#include <psemek/audio/duplicate.hpp>

#include <vector>

namespace psemek::audio
{

	namespace
	{

		struct duplicate_common
		{
			duplicate_common(stream_ptr stream)
				: stream(std::move(stream))
			{}

			stream_ptr stream;
			std::vector<float> buffer;
			std::size_t counter = 0;
			std::size_t read = 0;
		};

		struct duplicate_impl
			: stream
		{
			duplicate_impl(std::shared_ptr<duplicate_common> common)
				: common_(std::move(common))
			{}

			std::size_t read(float * data, std::size_t sample_count) override
			{
				if (counter_ == common_->counter)
				{
					++common_->counter;
					if (common_->buffer.size() < sample_count)
						common_->buffer.resize(sample_count);
					common_->read = common_->stream->read(common_->buffer.data(), sample_count);
				}

				std::copy(common_->buffer.data(), common_->buffer.data() + common_->read, data);
				++counter_;
				return common_->read;
			}

		private:
			std::shared_ptr<duplicate_common> common_;
			std::size_t counter_ = 0;
		};

	}

	std::pair<stream_ptr, stream_ptr> duplicate(stream_ptr stream)
	{
		auto common = std::make_shared<duplicate_common>(std::move(stream));
		return {std::make_shared<duplicate_impl>(common), std::make_shared<duplicate_impl>(common)};
	}

}