<?php
declare(strict_types=1);

use PHPUnit\Framework\TestCase;

/**
 * Tests for WPDO_HivePress_Benchmark.
 *
 * @covers WPDO_HivePress_Benchmark
 */
class HivePressBenchmarkTest extends TestCase {

	public function test_default_iterations_is_fifty(): void {
		$this->assertSame( 50, WPDO_HivePress_Benchmark::DEFAULT_ITERATIONS );
	}

	public function test_run_returns_mean_milliseconds(): void {
		$ms = WPDO_HivePress_Benchmark::run( static function () {
			usleep( 1000 ); // 1 ms
		}, 5 );

		// Allow generous slack for slow CI runners; we just need it to be > 0.
		$this->assertGreaterThan( 0.0, $ms );
	}

	public function test_compare_returns_speedup_ratio(): void {
		$result = WPDO_HivePress_Benchmark::compare(
			'sample',
			static function () { usleep( 4000 ); }, // ~4 ms baseline
			static function () { usleep( 1000 ); }, // ~1 ms target
			3
		);

		$this->assertSame( 'sample', $result['name'] );
		$this->assertGreaterThan( 0.0, $result['baseline_ms'] );
		$this->assertGreaterThan( 0.0, $result['target_ms'] );
		// Baseline is roughly 4× target — ratio should be > 1 (faster).
		$this->assertGreaterThan( 1.0, $result['ratio'] );
		$this->assertSame( 3, $result['iterations'] );
	}

	public function test_compare_handles_zero_target_time(): void {
		// If target is suspiciously fast, ratio falls back to 0 (no division).
		$result = WPDO_HivePress_Benchmark::compare(
			'instant',
			static function () { /* noop */ },
			static function () { /* noop */ },
			1
		);
		// Either ratio > 0 (both nonzero) or 0 (target_ms was 0); never NaN/inf.
		$this->assertIsFloat( $result['ratio'] );
		$this->assertFalse( is_nan( $result['ratio'] ) );
		$this->assertFalse( is_infinite( $result['ratio'] ) );
	}

	public function test_run_suite_aggregates_samples(): void {
		$report = WPDO_HivePress_Benchmark::run_suite( array(
			array(
				'name'       => 'a',
				'baseline'   => static function () { usleep( 2000 ); },
				'target'     => static function () { usleep( 500 ); },
				'iterations' => 2,
			),
			array(
				'name'       => 'b',
				'baseline'   => static function () { usleep( 4000 ); },
				'target'     => static function () { usleep( 1000 ); },
				'iterations' => 2,
			),
		) );

		$this->assertSame( 2, $report['sample_count'] );
		$this->assertGreaterThan( 0.0, $report['geomean_ratio'] );
	}

	public function test_run_suite_skips_malformed_sample(): void {
		$report = WPDO_HivePress_Benchmark::run_suite( array(
			array( 'name' => 'incomplete' ), // missing baseline + target
			array(
				'name'     => 'ok',
				'baseline' => static function () { usleep( 100 ); },
				'target'   => static function () { usleep( 100 ); },
				'iterations' => 1,
			),
		) );

		$this->assertSame( 1, $report['sample_count'] );
	}

	public function test_geometric_mean_with_empty_values_returns_zero(): void {
		$this->assertSame( 0.0, WPDO_HivePress_Benchmark::geometric_mean( array() ) );
	}

	public function test_geometric_mean_resists_outliers(): void {
		// Geomean of (2, 8) = sqrt(16) = 4 (vs arithmetic mean 5).
		$this->assertSame( 4.0, WPDO_HivePress_Benchmark::geometric_mean( array( 2.0, 8.0 ) ) );
	}
}