DVX_GUI/dvx/widgets/widgetTimer.c

// widgetTimer.c  -- Invisible timer widget
//
// Fires onChange callbacks at a configurable interval.  Supports both
// one-shot and repeating modes.  The timer is invisible  -- it takes no
// space in layout and produces no visual output.
//
// Active timers are tracked via a module-level linked list (using the
// stb_ds dynamic array) so wgtUpdateTimers can check only timers, not
// walk the entire widget tree each frame.

#include "widgetInternal.h"

#include <time.h>

#include "thirdparty/stb_ds.h"


// Active timer list  -- avoids walking the widget tree per frame
static WidgetT **sActiveTimers = NULL;


// ============================================================
// widgetTimerCalcMinSize
// ============================================================

void widgetTimerCalcMinSize(WidgetT *w, const BitmapFontT *font) {
    (void)font;
    w->calcMinW = 0;
    w->calcMinH = 0;
}


// ============================================================
// widgetTimerDestroy
// ============================================================

void widgetTimerDestroy(WidgetT *w) {
    // Remove from active list
    for (int32_t i = 0; i < arrlen(sActiveTimers); i++) {
        if (sActiveTimers[i] == w) {
            arrdel(sActiveTimers, i);
            break;
        }
    }
}


// ============================================================
// addToActiveList / removeFromActiveList
// ============================================================

static void addToActiveList(WidgetT *w) {
    // Check if already present
    for (int32_t i = 0; i < arrlen(sActiveTimers); i++) {
        if (sActiveTimers[i] == w) {
            return;
        }
    }

    arrput(sActiveTimers, w);
}


static void removeFromActiveList(WidgetT *w) {
    for (int32_t i = 0; i < arrlen(sActiveTimers); i++) {
        if (sActiveTimers[i] == w) {
            arrdel(sActiveTimers, i);
            return;
        }
    }
}


// ============================================================
// wgtTimer
// ============================================================

WidgetT *wgtTimer(WidgetT *parent, int32_t intervalMs, bool repeat) {
    WidgetT *w = widgetAlloc(parent, WidgetTimerE);

    if (w) {
        w->visible            = false;
        w->as.timer.intervalMs = intervalMs;
        w->as.timer.repeat     = repeat;
        w->as.timer.running    = false;
        w->as.timer.lastFire   = 0;
    }

    return w;
}


// ============================================================
// wgtTimerIsRunning
// ============================================================

bool wgtTimerIsRunning(const WidgetT *w) {
    if (!w || w->type != WidgetTimerE) {
        return false;
    }

    return w->as.timer.running;
}


// ============================================================
// wgtTimerSetInterval
// ============================================================

void wgtTimerSetInterval(WidgetT *w, int32_t intervalMs) {
    if (!w || w->type != WidgetTimerE) {
        return;
    }

    w->as.timer.intervalMs = intervalMs;
}


// ============================================================
// wgtTimerStart
// ============================================================

void wgtTimerStart(WidgetT *w) {
    if (!w || w->type != WidgetTimerE) {
        return;
    }

    w->as.timer.running  = true;
    w->as.timer.lastFire = clock();
    addToActiveList(w);
}


// ============================================================
// wgtTimerStop
// ============================================================

void wgtTimerStop(WidgetT *w) {
    if (!w || w->type != WidgetTimerE) {
        return;
    }

    w->as.timer.running = false;
    removeFromActiveList(w);
}


// ============================================================
// wgtUpdateTimers
// ============================================================
//
// Called once per frame from dvxUpdate.  Iterates the active timer
// list (not the widget tree) so cost is proportional to timer count,
// not total widget count.  One-shot timers are removed after firing.

void wgtUpdateTimers(void) {
    clock_t now = clock();

    // Iterate backwards so arrdel doesn't skip entries
    for (int32_t i = arrlen(sActiveTimers) - 1; i >= 0; i--) {
        WidgetT *w = sActiveTimers[i];

        if (!w->as.timer.running) {
            arrdel(sActiveTimers, i);
            continue;
        }

        clock_t elapsed  = now - w->as.timer.lastFire;
        clock_t interval = (clock_t)w->as.timer.intervalMs * CLOCKS_PER_SEC / 1000;

        if (elapsed >= interval) {
            w->as.timer.lastFire = now;

            if (w->onChange) {
                w->onChange(w);
            }

            if (!w->as.timer.repeat) {
                w->as.timer.running = false;
                arrdel(sActiveTimers, i);
            }
        }
    }
}