/*
 * BlueALSA - delay-report.c
 * SPDX-FileCopyrightText: 2016-2025 BlueALSA developers
 * SPDX-License-Identifier: MIT
 */

#include "delay-report.h"

#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>

#include <alsa/asoundlib.h>
#include <dbus/dbus.h>

#include "shared/dbus-client.h"
#include "shared/dbus-client-pcm.h"
#include "shared/defs.h"
#include "shared/rt.h"

void delay_report_init(
		struct delay_report *dr,
		struct ba_dbus_ctx *dbus_ctx,
		struct ba_pcm *ba_pcm) {
	memset(dr, 0, sizeof(*dr));
	dr->dbus_ctx = dbus_ctx;
	dr->ba_pcm = ba_pcm;
}

void delay_report_reset(
		struct delay_report *dr) {
	memset(dr->values, 0, sizeof(dr->values));
	dr->values_i = 0;
}

bool delay_report_update(
		struct delay_report *dr,
		snd_pcm_uframes_t delay,
		DBusError *err) {

	const size_t num_values = ARRAYSIZE(dr->values);
	dr->values[dr->values_i % num_values] = delay;
	dr->values_i++;

	struct timespec ts_now;
	/* Rate limit delay updates to 1 update per second. */
	struct timespec ts_delay = { .tv_sec = 1 };

	gettimestamp(&ts_now);
	timespecadd(&dr->update_ts, &ts_delay, &ts_delay);

	snd_pcm_uframes_t delay_frames_avg = 0;
	for (size_t i = 0; i < num_values; i++)
		delay_frames_avg += dr->values[i];
	if (dr->values_i < num_values)
		delay_frames_avg /= dr->values_i;
	else
		delay_frames_avg /= num_values;
	dr->avg_value = delay_frames_avg;

	const int client_delay = delay_frames_avg * 10000 / dr->ba_pcm->rate;
	if (difftimespec(&ts_now, &ts_delay, &ts_delay) >= 0 ||
			abs(client_delay - dr->ba_pcm->client_delay) < 100 /* 10ms */)
		return true;

	dr->update_ts = ts_now;
	dr->ba_pcm->client_delay = client_delay;
	return ba_dbus_pcm_update(dr->dbus_ctx, dr->ba_pcm, BLUEALSA_PCM_CLIENT_DELAY, err);
}