/**
 * beyond_spike_monitor — OpenVR background client that monitors HMD proximity
 * state via three independent signals:
 *   1. ActivityLevel (GetTrackedDeviceActivityLevel)
 *   2. ButtonPressed bit 31 (GetControllerState, legacy)
 *   3. UserInteraction events (PollNextEvent)
 *
 * Purpose: The driver-side IVRDriverInput API is write-only (no
 * GetBooleanComponent). To determine which handle corresponds to /proximity,
 * we need a client-side observer that detects when UpdateBooleanComponent
 * actually changes the proximity state visible to applications.
 */

#include <openvr.h>
#include <cstdio>
#include <windows.h>

int main()
{
    setvbuf(stdout, NULL, _IONBF, 0);
    printf("beyond_spike_monitor — OpenVR proximity state monitor\n");

    vr::EVRInitError eError = vr::VRInitError_None;
    vr::IVRSystem* pSystem = vr::VR_Init(&eError, vr::VRApplication_Background);
    if (!pSystem) {
        printf("VR_Init failed: %s\n",
               vr::VR_GetVRInitErrorAsEnglishDescription(eError));
        return 1;
    }

    printf("Connected to SteamVR. Monitoring HMD (device 0) proximity...\n"
           "Press Ctrl+C to exit.\n\n");

    vr::EDeviceActivityLevel lastLevel = vr::k_EDeviceActivityLevel_Unknown;
    uint64_t lastButtonState = 0;

    for (;;) {
        // Signal 1 — Activity Level
        vr::EDeviceActivityLevel level = pSystem->GetTrackedDeviceActivityLevel(0);
        if (level != lastLevel) {
            const char* names[] = {"Unknown(-1)", "Idle", "UserInteraction",
                                   "UserInteraction_Timeout", "Standby", "Idle_Timeout"};
            int idx = (int)level + 1;
            printf("[ActivityLevel] %s (%d)\n",
                   (idx >= 0 && idx < 6) ? names[idx] : "?", (int)level);
            lastLevel = level;
        }

        // Signal 2 — Button State (legacy, may not work for HMD)
        vr::VRControllerState_t state = {};
        if (pSystem->GetControllerState(0, &state, sizeof(state))) {
            uint64_t proxBit = state.ulButtonPressed &
                               vr::ButtonMaskFromId(vr::k_EButton_ProximitySensor);
            if (proxBit != lastButtonState) {
                printf("[ButtonState] ProximitySensor bit=%s\n",
                       proxBit ? "PRESSED" : "released");
                lastButtonState = proxBit;
            }
        }

        // Signal 3 — Events
        vr::VREvent_t event;
        while (pSystem->PollNextEvent(&event, sizeof(event))) {
            if (event.eventType == vr::VREvent_TrackedDeviceUserInteractionStarted)
                printf("[Event] UserInteractionStarted (device %u)\n",
                       event.trackedDeviceIndex);
            if (event.eventType == vr::VREvent_TrackedDeviceUserInteractionEnded)
                printf("[Event] UserInteractionEnded (device %u)\n",
                       event.trackedDeviceIndex);
            if (event.eventType == vr::VREvent_ButtonPress)
                printf("[Event] ButtonPress button=%u (device %u)\n",
                       event.data.controller.button, event.trackedDeviceIndex);
            if (event.eventType == vr::VREvent_ButtonUnpress)
                printf("[Event] ButtonUnpress button=%u (device %u)\n",
                       event.data.controller.button, event.trackedDeviceIndex);
        }

        Sleep(100);
    }

    vr::VR_Shutdown();
    return 0;
}