<?php

declare(strict_types=1);

namespace Tests\Performance;

use App\Framework\Performance\Contracts\PerformanceCollectorInterface;
use App\Framework\Performance\PerformanceCategory;
use App\Framework\Core\ValueObjects\Duration;

/**
 * Base class for performance tests
 *
 * Provides utilities for benchmarking and performance measurement
 */
abstract readonly class PerformanceTestCase
{
    public function __construct(
        protected PerformanceCollectorInterface $collector
    ) {}

    /**
     * Benchmark a callable operation
     *
     * @param callable $operation The operation to benchmark
     * @param int $iterations Number of iterations to run
     * @param string $name Benchmark name for reporting
     * @return PerformanceBenchmarkResult
     */
    protected function benchmark(
        callable $operation,
        int $iterations = 1000,
        string $name = 'benchmark'
    ): PerformanceBenchmarkResult {
        // Warmup run
        $operation();

        // Clear any existing metrics
        gc_collect_cycles();

        $durations = [];
        $memoryUsages = [];
        $startMemory = memory_get_usage(true);
        $startTime = microtime(true);

        for ($i = 0; $i < $iterations; $i++) {
            $iterationStart = hrtime(true);
            $iterationMemoryStart = memory_get_usage(true);

            $operation();

            $iterationEnd = hrtime(true);
            $iterationMemoryEnd = memory_get_usage(true);

            $durations[] = ($iterationEnd - $iterationStart) / 1e6; // Convert to milliseconds
            $memoryUsages[] = $iterationMemoryEnd - $iterationMemoryStart;
        }

        $endTime = microtime(true);
        $endMemory = memory_get_usage(true);

        $totalTime = ($endTime - $startTime) * 1000; // milliseconds
        $avgTime = $totalTime / $iterations;
        $minTime = min($durations);
        $maxTime = max($durations);
        $medianTime = $this->calculateMedian($durations);
        $p95Time = $this->calculatePercentile($durations, 95);
        $p99Time = $this->calculatePercentile($durations, 99);

        $avgMemory = array_sum($memoryUsages) / count($memoryUsages);
        $peakMemory = $endMemory - $startMemory;

        $operationsPerSecond = 1000 / $avgTime;

        return new PerformanceBenchmarkResult(
            name: $name,
            iterations: $iterations,
            totalTimeMs: $totalTime,
            avgTimeMs: $avgTime,
            minTimeMs: $minTime,
            maxTimeMs: $maxTime,
            medianTimeMs: $medianTime,
            p95TimeMs: $p95Time,
            p99TimeMs: $p99Time,
            avgMemoryBytes: (int) $avgMemory,
            peakMemoryBytes: $peakMemory,
            operationsPerSecond: $operationsPerSecond
        );
    }

    /**
     * Assert performance meets threshold
     */
    protected function assertPerformanceThreshold(
        PerformanceBenchmarkResult $result,
        float $maxAvgTimeMs,
        ?int $maxMemoryBytes = null
    ): void {
        if ($result->avgTimeMs > $maxAvgTimeMs) {
            throw new \RuntimeException(
                "Performance threshold exceeded: {$result->name} took {$result->avgTimeMs}ms (limit: {$maxAvgTimeMs}ms)"
            );
        }

        if ($maxMemoryBytes !== null && $result->peakMemoryBytes > $maxMemoryBytes) {
            $peakMb = round($result->peakMemoryBytes / 1024 / 1024, 2);
            $limitMb = round($maxMemoryBytes / 1024 / 1024, 2);
            throw new \RuntimeException(
                "Memory threshold exceeded: {$result->name} used {$peakMb}MB (limit: {$limitMb}MB)"
            );
        }
    }

    /**
     * Record benchmark result in performance collector
     */
    protected function recordBenchmark(
        PerformanceBenchmarkResult $result,
        PerformanceCategory $category = PerformanceCategory::CUSTOM
    ): void {
        $this->collector->recordMetric(
            "benchmark_{$result->name}",
            $category,
            $result->avgTimeMs,
            [
                'iterations' => $result->iterations,
                'min_ms' => $result->minTimeMs,
                'max_ms' => $result->maxTimeMs,
                'median_ms' => $result->medianTimeMs,
                'p95_ms' => $result->p95TimeMs,
                'p99_ms' => $result->p99TimeMs,
                'ops_per_sec' => $result->operationsPerSecond,
                'memory_avg_mb' => round($result->avgMemoryBytes / 1024 / 1024, 2),
                'memory_peak_mb' => round($result->peakMemoryBytes / 1024 / 1024, 2)
            ]
        );
    }

    /**
     * Calculate median value
     */
    private function calculateMedian(array $values): float
    {
        sort($values);
        $count = count($values);
        $middle = floor($count / 2);

        if ($count % 2 === 0) {
            return ($values[$middle - 1] + $values[$middle]) / 2;
        }

        return $values[$middle];
    }

    /**
     * Calculate percentile value
     */
    private function calculatePercentile(array $values, int $percentile): float
    {
        sort($values);
        $count = count($values);
        $index = ceil($count * ($percentile / 100)) - 1;

        return $values[(int) max(0, min($index, $count - 1))];
    }
}