#include "precompile.h"
#include "audiodbmeter.h"
#include "audiocontext.h"

#include <math.h>
#include <assert.h>
#include <crtdbg.h>

#define DB_RANGE	60.0

#define READ_IDX	(STREAM_DIR_READ-1)
#define WRITE_IDX	(STREAM_DIR_WRITE-1)

static const float const_1_div_32768_ = 1.0f / 32768.f; /* 16 bit multiplier */

static float ClipZeroToOne(float z)
{
	if (z > 1.0)
		return 1.0;
	else if (z < 0.0)
		return 0.0;
	else
		return z;
}

static float ToDB(float v, float range)
{
	float db;
	if (v > 0)
		db = 20 * log10(fabs(v));
	else
		db = -999;
	return ClipZeroToOne((db + range) / range);
}

static apr_status_t read_frame(void *self, audioframe_t *frame)
{
	audiodbmeter_t *audiometer = CONTAINING_RECORD(self, audiodbmeter_t, base);
	apr_status_t status;

	status = audiometer->base.downstream->vtbl->read_frame(audiometer->base.downstream, frame);

	if (status == APR_SUCCESS && frame->size > 0) {
		int i;
		int frames = frame->size / 2;
		short *sptr = (short*)frame->buffer;
		float peak = 0.0;
		float rms = 0.0;
		int old;

		for (i = 0; i < frames; ++i) {
			float v = *sptr * const_1_div_32768_;
			peak = (float)max(v, peak);
			rms += (float)(v * v);
			sptr++;
		}

		rms = sqrt(rms / frames);
		rms = ToDB(rms, DB_RANGE);
		peak = ToDB(peak, DB_RANGE);

		old = audiometer->stat[READ_IDX].rms;
		audiometer->stat[READ_IDX].rms = (old * 9 + (int)(100*rms)) / 10;
		old = audiometer->stat[READ_IDX].peak;
		audiometer->stat[READ_IDX].peak = (old * 9 + (int)(100*peak)) / 10;
	}

	return APR_SUCCESS;
}

static apr_status_t write_frame(void *self, const audioframe_t *frame)
{
	audiodbmeter_t *audiometer = CONTAINING_RECORD(self, audiodbmeter_t, base);
	apr_status_t status;

	status = audiometer->base.downstream->vtbl->write_frame(audiometer->base.downstream, frame);

	if (status == APR_SUCCESS && frame->size > 0) {
		int i;
		int frames = frame->size / 2;
		const short *sptr = (const short *)frame->buffer;
		float peak = 0.0;
		float rms = 0.0;
		int old;

		for (i = 0; i < frames; ++i) {
			float v = *sptr * const_1_div_32768_;
			peak = (float)max(v, peak);
			rms += (float)(v * v);
			sptr++;
		}

		rms = sqrt(rms / frames);
		rms = ToDB(rms, DB_RANGE);
		peak = ToDB(peak, DB_RANGE);

		old = audiometer->stat[WRITE_IDX].rms;
		audiometer->stat[WRITE_IDX].rms = (old * 9 + (int)(100*rms)) / 10;
		old = audiometer->stat[WRITE_IDX].peak;
		audiometer->stat[WRITE_IDX].peak = (old * 9 + (int)(100*peak)) / 10;
	}

	return APR_SUCCESS;
}

static audiostream_vtbl_t g_stream_vtbl = {
	&read_frame,
	&write_frame,
};

apr_status_t audiodbmeter_create(apr_pool_t *pool, audioengine_t *engine, audiodbmeter_t **p_audiometer)
{
	audiodbmeter_t *audiometer;

	audiometer = apr_palloc(pool, sizeof(audiodbmeter_t));
	memset(audiometer, 0, sizeof(audiodbmeter_t));
	assert(0 == READ_IDX);
	assert(1 == WRITE_IDX);
	audiostream_init(engine, &g_stream_vtbl, &audiometer->base);
	*p_audiometer = audiometer;
	return APR_SUCCESS;
}

apr_status_t audiodbmeter_destroy(audiodbmeter_t *audiometer)
{
	return APR_SUCCESS;
}

apr_status_t audiodbmeter_get_peak_db(audiodbmeter_t *audiometer, int direction, int *pval)
{
	int idx = direction - 1;
	*pval = audiometer->stat[idx].peak;
	return APR_SUCCESS;
}

apr_status_t audiodbmeter_get_rms_db(audiodbmeter_t *audiometer, int direction, int *pval)
{
	int idx = direction - 1;
	*pval = audiometer->stat[idx].rms;
	return APR_SUCCESS;
}