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

   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.

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

#pragma once

namespace juce
{

//==============================================================================
/** Holds a set of VSTMidiEvent objects and makes it easy to add
    events to the list.

    This is used by both the VST hosting code and the plugin wrapper.

    @tags{Audio}
*/
class VSTMidiEventList
{
    // "events" is expected to be a const- or non-const-ref to Vst2::VstEvents.
    template <typename Events>
    static auto& getEvent (Events& events, int index)
    {
        using EventType = decltype (&*events.events);
        static constexpr auto offset = offsetof (Vst2::VstEvents, events);

        auto* bytes = reinterpret_cast<std::conditional_t<std::is_const_v<std::remove_pointer_t<EventType>>,
                                                          const std::byte*,
                                                          std::byte*>> (&events);
        auto* array = reinterpret_cast<EventType> (bytes + offset);

        return array[index];
    }

    Vst2::VstEvent* const& getEvent (int index) const { return getEvent (*events, index); }
    Vst2::VstEvent*      & getEvent (int index)       { return getEvent (*events, index); }

public:
    //==============================================================================
    VSTMidiEventList()
        : numEventsUsed (0), numEventsAllocated (0)
    {
    }

    ~VSTMidiEventList()
    {
        freeEvents();
    }

    //==============================================================================
    void clear()
    {
        numEventsUsed = 0;

        if (events != nullptr)
            events->numEvents = 0;
    }

    void addEvent (const void* const midiData, int numBytes, int frameOffset)
    {
        ensureSize (numEventsUsed + 1);

        void* const ptr = getEvent (numEventsUsed);
        events->numEvents = ++numEventsUsed;

        if (numBytes <= 4)
        {
            auto* const e = static_cast<Vst2::VstMidiEvent*> (ptr);

            if (e->type == Vst2::kVstSysExType)
            {
                delete[] reinterpret_cast<Vst2::VstMidiSysexEvent*> (e)->sysexDump;
                e->type = Vst2::kVstMidiType;
                e->byteSize = sizeof (Vst2::VstMidiEvent);
                e->noteLength = 0;
                e->noteOffset = 0;
                e->detune = 0;
                e->noteOffVelocity = 0;
            }

            e->deltaFrames = frameOffset;
            memcpy (e->midiData, midiData, (size_t) numBytes);
        }
        else
        {
            auto* const se = static_cast<Vst2::VstMidiSysexEvent*> (ptr);

            if (se->type == Vst2::kVstSysExType)
                delete[] se->sysexDump;

            se->sysexDump = new char [(size_t) numBytes];
            memcpy (se->sysexDump, midiData, (size_t) numBytes);

            se->type = Vst2::kVstSysExType;
            se->byteSize = sizeof (Vst2::VstMidiSysexEvent);
            se->deltaFrames = frameOffset;
            se->flags = 0;
            se->dumpBytes = numBytes;
            se->resvd1 = 0;
            se->resvd2 = 0;
        }
    }

    //==============================================================================
    // Handy method to pull the events out of an event buffer supplied by the host
    // or plugin.
    static void addEventsToMidiBuffer (const Vst2::VstEvents* events, MidiBuffer& dest)
    {
        for (int i = 0; i < events->numEvents; ++i)
        {
            const auto* const e = getEvent (*events, i);

            if (e != nullptr)
            {
                const void* const ptr = e;

                if (e->type == Vst2::kVstMidiType)
                {
                    dest.addEvent ((const juce::uint8*) static_cast<const Vst2::VstMidiEvent*> (ptr)->midiData,
                                   4, e->deltaFrames);
                }
                else if (e->type == Vst2::kVstSysExType)
                {
                    const auto* se = static_cast<const Vst2::VstMidiSysexEvent*> (ptr);
                    dest.addEvent ((const juce::uint8*) se->sysexDump,
                                   (int) se->dumpBytes,
                                   e->deltaFrames);
                }
            }
        }
    }

    //==============================================================================
    void ensureSize (int numEventsNeeded)
    {
        if (numEventsNeeded > numEventsAllocated)
        {
            numEventsNeeded = (numEventsNeeded + 32) & ~31;

            const size_t size = 20 + (size_t) numEventsNeeded * sizeof (Vst2::VstEvent*);

            if (events == nullptr)
                events.calloc (size, 1);
            else
                events.realloc (size, 1);

            for (int i = numEventsAllocated; i < numEventsNeeded; ++i)
                getEvent (i) = allocateVSTEvent();

            numEventsAllocated = numEventsNeeded;
        }
    }

    void freeEvents()
    {
        if (events != nullptr)
        {
            for (int i = numEventsAllocated; --i >= 0;)
                freeVSTEvent (getEvent (i));

            events.free();
            numEventsUsed = 0;
            numEventsAllocated = 0;
        }
    }

    //==============================================================================
    HeapBlock<Vst2::VstEvents> events;

private:
    int numEventsUsed, numEventsAllocated;

    static Vst2::VstEvent* allocateVSTEvent()
    {
        constexpr auto size = jmax (sizeof (Vst2::VstMidiEvent), sizeof (Vst2::VstMidiSysexEvent));

        if (auto* e = static_cast<Vst2::VstEvent*> (std::calloc (1, size)))
        {
            e->type = Vst2::kVstMidiType;
            e->byteSize = sizeof (Vst2::VstMidiEvent);
            return e;
        }

        return nullptr;
    }

    static void freeVSTEvent (Vst2::VstEvent* e)
    {
        if (e->type == Vst2::kVstSysExType)
        {
            delete[] (reinterpret_cast<Vst2::VstMidiSysexEvent*> (e)->sysexDump);
        }

        std::free (e);
    }
};

} // namespace juce
