#include "buffer.hpp"

/*
A Buffer consists of three parts:
an incoming vector, a rollingbuffer, and an output vector.

Note that the RollingBuffer class does most of the work:
its `get` and `put` methods move the values in our
input and output vectors.
*/

Buffer::Buffer(
		const char *pipe_file,
		size_t buffer_size,
		size_t output_size
	):
		buffer_size(buffer_size),
		output_size(output_size),
		pipe_file(pipe_file)
	{

	sample_con_rate = 5;
	sample_con_rate_up_ctr = 0;
	sample_con_rate_dn_ctr = 0;

	incoming.resize(buffer_size);
	rolling_buffer.resize(buffer_size);

	output.resize(output_size);
}


void Buffer::update() {
	// TODO:
	// Disable and enable FIFO here to get rid of
	// the difference between audio and visualization.

	int fd = open(pipe_file, O_RDONLY);

	ssize_t bytes_read = read(
		fd,
		incoming.data(),
		sizeof(int16_t) * incoming.size()
	);

	const auto begin = incoming.begin();
	const auto end = incoming.begin() + bytes_read/sizeof(int16_t);

	// Autoscale here

	rolling_buffer.put(begin, end);

	// 44100 samples per second / fps = samples per frame
	// 60 fps
	// *2 if stereo
	size_t requested_samples = (44100 / 60) * pow(1.1, sample_con_rate);

	size_t new_samples = rolling_buffer.get(
		requested_samples,
		output
	);

	if (new_samples == 0) {
		printf("no new samples\n");
		return;
	}

	// A crude way to adjust the amount of samples consumed from the buffer
	// depending on how fast the rendering is.
	if (rolling_buffer.size() > 0) {
		if (++sample_con_rate_up_ctr > 8) {
			sample_con_rate_up_ctr = 0;
			++sample_con_rate;
		}
	} else if (sample_con_rate > 0) {
		if (++sample_con_rate_dn_ctr > 4) {
			sample_con_rate_dn_ctr = 0;
			--sample_con_rate;
		}
		sample_con_rate_up_ctr = 0;
	}

	if (fd >= 0) {
		close(fd);
	}
}