/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef _UI_INPUT_DISPATCHER_H
#define _UI_INPUT_DISPATCHER_H

#include "CancelationOptions.h"
#include "Entry.h"
#include "InjectionState.h"
#include "InputDispatcherConfiguration.h"
#include "InputDispatcherInterface.h"
#include "InputDispatcherPolicyInterface.h"
#include "InputState.h"
#include "InputTarget.h"
#include "Monitor.h"
#include "Queue.h"
#include "TouchState.h"
#include "TouchedWindow.h"

#include <cutils/atomic.h>
#include <input/Input.h>
#include <input/InputApplication.h>
#include <input/InputTransport.h>
#include <input/InputWindow.h>
#include <limits.h>
#include <stddef.h>
#include <ui/Region.h>
#include <unistd.h>
#include <utils/BitSet.h>
#include <utils/Looper.h>
#include <utils/RefBase.h>
#include <utils/Timers.h>
#include <utils/threads.h>
#include <condition_variable>
#include <deque>
#include <optional>
#include <unordered_map>

#include <InputListener.h>
#include <InputReporterInterface.h>

namespace android::inputdispatcher {

class Connection;

/* Dispatches events to input targets.  Some functions of the input dispatcher, such as
 * identifying input targets, are controlled by a separate policy object.
 *
 * IMPORTANT INVARIANT:
 *     Because the policy can potentially block or cause re-entrance into the input dispatcher,
 *     the input dispatcher never calls into the policy while holding its internal locks.
 *     The implementation is also carefully designed to recover from scenarios such as an
 *     input channel becoming unregistered while identifying input targets or processing timeouts.
 *
 *     Methods marked 'Locked' must be called with the lock acquired.
 *
 *     Methods marked 'LockedInterruptible' must be called with the lock acquired but
 *     may during the course of their execution release the lock, call into the policy, and
 *     then reacquire the lock.  The caller is responsible for recovering gracefully.
 *
 *     A 'LockedInterruptible' method may called a 'Locked' method, but NOT vice-versa.
 */
class InputDispatcher : public android::InputDispatcherInterface {
protected:
    virtual ~InputDispatcher();

public:
    explicit InputDispatcher(const sp<InputDispatcherPolicyInterface>& policy);

    virtual void dump(std::string& dump) override;
    virtual void monitor() override;

    virtual void dispatchOnce() override;

    virtual void notifyConfigurationChanged(const NotifyConfigurationChangedArgs* args) override;
    virtual void notifyKey(const NotifyKeyArgs* args) override;
    virtual void notifyMotion(const NotifyMotionArgs* args) override;
    virtual void notifySwitch(const NotifySwitchArgs* args) override;
    virtual void notifyDeviceReset(const NotifyDeviceResetArgs* args) override;

    virtual int32_t injectInputEvent(const InputEvent* event, int32_t injectorPid,
                                     int32_t injectorUid, int32_t syncMode, int32_t timeoutMillis,
                                     uint32_t policyFlags) override;

    virtual void setInputWindows(
            const std::vector<sp<InputWindowHandle>>& inputWindowHandles, int32_t displayId,
            const sp<ISetInputWindowsListener>& setInputWindowsListener = nullptr) override;
    virtual void setFocusedApplication(
            int32_t displayId, const sp<InputApplicationHandle>& inputApplicationHandle) override;
    virtual void setFocusedDisplay(int32_t displayId) override;
    virtual void setInputDispatchMode(bool enabled, bool frozen) override;
    virtual void setInputFilterEnabled(bool enabled) override;

    virtual bool transferTouchFocus(const sp<IBinder>& fromToken,
                                    const sp<IBinder>& toToken) override;

    virtual status_t registerInputChannel(const sp<InputChannel>& inputChannel,
                                          int32_t displayId) override;
    virtual status_t registerInputMonitor(const sp<InputChannel>& inputChannel, int32_t displayId,
                                          bool isGestureMonitor) override;
    virtual status_t unregisterInputChannel(const sp<InputChannel>& inputChannel) override;
    virtual status_t pilferPointers(const sp<IBinder>& token) override;

private:

    enum DropReason {
        DROP_REASON_NOT_DROPPED = 0,
        DROP_REASON_POLICY = 1,
        DROP_REASON_APP_SWITCH = 2,
        DROP_REASON_DISABLED = 3,
        DROP_REASON_BLOCKED = 4,
        DROP_REASON_STALE = 5,
    };

    sp<InputDispatcherPolicyInterface> mPolicy;
    android::InputDispatcherConfiguration mConfig;

    std::mutex mLock;

    std::condition_variable mDispatcherIsAlive;

    sp<Looper> mLooper;

    EventEntry* mPendingEvent GUARDED_BY(mLock);
    Queue<EventEntry> mInboundQueue GUARDED_BY(mLock);
    Queue<EventEntry> mRecentQueue GUARDED_BY(mLock);
    Queue<CommandEntry> mCommandQueue GUARDED_BY(mLock);

    DropReason mLastDropReason GUARDED_BY(mLock);

    void dispatchOnceInnerLocked(nsecs_t* nextWakeupTime) REQUIRES(mLock);

    // Enqueues an inbound event.  Returns true if mLooper->wake() should be called.
    bool enqueueInboundEventLocked(EventEntry* entry) REQUIRES(mLock);

    // Cleans up input state when dropping an inbound event.
    void dropInboundEventLocked(EventEntry* entry, DropReason dropReason) REQUIRES(mLock);

    // Adds an event to a queue of recent events for debugging purposes.
    void addRecentEventLocked(EventEntry* entry) REQUIRES(mLock);

    // App switch latency optimization.
    bool mAppSwitchSawKeyDown GUARDED_BY(mLock);
    nsecs_t mAppSwitchDueTime GUARDED_BY(mLock);

    bool isAppSwitchKeyEvent(KeyEntry* keyEntry);
    bool isAppSwitchPendingLocked() REQUIRES(mLock);
    void resetPendingAppSwitchLocked(bool handled) REQUIRES(mLock);

    // Stale event latency optimization.
    static bool isStaleEvent(nsecs_t currentTime, EventEntry* entry);

    // Blocked event latency optimization.  Drops old events when the user intends
    // to transfer focus to a new application.
    EventEntry* mNextUnblockedEvent GUARDED_BY(mLock);

    sp<InputWindowHandle> findTouchedWindowAtLocked(int32_t displayId, int32_t x, int32_t y,
                                                    bool addOutsideTargets = false,
                                                    bool addPortalWindows = false) REQUIRES(mLock);

    // All registered connections mapped by channel file descriptor.
    KeyedVector<int, sp<Connection>> mConnectionsByFd GUARDED_BY(mLock);

    struct IBinderHash {
        std::size_t operator()(const sp<IBinder>& b) const {
            return std::hash<IBinder*>{}(b.get());
        }
    };
    std::unordered_map<sp<IBinder>, sp<InputChannel>, IBinderHash> mInputChannelsByToken
            GUARDED_BY(mLock);

    // Finds the display ID of the gesture monitor identified by the provided token.
    std::optional<int32_t> findGestureMonitorDisplayByTokenLocked(const sp<IBinder>& token)
            REQUIRES(mLock);

    ssize_t getConnectionIndexLocked(const sp<InputChannel>& inputChannel) REQUIRES(mLock);

    // Input channels that will receive a copy of all input events sent to the provided display.
    std::unordered_map<int32_t, std::vector<Monitor>> mGlobalMonitorsByDisplay GUARDED_BY(mLock);

    // Input channels that will receive pointer events that start within the corresponding display.
    // These are a bit special when compared to global monitors since they'll cause gesture streams
    // to continue even when there isn't a touched window,and have the ability to steal the rest of
    // the pointer stream in order to claim it for a system gesture.
    std::unordered_map<int32_t, std::vector<Monitor>> mGestureMonitorsByDisplay GUARDED_BY(mLock);

    // Event injection and synchronization.
    std::condition_variable mInjectionResultAvailable;
    bool hasInjectionPermission(int32_t injectorPid, int32_t injectorUid);
    void setInjectionResult(EventEntry* entry, int32_t injectionResult);

    std::condition_variable mInjectionSyncFinished;
    void incrementPendingForegroundDispatches(EventEntry* entry);
    void decrementPendingForegroundDispatches(EventEntry* entry);

    // Key repeat tracking.
    struct KeyRepeatState {
        KeyEntry* lastKeyEntry; // or null if no repeat
        nsecs_t nextRepeatTime;
    } mKeyRepeatState GUARDED_BY(mLock);

    void resetKeyRepeatLocked() REQUIRES(mLock);
    KeyEntry* synthesizeKeyRepeatLocked(nsecs_t currentTime) REQUIRES(mLock);

    // Key replacement tracking
    struct KeyReplacement {
        int32_t keyCode;
        int32_t deviceId;
        bool operator==(const KeyReplacement& rhs) const {
            return keyCode == rhs.keyCode && deviceId == rhs.deviceId;
        }
        bool operator<(const KeyReplacement& rhs) const {
            return keyCode != rhs.keyCode ? keyCode < rhs.keyCode : deviceId < rhs.deviceId;
        }
    };
    // Maps the key code replaced, device id tuple to the key code it was replaced with
    KeyedVector<KeyReplacement, int32_t> mReplacedKeys GUARDED_BY(mLock);
    // Process certain Meta + Key combinations
    void accelerateMetaShortcuts(const int32_t deviceId, const int32_t action, int32_t& keyCode,
                                 int32_t& metaState);

    // Deferred command processing.
    bool haveCommandsLocked() const REQUIRES(mLock);
    bool runCommandsLockedInterruptible() REQUIRES(mLock);
    CommandEntry* postCommandLocked(Command command) REQUIRES(mLock);

    // Input filter processing.
    bool shouldSendKeyToInputFilterLocked(const NotifyKeyArgs* args) REQUIRES(mLock);
    bool shouldSendMotionToInputFilterLocked(const NotifyMotionArgs* args) REQUIRES(mLock);

    // Inbound event processing.
    void drainInboundQueueLocked() REQUIRES(mLock);
    void releasePendingEventLocked() REQUIRES(mLock);
    void releaseInboundEventLocked(EventEntry* entry) REQUIRES(mLock);

    // Dispatch state.
    bool mDispatchEnabled GUARDED_BY(mLock);
    bool mDispatchFrozen GUARDED_BY(mLock);
    bool mInputFilterEnabled GUARDED_BY(mLock);

    std::unordered_map<int32_t, std::vector<sp<InputWindowHandle>>> mWindowHandlesByDisplay
            GUARDED_BY(mLock);
    // Get window handles by display, return an empty vector if not found.
    std::vector<sp<InputWindowHandle>> getWindowHandlesLocked(int32_t displayId) const
            REQUIRES(mLock);
    sp<InputWindowHandle> getWindowHandleLocked(const sp<IBinder>& windowHandleToken) const
            REQUIRES(mLock);
    sp<InputChannel> getInputChannelLocked(const sp<IBinder>& windowToken) const REQUIRES(mLock);
    bool hasWindowHandleLocked(const sp<InputWindowHandle>& windowHandle) const REQUIRES(mLock);

    // Focus tracking for keys, trackball, etc.
    std::unordered_map<int32_t, sp<InputWindowHandle>> mFocusedWindowHandlesByDisplay
            GUARDED_BY(mLock);

    KeyedVector<int32_t, TouchState> mTouchStatesByDisplay GUARDED_BY(mLock);
    TouchState mTempTouchState GUARDED_BY(mLock);

    // Focused applications.
    std::unordered_map<int32_t, sp<InputApplicationHandle>> mFocusedApplicationHandlesByDisplay
            GUARDED_BY(mLock);

    // Top focused display.
    int32_t mFocusedDisplayId GUARDED_BY(mLock);

    // Dispatcher state at time of last ANR.
    std::string mLastANRState GUARDED_BY(mLock);

    // Dispatch inbound events.
    bool dispatchConfigurationChangedLocked(nsecs_t currentTime, ConfigurationChangedEntry* entry)
            REQUIRES(mLock);
    bool dispatchDeviceResetLocked(nsecs_t currentTime, DeviceResetEntry* entry) REQUIRES(mLock);
    bool dispatchKeyLocked(nsecs_t currentTime, KeyEntry* entry, DropReason* dropReason,
                           nsecs_t* nextWakeupTime) REQUIRES(mLock);
    bool dispatchMotionLocked(nsecs_t currentTime, MotionEntry* entry, DropReason* dropReason,
                              nsecs_t* nextWakeupTime) REQUIRES(mLock);
    void dispatchEventLocked(nsecs_t currentTime, EventEntry* entry,
                             const std::vector<InputTarget>& inputTargets) REQUIRES(mLock);

    void logOutboundKeyDetails(const char* prefix, const KeyEntry* entry);
    void logOutboundMotionDetails(const char* prefix, const MotionEntry* entry);

    // Keeping track of ANR timeouts.
    enum InputTargetWaitCause {
        INPUT_TARGET_WAIT_CAUSE_NONE,
        INPUT_TARGET_WAIT_CAUSE_SYSTEM_NOT_READY,
        INPUT_TARGET_WAIT_CAUSE_APPLICATION_NOT_READY,
    };

    InputTargetWaitCause mInputTargetWaitCause GUARDED_BY(mLock);
    nsecs_t mInputTargetWaitStartTime GUARDED_BY(mLock);
    nsecs_t mInputTargetWaitTimeoutTime GUARDED_BY(mLock);
    bool mInputTargetWaitTimeoutExpired GUARDED_BY(mLock);
    sp<IBinder> mInputTargetWaitApplicationToken GUARDED_BY(mLock);

    // Contains the last window which received a hover event.
    sp<InputWindowHandle> mLastHoverWindowHandle GUARDED_BY(mLock);

    // Finding targets for input events.
    int32_t handleTargetsNotReadyLocked(nsecs_t currentTime, const EventEntry* entry,
                                        const sp<InputApplicationHandle>& applicationHandle,
                                        const sp<InputWindowHandle>& windowHandle,
                                        nsecs_t* nextWakeupTime, const char* reason)
            REQUIRES(mLock);

    void removeWindowByTokenLocked(const sp<IBinder>& token) REQUIRES(mLock);

    void resumeAfterTargetsNotReadyTimeoutLocked(nsecs_t newTimeout,
                                                 const sp<InputChannel>& inputChannel)
            REQUIRES(mLock);
    nsecs_t getTimeSpentWaitingForApplicationLocked(nsecs_t currentTime) REQUIRES(mLock);
    void resetANRTimeoutsLocked() REQUIRES(mLock);

    int32_t getTargetDisplayId(const EventEntry* entry);
    int32_t findFocusedWindowTargetsLocked(nsecs_t currentTime, const EventEntry* entry,
                                           std::vector<InputTarget>& inputTargets,
                                           nsecs_t* nextWakeupTime) REQUIRES(mLock);
    int32_t findTouchedWindowTargetsLocked(nsecs_t currentTime, const MotionEntry* entry,
                                           std::vector<InputTarget>& inputTargets,
                                           nsecs_t* nextWakeupTime,
                                           bool* outConflictingPointerActions) REQUIRES(mLock);
    std::vector<TouchedMonitor> findTouchedGestureMonitorsLocked(
            int32_t displayId, const std::vector<sp<InputWindowHandle>>& portalWindows)
            REQUIRES(mLock);
    void addGestureMonitors(const std::vector<Monitor>& monitors,
                            std::vector<TouchedMonitor>& outTouchedMonitors, float xOffset = 0,
                            float yOffset = 0);

    void addWindowTargetLocked(const sp<InputWindowHandle>& windowHandle, int32_t targetFlags,
                               BitSet32 pointerIds, std::vector<InputTarget>& inputTargets)
            REQUIRES(mLock);
    void addMonitoringTargetLocked(const Monitor& monitor, float xOffset, float yOffset,
                                   std::vector<InputTarget>& inputTargets) REQUIRES(mLock);
    void addGlobalMonitoringTargetsLocked(std::vector<InputTarget>& inputTargets, int32_t displayId,
                                          float xOffset = 0, float yOffset = 0) REQUIRES(mLock);

    void pokeUserActivityLocked(const EventEntry* eventEntry) REQUIRES(mLock);
    bool checkInjectionPermission(const sp<InputWindowHandle>& windowHandle,
                                  const InjectionState* injectionState);
    bool isWindowObscuredAtPointLocked(const sp<InputWindowHandle>& windowHandle, int32_t x,
                                       int32_t y) const REQUIRES(mLock);
    bool isWindowObscuredLocked(const sp<InputWindowHandle>& windowHandle) const REQUIRES(mLock);
    std::string getApplicationWindowLabel(const sp<InputApplicationHandle>& applicationHandle,
                                          const sp<InputWindowHandle>& windowHandle);

    std::string checkWindowReadyForMoreInputLocked(nsecs_t currentTime,
                                                   const sp<InputWindowHandle>& windowHandle,
                                                   const EventEntry* eventEntry,
                                                   const char* targetType) REQUIRES(mLock);

    // Manage the dispatch cycle for a single connection.
    // These methods are deliberately not Interruptible because doing all of the work
    // with the mutex held makes it easier to ensure that connection invariants are maintained.
    // If needed, the methods post commands to run later once the critical bits are done.
    void prepareDispatchCycleLocked(nsecs_t currentTime, const sp<Connection>& connection,
                                    EventEntry* eventEntry, const InputTarget* inputTarget)
            REQUIRES(mLock);
    void enqueueDispatchEntriesLocked(nsecs_t currentTime, const sp<Connection>& connection,
                                      EventEntry* eventEntry, const InputTarget* inputTarget)
            REQUIRES(mLock);
    void enqueueDispatchEntryLocked(const sp<Connection>& connection, EventEntry* eventEntry,
                                    const InputTarget* inputTarget, int32_t dispatchMode)
            REQUIRES(mLock);
    void startDispatchCycleLocked(nsecs_t currentTime, const sp<Connection>& connection)
            REQUIRES(mLock);
    void finishDispatchCycleLocked(nsecs_t currentTime, const sp<Connection>& connection,
                                   uint32_t seq, bool handled) REQUIRES(mLock);
    void abortBrokenDispatchCycleLocked(nsecs_t currentTime, const sp<Connection>& connection,
                                        bool notify) REQUIRES(mLock);
    void drainDispatchQueue(Queue<DispatchEntry>* queue);
    void releaseDispatchEntry(DispatchEntry* dispatchEntry);
    static int handleReceiveCallback(int fd, int events, void* data);
    // The action sent should only be of type AMOTION_EVENT_*
    void dispatchPointerDownOutsideFocus(uint32_t source, int32_t action,
                                         const sp<IBinder>& newToken) REQUIRES(mLock);

    void synthesizeCancelationEventsForAllConnectionsLocked(const CancelationOptions& options)
            REQUIRES(mLock);
    void synthesizeCancelationEventsForMonitorsLocked(const CancelationOptions& options)
            REQUIRES(mLock);
    void synthesizeCancelationEventsForMonitorsLocked(
            const CancelationOptions& options,
            std::unordered_map<int32_t, std::vector<Monitor>>& monitorsByDisplay) REQUIRES(mLock);
    void synthesizeCancelationEventsForInputChannelLocked(const sp<InputChannel>& channel,
                                                          const CancelationOptions& options)
            REQUIRES(mLock);
    void synthesizeCancelationEventsForConnectionLocked(const sp<Connection>& connection,
                                                        const CancelationOptions& options)
            REQUIRES(mLock);

    // Splitting motion events across windows.
    MotionEntry* splitMotionEvent(const MotionEntry* originalMotionEntry, BitSet32 pointerIds);

    // Reset and drop everything the dispatcher is doing.
    void resetAndDropEverythingLocked(const char* reason) REQUIRES(mLock);

    // Dump state.
    void dumpDispatchStateLocked(std::string& dump) REQUIRES(mLock);
    void dumpMonitors(std::string& dump, const std::vector<Monitor>& monitors);
    void logDispatchStateLocked() REQUIRES(mLock);

    // Registration.
    void removeMonitorChannelLocked(const sp<InputChannel>& inputChannel) REQUIRES(mLock);
    void removeMonitorChannelLocked(
            const sp<InputChannel>& inputChannel,
            std::unordered_map<int32_t, std::vector<Monitor>>& monitorsByDisplay) REQUIRES(mLock);
    status_t unregisterInputChannelLocked(const sp<InputChannel>& inputChannel, bool notify)
            REQUIRES(mLock);

    // Interesting events that we might like to log or tell the framework about.
    void onDispatchCycleFinishedLocked(nsecs_t currentTime, const sp<Connection>& connection,
                                       uint32_t seq, bool handled) REQUIRES(mLock);
    void onDispatchCycleBrokenLocked(nsecs_t currentTime, const sp<Connection>& connection)
            REQUIRES(mLock);
    void onFocusChangedLocked(const sp<InputWindowHandle>& oldFocus,
                              const sp<InputWindowHandle>& newFocus) REQUIRES(mLock);
    void onANRLocked(nsecs_t currentTime, const sp<InputApplicationHandle>& applicationHandle,
                     const sp<InputWindowHandle>& windowHandle, nsecs_t eventTime,
                     nsecs_t waitStartTime, const char* reason) REQUIRES(mLock);

    // Outbound policy interactions.
    void doNotifyConfigurationChangedLockedInterruptible(CommandEntry* commandEntry)
            REQUIRES(mLock);
    void doNotifyInputChannelBrokenLockedInterruptible(CommandEntry* commandEntry) REQUIRES(mLock);
    void doNotifyFocusChangedLockedInterruptible(CommandEntry* commandEntry) REQUIRES(mLock);
    void doNotifyANRLockedInterruptible(CommandEntry* commandEntry) REQUIRES(mLock);
    void doInterceptKeyBeforeDispatchingLockedInterruptible(CommandEntry* commandEntry)
            REQUIRES(mLock);
    void doDispatchCycleFinishedLockedInterruptible(CommandEntry* commandEntry) REQUIRES(mLock);
    bool afterKeyEventLockedInterruptible(const sp<Connection>& connection,
                                          DispatchEntry* dispatchEntry, KeyEntry* keyEntry,
                                          bool handled) REQUIRES(mLock);
    bool afterMotionEventLockedInterruptible(const sp<Connection>& connection,
                                             DispatchEntry* dispatchEntry, MotionEntry* motionEntry,
                                             bool handled) REQUIRES(mLock);
    void doPokeUserActivityLockedInterruptible(CommandEntry* commandEntry) REQUIRES(mLock);
    void initializeKeyEvent(KeyEvent* event, const KeyEntry* entry);
    void doOnPointerDownOutsideFocusLockedInterruptible(CommandEntry* commandEntry) REQUIRES(mLock);

    // Statistics gathering.
    void updateDispatchStatistics(nsecs_t currentTime, const EventEntry* entry,
                                  int32_t injectionResult, nsecs_t timeSpentWaitingForApplication);
    void traceInboundQueueLengthLocked() REQUIRES(mLock);
    void traceOutboundQueueLength(const sp<Connection>& connection);
    void traceWaitQueueLength(const sp<Connection>& connection);

    sp<InputReporterInterface> mReporter;
};

} // namespace android::inputdispatcher

#endif // _UI_INPUT_DISPATCHER_H