#include <psemek/audio/effect/loop.hpp>
#include <psemek/audio/duplicate.hpp>

namespace psemek::audio
{

	namespace
	{

		struct loop_impl
			: stream
		{
			loop_impl(duplicator dup, std::optional<std::size_t> count)
				: dup_(std::move(dup))
				, stream_(dup_())
				, count_(count)
			{}

			std::optional<std::size_t> length() const override
			{
				if (count_)
					return (*stream_->length()) * (*count_);
				return std::nullopt;
			}

			std::size_t read(float * data, std::size_t sample_count) override
			{
				std::size_t result = 0;
				while (result < sample_count && (!count_ || repeated_ < *count_))
				{
					auto need = sample_count - result;
					auto count = stream_->read(data + result, need);
					result += count;
					if (count < need)
					{
						++repeated_;
						stream_ = dup_();
					}
				}
				return result;
			}

			std::size_t played() const override
			{
				return stream_->played() + (*stream_->length()) * repeated_;
			}

		private:
			duplicator dup_;
			stream_ptr stream_;
			std::optional<std::size_t> count_;
			std::size_t repeated_ = 0;
		};

	}

	stream_ptr loop(stream_ptr stream, std::optional<std::size_t> count)
	{
		if (!stream->length())
			return stream;
		return std::make_shared<loop_impl>(make_duplicator(std::move(stream)), count);
	}

}