t i = 0; i < ctx->stack.count; i++) {
                if (ctx->stack.windows[i]->appId == appId) {
                    hasWindows = true;
                    break;
                }
            }

            if (!hasWindows) {
                app->state = AppStateTerminatingE;
            }
        }
    }
}


// ============================================================
// Wrapper export table
// ============================================================

// Only three entries: the resource-tracking wrappers exported under
// the original function names.  All other symbols come from the
// loaded DXE modules (via RTLD_GLOBAL) and the loader's dlregsym.
DXE_EXPORT_TABLE(sWrapperTable)
    { "_dvxCreateWindow",         (void *)shellWrapCreateWindow },
    { "_dvxCreateWindowCentered", (void *)shellWrapCreateWindowCentered },
    { "_dvxDestroyWindow",        (void *)shellWrapDestroyWindow },
DXE_EXPORT_END


// ============================================================
// shellExportInit
// ============================================================

// Register the wrapper overrides.  Must be called before any
// shellLoadApp() -- wrappers only affect subsequently loaded DXEs.
void shellExportInit(void) {
    dlregsym(sWrapperTable);
}