/*
 * 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 "AAudioService"
//#define LOG_NDEBUG 0
#include <utils/Log.h>

#include <algorithm>
#include <assert.h>
#include <map>
#include <mutex>
#include <sstream>
#include <vector>

#include <utils/Singleton.h>

#include "AAudioEndpointManager.h"
#include "AAudioServiceEndpoint.h"

#include "core/AudioStreamBuilder.h"
#include "AAudioServiceEndpoint.h"
#include "AAudioServiceStreamShared.h"

using namespace android;  // TODO just import names needed
using namespace aaudio;   // TODO just import names needed

#define MIN_TIMEOUT_NANOS        (1000 * AAUDIO_NANOS_PER_MILLISECOND)

// Wait at least this many times longer than the operation should take.
#define MIN_TIMEOUT_OPERATIONS    4

// This is the maximum size in frames. The effective size can be tuned smaller at runtime.
#define DEFAULT_BUFFER_CAPACITY   (48 * 8)

std::string AAudioServiceEndpoint::dump() const {
    std::stringstream result;

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

    AudioStreamInternal     *stream = mStreamInternal;
    if (stream == nullptr) {
        result << "null stream!" << "\n";
    } else {
        result << "mmap stream: rate = " << stream->getSampleRate() << "\n";
    }

    result << "    Registered Streams:" << "\n";
    for (sp<AAudioServiceStreamShared> sharedStream : mRegisteredStreams) {
        result << sharedStream->dump();
    }

    if (isLocked) {
        mLockStreams.unlock();
    }
    return result.str();
}

// Set up an EXCLUSIVE MMAP stream that will be shared.
aaudio_result_t AAudioServiceEndpoint::open(const AAudioStreamConfiguration& configuration) {
    mRequestedDeviceId = configuration.getDeviceId();
    mStreamInternal = getStreamInternal();

    AudioStreamBuilder builder;
    builder.setSharingMode(AAUDIO_SHARING_MODE_EXCLUSIVE);
    // Don't fall back to SHARED because that would cause recursion.
    builder.setSharingModeMatchRequired(true);
    builder.setDeviceId(mRequestedDeviceId);
    builder.setFormat(configuration.getAudioFormat());
    builder.setSampleRate(configuration.getSampleRate());
    builder.setSamplesPerFrame(configuration.getSamplesPerFrame());
    builder.setDirection(getDirection());
    builder.setBufferCapacity(DEFAULT_BUFFER_CAPACITY);

    return getStreamInternal()->open(builder);
}

aaudio_result_t AAudioServiceEndpoint::close() {
    return getStreamInternal()->close();
}

// TODO, maybe use an interface to reduce exposure
aaudio_result_t AAudioServiceEndpoint::registerStream(sp<AAudioServiceStreamShared>sharedStream) {
    std::lock_guard<std::mutex> lock(mLockStreams);
    mRegisteredStreams.push_back(sharedStream);
    return AAUDIO_OK;
}

aaudio_result_t AAudioServiceEndpoint::unregisterStream(sp<AAudioServiceStreamShared>sharedStream) {
    std::lock_guard<std::mutex> lock(mLockStreams);
    mRegisteredStreams.erase(std::remove(mRegisteredStreams.begin(), mRegisteredStreams.end(), sharedStream),
              mRegisteredStreams.end());
    return AAUDIO_OK;
}

aaudio_result_t AAudioServiceEndpoint::startStream(sp<AAudioServiceStreamShared> sharedStream) {
    // TODO use real-time technique to avoid mutex, eg. atomic command FIFO
    std::lock_guard<std::mutex> lock(mLockStreams);
    mRunningStreams.push_back(sharedStream);
    if (mRunningStreams.size() == 1) {
        startSharingThread_l();
    }
    return AAUDIO_OK;
}

aaudio_result_t AAudioServiceEndpoint::stopStream(sp<AAudioServiceStreamShared> sharedStream) {
    int numRunningStreams = 0;
    {
        std::lock_guard<std::mutex> lock(mLockStreams);
        mRunningStreams.erase(
                std::remove(mRunningStreams.begin(), mRunningStreams.end(), sharedStream),
                mRunningStreams.end());
        numRunningStreams = mRunningStreams.size();
    }
    if (numRunningStreams == 0) {
        // Don't call this under a lock because the callbackLoop also uses the lock.
        stopSharingThread();
    }
    return AAUDIO_OK;
}

static void *aaudio_endpoint_thread_proc(void *context) {
    AAudioServiceEndpoint *endpoint = (AAudioServiceEndpoint *) context;
    if (endpoint != NULL) {
        return endpoint->callbackLoop();
    } else {
        return NULL;
    }
}

aaudio_result_t AAudioServiceEndpoint::startSharingThread_l() {
    // Launch the callback loop thread.
    int64_t periodNanos = getStreamInternal()->getFramesPerBurst()
                          * AAUDIO_NANOS_PER_SECOND
                          / getSampleRate();
    mCallbackEnabled.store(true);
    return getStreamInternal()->createThread(periodNanos, aaudio_endpoint_thread_proc, this);
}

aaudio_result_t AAudioServiceEndpoint::stopSharingThread() {
    mCallbackEnabled.store(false);
    aaudio_result_t result = getStreamInternal()->joinThread(NULL);
    return result;
}

void AAudioServiceEndpoint::disconnectRegisteredStreams() {
    std::lock_guard<std::mutex> lock(mLockStreams);
    for(auto baseStream : mRunningStreams) {
        baseStream->onStop();
    }
    mRunningStreams.clear();
    for(auto sharedStream : mRegisteredStreams) {
        sharedStream->disconnect();
    }
    mRegisteredStreams.clear();
}

bool AAudioServiceEndpoint::matches(const AAudioStreamConfiguration& configuration) {
    if (configuration.getDeviceId() != AAUDIO_UNSPECIFIED &&
            configuration.getDeviceId() != mStreamInternal->getDeviceId()) {
        return false;
    }
    if (configuration.getSampleRate() != AAUDIO_UNSPECIFIED &&
            configuration.getSampleRate() != mStreamInternal->getSampleRate()) {
        return false;
    }
    if (configuration.getSamplesPerFrame() != AAUDIO_UNSPECIFIED &&
            configuration.getSamplesPerFrame() != mStreamInternal->getSamplesPerFrame()) {
        return false;
    }

    return true;
}