<?php
/**
 * Cron Scheduling and Email Reporting for ErrorWatcher.
 *
 * @package ErrorWatcher
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

class ErrorWatcher_Cron {

	/**
	 * Single instance.
	 *
	 * @var ErrorWatcher_Cron|null
	 */
	private static $instance = null;

	/**
	 * Get singleton instance.
	 *
	 * @return ErrorWatcher_Cron
	 */
	public static function get_instance(): ErrorWatcher_Cron {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	/**
	 * Constructor.
	 */
	private function __construct() {
		// Hook scheduled cron actions.
		add_action( 'errorwatcher_morning_report', array( $this, 'send_morning_report' ) );
		add_action( 'errorwatcher_evening_report', array( $this, 'send_evening_report' ) );
		add_action( 'errorwatcher_cleanup_logs', array( $this, 'run_log_cleanup' ) );
	}

	/**
	 * Schedule all cron events.
	 *
	 * @return void
	 */
	public function schedule_events(): void {
		$options = get_option( 'errorwatcher_settings', array() );

		// Schedule daily log cleanup.
		if ( ! wp_next_scheduled( 'errorwatcher_cleanup_logs' ) ) {
			wp_schedule_event( time() + HOUR_IN_SECONDS, 'daily', 'errorwatcher_cleanup_logs' );
		}

		// If email reports are disabled, don't schedule them.
		if ( empty( $options['email_reports_enabled'] ) ) {
			$this->clear_report_events();
			return;
		}

		$morning_time = ! empty( $options['morning_time'] ) ? $options['morning_time'] : '08:00';
		$evening_time = ! empty( $options['evening_time'] ) ? $options['evening_time'] : '20:00';

		$morning_timestamp = $this->calculate_next_timestamp( $morning_time );
		$evening_timestamp = $this->calculate_next_timestamp( $evening_time );

		if ( ! wp_next_scheduled( 'errorwatcher_morning_report' ) ) {
			wp_schedule_event( $morning_timestamp, 'daily', 'errorwatcher_morning_report' );
		}

		if ( ! wp_next_scheduled( 'errorwatcher_evening_report' ) ) {
			wp_schedule_event( $evening_timestamp, 'daily', 'errorwatcher_evening_report' );
		}
	}

	/**
	 * Reschedule cron events (called after settings update).
	 *
	 * @return void
	 */
	public function reschedule_events(): void {
		$this->clear_report_events();
		$this->schedule_events();
	}

	/**
	 * Clear scheduled report hooks.
	 *
	 * @return void
	 */
	public function clear_report_events(): void {
		wp_clear_scheduled_hook( 'errorwatcher_morning_report' );
		wp_clear_scheduled_hook( 'errorwatcher_evening_report' );
	}

	/**
	 * Clear all plugin scheduled cron hooks (on deactivation).
	 *
	 * @return void
	 */
	public function clear_all_events(): void {
		$this->clear_report_events();
		wp_clear_scheduled_hook( 'errorwatcher_cleanup_logs' );
	}

	/**
	 * Calculate the next UNIX timestamp for a given time string (HH:MM) in site timezone.
	 *
	 * @param string $time_str Time in 'HH:MM' 24-hour format.
	 * @return int Next UNIX timestamp.
	 */
	private function calculate_next_timestamp( string $time_str ): int {
		$parts   = explode( ':', $time_str );
		$hours   = isset( $parts[0] ) ? (int) $parts[0] : 8;
		$minutes = isset( $parts[1] ) ? (int) $parts[1] : 0;

		$timezone = wp_timezone();
		$now      = new \DateTime( 'now', $timezone );

		$target = clone $now;
		$target->setTime( $hours, $minutes, 0 );

		// If time for today has already passed, schedule for tomorrow.
		if ( $target->getTimestamp() <= $now->getTimestamp() ) {
			$target->modify( '+1 day' );
		}

		return $target->getTimestamp();
	}

	/**
	 * Send morning email report.
	 *
	 * @return void
	 */
	public function send_morning_report( bool $force = false ): bool {
		return $this->dispatch_report( '', __( 'Morning Error Digest', 'errorwatcher' ), $force );
	}

	/**
	 * Send evening email report.
	 *
	 * @param bool $force Force dispatch even if reports toggle is off.
	 * @return bool
	 */
	public function send_evening_report( bool $force = false ): bool {
		return $this->dispatch_report( '', __( 'Evening Error Digest', 'errorwatcher' ), $force );
	}

	/**
	 * Dispatch email report with statistics and attached .txt log.
	 *
	 * @param string $since_datetime MySQL datetime string.
	 * @param string $report_label
	 * @param bool   $force Force dispatch.
	 * @return bool
	 */
	public function dispatch_report( string $since_datetime, string $report_label, bool $force = false ): bool {
		$options = get_option( 'errorwatcher_settings', array() );

		if ( ! $force && empty( $options['email_reports_enabled'] ) ) {
			return false;
		}

		$to_email_setting = ! empty( $options['notification_email'] ) ? $options['notification_email'] : get_option( 'admin_email' );
		$recipients       = array();
		if ( is_string( $to_email_setting ) ) {
			foreach ( explode( ',', $to_email_setting ) as $single ) {
				$cleaned = sanitize_email( trim( $single ) );
				if ( is_email( $cleaned ) ) {
					$recipients[] = $cleaned;
				}
			}
		}

		if ( empty( $recipients ) ) {
			$admin_email = get_option( 'admin_email' );
			if ( is_email( $admin_email ) ) {
				$recipients[] = $admin_email;
			}
		}

		if ( empty( $recipients ) ) {
			return false;
		}

		$db    = ErrorWatcher_DB::get_instance();
		$stats = $db->get_statistics( $since_datetime );
		$logs  = $db->get_logs_since( $since_datetime, 1000 );

		// If no errors were logged during this period, send a light summary or full report.
		$site_name   = get_bloginfo( 'name' );
		$site_url    = site_url();
		$time_format = get_option( 'date_format' ) . ' ' . get_option( 'time_format' );
		$period_to   = wp_date( $time_format, current_time( 'timestamp' ) );

		if ( ! empty( $since_datetime ) ) {
			$period_from = wp_date( $time_format, strtotime( $since_datetime ) );
		} else {
			$period_from = __( 'All Active Errors', 'errorwatcher' );
		}

		$subject = sprintf( '[%s] %s: %d Total Issues', $site_name, $report_label, $stats['total'] );

		// Create temporary .txt log file for attachment.
		$attachment_path = $this->generate_txt_attachment( $logs, $report_label, $period_from, $period_to );

		// Build HTML message.
		$message = $this->render_email_template( array(
			'site_name'    => $site_name,
			'site_url'     => $site_url,
			'report_label' => $report_label,
			'period_from'  => $period_from,
			'period_to'    => $period_to,
			'stats'        => $stats,
			'logs_count'   => count( $logs ),
			'logs'         => array_slice( $logs, 0, 15 ), // Preview first 15 logs
		) );

		$headers = array(
			'Content-Type: text/html; charset=UTF-8',
			sprintf( 'From: %s <%s>', esc_html( $site_name ), get_option( 'admin_email' ) ),
		);

		$attachments = array();
		if ( $attachment_path && file_exists( $attachment_path ) ) {
			$attachments[] = $attachment_path;
		}

		$sent = wp_mail( $recipients, $subject, $message, $headers, $attachments );

		// Clean up temporary attachment file immediately.
		if ( $attachment_path && file_exists( $attachment_path ) ) {
			wp_delete_file( $attachment_path );
		}

		return (bool) $sent;
	}

	/**
	 * Send test email report.
	 *
	 * @param string $recipient Optional custom recipient.
	 * @return array { success: bool, message: string }
	 */
	public function send_test_email( string $recipient = '' ): array {
		$options = get_option( 'errorwatcher_settings', array() );

		if ( empty( $recipient ) ) {
			$recipient = ! empty( $options['notification_email'] ) ? $options['notification_email'] : get_option( 'admin_email' );
		}

		$recipients = array();
		if ( is_string( $recipient ) ) {
			foreach ( explode( ',', $recipient ) as $single ) {
				$cleaned = sanitize_email( trim( $single ) );
				if ( is_email( $cleaned ) ) {
					$recipients[] = $cleaned;
				}
			}
		}

		if ( empty( $recipients ) ) {
			return array(
				'success' => false,
				'message' => __( 'Invalid recipient email address.', 'errorwatcher' ),
			);
		}

		$db    = ErrorWatcher_DB::get_instance();
		$stats = $db->get_statistics();
		$logs  = $db->get_logs( array( 'per_page' => 10 ) )['items'];

		$site_name   = get_bloginfo( 'name' );
		$time_format = get_option( 'date_format' ) . ' ' . get_option( 'time_format' );
		$period_to   = wp_date( $time_format, current_time( 'timestamp' ) );

		$subject = sprintf( '[%s] Test Email Report - ErrorWatcher', $site_name );

		$attachment_path = $this->generate_txt_attachment( $logs, 'Test Report', 'All Time', $period_to );

		$message = $this->render_email_template( array(
			'site_name'    => $site_name,
			'site_url'     => site_url(),
			'report_label' => __( 'Test Email Report', 'errorwatcher' ),
			'period_from'  => __( 'Test Period', 'errorwatcher' ),
			'period_to'    => $period_to,
			'stats'        => $stats,
			'logs_count'   => count( $logs ),
			'logs'         => $logs,
			'is_test'      => true,
		) );

		$headers = array(
			'Content-Type: text/html; charset=UTF-8',
			sprintf( 'From: %s <%s>', esc_html( $site_name ), get_option( 'admin_email' ) ),
		);

		$attachments = array();
		if ( $attachment_path && file_exists( $attachment_path ) ) {
			$attachments[] = $attachment_path;
		}

		$sent = wp_mail( $recipients, $subject, $message, $headers, $attachments );

		if ( $attachment_path && file_exists( $attachment_path ) ) {
			wp_delete_file( $attachment_path );
		}

		if ( $sent ) {
			/* translators: %s: Recipient email address. */
			$message = sprintf( __( 'Test email sent successfully to %s!', 'errorwatcher' ), esc_html( $recipient ) );

			return array(
				'success' => true,
				'message' => $message,
			);
		}

		return array(
			'success' => false,
			'message' => __( 'Failed to send test email. Please verify your WordPress mail/SMTP configuration.', 'errorwatcher' ),
		);
	}

	/**
	 * Generate a secure temporary .txt attachment file.
	 *
	 * @param array  $logs
	 * @param string $label
	 * @param string $from
	 * @param string $to
	 * @return string|false Path to temporary file or false.
	 */
	private function generate_txt_attachment( array $logs, string $label, string $from, string $to ) {
		$upload_dir = wp_upload_dir();
		$temp_dir   = trailingslashit( $upload_dir['basedir'] ) . 'errorwatcher-temp';

		if ( ! file_exists( $temp_dir ) ) {
			wp_mkdir_p( $temp_dir );
			// Add an index.html and .htaccess to block direct access.
			@file_put_contents( $temp_dir . '/index.html', '' );
			@file_put_contents( $temp_dir . '/.htaccess', "Order Deny,Allow\nDeny from all" );
		}

		$filename = sprintf( 'error-logs-%s-%s.txt', sanitize_title( $label ), gmdate( 'Y-m-d-His' ) );
		$filepath = $temp_dir . '/' . $filename;

		$content  = "=======================================================\n";
		$content .= " ERRORWATCHER - " . strtoupper( $label ) . "\n";
		$content .= " Site: " . get_bloginfo( 'name' ) . " (" . site_url() . ")\n";
		$content .= " Period: {$from} to {$to}\n";
		$content .= " Total Records: " . count( $logs ) . "\n";
		$content .= " Generated At: " . current_time( 'mysql' ) . "\n";
		$content .= "=======================================================\n\n";

		if ( empty( $logs ) ) {
			$content .= "No error logs recorded for this reporting period.\n";
		} else {
			foreach ( $logs as $index => $log ) {
				$num      = $index + 1;
				$content .= "-------------------------------------------------------\n";
				$content .= "[#{$num}] {$log->error_type} (Severity: {$log->severity_code})\n";
				$content .= "Occurrences: " . ( $log->occurrences ?? 1 ) . "\n";
				$content .= "First Seen:  {$log->created_at}\n";
				$content .= "Last Seen:   " . ( $log->last_seen ?? $log->created_at ) . "\n";
				$content .= "File:        {$log->file}:{$log->line}\n";
				$content .= "Source:      " . ErrorWatcher_DB::detect_source( $log->file ) . "\n";
				$content .= "Request URL: " . ( $log->request_url ?: 'N/A' ) . " [{$log->http_method}]\n";
				$content .= "Message:     {$log->message}\n";

				if ( ! empty( $log->stack_trace ) ) {
					$content .= "Stack Trace:\n" . $log->stack_trace . "\n";
				}
				$content .= "\n";
			}
		}

		$written = @file_put_contents( $filepath, $content );
		return false !== $written ? $filepath : false;
	}

	/**
	 * Build HTML email template without inline style tags to comply with WordPress.org guidelines.
	 *
	 * @param array $data
	 * @return string HTML
	 */
	private function render_email_template( array $data ): string {
		$dashboard_url = admin_url( 'admin.php?page=errorwatcher' );

		ob_start();
		?>
		<!DOCTYPE html>
		<html>
		<head>
			<meta charset="utf-8">
			<meta name="viewport" content="width=device-width, initial-scale=1.0">
			<title><?php echo esc_html( $data['report_label'] ); ?></title>
		</head>
		<body style="font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif; background-color: #f0f2f5; margin: 0; padding: 20px; color: #2c3338;">
			<div style="max-width: 650px; margin: 0 auto; background: #ffffff; border-radius: 8px; overflow: hidden; box-shadow: 0 4px 12px rgba(0,0,0,0.05);">
				<div style="background: #1e293b; color: #ffffff; padding: 24px 30px; text-align: left;">
					<h1 style="margin: 0 0 6px 0; font-size: 20px; font-weight: 600; color: #ffffff;"><?php echo esc_html( $data['report_label'] ); ?></h1>
					<p style="margin: 0; font-size: 13px; color: #94a3b8;"><?php echo esc_html( $data['site_name'] ); ?> &bull; <?php echo esc_html( $data['period_from'] ); ?> &mdash; <?php echo esc_html( $data['period_to'] ); ?></p>
				</div>
				<div style="padding: 30px;">
					<?php if ( ! empty( $data['is_test'] ) ) : ?>
						<p style="background: #e0f2fe; color: #0369a1; padding: 10px 14px; border-radius: 6px; font-size: 13px; margin: 0 0 20px 0;">
							&check; <strong>Test Delivery Notice:</strong> This is a test email dispatched from your ErrorWatcher settings.
						</p>
					<?php endif; ?>

					<p style="margin-top: 0; font-size: 14px; line-height: 1.5;">Below is the error activity digest for <strong><?php echo esc_html( $data['site_name'] ); ?></strong>.</p>

					<table style="width: 100%; margin: 20px 0; border-collapse: separate; border-spacing: 8px;">
						<tr>
							<td style="width: 20%; padding: 14px 10px; background: #f8fafc; border: 1px solid #e2e8f0; border-radius: 6px; text-align: center;">
								<span style="font-size: 20px; font-weight: bold; margin-bottom: 4px; display: block; color: #dc2626;"><?php echo (int) ( $data['stats']['fatal'] ?? 0 ); ?></span>
								<span style="font-size: 11px; text-transform: uppercase; letter-spacing: 0.5px; color: #64748b;">Fatal</span>
							</td>
							<td style="width: 20%; padding: 14px 10px; background: #f8fafc; border: 1px solid #e2e8f0; border-radius: 6px; text-align: center;">
								<span style="font-size: 20px; font-weight: bold; margin-bottom: 4px; display: block; color: #ea580c;"><?php echo (int) ( $data['stats']['error'] ?? 0 ); ?></span>
								<span style="font-size: 11px; text-transform: uppercase; letter-spacing: 0.5px; color: #64748b;">Errors</span>
							</td>
							<td style="width: 20%; padding: 14px 10px; background: #f8fafc; border: 1px solid #e2e8f0; border-radius: 6px; text-align: center;">
								<span style="font-size: 20px; font-weight: bold; margin-bottom: 4px; display: block; color: #d97706;"><?php echo (int) ( $data['stats']['warning'] ?? 0 ); ?></span>
								<span style="font-size: 11px; text-transform: uppercase; letter-spacing: 0.5px; color: #64748b;">Warnings</span>
							</td>
							<td style="width: 20%; padding: 14px 10px; background: #f8fafc; border: 1px solid #e2e8f0; border-radius: 6px; text-align: center;">
								<span style="font-size: 20px; font-weight: bold; margin-bottom: 4px; display: block; color: #2563eb;"><?php echo (int) ( $data['stats']['notice'] ?? 0 ); ?></span>
								<span style="font-size: 11px; text-transform: uppercase; letter-spacing: 0.5px; color: #64748b;">Notices</span>
							</td>
							<td style="width: 20%; padding: 14px 10px; background: #f8fafc; border: 1px solid #e2e8f0; border-radius: 6px; text-align: center;">
								<span style="font-size: 20px; font-weight: bold; margin-bottom: 4px; display: block; color: #7c3aed;"><?php echo (int) ( $data['stats']['deprecated'] ?? 0 ); ?></span>
								<span style="font-size: 11px; text-transform: uppercase; letter-spacing: 0.5px; color: #64748b;">Deprecated</span>
							</td>
						</tr>
					</table>

					<div style="margin-top: 25px;">
						<h3 style="font-size: 15px; margin-bottom: 12px; color: #1e293b;">Recent Log Highlights</h3>
						<?php if ( empty( $data['logs'] ) ) : ?>
							<p style="color: #64748b; font-style: italic; font-size: 13px;">No errors recorded during this timeframe. Your site is running smoothly!</p>
						<?php else : ?>
							<?php foreach ( $data['logs'] as $log ) :
								$border_color = '#94a3b8';
								$low_type     = strtolower( $log->error_type );
								if ( false !== strpos( $low_type, 'fatal' ) ) {
									$border_color = '#dc2626';
								} elseif ( false !== strpos( $low_type, 'warning' ) ) {
									$border_color = '#d97706';
								} elseif ( false !== strpos( $low_type, 'notice' ) ) {
									$border_color = '#2563eb';
								} elseif ( false !== strpos( $low_type, 'deprecated' ) ) {
									$border_color = '#7c3aed';
								}
							?>
								<div style="background: #f8fafc; border-left: 4px solid <?php echo esc_attr( $border_color ); ?>; border-radius: 0 4px 4px 0; padding: 12px 16px; margin-bottom: 12px; font-size: 13px;">
									<div style="font-weight: 600; display: inline-block; margin-bottom: 4px;"><?php echo esc_html( $log->error_type ); ?></div>
									<div style="color: #1e293b; font-family: monospace, Courier, monospace; font-size: 12px; word-break: break-all; margin: 4px 0;"><?php echo esc_html( wp_trim_words( $log->message, 25 ) ); ?></div>
									<div style="font-size: 11px; color: #64748b;">
										<?php echo esc_html( basename( $log->file ) ); ?>:<?php echo (int) $log->line; ?> &bull; <?php echo esc_html( $log->created_at ); ?>
									</div>
								</div>
							<?php endforeach; ?>
						<?php endif; ?>
					</div>

					<p style="margin-top: 20px; font-size: 13px; color: #64748b;">
						<em>A complete detailed log file (.txt) is attached to this email.</em>
					</p>

					<p style="text-align: center; margin-top: 30px;">
						<a href="<?php echo esc_url( $dashboard_url ); ?>" style="display: inline-block; background: #2563eb; color: #ffffff !important; text-decoration: none; padding: 10px 20px; border-radius: 6px; font-weight: 500; font-size: 14px;">Open ErrorWatcher Dashboard</a>
					</p>
				</div>
				<div style="background: #f8fafc; border-top: 1px solid #e2e8f0; padding: 16px 30px; font-size: 12px; color: #94a3b8; text-align: center;">
					<p style="margin: 0;">Sent by ErrorWatcher on <a href="<?php echo esc_url( $data['site_url'] ); ?>" style="color: #64748b;"><?php echo esc_html( $data['site_name'] ); ?></a></p>
				</div>
			</div>
		</body>
		</html>
		<?php
		return ob_get_clean();
	}

	/**
	 * Run log retention cleanup / prune resolved errors.
	 *
	 * @return void
	 */
	public function run_log_cleanup(): void {
		ErrorWatcher_DB::get_instance()->prune_resolved_errors();
	}
}