#include <stdlib.h>
#include <string.h>
#include "mutex.h"
#include "channel.h"


void mossrose_channel_init(struct mossrose_channel_t *chan)
{
	mossrose_mutex_init(&(chan->mutex));
	chan->left = NULL;
	chan->right = NULL;
	chan->n_samples = 0;
	chan->pos = 0;
}


int mossrose_channel_set(struct mossrose_channel_t *chan, float *left, float *right, size_t len, int force)
{
	int result = 0;
	mossrose_mutex_lock(&(chan->mutex));
	if (chan->n_samples != 0 && !force) {
		/* channel is still playing! */
		result = 1; goto unlock;
	}

	chan->n_samples = len;
	chan->pos = 0;
	
	/* left channel */
	if (chan->left != NULL)  free(chan->left);
	if (left == NULL)
		chan->left = NULL;
	else {
		chan->left = malloc(len * sizeof(float));
		if (chan->left == NULL) { result = 2; goto unlock; }
		memcpy(chan->left, left, len * sizeof(float));
	}

	/* right channel */
	if (chan->right != NULL)  free(chan->right);
	if (right == NULL)
		chan->right = NULL;
	else {
		chan->right = malloc(len * sizeof(float));
		if (chan->right == NULL) { result = 3; goto unlock; }
		memcpy(chan->right, right, len * sizeof(float));
	}

	unlock:
	mossrose_mutex_unlock(&(chan->mutex));
	return result;
}


void mossrose_channel_reset(struct mossrose_channel_t *chan)
{
	chan->n_samples = 0;
	chan->pos = 0;
}


int mossrose_channel_advance(float *left, float *right, struct mossrose_channel_t *chan)
{
	if (chan->pos >= chan->n_samples) return 1;
	if (chan->left != NULL)
		*left = chan->left[chan->pos];
	else
		*left = 0;
	if (chan->right != NULL)
		*right = chan->right[chan->pos];
	else
		*right = 0;
	chan->pos += 1;
	return 0;
}


void mossrose_channel_destroy(struct mossrose_channel_t *chan)
{
	mossrose_mutex_destroy(&(chan->mutex));
	if (chan->left != NULL)  free(chan->left);
	if (chan->right != NULL) free(chan->right);
}