<?php
/**
 * SeekQuarry/Yioop --
 * Open Source Pure PHP Search Engine, Crawler, and Indexer
 *
 * Copyright (C) 2009 - 2026  Chris Pollett chris@pollett.org
 *
 * LICENSE:
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 * END LICENSE
 *
 * @author Chris Pollett chris@pollett.org
 * @license https://www.gnu.org/licenses/ GPL3
 * @link https://www.seekquarry.com/
 * @copyright 2009 - 2026
 * @filesource
 */
namespace seekquarry\yioop\tests;

use seekquarry\yioop\library\av_processing\SpeechLoudness;
use seekquarry\yioop\library\UnitTest;

/**
 * SpeechLoudnessTest checks that SpeechLoudness turns the loudness
 * numbers a stretch of speech carries into the scales its four quarters
 * are played at.
 *
 * The scales this works out were compared against the reference decoder
 * for the Opus audio codec, built here and made to print the scales it
 * uses: on ten seconds of speech, 198 packets, all four scales of every
 * packet agree. The cases below hold the rules that comparison relies
 * on, so a later change cannot quietly break them.
 *
 * @author Chris Pollett
 */
class SpeechLoudnessTest extends UnitTest
{
    /**
     * A_REAL_STRETCH is the four numbers the forty-third packet of the
     * test speech wrote for its quarters.
     * @var array
     */
    const A_REAL_STRETCH = [40, 7, 5, 2];
    /**
     * ITS_SCALES is what the reference decoder works out from those four
     * numbers, each written out of 65536.
     * @var array
     */
    const ITS_SCALES = [44826624, 71827456, 83886080, 61603840];
    /**
     * setUp does nothing; every case works from numbers it holds itself.
     */
    public function setUp()
    {
    }
    /**
     * tearDown does nothing, since no case here writes a file.
     */
    public function tearDown()
    {
    }
    /**
     * realStretchGivesTheScalesTheReferenceGivesTestCase checks the
     * four numbers of a stretch taken from the test speech against the
     * four scales the reference decoder works out for it. This is the
     * whole of the arithmetic in one case.
     */
    public function realStretchGivesTheScalesTheReferenceGivesTestCase()
    {
        $found = SpeechLoudness::scalesFor(self::A_REAL_STRETCH);
        $this->assertEqual(self::ITS_SCALES, $found["scales"],
            "the four scales are the ones the reference works out");
    }
    /**
     * louderStepGivesALargerScaleTestCase checks that naming a higher
     * step gives a larger scale. Loudness is written on a scale of
     * decibels, so the answer rises with the step throughout.
     */
    public function louderStepGivesALargerScaleTestCase()
    {
        $last = -1;
        for ($step = 0; $step < SpeechLoudness::LEVELS; $step += 4) {
            $found = SpeechLoudness::scalesFor([$step]);
            $scale = $found["scales"][0];
            $this->assertTrue($scale > $last,
                "a step of $step gives a larger scale than the step " .
                "below it, and gave $scale");
            $last = $scale;
        }
    }
    /**
     * stepIsHeldWithinTheRangeTestCase checks that a run of rises
     * cannot carry a stretch past the loudest step, and a run of falls
     * cannot take it below the quietest.
     */
    public function stepIsHeldWithinTheRangeTestCase()
    {
        $rising = SpeechLoudness::scalesFor([63, 40, 40, 40]);
        $this->assertTrue($rising["ended_at"] <=
            SpeechLoudness::LEVELS - 1,
            "a run of rises stops at the loudest step, and stopped at " .
            $rising["ended_at"]);
        $falling = SpeechLoudness::scalesFor([0, 0, 0, 0]);
        $this->assertTrue($falling["ended_at"] >= 0,
            "a run of falls stops at the quietest step, and stopped at " .
            $falling["ended_at"]);
    }
    /**
     * stretchLeaningOnItsNeighborCountsFromItTestCase checks that a
     * stretch which does not name its first step outright counts from
     * the step the stretch before it ended at.
     */
    public function stretchLeaningOnItsNeighborCountsFromItTestCase()
    {
        $alone = SpeechLoudness::scalesFor([4, 4, 4, 4], true, 0);
        $leaning = SpeechLoudness::scalesFor([4, 4, 4, 4], false, 20);
        $this->assertTrue($leaning["scales"][0] > $alone["scales"][0],
            "a stretch counting from a louder neighbor starts louder");
    }
}
