/*
 * Copyright (C) 2011 Google Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 *  THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
 *  EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 *  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 *  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 *  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 *  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "config.h"
#include "ScriptedAnimationController.h"

#include "Chrome.h"
#include "ChromeClient.h"
#include "CustomHeaderFields.h"
#include "DOMWindow.h"
#include "Document.h"
#include "DocumentLoader.h"
#include "Frame.h"
#include "FrameView.h"
#include "InspectorInstrumentation.h"
#include "Logging.h"
#include "Page.h"
#include "RequestAnimationFrameCallback.h"
#include "Settings.h"
#include <algorithm>
#include <wtf/Ref.h>
#include <wtf/SystemTracing.h>
#include <wtf/text/StringBuilder.h>

// Allow a little more than 60fps to make sure we can at least hit that frame rate.
static const Seconds fullSpeedAnimationInterval { 15_ms };
// Allow a little more than 30fps to make sure we can at least hit that frame rate.
static const Seconds halfSpeedThrottlingAnimationInterval { 30_ms };
static const Seconds aggressiveThrottlingAnimationInterval { 10_s };

#define RELEASE_LOG_IF_ALLOWED(fmt, ...) RELEASE_LOG_IF(page() && page()->isAlwaysOnLoggingAllowed(), PerformanceLogging, "%p - ScriptedAnimationController::" fmt, this, ##__VA_ARGS__)

namespace WebCore {

ScriptedAnimationController::ScriptedAnimationController(Document& document)
    : m_document(makeWeakPtr(document))
    , m_animationTimer(*this, &ScriptedAnimationController::animationTimerFired)
{
}

ScriptedAnimationController::~ScriptedAnimationController() = default;

bool ScriptedAnimationController::requestAnimationFrameEnabled() const
{
    return m_document && m_document->settings().requestAnimationFrameEnabled();
}

void ScriptedAnimationController::suspend()
{
    ++m_suspendCount;
}

void ScriptedAnimationController::resume()
{
    // It would be nice to put an ASSERT(m_suspendCount > 0) here, but in WK1 resume() can be called
    // even when suspend hasn't (if a tab was created in the background).
    if (m_suspendCount > 0)
        --m_suspendCount;

    if (!m_suspendCount && m_callbacks.size())
        scheduleAnimation();
}

#if USE(REQUEST_ANIMATION_FRAME_DISPLAY_MONITOR) && !RELEASE_LOG_DISABLED

static const char* throttlingReasonToString(ScriptedAnimationController::ThrottlingReason reason)
{
    switch (reason) {
    case ScriptedAnimationController::ThrottlingReason::VisuallyIdle:
        return "VisuallyIdle";
    case ScriptedAnimationController::ThrottlingReason::OutsideViewport:
        return "OutsideViewport";
    case ScriptedAnimationController::ThrottlingReason::LowPowerMode:
        return "LowPowerMode";
    case ScriptedAnimationController::ThrottlingReason::NonInteractedCrossOriginFrame:
        return "NonInteractiveCrossOriginFrame";
    }
    RELEASE_ASSERT_NOT_REACHED();
    return "";
}

static String throttlingReasonsToString(OptionSet<ScriptedAnimationController::ThrottlingReason> reasons)
{
    if (reasons.isEmpty())
        return "[Unthrottled]"_s;

    StringBuilder builder;
    for (auto reason : reasons) {
        if (!builder.isEmpty())
            builder.append('|');
        builder.append(throttlingReasonToString(reason));
    }
    return builder.toString();
}

#endif

void ScriptedAnimationController::addThrottlingReason(ThrottlingReason reason)
{
#if USE(REQUEST_ANIMATION_FRAME_DISPLAY_MONITOR)
    if (m_throttlingReasons.contains(reason))
        return;

    m_throttlingReasons.add(reason);

    RELEASE_LOG_IF_ALLOWED("addThrottlingReason(%s) -> %s", throttlingReasonToString(reason), throttlingReasonsToString(m_throttlingReasons).utf8().data());

    if (m_animationTimer.isActive()) {
        m_animationTimer.stop();
        scheduleAnimation();
    }
#else
    UNUSED_PARAM(reason);
#endif
}

void ScriptedAnimationController::removeThrottlingReason(ThrottlingReason reason)
{
#if USE(REQUEST_ANIMATION_FRAME_DISPLAY_MONITOR)
    if (!m_throttlingReasons.contains(reason))
        return;

    m_throttlingReasons.remove(reason);

    RELEASE_LOG_IF_ALLOWED("removeThrottlingReason(%s) -> %s", throttlingReasonToString(reason), throttlingReasonsToString(m_throttlingReasons).utf8().data());

    if (m_animationTimer.isActive()) {
        m_animationTimer.stop();
        scheduleAnimation();
    }
#else
    UNUSED_PARAM(reason);
#endif
}

bool ScriptedAnimationController::isThrottled() const
{
#if USE(REQUEST_ANIMATION_FRAME_DISPLAY_MONITOR)
    return !m_throttlingReasons.isEmpty();
#else
    return false;
#endif
}

ScriptedAnimationController::CallbackId ScriptedAnimationController::registerCallback(Ref<RequestAnimationFrameCallback>&& callback)
{
    ScriptedAnimationController::CallbackId id = ++m_nextCallbackId;
    callback->m_firedOrCancelled = false;
    callback->m_id = id;
    m_callbacks.append(WTFMove(callback));

    if (m_document)
        InspectorInstrumentation::didRequestAnimationFrame(*m_document, id);

    if (!m_suspendCount)
        scheduleAnimation();
    return id;
}

void ScriptedAnimationController::cancelCallback(CallbackId id)
{
    for (size_t i = 0; i < m_callbacks.size(); ++i) {
        if (m_callbacks[i]->m_id == id) {
            m_callbacks[i]->m_firedOrCancelled = true;
            InspectorInstrumentation::didCancelAnimationFrame(*m_document, id);
            m_callbacks.remove(i);
            return;
        }
    }
}

void ScriptedAnimationController::serviceRequestAnimationFrameCallbacks(DOMHighResTimeStamp timestamp)
{
    if (!m_callbacks.size() || m_suspendCount || !requestAnimationFrameEnabled())
        return;

    TraceScope tracingScope(RAFCallbackStart, RAFCallbackEnd);

    // We round this to the nearest microsecond so that we can return a time that matches what is returned by document.timeline.currentTime.
    DOMHighResTimeStamp highResNowMs = std::round(1000 * timestamp);

    // First, generate a list of callbacks to consider.  Callbacks registered from this point
    // on are considered only for the "next" frame, not this one.
    CallbackList callbacks(m_callbacks);

    // Invoking callbacks may detach elements from our document, which clears the document's
    // reference to us, so take a defensive reference.
    Ref<ScriptedAnimationController> protectedThis(*this);
    Ref<Document> protectedDocument(*m_document);

    for (auto& callback : callbacks) {
        if (callback->m_firedOrCancelled)
            continue;
        callback->m_firedOrCancelled = true;

        InspectorInstrumentation::willFireAnimationFrame(protectedDocument, callback->m_id);
        callback->handleEvent(highResNowMs);
        InspectorInstrumentation::didFireAnimationFrame(protectedDocument);
    }

    // Remove any callbacks we fired from the list of pending callbacks.
    m_callbacks.removeAllMatching([](auto& callback) {
        return callback->m_firedOrCancelled;
    });

    if (m_callbacks.size())
        scheduleAnimation();
}

Seconds ScriptedAnimationController::interval() const
{
#if USE(REQUEST_ANIMATION_FRAME_DISPLAY_MONITOR)
    if (m_throttlingReasons.contains(ThrottlingReason::VisuallyIdle) || m_throttlingReasons.contains(ThrottlingReason::OutsideViewport))
        return aggressiveThrottlingAnimationInterval;

    if (m_throttlingReasons.contains(ThrottlingReason::LowPowerMode))
        return halfSpeedThrottlingAnimationInterval;

    if (m_throttlingReasons.contains(ThrottlingReason::NonInteractedCrossOriginFrame))
        return halfSpeedThrottlingAnimationInterval;

    ASSERT(m_throttlingReasons.isEmpty());
#endif
    return fullSpeedAnimationInterval;
}

Page* ScriptedAnimationController::page() const
{
    return m_document ? m_document->page() : nullptr;
}

void ScriptedAnimationController::scheduleAnimation()
{
    if (!requestAnimationFrameEnabled())
        return;

#if USE(REQUEST_ANIMATION_FRAME_DISPLAY_MONITOR)
    if (!m_isUsingTimer && !isThrottled()) {
        if (auto* page = this->page()) {
            page->renderingUpdateScheduler().scheduleTimedRenderingUpdate();
            return;
        }

        m_isUsingTimer = true;
    }
#endif
    if (m_animationTimer.isActive())
        return;

    Seconds animationInterval = interval();
    Seconds scheduleDelay = std::max(animationInterval - Seconds(m_document->domWindow()->nowTimestamp() - m_lastAnimationFrameTimestamp), 0_s);

    if (isThrottled()) {
        // FIXME: not ideal to snapshot time both in now() and nowTimestamp(), the latter of which also has reduced resolution.
        MonotonicTime now = MonotonicTime::now();

        MonotonicTime fireTime = now + scheduleDelay;
        Seconds alignmentInterval = 10_ms;
        // Snap to the nearest alignmentInterval.
        Seconds alignment = (fireTime + alignmentInterval / 2) % alignmentInterval;
        MonotonicTime alignedFireTime = fireTime - alignment;
        scheduleDelay = alignedFireTime - now;
    }

    m_animationTimer.startOneShot(scheduleDelay);
}

void ScriptedAnimationController::animationTimerFired()
{
    m_lastAnimationFrameTimestamp = m_document->domWindow()->nowTimestamp();
    serviceRequestAnimationFrameCallbacks(m_lastAnimationFrameTimestamp);
}

}