<?php
namespace JVBase\managers;

use JVBase\JVB;
use WP_Error;
use Exception;
use WP_REST_Request;

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

class ErrorHandler
{
    protected object $wpdb;
	protected string $tableName;
    protected int $notification_threshold = 5; // Critical errors within 1 hour

    protected array $error_levels = [
        'debug' => 0,
        'info' => 1,
        'warning' => 2,
        'error' => 3,
        'critical' => 4
    ];

	protected CustomTable $table;

    public function __construct()
    {
		$this->defineTables();
//        global $wpdb;
//        $this->wpdb = $wpdb;
//		$this->tableName = $wpdb->prefix . BASE . 'error_log';

        add_filter(BASE.'handle_bulk_operation', [$this, 'processOperation'], 10, 3);

        // Hook our send function to the cron event
        add_action('jvb_daily_error_summary', [$this, 'sendErrorSummary']);

        jvb_register_do_once('error_admin_action_registered', [$this, 'registerAdminAction']);
//        add_filter(BASE.'admin_action_filter', [$this, 'adminActionFilter'], 10, 3);
    }

	public function defineTables():void
	{
		$table = CustomTable::for('error_log');
		$table->setColumns([
			'id'			=> 'bigint(20) unsigned NOT NULL AUTO_INCREMENT',
			'error_type'	=> 'varchar(50) NOT NULL',
			'component'		=> 'varchar(100) NOT NULL',
			'method'		=> 'varchar(100) DEFAULT NULL',
			'page_url'		=> 'varchar(255) DEFAULT NULL',
			'message'		=> 'text NOT NULL',
			'context'		=> 'JSON',
			'severity'		=> 'ENUM(\'high\',\'normal\',\'low\') DEFAULT \'normal\'',
			'user_id'		=> $table->getUserIDType().' DEFAULT NULL',
			'user_was_logged_in'	=> 'tinyint(1) NOT NULL',
			'source'		=> 'ENUM(\'frontend\', \'backend\') NOT NULL',
			'created_at'	=> 'timestamp DEFAULT CURRENT_TIMESTAMP',
		]);

		$table->setKeys([
			['key' => 'PRIMARY', 'value' => 'id'],
			'`created_at` (`created_at`)',
			'`component_severity_date` (`component`, `severity`, `created_at`)',
			'`error_type_date` (`error_type`, `created_at`)',
			'`severity_date` (`severity`, `created_at`)'
		]);

		$table->defineTable();
		$this->table = $table;
	}
    public function registerAdminAction():void
    {
        $admin = JVB()->admin();

        $admin->registerSubpage(
            'Error Log',
            'Errors',
            'manage_options',
            'jvb-error-log',
            [$this, 'renderAdminPage'],
        );
    }

    /**
     * Process error log operations queued through OperationQueue
     *
     * @param WP_Error|array $result The result we are filtering
     * @param object $operation The operation information
     * @param array $data The current chunk of data to process
     *
     * @return WP_Error|array Either the unfiltered WP_Error, or the result of the operation
     */
    public function processOperation(WP_Error|array $result, object $operation, array $data):WP_Error|array
    {
        if ($operation->type !== 'error_log') {
            return $result;
        }

        try {
            $table = $this->tableName;
            // Extract error data
            $component = sanitize_text_field($data['component'] ?? '');
            $message = sanitize_textarea_field($data['message'] ?? '');
            $context = $data['context'] ?? [];
            $severity = sanitize_text_field($data['severity'] ?? 'error');

            // Validate severity level
            if (!array_key_exists($severity, $this->error_levels)) {
                $severity = 'error'; // Default to error if invalid severity provided
            }

            // Determine error type from context or use component as fallback
            $error_type = sanitize_text_field($context['error_type'] ?? $component);

            // Store context as JSON
            $context_json = json_encode($context);
            if (json_last_error() !== JSON_ERROR_NONE) {
                // If JSON encoding fails, store only basic info
                $context_json = json_encode([
                    'error' => 'Failed to encode original context',
                    'json_error' => json_last_error_msg()
                ]);
            }

            // Insert into database
            $result = $this->wpdb->insert(
                $table,
                [
                    'error_type' => $error_type,
                    'component' => $component,
                    'message' => $message,
                    'context' => $context_json,
                    'severity' => $severity,
                    'user_id' => get_current_user_id(),
                    'created_at' => current_time('mysql')
                ],
                [
                    '%s', // error_type
                    '%s', // component
                    '%s', // message
                    '%s', // context (JSON)
                    '%s', // severity
                    '%d', // user_id
                    '%s'  // created_at
                ]
            );

            if ($result === false) {
                // If insert fails, log to PHP error log as fallback
                error_log("[ErrorHandler] Database insert failed: " . $this->wpdb->last_error);
                return [
					'success'	=> false,
					'message'	=> "[ErrorHandler] Database insert failed: " . $this->wpdb->last_error
				];
            }

            // Potentially track error metrics or trigger additional actions for critical errors
            if ($severity === 'critical') {
                $this->checkErrorThreshold($error_type, $component);
            }

            return [
                'success' => true,
                'result'	=> $result
            ];

        } catch (Exception $e) {
            // Fallback to PHP error log if our error handler itself fails
            error_log("[ErrorHandler Exception] " . $e->getMessage());
            return [
				'success'	=> false,
				'message'	=> $e->getMessage()
			];
        }
    }

    /**
     * Check if error threshold has been reached for a specific error type/component
     * and take additional actions if needed
     *
     * @param string $error_type The type of error
     * @param string $component The component where the error occurred
     */
    protected function checkErrorThreshold(string $error_type, string $component)
    {
        // Get count of similar critical errors in the last hour
        $count = $this->wpdb->get_var($this->wpdb->prepare(
            "SELECT COUNT(*)
         FROM {$this->tableName}
         WHERE error_type = %s
         AND component = %s
         AND severity = 'critical'
         AND created_at > DATE_SUB(NOW(), INTERVAL 1 HOUR)",
            $error_type,
            $component
        ));

        // If threshold reached, take additional actions (e.g., notify developers)
        if ((int)$count >= $this->notification_threshold) {
            // You could send an urgent notification, Slack message, etc.
            $admin_email = get_option('admin_email');
            $subject = "[URGENT] Error Threshold Exceeded for {$component}";
            $message = "The error '{$error_type}' in component '{$component}' has occurred {$count} times in the last hour.";

            wp_mail($admin_email, $subject, $message);
        }
    }


    /**
     * @param string $component Where the error is being logged from
     * @param string $message The error message, usually extracted from $e->getMessage())
     * @param array $context Additional context (i.e: data that was attempted to be acted on)
     * @param string $severity
     *
     * @return bool Whether it gets logged successfully
     */
	public function log(string $component, string $message, array $context = [], string $severity = 'error'): array
	{
		try {
			$table = $this->wpdb->prefix . BASE . 'error_log';

			// Validate severity
			if (!array_key_exists($severity, $this->error_levels)) {
				$severity = 'error';
			}

			// Extract info
			$error_type = sanitize_text_field($context['error_type'] ?? $component);
			$method = isset($context['method']) ? sanitize_text_field($context['method']) : null;
			$page_url = isset($context['url']) ? esc_url_raw($context['url']) : null;
			$user_id = get_current_user_id();
			$user_was_logged_in = $user_id > 0 || (!empty($context['isLoggedIn']));

			// Determine source from context
			$source = isset($context['source']) ? $context['source'] :
				(isset($context['url']) ? 'frontend' : 'backend');

			$result = $this->wpdb->insert(
				$table,
				[
					'error_type' => $error_type,
					'component' => $component,
					'method' => $method,
					'page_url' => $page_url,
					'message' => sanitize_textarea_field($message),
					'context' => json_encode($context),
					'severity' => $severity,
					'user_id' => $user_id ?: null,
					'user_was_logged_in' => $user_was_logged_in ? 1 : 0,
					'source' => $source,
					'created_at' => current_time('mysql')
				],
				['%s', '%s', '%s', '%s', '%s', '%s', '%s', '%d', '%d', '%s', '%s']
			);

			if ($result === false) {
				error_log("[ErrorHandler] Database insert failed: " . $this->wpdb->last_error);
				return ['success' => false, 'message' => $this->wpdb->last_error];
			}

			if ($severity === 'critical') {
				$this->checkErrorThreshold($error_type, $component);
			}

			return ['success' => true, 'id' => $this->wpdb->insert_id];

		} catch (Exception $e) {
			error_log("[ErrorHandler Exception] " . $e->getMessage());
			return ['success' => false, 'message' => $e->getMessage()];
		}
	}

    /**
     * @param string $component What class or function logs the error
     * @param string $message Details on the error
     * @param array $context additional context of the data that was being processed
     *
     * @return bool Whether the notification is sent successfully
     */
	protected function notifyAdmin(string $component, string $message, array $context):bool
	{
		$admin_email = get_option('admin_email');
		$subject = "[" . get_bloginfo('name') . " Critical Error] {$component}";

		$body = JVB()->email()->alert(
			'A critical error has occurred and requires immediate attention',
			'error'
		);

		$body .= JVB()->email()->h2('Error Details');
		$body .= JVB()->email()->card(
			'<p><strong>Component:</strong> ' . esc_html($component) . '</p>' .
			'<p><strong>Message:</strong></p>' .
			JVB()->email()->codeBlock($message),
			'Error Information'
		);

		if (!empty($context)) {
			$body .= JVB()->email()->h3('Additional Context');
			$body .= JVB()->email()->codeBlock(json_encode($context, JSON_PRETTY_PRINT));
		}

		return JVB()->email()->sendEmail($admin_email, $subject, $body, 'CRITICAL ERROR');
	}

    /**
     * Gather summary of the most important errors
	 * @param ?string $start_date Defaults to today
	 * @param ?string $end_date Defaults to today
     * @return array
     */
	public function gatherErrorSummary(?string $start_date = null, ?string $end_date = null): array
	{
		$table = $this->wpdb->prefix . BASE . 'error_log';

		if (!$start_date) {
			$start_date = gmdate('Y-m-d 00:00:00', strtotime('-1 day'));
		}
		if (!$end_date) {
			$end_date = gmdate('Y-m-d 23:59:59');
		}

		// Most frequent error patterns (deduplicated by component/method/message)
		$frequent = $this->wpdb->get_results($this->wpdb->prepare(
			"SELECT
            component,
            method,
            error_type,
            message,
            severity,
            source,
            COUNT(*) as count,
            SUM(CASE WHEN user_was_logged_in = 1 THEN 1 ELSE 0 END) as logged_in_count,
            SUM(CASE WHEN user_was_logged_in = 0 THEN 1 ELSE 0 END) as logged_out_count,
            MIN(created_at) as first_seen,
            MAX(created_at) as last_seen
         FROM {$table}
         WHERE created_at BETWEEN %s AND %s
         GROUP BY component, method, error_type, message, severity, source
         ORDER BY count DESC, severity DESC
         LIMIT 10",
			$start_date,
			$end_date
		));

		// Critical errors
		$critical = $this->wpdb->get_results($this->wpdb->prepare(
			"SELECT
            component,
            method,
            error_type,
            message,
            source,
            COUNT(*) as count,
            SUM(CASE WHEN user_was_logged_in = 1 THEN 1 ELSE 0 END) as logged_in_count,
            SUM(CASE WHEN user_was_logged_in = 0 THEN 1 ELSE 0 END) as logged_out_count,
            MIN(created_at) as first_seen,
            MAX(created_at) as last_seen
         FROM {$table}
         WHERE created_at BETWEEN %s AND %s AND severity = 'critical'
         GROUP BY component, method, error_type, message, source
         ORDER BY count DESC
         LIMIT 5",
			$start_date,
			$end_date
		));

		// Overall stats
		$stats = $this->wpdb->get_row($this->wpdb->prepare(
			"SELECT
            COUNT(*) as total_errors,
            COUNT(DISTINCT CONCAT(component, '-', COALESCE(method, ''), '-', error_type)) as unique_error_types,
            SUM(CASE WHEN user_was_logged_in = 1 THEN 1 ELSE 0 END) as logged_in_errors,
            SUM(CASE WHEN user_was_logged_in = 0 THEN 1 ELSE 0 END) as logged_out_errors,
            SUM(CASE WHEN source = 'frontend' THEN 1 ELSE 0 END) as frontend_errors,
            SUM(CASE WHEN source = 'backend' THEN 1 ELSE 0 END) as backend_errors,
            SUM(CASE WHEN severity = 'critical' THEN 1 ELSE 0 END) as critical_count,
            SUM(CASE WHEN severity = 'error' THEN 1 ELSE 0 END) as error_count,
            SUM(CASE WHEN severity = 'warning' THEN 1 ELSE 0 END) as warning_count
         FROM {$table}
         WHERE created_at BETWEEN %s AND %s",
			$start_date,
			$end_date
		));

		return [
			'frequent' => $frequent,
			'critical' => $critical,
			'stats' => $stats,
			'date_range' => ['start' => $start_date, 'end' => $end_date]
		];
	}

    /**
     * Send daily error summary email to administrator
     * @return bool Whether email is sent
     */
	public function sendErrorSummary():bool
	{
		$summary = $this->gatherErrorSummary();

		if (empty($summary['frequent']) && empty($summary['critical'])) {
			return false;
		}

		$admin_email = get_option('admin_email');
		$site_name = get_bloginfo('name');
		$yesterday = date('Y-m-d', strtotime('-1 day'));
		$subject = "[{$site_name}] Daily Error Summary - " . date('Y-m-d');

		// Header with alert
		$body = JVB()->email()->h1('Daily Error Summary');
		$body .= sprintf('<p>Error summary for <strong>%s</strong></p>', $yesterday);

		// Summary stats in a grid
		if (!empty($summary['stats'])) {
			$stats = [
				JVB()->email()->stat($summary['stats']->total_errors, 'Total Errors'),
				JVB()->email()->stat($summary['stats']->critical_count, 'Critical', 'Requires attention'),
				JVB()->email()->stat($summary['stats']->error_count, 'Errors'),
				JVB()->email()->stat($summary['stats']->warning_count, 'Warnings')
			];
			$body .= JVB()->email()->grid($stats, 4);
		}

		// Alert if critical errors exist
		if (!empty($summary['critical'])) {
			$body .= JVB()->email()->alert(
				sprintf('Found %d critical errors that need immediate attention', count($summary['critical'])),
				'error'
			);
		}

		$body .= JVB()->email()->spacer(20);

		// Frequent errors section
		if (!empty($summary['frequent'])) {
			$body .= JVB()->email()->h2('Most Frequent Errors');

			foreach ($summary['frequent'] as $error) {
				$cardContent = JVB()->email()->badge($error->count . 'x', 'warning') . ' ';
				$cardContent .= '<strong>' . esc_html($error->error_type) . '</strong>';
				$cardContent .= '<p style="margin:10px 0 5px 0;font-size:13px;">' . esc_html(wp_trim_words($error->message, 15)) . '</p>';
				$cardContent .= '<p style="margin:0;font-size:12px;color:' . JVB()->email()->colours['dark-200'] . ';">
                Source: ' . esc_html($error->source) . ' |
                Logged in: ' . $error->logged_in_count . ' |
                Logged out: ' . $error->logged_out_count . '
            </p>';

				$body .= JVB()->email()->card($cardContent, $error->component);
			}
		}

		// Critical errors section
		if (!empty($summary['critical'])) {
			$body .= JVB()->email()->spacer(30);
			$body .= JVB()->email()->h2('Recent Critical Errors');

			foreach ($summary['critical'] as $error) {
				$cardContent = '<p><strong>Time:</strong> ' . esc_html($error->created_at) . '</p>';
				$cardContent .= '<p><strong>Message:</strong></p>';
				$cardContent .= JVB()->email()->codeBlock($error->message);

				// Include context if available
				if (!empty($error->context)) {
					$context = json_decode($error->context, true);
					if (is_array($context)) {
						$cardContent .= '<p><strong>Context:</strong></p>';
						$cardContent .= JVB()->email()->codeBlock(json_encode($context, JSON_PRETTY_PRINT));
					}
				}

				$body .= JVB()->email()->card($cardContent, $error->component . ': ' . $error->error_type);
			}
		}

		// Dashboard link
		$admin_url = admin_url('admin.php?page=jvb-error-logs');
		$body .= JVB()->email()->spacer(30);
		$body .= JVB()->email()->button($admin_url, 'View Detailed Logs');

		return JVB()->email()->sendEmail($admin_email, $subject, $body, 'ERROR SUMMARY');
	}

    /**
     * Get HTML version of the error summary for nicer emails
     *
     * @param array $summary The error summary data
     * @return string HTML formatted error summary
     */
    protected function getHtmlErrorSummary(array $summary):string
    {
        $html = '<div style="font-family: sans-serif; max-width: 800px; margin: 0 auto;">';
        $html .= '<h1 style="color:#FF0080;border-bottom:2px solid #1B1B1B;padding-bottom:10px;">Error Summary</h1>';

        // Frequent errors table
        if (!empty($summary['frequent'])) {
            $html .= '<h2>Most Frequent Errors</h2>';
            $html .= '<table style="width: 100%; border-collapse: collapse; margin-bottom: 20px;">';
            $html .= '<tr style="background-color: #1B1B1B; color: #EFEFEF;">';
            $html .= '<th style="padding: 8px; text-align: left; border: 1px solid #ddd;">Component</th>';
            $html .= '<th style="padding: 8px; text-align: left; border: 1px solid #ddd;">Error Type</th>';
            $html .= '<th style="padding: 8px; text-align: left; border: 1px solid #ddd;">Message</th>';
            $html .= '<th style="padding: 8px; text-align: center; border: 1px solid #ddd;">Count</th>';
            $html .= '</tr>';

            foreach ($summary['frequent'] as $error) {
                $html .= '<tr>';
                $html .= '<td style="padding:8px;border:1px solid #ddd;">' . esc_html($error->component) . '</td>';
                $html .= '<td style="padding:8px;border:1px solid #ddd;">' . esc_html($error->error_type) . '</td>';
                $html .= '<td style="padding:8px;border:1px solid #ddd;">' . esc_html(wp_trim_words($error->message, 10, '...')) . '</td>';
                $html .= '<td style="padding:8px;border:1px solid #ddd;text-align:center;"><strong>' . esc_html($error->count) . '</strong></td>';
                $html .= '</tr>';
            }

            $html .= '</table>';
        }

        // Critical errors section
        if (!empty($summary['critical'])) {
            $html .= '<h2>Recent Critical Errors</h2>';

            foreach ($summary['critical'] as $error) {
                $html .= '<div style="margin-bottom: 20px; padding: 15px; border-left: 4px solid #FF0080; background-color: #fff9fb;">';
                $html .= '<h3 style="margin-top: 0; color: #1B1B1B;">' . esc_html($error->component) . ': ' . esc_html($error->error_type) . '</h3>';
                $html .= '<p><strong>Time:</strong> ' . esc_html($error->created_at) . '</p>';
                $html .= '<p><strong>Message:</strong> ' . esc_html($error->message) . '</p>';

                // Context display
                if (!empty($error->context)) {
                    $context = json_decode($error->context, true);
                    if (is_array($context)) {
                        $html .= '<div style="margin-top: 10px;">';
                        $html .= '<strong>Context:</strong>';
                        $html .= '<pre style="background-color: #f5f5f5; padding: 10px; border-radius: 4px; overflow: auto; max-height: 200px;">';
                        $html .= esc_html(json_encode($context, JSON_PRETTY_PRINT));
                        $html .= '</pre>';
                        $html .= '</div>';
                    }
                }

                $html .= '</div>';
            }
        }

        // Dashboard link
        $admin_url = admin_url('admin.php?page=jvb-error-logs');
        $html .= '<p style="margin-top: 30px; padding-top: 15px; border-top: 1px solid #ddd;">';
        $html .= '<a href="' . esc_url($admin_url) . '" style="display: inline-block; background-color: #FF0080; color: white; padding: 10px 15px; text-decoration: none; border-radius: 4px;">View All Errors in Dashboard</a>';
        $html .= '</p>';

        $html .= '</div>';

        return $html;
    }

    public function renderAdminPage()
    {
        ?>
        <h1>Error Logs</h1>
        <?php
    }

    public function getErrors(WP_REST_Request $request) {
        $params = $this->buildParams($request);

    }


    protected function buildParams(WP_REST_Request $request):array {
        $allowedSeverity = [
            'all',
            'notice',
            'warning',
            'error',
            'critical',
        ];
        $allowedComponents = [
            'all',
            //Get all components
        ];
        $severity = $request->get_param('severity')??'all';
        $component = $request->get_param('component')??'all';

        return [
            'page'  => (int)$request->get_param('page'),
            'severity'  => (in_array($severity, $allowedSeverity)) ? $severity : 'all',
            'component' => (in_array($component, $allowedComponents)) ? $component : 'all',
        ];
    }
}