<?php

declare(strict_types=1);

namespace App\Framework\Telemetry\Adapters;

use App\Framework\Performance\Contracts\PerformanceCollectorInterface;
use App\Framework\Performance\PerformanceCategory;
use App\Framework\Performance\PerformanceMetric;
use App\Framework\Telemetry\UnifiedTelemetryService;

/**
 * Adapts the UnifiedTelemetryService to the PerformanceCollectorInterface
 * This allows the telemetry system to be used as a drop-in replacement for the existing performance collector
 */
final class PerformanceCollectorAdapter implements PerformanceCollectorInterface
{
    /**
     * @var array<string, array{start: float, category: PerformanceCategory, context: array<string, mixed>}> Active timings
     */
    private array $timings = [];

    /**
     * @var array<string, PerformanceMetric> Collected metrics
     */
    private array $metrics = [];

    /**
     * @var float Start time of the request
     */
    private float $requestStartTime;

    /**
     * @var int Start memory usage of the request
     */
    private int $requestStartMemory;

    /**
     * @var bool Whether performance tracking is enabled
     */
    private bool $enabled = true;

    /**
     * @param UnifiedTelemetryService $telemetryService Telemetry service to adapt
     * @param PerformanceCollectorInterface $originalCollector Original collector for fallback
     */
    public function __construct(
        private readonly UnifiedTelemetryService $telemetryService,
        private readonly PerformanceCollectorInterface $originalCollector
    ) {
        $this->requestStartTime = $originalCollector->getTotalRequestTime();
        $this->requestStartMemory = $originalCollector->getTotalRequestMemory();
    }

    /**
     * Start timing an operation
     */
    public function startTiming(string $key, PerformanceCategory $category, array $context = []): void
    {
        if (! $this->enabled) {
            return;
        }

        // Record in original collector
        $this->originalCollector->startTiming($key, $category, $context);

        // Record in telemetry service
        $this->telemetryService->startOperation(
            $key,
            $category->value,
            $context
        );

        // Record locally for endTiming
        $this->timings[$key] = [
            'start' => microtime(true),
            'category' => $category,
            'context' => $context,
        ];
    }

    /**
     * End timing an operation
     */
    public function endTiming(string $key): void
    {
        if (! $this->enabled || ! isset($this->timings[$key])) {
            return;
        }

        // End in original collector
        $this->originalCollector->endTiming($key);

        // End in telemetry service
        $this->telemetryService->endOperation($key);

        // Calculate duration and record as metric
        $duration = (microtime(true) - $this->timings[$key]['start']) * 1000;
        $this->recordMetric(
            "{$key}_duration",
            $this->timings[$key]['category'],
            $duration,
            array_merge($this->timings[$key]['context'], ['unit' => 'ms'])
        );

        // Remove from active timings
        unset($this->timings[$key]);
    }

    /**
     * Measure a callable's execution time and memory usage
     */
    public function measure(string $key, PerformanceCategory $category, callable $callback, array $context = []): mixed
    {
        if (! $this->enabled) {
            return $callback();
        }

        // Use telemetry service's trace method
        return $this->telemetryService->trace(
            $key,
            $category->value,
            $callback,
            $context
        );
    }

    /**
     * Record a metric value
     */
    public function recordMetric(string $key, PerformanceCategory $category, float $value, array $context = []): void
    {
        if (! $this->enabled) {
            return;
        }

        // Record in original collector
        $this->originalCollector->recordMetric($key, $category, $value, $context);

        // Record in telemetry service
        $unit = $context['unit'] ?? '';
        $this->telemetryService->recordMetric(
            $key,
            $value,
            $unit,
            array_merge($context, ['category' => $category->value])
        );

        // Store locally
        $this->metrics[$key] = PerformanceMetric::create($key, $category, $context)
            ->withValue($value);
    }

    /**
     * Increment a counter
     */
    public function increment(string $key, PerformanceCategory $category, int $amount = 1, array $context = []): void
    {
        if (! $this->enabled) {
            return;
        }

        // Increment in original collector
        $this->originalCollector->increment($key, $category, $amount, $context);

        // Get current value or default to 0
        $currentValue = 0;
        if (isset($this->metrics[$key])) {
            $currentValue = $this->metrics[$key]->getValue();
        }

        // Record new value
        $this->recordMetric(
            $key,
            $category,
            $currentValue + $amount,
            array_merge($context, ['type' => 'counter'])
        );
    }

    /**
     * Get all metrics, optionally filtered by category
     *
     * @return array<string, PerformanceMetric>
     */
    public function getMetrics(?PerformanceCategory $category = null): array
    {
        // Get metrics from original collector
        $originalMetrics = $this->originalCollector->getMetrics($category);

        // Filter local metrics by category if needed
        if ($category !== null) {
            $filteredMetrics = [];
            foreach ($this->metrics as $key => $metric) {
                if ($metric->getCategory() === $category) {
                    $filteredMetrics[$key] = $metric;
                }
            }

            return array_merge($originalMetrics, $filteredMetrics);
        }

        return array_merge($originalMetrics, $this->metrics);
    }

    /**
     * Get a specific metric by key
     */
    public function getMetric(string $key): ?PerformanceMetric
    {
        if (isset($this->metrics[$key])) {
            return $this->metrics[$key];
        }

        return $this->originalCollector->getMetric($key);
    }

    /**
     * Get total request time in milliseconds
     */
    public function getTotalRequestTime(): float
    {
        return (microtime(true) - $this->requestStartTime) * 1000;
    }

    /**
     * Get total request memory usage in bytes
     */
    public function getTotalRequestMemory(): int
    {
        return memory_get_usage() - $this->requestStartMemory;
    }

    /**
     * Get peak memory usage in bytes
     */
    public function getPeakMemory(): int
    {
        return memory_get_peak_usage();
    }

    /**
     * Reset all collected metrics
     */
    public function reset(): void
    {
        $this->metrics = [];
        $this->timings = [];
        $this->originalCollector->reset();
    }

    /**
     * Check if performance tracking is enabled
     */
    public function isEnabled(): bool
    {
        return $this->enabled;
    }

    /**
     * Enable or disable performance tracking
     */
    public function setEnabled(bool $enabled): void
    {
        $this->enabled = $enabled;
        $this->originalCollector->setEnabled($enabled);
    }
}