<?php
/**
 * Performance Profiler Module
 *
 * Mide tiempos de ejecución, memoria y detecta bottlenecks
 *
 * @package WP_Debug
 * @since 1.0.0
 */

// Exit if accessed directly
if (!defined('ABSPATH')) {
    exit;
}

/**
 * WP_Debug_Profiler class
 */
class WP_Debug_Profiler {

    /**
     * Active timers
     *
     * @var array
     */
    private static $timers = array();

    /**
     * Completed timers
     *
     * @var array
     */
    private static $completed_timers = array();

    /**
     * Memory snapshots
     *
     * @var array
     */
    private static $memory_snapshots = array();

    /**
     * Initialize profiler
     */
    public static function init() {
        // Start tracking on init
        add_action('init', array(__CLASS__, 'start_tracking'), 1);

        // Record metrics on shutdown
        add_action('shutdown', array(__CLASS__, 'record_metrics'), 999);

        // Track query execution
        add_filter('query', array(__CLASS__, 'track_query'));
    }

    /**
     * Start tracking
     */
    public static function start_tracking() {
        self::$memory_snapshots['init'] = memory_get_usage();

        // Log page load start
        if (class_exists('WP_Debug_Logger')) {
            WP_Debug_Logger::debug('Page load started', array(
                'url' => isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : '',
                'memory' => self::format_bytes(memory_get_usage()),
            ));
        }
    }

    /**
     * Start a timer
     *
     * @param string $name Timer name
     * @return bool True on success
     */
    public static function start_timer($name) {
        self::$timers[$name] = array(
            'start' => microtime(true),
            'memory_start' => memory_get_usage(),
        );

        return true;
    }

    /**
     * End a timer
     *
     * @param string $name Timer name
     * @return float|bool Elapsed time in seconds, or false
     */
    public static function end_timer($name) {
        if (!isset(self::$timers[$name])) {
            return false;
        }

        $end_time = microtime(true);
        $memory_end = memory_get_usage();

        $elapsed = $end_time - self::$timers[$name]['start'];
        $memory_used = $memory_end - self::$timers[$name]['memory_start'];

        self::$completed_timers[$name] = array(
            'elapsed' => $elapsed,
            'memory_used' => $memory_used,
            'memory_peak' => memory_get_peak_usage(),
        );

        // Log if exceeds threshold
        $threshold = get_option('wp_debug_profiler_threshold', 1000); // milliseconds
        if ($elapsed * 1000 > $threshold) {
            if (class_exists('WP_Debug_Logger')) {
                WP_Debug_Logger::warning("Slow execution: {$name}", array(
                    'elapsed_ms' => round($elapsed * 1000, 2),
                    'memory' => self::format_bytes($memory_used),
                ));
            }
        }

        unset(self::$timers[$name]);

        return $elapsed;
    }

    /**
     * Get completed timers
     *
     * @return array Timers
     */
    public static function get_timers() {
        return self::$completed_timers;
    }

    /**
     * Track query execution
     *
     * @param string $query SQL query
     * @return string Query
     */
    public static function track_query($query) {
        // This will be used by query analyzer
        return $query;
    }

    /**
     * Record metrics on shutdown
     */
    public static function record_metrics() {
        // Calculate total execution time
        $total_time = timer_stop(0, 3);

        // Get memory stats
        $memory_current = memory_get_usage();
        $memory_peak = memory_get_peak_usage();

        // Get server load if available
        $server_load = self::get_server_load();

        // Prepare metrics
        $metrics = array(
            'execution_time' => $total_time,
            'memory_current' => $memory_current,
            'memory_peak' => $memory_peak,
            'server_load' => $server_load,
            'timers' => self::$completed_timers,
            'url' => isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : '',
            'timestamp' => current_time('mysql'),
        );

        // Log metrics
        if (class_exists('WP_Debug_Logger')) {
            WP_Debug_Logger::info('Page load completed', array(
                'time' => round($total_time, 3) . 's',
                'memory_peak' => self::format_bytes($memory_peak),
                'timers_count' => count(self::$completed_timers),
            ));
        }

        // Store metrics in transient for frontend panel
        set_transient('wp_debug_last_metrics', $metrics, 3600);
    }

    /**
     * Get server load
     *
     * @return string|null Server load
     */
    private static function get_server_load() {
        if (function_exists('sys_getloadavg')) {
            $load = sys_getloadavg();
            return implode(', ', array_map(function($val) {
                return round($val, 2);
            }, $load));
        }

        return null;
    }

    /**
     * Format bytes to human readable
     *
     * @param int $bytes Bytes
     * @return string Formatted string
     */
    public static function format_bytes($bytes) {
        $units = array('B', 'KB', 'MB', 'GB');
        $bytes = max($bytes, 0);
        $pow = floor(($bytes ? log($bytes) : 0) / log(1024));
        $pow = min($pow, count($units) - 1);

        $bytes /= (1 << (10 * $pow));

        return round($bytes, 2) . ' ' . $units[$pow];
    }

    /**
     * Get performance report
     *
     * @return array Performance report
     */
    public static function get_performance_report() {
        $metrics = get_transient('wp_debug_last_metrics');

        if (!$metrics) {
            return array(
                'error' => 'No metrics available',
            );
        }

        // Analyze and provide suggestions
        $suggestions = array();

        // Check execution time
        if ($metrics['execution_time'] > 3) {
            $suggestions[] = 'Page load time exceeds 3 seconds. Consider caching or optimizing queries.';
        }

        // Check memory
        if ($metrics['memory_peak'] > 128 * 1024 * 1024) { // 128MB
            $suggestions[] = 'Memory usage is high (' . self::format_bytes($metrics['memory_peak']) . '). Check for memory leaks.';
        }

        // Check slow timers
        $slow_timers = array();
        foreach ($metrics['timers'] as $name => $timer) {
            if ($timer['elapsed'] > 1) {
                $slow_timers[$name] = round($timer['elapsed'], 3) . 's';
            }
        }

        if (!empty($slow_timers)) {
            $suggestions[] = 'Slow functions detected: ' . implode(', ', array_keys($slow_timers));
        }

        return array(
            'metrics' => $metrics,
            'suggestions' => $suggestions,
            'formatted' => array(
                'execution_time' => round($metrics['execution_time'], 3) . 's',
                'memory_current' => self::format_bytes($metrics['memory_current']),
                'memory_peak' => self::format_bytes($metrics['memory_peak']),
                'server_load' => $metrics['server_load'],
            ),
        );
    }
}