/*
 * Copyright (C) 2017 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.
 */

#define LOG_TAG "AAudioEndpointManager"
//#define LOG_NDEBUG 0
#include <utils/Log.h>

#include <assert.h>
#include <functional>
#include <map>
#include <mutex>
#include <sstream>
#include <utility/AAudioUtilities.h>

#include "AAudioClientTracker.h"
#include "AAudioEndpointManager.h"
#include "AAudioServiceEndpointShared.h"
#include "AAudioServiceEndpointMMAP.h"
#include "AAudioServiceEndpointCapture.h"
#include "AAudioServiceEndpointPlay.h"

using namespace android;
using namespace aaudio;

ANDROID_SINGLETON_STATIC_INSTANCE(AAudioEndpointManager);

AAudioEndpointManager::AAudioEndpointManager()
        : Singleton<AAudioEndpointManager>()
        , mSharedStreams()
        , mExclusiveStreams() {
}

std::string AAudioEndpointManager::dump() const {
    std::stringstream result;
    int index = 0;

    result << "AAudioEndpointManager:" << "\n";

    const bool isSharedLocked = AAudio_tryUntilTrue(
            [this]()->bool { return mSharedLock.try_lock(); } /* f */,
            50 /* times */,
            20 /* sleepMs */);
    if (!isSharedLocked) {
        result << "AAudioEndpointManager Shared may be deadlocked\n";
    }

    {
        const bool isExclusiveLocked = AAudio_tryUntilTrue(
                [this]() -> bool { return mExclusiveLock.try_lock(); } /* f */,
                50 /* times */,
                20 /* sleepMs */);
        if (!isExclusiveLocked) {
            result << "AAudioEndpointManager Exclusive may be deadlocked\n";
        }

        result << "Exclusive MMAP Endpoints: " << mExclusiveStreams.size() << "\n";
        index = 0;
        for (const auto &stream : mExclusiveStreams) {
            result << "  #" << index++ << ":";
            result << stream->dump() << "\n";
        }

        result << "  ExclusiveSearchCount:  " << mExclusiveSearchCount << "\n";
        result << "  ExclusiveFoundCount:   " << mExclusiveFoundCount << "\n";
        result << "  ExclusiveOpenCount:    " << mExclusiveOpenCount << "\n";
        result << "  ExclusiveCloseCount:   " << mExclusiveCloseCount << "\n";
        result << "  ExclusiveStolenCount:  " << mExclusiveStolenCount << "\n";
        result << "\n";

        if (isExclusiveLocked) {
            mExclusiveLock.unlock();
        }
    }

    result << "Shared Endpoints: " << mSharedStreams.size() << "\n";
    index = 0;
    for (const auto &stream : mSharedStreams) {
        result << "  #" << index++ << ":";
        result << stream->dump() << "\n";
    }

    result << "  SharedSearchCount:     " << mSharedSearchCount << "\n";
    result << "  SharedFoundCount:      " << mSharedFoundCount << "\n";
    result << "  SharedOpenCount:       " << mSharedOpenCount << "\n";
    result << "  SharedCloseCount:      " << mSharedCloseCount << "\n";
    result << "\n";

    if (isSharedLocked) {
        mSharedLock.unlock();
    }
    return result.str();
}


// Try to find an existing endpoint.
sp<AAudioServiceEndpoint> AAudioEndpointManager::findExclusiveEndpoint_l(
        const AAudioStreamConfiguration &configuration) {
    sp<AAudioServiceEndpoint> endpoint;
    mExclusiveSearchCount++;
    for (const auto& ep : mExclusiveStreams) {
        if (ep->matches(configuration)) {
            mExclusiveFoundCount++;
            endpoint = ep;
            break;
        }
    }

    ALOGV("findExclusiveEndpoint_l(), found %p for device = %d, sessionId = %d",
          endpoint.get(), configuration.getDeviceId(), configuration.getSessionId());
    return endpoint;
}

// Try to find an existing endpoint.
sp<AAudioServiceEndpointShared> AAudioEndpointManager::findSharedEndpoint_l(
        const AAudioStreamConfiguration &configuration) {
    sp<AAudioServiceEndpointShared> endpoint;
    mSharedSearchCount++;
    for (const auto& ep  : mSharedStreams) {
        if (ep->matches(configuration)) {
            mSharedFoundCount++;
            endpoint = ep;
            break;
        }
    }

    ALOGV("findSharedEndpoint_l(), found %p for device = %d, sessionId = %d",
          endpoint.get(), configuration.getDeviceId(), configuration.getSessionId());
    return endpoint;
}

sp<AAudioServiceEndpoint> AAudioEndpointManager::openEndpoint(AAudioService &audioService,
                                        const aaudio::AAudioStreamRequest &request) {
    if (request.getConstantConfiguration().getSharingMode() == AAUDIO_SHARING_MODE_EXCLUSIVE) {
        sp<AAudioServiceEndpoint> endpointToSteal;
        sp<AAudioServiceEndpoint> foundEndpoint =
                openExclusiveEndpoint(audioService, request, endpointToSteal);
        if (endpointToSteal.get()) {
            endpointToSteal->releaseRegisteredStreams(); // free the MMAP resource
        }
        return foundEndpoint;
    } else {
        return openSharedEndpoint(audioService, request);
    }
}

sp<AAudioServiceEndpoint> AAudioEndpointManager::openExclusiveEndpoint(
        AAudioService &aaudioService,
        const aaudio::AAudioStreamRequest &request,
        sp<AAudioServiceEndpoint> &endpointToSteal) {

    std::lock_guard<std::mutex> lock(mExclusiveLock);

    const AAudioStreamConfiguration &configuration = request.getConstantConfiguration();

    // Try to find an existing endpoint.
    sp<AAudioServiceEndpoint> endpoint = findExclusiveEndpoint_l(configuration);

    // If we find an existing one then this one cannot be exclusive.
    if (endpoint.get() != nullptr) {
        if (kStealingEnabled
                && !endpoint->isForSharing() // not currently SHARED
                && !request.isSharingModeMatchRequired()) { // app did not request a shared stream
            ALOGD("%s() endpoint in EXCLUSIVE use. Steal it!", __func__);
            mExclusiveStolenCount++;
            // Prevent this process from getting another EXCLUSIVE stream.
            // This will prevent two clients from colliding after a DISCONNECTION
            // when they both try to open an exclusive stream at the same time.
            // That can result in a stream getting disconnected between the OPEN
            // and START calls. This will help preserve app compatibility.
            // An app can avoid having this happen by closing their streams when
            // the app is paused.
            AAudioClientTracker::getInstance().setExclusiveEnabled(request.getProcessId(), false);
            endpointToSteal = endpoint; // return it to caller
        }
        return nullptr;
    } else {
        sp<AAudioServiceEndpointMMAP> endpointMMap = new AAudioServiceEndpointMMAP(aaudioService);
        ALOGV("%s(), no match so try to open MMAP %p for dev %d",
              __func__, endpointMMap.get(), configuration.getDeviceId());
        endpoint = endpointMMap;

        aaudio_result_t result = endpoint->open(request);
        if (result != AAUDIO_OK) {
            endpoint.clear();
        } else {
            mExclusiveStreams.push_back(endpointMMap);
            mExclusiveOpenCount++;
        }
    }

    if (endpoint.get() != nullptr) {
        // Increment the reference count under this lock.
        endpoint->setOpenCount(endpoint->getOpenCount() + 1);
        endpoint->setForSharing(request.isSharingModeMatchRequired());
    }

    return endpoint;
}

sp<AAudioServiceEndpoint> AAudioEndpointManager::openSharedEndpoint(
        AAudioService &aaudioService,
        const aaudio::AAudioStreamRequest &request) {

    std::lock_guard<std::mutex> lock(mSharedLock);

    const AAudioStreamConfiguration &configuration = request.getConstantConfiguration();
    aaudio_direction_t direction = configuration.getDirection();

    // Try to find an existing endpoint.
    sp<AAudioServiceEndpointShared> endpoint = findSharedEndpoint_l(configuration);

    // If we can't find an existing one then open a new one.
    if (endpoint.get() == nullptr) {
        // we must call openStream with audioserver identity
        int64_t token = IPCThreadState::self()->clearCallingIdentity();
        switch (direction) {
            case AAUDIO_DIRECTION_INPUT:
                endpoint = new AAudioServiceEndpointCapture(aaudioService);
                break;
            case AAUDIO_DIRECTION_OUTPUT:
                endpoint = new AAudioServiceEndpointPlay(aaudioService);
                break;
            default:
                break;
        }

        if (endpoint.get() != nullptr) {
            aaudio_result_t result = endpoint->open(request);
            if (result != AAUDIO_OK) {
                endpoint.clear();
            } else {
                mSharedStreams.push_back(endpoint);
                mSharedOpenCount++;
            }
        }
        ALOGV("%s(), created endpoint %p, requested device = %d, dir = %d",
              __func__, endpoint.get(), configuration.getDeviceId(), (int)direction);
        IPCThreadState::self()->restoreCallingIdentity(token);
    }

    if (endpoint.get() != nullptr) {
        // Increment the reference count under this lock.
        endpoint->setOpenCount(endpoint->getOpenCount() + 1);
    }
    return endpoint;
}

void AAudioEndpointManager::closeEndpoint(sp<AAudioServiceEndpoint>serviceEndpoint) {
    if (serviceEndpoint->getSharingMode() == AAUDIO_SHARING_MODE_EXCLUSIVE) {
        return closeExclusiveEndpoint(serviceEndpoint);
    } else {
        return closeSharedEndpoint(serviceEndpoint);
    }
}

void AAudioEndpointManager::closeExclusiveEndpoint(sp<AAudioServiceEndpoint> serviceEndpoint) {
    if (serviceEndpoint.get() == nullptr) {
        return;
    }

    // Decrement the reference count under this lock.
    std::lock_guard<std::mutex> lock(mExclusiveLock);
    int32_t newRefCount = serviceEndpoint->getOpenCount() - 1;
    serviceEndpoint->setOpenCount(newRefCount);

    // If no longer in use then actually close it.
    if (newRefCount <= 0) {
        mExclusiveStreams.erase(
                std::remove(mExclusiveStreams.begin(), mExclusiveStreams.end(), serviceEndpoint),
                mExclusiveStreams.end());

        serviceEndpoint->close();
        mExclusiveCloseCount++;
        ALOGV("%s() %p for device %d",
              __func__, serviceEndpoint.get(), serviceEndpoint->getDeviceId());
    }
}

void AAudioEndpointManager::closeSharedEndpoint(sp<AAudioServiceEndpoint> serviceEndpoint) {
    if (serviceEndpoint.get() == nullptr) {
        return;
    }

    // Decrement the reference count under this lock.
    std::lock_guard<std::mutex> lock(mSharedLock);
    int32_t newRefCount = serviceEndpoint->getOpenCount() - 1;
    serviceEndpoint->setOpenCount(newRefCount);

    // If no longer in use then actually close it.
    if (newRefCount <= 0) {
        mSharedStreams.erase(
                std::remove(mSharedStreams.begin(), mSharedStreams.end(), serviceEndpoint),
                mSharedStreams.end());

        serviceEndpoint->close();
        mSharedCloseCount++;
        ALOGV("%s(%p) closed for device %d",
              __func__, serviceEndpoint.get(), serviceEndpoint->getDeviceId());
    }
}