<?php

declare(strict_types=1);

namespace App\Framework\ExceptionHandling\Metrics;

use App\Framework\Cache\Cache;
use App\Framework\Cache\CacheItem;
use App\Framework\Cache\CacheKey;
use App\Framework\Core\ValueObjects\Duration;
use App\Framework\ExceptionHandling\Context\ExceptionContextData;
use Throwable;

/**
 * Exception Metrics Collector
 *
 * Collects metrics for exceptions (rate, top exceptions, error rate by component).
 */
final readonly class ExceptionMetricsCollector
{
    private const string CACHE_PREFIX = 'exception_metrics:';
    private const int METRICS_TTL = 3600; // 1 hour

    public function __construct(
        private Cache $cache
    ) {
    }

    /**
     * Record exception metric
     *
     * @param Throwable $exception Exception to record
     * @param ExceptionContextData|null $context Optional context
     * @param float|null $executionTimeMs Optional execution time in milliseconds
     */
    public function record(
        Throwable $exception,
        ?ExceptionContextData $context = null,
        ?float $executionTimeMs = null
    ): void {
        $exceptionClass = get_class($exception);
        $component = $context?->component ?? 'unknown';

        // Increment total count
        $this->incrementMetric('total');

        // Increment by class
        $this->incrementMetric('class:' . $exceptionClass);

        // Increment by component
        $this->incrementMetric('component:' . $component);

        // Record execution time if available
        if ($executionTimeMs !== null) {
            $this->recordExecutionTime($executionTimeMs);
        }
    }

    /**
     * Get current metrics
     *
     * @return ExceptionMetrics Current metrics
     */
    public function getMetrics(): ExceptionMetrics
    {
        $totalCount = $this->getMetric('total');
        $byClass = $this->getMetricsByPrefix('class:');
        $byComponent = $this->getMetricsByPrefix('component:');
        $avgExecutionTime = $this->getAverageExecutionTime();

        return new ExceptionMetrics(
            totalCount: $totalCount,
            byClass: $byClass,
            byComponent: $byComponent,
            averageExecutionTimeMs: $avgExecutionTime
        );
    }

    /**
     * Increment metric
     */
    private function incrementMetric(string $metricName): void
    {
        $cacheKey = CacheKey::fromString(self::CACHE_PREFIX . $metricName);
        $current = $this->getMetricValue($cacheKey);
        $newValue = $current + 1;

        $cacheItem = CacheItem::fromKey(
            $cacheKey,
            $newValue,
            Duration::fromSeconds(self::METRICS_TTL)
        );

        $this->cache->set($cacheItem);
    }

    /**
     * Get metric value
     */
    private function getMetric(string $metricName): int
    {
        $cacheKey = CacheKey::fromString(self::CACHE_PREFIX . $metricName);

        return $this->getMetricValue($cacheKey);
    }

    /**
     * Get metric value from cache
     */
    private function getMetricValue(CacheKey $cacheKey): int
    {
        $result = $this->cache->get($cacheKey);
        $item = $result->getItem($cacheKey);

        if (! $item->isHit) {
            return 0;
        }

        $value = $item->value;

        return is_int($value) ? $value : 0;
    }

    /**
     * Get metrics by prefix
     */
    private function getMetricsByPrefix(string $prefix): array
    {
        // Simplified implementation - in production, would use cache prefix scanning
        return [];
    }

    /**
     * Record execution time
     */
    private function recordExecutionTime(float $executionTimeMs): void
    {
        $cacheKey = CacheKey::fromString(self::CACHE_PREFIX . 'execution_times');
        $result = $this->cache->get($cacheKey);
        $item = $result->getItem($cacheKey);

        $times = $item->isHit && is_array($item->value) ? $item->value : [];
        $times[] = $executionTimeMs;

        // Keep only last 1000 execution times
        if (count($times) > 1000) {
            $times = array_slice($times, -1000);
        }

        $cacheItem = CacheItem::fromKey(
            $cacheKey,
            $times,
            Duration::fromSeconds(self::METRICS_TTL)
        );

        $this->cache->set($cacheItem);
    }

    /**
     * Get average execution time
     */
    private function getAverageExecutionTime(): float
    {
        $cacheKey = CacheKey::fromString(self::CACHE_PREFIX . 'execution_times');
        $result = $this->cache->get($cacheKey);
        $item = $result->getItem($cacheKey);

        if (! $item->isHit || ! is_array($item->value)) {
            return 0.0;
        }

        $times = $item->value;
        if (empty($times)) {
            return 0.0;
        }

        return array_sum($times) / count($times);
    }
}