// yabridge: a Wine VST bridge
// Copyright (C) 2020-2021 Robbert van der Helm
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

#pragma once

#include <pluginterfaces/vst/ivstparameterchanges.h>
#include <boost/container/small_vector.hpp>

#include "../../bitsery/traits/small-vector.h"
#include "base.h"

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wnon-virtual-dtor"
// FIXME: When used in a Boost.Containers small vector, GCC somehow complains
//        that the fields in this class may be uninitialized (during the
//        deserialization). This warning only shows up during a unity build.
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"

/**
 * Wraps around `IParamValueQueue` for serializing a queue containing changes to
 * a single parameter during the current processing cycle. Used in
 * `YaParameterChanges`.
 */
class alignas(16) YaParamValueQueue : public Steinberg::Vst::IParamValueQueue {
   public:
    /**
     * We only provide a default constructor here, because we need to fill the
     * existing object with new data every processing cycle to avoid
     * reallocating a new object every time.
     */
    YaParamValueQueue() noexcept;

    /**
     * Clear this queue in place so that it can be used to write parameter data
     * to. Used in `YaParameterChanges::addParameterData`.
     */
    void clear_for_parameter(Steinberg::Vst::ParamID parameter_id) noexcept;

    /**
     * Read data from an `IParamValueQueue` object into this existing object.
     */
    void repopulate(Steinberg::Vst::IParamValueQueue& original_queue);

    ~YaParamValueQueue() noexcept;

    DECLARE_FUNKNOWN_METHODS

    /**
     * Write this queue back the output parameter changes object on the
     * `ProcessData` object provided by the host.
     */
    void write_back_outputs(
        Steinberg::Vst::IParamValueQueue& output_queue) const;

    // From `IParamValueQueue`
    Steinberg::Vst::ParamID PLUGIN_API getParameterId() override;
    int32 PLUGIN_API getPointCount() override;
    tresult PLUGIN_API
    getPoint(int32 index,
             int32& sampleOffset /*out*/,
             Steinberg::Vst::ParamValue& value /*out*/) override;
    tresult PLUGIN_API addPoint(int32 sampleOffset,
                                Steinberg::Vst::ParamValue value,
                                int32& index /*out*/) override;

    template <typename S>
    void serialize(S& s) {
        s.value4b(parameter_id);
        // TODO: Does bitsery have a built in way to serialize pairs?
        s.container(queue, 1 << 16, [](S& s, std::pair<int32, double>& pair) {
            s.value4b(pair.first);
            s.value8b(pair.second);
        });
    }

    /**
     * For `IParamValueQueue::getParameterId`.
     */
    Steinberg::Vst::ParamID parameter_id;

   private:
    /**
     * The actual parameter changes queue. The specification doesn't mention
     * that this should be a priority queue or something, but I'd assume both
     * the plugin and the host will insert the values in chronological order
     * (because, why would they not?).
     *
     * This contains pairs of `(sample_offset, value)`.
     */
    boost::container::small_vector<std::pair<int32, Steinberg::Vst::ParamValue>,
                                   16>
        queue;
};

#pragma GCC diagnostic pop