// Optional firmware-event driver using the resident ACPICA namespace.
#include <ntlite/ddk/module.h>
#include <ntlite/atomic.h>
#include <ntlite/ddk/platform.h>
#include <ntlite/ddk/debug.h>
#include <ntlite/ddk/power.h>
#include "third_party/acpica/include/acpi.h"
#include "third_party/acpica/include/aclocal.h"
#include "third_party/acpica/include/acobject.h"
#include "third_party/acpica/include/acglobal.h"
#include "acpi_local.h"
#include <ntlite/ddk/irql.h>
#include <ntlite/syscall.h>

// Firmware callbacks remain resident until the final ACPI S5 transition.
static KSTATUS AcpiNtlPreparePower(void* context, uint32_t action) {
    (void)context;
    if (action != SYS_POWER_ACTION_SHUTDOWN) return NTLSTATUS_NOT_SUPPORTED;
    ACPI_STATUS status = AcpiEnterSleepStatePrep(ACPI_STATE_S5);
    if (ACPI_FAILURE(status)) {
        DbgPrint("acpi: S5 preparation failed status=0x%x\n", (unsigned)status);
        return NTLSTATUS_NOT_SUPPORTED;
    }
    return NTLSTATUS_SUCCESS;
}

static KSTATUS AcpiNtlEnterPower(void* context, uint32_t action) {
    (void)context;
    if (action != SYS_POWER_ACTION_SHUTDOWN) return NTLSTATUS_NOT_SUPPORTED;
    // ACPICA requires interrupts disabled for the final sleep-control writes.
    uintptr_t flags = KeDisableInterrupts();
    ACPI_STATUS status = AcpiEnterSleepState(ACPI_STATE_S5);
    KeRestoreInterrupts(flags);
    DbgPrint("acpi: S5 transition returned status=0x%x\n", (unsigned)status);
    return NTLSTATUS_NOT_SUPPORTED;
}

static volatile int32_t gFixedButtonPending;
static uint32_t gFixedButtonEvents;
static uint32_t gMethodButtonEvents;
static uint32_t gMethodButtons;

static void AcpiNtlDeliverButton(void* context) {
    (void)context;
    KSTATUS result = KeNotifyPowerButton();
    if (!KSUCCESS(result)) DbgPrint("acpi: power button delivery failed status=0x%x\n", result);
}

static void AcpiNtlDeliverFixedButton(void* context) {
    AcpiNtlDeliverButton(context);
    NtlAtomicExchange32(&gFixedButtonPending, 0);
}

bool AcpiNtlFixedButtonHasDeferred(void) {
    return NtlAtomicLoad32(&gFixedButtonPending) == 2;
}

void AcpiNtlFixedButtonDrainDeferred(void) {
    if (NtlAtomicCompareExchange32(&gFixedButtonPending, 1, 2) == 2)
        AcpiNtlDeliverFixedButton(NULL);
}

// Fixed-event handlers run in the SCI and delegate delivery to passive work.
static UINT32 AcpiNtlFixedButton(void* context) {
    (void)context;
    gFixedButtonEvents++;
    if (NtlAtomicCompareExchange32(&gFixedButtonPending, 1, 0) == 0 &&
        ACPI_FAILURE(AcpiOsExecute(OSL_NOTIFY_HANDLER, AcpiNtlDeliverFixedButton, NULL))) {
        NtlAtomicExchange32(&gFixedButtonPending, 2);
        AcpiNtlWakeExecutor();
    }
    return ACPI_INTERRUPT_HANDLED;
}

// 0x80 is the normal S0 press event; 0x02 is a wake notification.
static void AcpiNtlButtonNotify(ACPI_HANDLE handle, UINT32 event, void* context) {
    (void)handle; (void)context;
    if (event == 0x80u) {
        gMethodButtonEvents++;
        AcpiNtlDeliverButton(NULL);
    }
}

static ACPI_STATUS AcpiNtlFindButton(ACPI_HANDLE handle, UINT32 depth,
                                      void* context, void** returnValue) {
    (void)depth; (void)context; (void)returnValue;
    ACPI_STATUS result = AcpiInstallNotifyHandler(handle, ACPI_DEVICE_NOTIFY,
                                                   AcpiNtlButtonNotify, NULL);
    if (ACPI_SUCCESS(result)) gMethodButtons++;
    return AE_OK;
}

static KSTATUS AcpiDriverInitialize(NTL_MODULE* module) {
    (void)module;
    uint64_t root = 0;
    KSTATUS status = KeFirmwareQueryAcpiRsdp(&root);
    if (!KSUCCESS(status)) {
        DbgPrint("acpi: RSDP query failed status=0x%x\n", status);
        return status;
    }
    ACPI_STATUS result = AcpiInitializeSubsystem();
    if (ACPI_FAILURE(result)) goto fail;
    result = AcpiInitializeTables(NULL, 32, TRUE);
    if (ACPI_FAILURE(result)) goto fail;
    result = AcpiLoadTables();
    if (ACPI_FAILURE(result)) goto fail;
    AcpiNtlRestrictRuntimeMappings();
    status = AcpiNtlPrepareMmioRegisters();
    if (!KSUCCESS(status)) {
        DbgPrint("acpi: MMIO register mappings unavailable st=0x%x\n", status);
        result = AE_NO_MEMORY;
        goto fail;
    }
    status = AcpiNtlStartExecutor();
    if (!KSUCCESS(status)) {
        DbgPrint("acpi: event worker unavailable st=0x%x\n", status);
        result = AE_NO_MEMORY;
        goto fail;
    }
    result = AcpiEnableSubsystem(0);
    if (ACPI_FAILURE(result)) goto fail;
    ACPI_STATUS ecStatus = AcpiNtlEcInitialize();
    if (ACPI_FAILURE(ecStatus))
        DbgPrint("acpi: EC enumeration failed status=0x%x\n", (unsigned)ecStatus);
    result = AcpiInitializeObjects(0);
    if (ACPI_FAILURE(result)) goto fail;
    AcpiNtlEcActivate();

    ACPI_STATUS fixedStatus = AE_SUPPORT;
    if (!(AcpiGbl_FADT.Flags & ACPI_FADT_POWER_BUTTON)) {
        fixedStatus = AcpiInstallFixedEventHandler(
            ACPI_EVENT_POWER_BUTTON, AcpiNtlFixedButton, NULL);
    }
    ACPI_STATUS methodStatus = AcpiGetDevices("PNP0C0C", AcpiNtlFindButton, NULL, NULL);
    DbgPrint("acpi: ready rsdp=0x%016llX fixed=0x%x method=0x%x buttons=%u ec=%u\n",
             (unsigned long long)root, (unsigned)fixedStatus,
             (unsigned)methodStatus, gMethodButtons, AcpiNtlEcCount());
    const NTL_FIRMWARE_POWER_PROVIDER provider = {
        .Size = sizeof(NTL_FIRMWARE_POWER_PROVIDER),
        .Context = NULL,
        .Prepare = AcpiNtlPreparePower,
        .Enter = AcpiNtlEnterPower,
    };
    status = KeRegisterFirmwarePowerProvider(&provider);
    if (!KSUCCESS(status)) DbgPrint("acpi: power provider registration failed status=0x%x\n", status);
    return NTLSTATUS_SUCCESS;
fail:
    DbgPrint("acpi: namespace initialization failed status=0x%x\n",
             (unsigned)result);
    AcpiNtlEcTerminate();
    (void)AcpiTerminate();
    AcpiNtlStopExecutor();
    AcpiNtlReleaseMmioRegisters();
    return NTLSTATUS_NOT_SUPPORTED;
}

NTL_DECLARE_MODULE(AcpiDriverInitialize);