/*
  ==============================================================================

   This file is part of the JUCE framework.
   Copyright (c) Raw Material Software Limited

   JUCE is an open source framework subject to commercial or open source
   licensing.

   By downloading, installing, or using the JUCE framework, or combining the
   JUCE framework with any other source code, object code, content or any other
   copyrightable work, you agree to the terms of the JUCE End User Licence
   Agreement, and all incorporated terms including the JUCE Privacy Policy and
   the JUCE Website Terms of Service, as applicable, which will bind you. If you
   do not agree to the terms of these agreements, we will not license the JUCE
   framework to you, and you must discontinue the installation or download
   process and cease use of the JUCE framework.

   JUCE End User Licence Agreement: https://juce.com/legal/juce-8-licence/
   JUCE Privacy Policy: https://juce.com/juce-privacy-policy
   JUCE Website Terms of Service: https://juce.com/juce-website-terms-of-service/

   Or:

   You may also use this code under the terms of the AGPLv3:
   https://www.gnu.org/licenses/agpl-3.0.en.html

   THE JUCE FRAMEWORK IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL
   WARRANTIES, WHETHER EXPRESSED OR IMPLIED, INCLUDING WARRANTY OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

//==============================================================================
/**
    Allows threads to wait for events triggered by other threads.

    A thread can call WaitableEvent::wait() to suspend the calling thread until
    another thread wakes it up by calling the WaitableEvent::signal() method.

    @tags{Core}
*/
class JUCE_API  WaitableEvent
{
public:
    //==============================================================================
    /** Creates a WaitableEvent object.

        The object is initially in an unsignalled state.

        @param manualReset  If this is false, the event will be reset automatically when the wait()
                            method is called. If manualReset is true, then once the event is signalled,
                            the only way to reset it will be by calling the reset() method.
    */
    explicit WaitableEvent (bool manualReset = false) noexcept;

    //==============================================================================
    /** Suspends the calling thread until the event has been signalled.

        This will wait until the object's signal() method is called by another thread,
        or until the timeout expires.

        After the event has been signalled, this method will return true and if manualReset
        was set to false in the WaitableEvent's constructor, then the event will be reset.

        @param timeOutMilliseconds  the maximum time to wait, in milliseconds. A negative
                                    value will cause it to wait forever.

        @returns    true if the object has been signalled, false if the timeout expires first.
        @see signal, reset
    */
    bool wait (double timeOutMilliseconds = -1.0) const;

    /** Wakes up any threads that are currently waiting on this object.

        If signal() is called when nothing is waiting, the next thread to call wait()
        will return immediately and reset the signal.

        If the WaitableEvent is manual reset, all current and future threads that wait upon this
        object will be woken, until reset() is explicitly called.

        If the WaitableEvent is automatic reset, and one or more threads is waiting upon the object,
        then one of them will be woken up. If no threads are currently waiting, then the next thread
        to call wait() will be woken up. As soon as a thread is woken, the signal is automatically
        reset.

        @see wait, reset
    */
    void signal() const;

    /** Resets the event to an unsignalled state.
        If it's not already signalled, this does nothing.
    */
    void reset() const;

private:
    //==============================================================================
    bool useManualReset;

    mutable std::mutex mutex;
    mutable std::condition_variable condition;
    mutable std::atomic<bool> triggered { false };

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (WaitableEvent)
};

} // namespace juce
