/*
 * DialogUXStateAggregator.cpp
 *
 * Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *     http://aws.amazon.com/apache2.0/
 *
 * or in the "license" file accompanying this file. This file 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.
 */

#include "AVSCommon/AVS/DialogUXStateAggregator.h"

namespace alexaClientSDK {
namespace avsCommon {
namespace avs {

using namespace sdkInterfaces;

/// String to identify log entries originating from this file.
static const std::string TAG("DialogUXStateAggregator");

/**
 * Create a LogEntry using this file's TAG and the specified event string.
 *
 * @param The event string for this @c LogEntry.
 */
#define LX(event) alexaClientSDK::avsCommon::utils::logger::LogEntry(TAG, event)

/**
 * A short timeout that is used to avoid going to the IDLE state immediately while waiting for other state changes.
 */
static const std::chrono::milliseconds SHORT_TIMEOUT{200};

DialogUXStateAggregator::DialogUXStateAggregator(std::chrono::milliseconds timeoutForThinkingToIdle) : 
        m_currentState{DialogUXStateObserverInterface::DialogUXState::IDLE}, 
        m_timeoutForThinkingToIdle{timeoutForThinkingToIdle} {
}

void DialogUXStateAggregator::addObserver(std::shared_ptr<DialogUXStateObserverInterface> observer) {
    if (!observer) {
        ACSDK_ERROR(LX("addObserverFailed").d("reason", "nullObserver"));
        return;
    }
    m_executor.submit(
        [this, observer] () {
            m_observers.insert(observer);
            observer->onDialogUXStateChanged(m_currentState);
        }
    );
}

void DialogUXStateAggregator::removeObserver(std::shared_ptr<DialogUXStateObserverInterface> observer) {
    if (!observer) {
        ACSDK_ERROR(LX("removeObserverFailed").d("reason", "nullObserver"));
        return;
    }
    m_executor.submit(
        [this, observer] () {
            m_observers.erase(observer);
        }
    ).wait();
}

void DialogUXStateAggregator::onStateChanged(AudioInputProcessorObserverInterface::State state) {
    m_executor.submit(
        [this, state] () {
            switch (state) {
                case AudioInputProcessorObserverInterface::State::IDLE:
                    if (DialogUXStateObserverInterface::DialogUXState::THINKING == m_currentState) {
                        return;
                    }
                    setState(DialogUXStateObserverInterface::DialogUXState::IDLE);
                    return;
                case AudioInputProcessorObserverInterface::State::RECOGNIZING:
                    setState(DialogUXStateObserverInterface::DialogUXState::LISTENING);
                    return;
                case AudioInputProcessorObserverInterface::State::EXPECTING_SPEECH:
                    setState(DialogUXStateObserverInterface::DialogUXState::LISTENING);
                    return;
                case AudioInputProcessorObserverInterface::State::BUSY:
                    setState(DialogUXStateObserverInterface::DialogUXState::THINKING);
                    if (!m_thinkingToIdleTimer.start(
                                m_timeoutForThinkingToIdle, std::bind(
                                        &DialogUXStateAggregator::transitionFromThinkingTimedOut, this)).valid()) {
                        ACSDK_ERROR(LX("failedToStartTimerFromThinkingToIdle"));
                    }
                    return;
            }
            ACSDK_ERROR(LX("unknownAudioInputProcessorState"));
        }
    );
}

void DialogUXStateAggregator::onStateChanged(SpeechSynthesizerObserver::SpeechSynthesizerState state) {
    m_executor.submit(
        [this, state] () {
            switch (state) {
                case SpeechSynthesizerObserver::SpeechSynthesizerState::PLAYING:
                    setState(DialogUXStateObserverInterface::DialogUXState::SPEAKING);
                    return;
                case SpeechSynthesizerObserver::SpeechSynthesizerState::FINISHED:
                    if (!m_multiturnSpeakingToListeningTimer.start(
                            SHORT_TIMEOUT, std::bind(
                                    &DialogUXStateAggregator::transitionFromSpeakingFinished, this)).valid()) {
                        ACSDK_ERROR(LX("failedToStartTimerFromSpeakingFinishedToIdle"));
                    }
                    return;
            }
            ACSDK_ERROR(LX("unknownSpeechSynthesizerState"));
        }
    );
}

void DialogUXStateAggregator::receive(const std::string & contextId, const std::string & message) {
    m_executor.submit(
        [this] () {
            if (DialogUXStateObserverInterface::DialogUXState::THINKING == m_currentState) {
                /* 
                 * Stop the long timer and start a short timer so that either the state will change (i.e. Speech begins)
                 * or we automatically go to idle after the short timeout (i.e. the directive received isn't related to
                 * speech, like a setVolume directive).
                 */
                m_thinkingToIdleTimer.stop();
                m_thinkingToIdleTimer.start(
                        SHORT_TIMEOUT, std::bind(
                                &DialogUXStateAggregator::transitionFromThinkingTimedOut, this));
            }
        }
    );
}

void DialogUXStateAggregator::notifyObserversOfState() {
    for (auto observer : m_observers) {
        if (observer) {
            observer->onDialogUXStateChanged(m_currentState);
        }
    }
}

void DialogUXStateAggregator::transitionFromThinkingTimedOut() {
    m_executor.submit(
        [this] () {
            if (DialogUXStateObserverInterface::DialogUXState::THINKING == m_currentState) {
                ACSDK_DEBUG(LX("transitionFromThinkingTimedOut"));
                setState(DialogUXStateObserverInterface::DialogUXState::IDLE);
            }
        }
    );
}

void DialogUXStateAggregator::transitionFromSpeakingFinished() {
    m_executor.submit(
        [this] () {
            if (DialogUXStateObserverInterface::DialogUXState::SPEAKING == m_currentState) {
                setState(DialogUXStateObserverInterface::DialogUXState::IDLE);
            }
        }
    );
}

void DialogUXStateAggregator::setState(sdkInterfaces::DialogUXStateObserverInterface::DialogUXState newState) {
    if (newState == m_currentState) {
        return;
    }
    m_thinkingToIdleTimer.stop();
    m_multiturnSpeakingToListeningTimer.stop();
    ACSDK_DEBUG(LX("setState").d("from", m_currentState).d("to", newState));
    m_currentState = newState;
    notifyObserversOfState();
}

} // namespace avs
} // namespace avsCommon
} // namespace alexaClientSDK