<?php
/**
 * Ads.txt Slot
 *
 * @package    AdX-Ad-Inserter
 * @subpackage Views/Slots
 */

defined( 'ABSPATH' ) || exit;

/**
 * Register /ads.txt rewrite → index.php?adxbyms_ads_txt=1.
 * (Called on init, and also from activation hook in the main file before flushing).
 *
 * @return void
 */
function adxbyms_register_ads_txt_rewrite(): void {
	add_rewrite_rule( '^ads\.txt$', 'index.php?adxbyms_ads_txt=1', 'top' );
}
add_action( 'init', 'adxbyms_register_ads_txt_rewrite' );

/** Allow our query var. */
add_filter(
	'query_vars',
	function ( $vars ) {
		$vars[] = 'adxbyms_ads_txt';
		return $vars;
	}
);

/**
 * Truthy helper function.
 *
 * @param mixed $v The value to check.
 * @return bool True if value is truthy.
 */
if ( ! function_exists( 'adxbyms_truthy' ) ) {
	function adxbyms_truthy( $v ): bool {
		if ( is_bool( $v ) ) {
			return $v;
		}
		if ( is_int( $v ) ) {
			return 1 === $v;
		}
		$v = is_string( $v ) ? strtolower( trim( $v ) ) : $v;
		return in_array( $v, array( '1', 'true', 'on', 'yes' ), true );
	}
}

add_action(
	'template_redirect',
	function () {
		if ( is_admin() ) {
			return;
		}

		// 1. Redirect /index.php/ads.txt to /ads.txt
		$request_uri_raw = filter_input( INPUT_SERVER, 'REQUEST_URI', FILTER_SANITIZE_URL );
		if ( false === $request_uri_raw ) {
			$request_uri_raw = '';
		}
		$request_uri = sanitize_text_field( wp_unslash( $request_uri_raw ) );
		$path        = strtolower( strtok( $request_uri, '?' ) );
		if ( '/index.php/ads.txt' === $path ) {
			wp_safe_redirect( home_url( '/ads.txt' ), 301 );
			exit;
		}

		// 2. Redirect /ads.txt/ to /ads.txt.
		if ( '/ads.txt/' === $path ) {
			wp_safe_redirect( home_url( '/ads.txt' ), 301 );
			exit;
		}

		// Original logic for serving ads.txt.
		$is_ads_rewrite = get_query_var( 'adxbyms_ads_txt' );
		$is_index_ads   = ( '/index.php/ads.txt' === $path );
		if ( ! $is_ads_rewrite && ! $is_index_ads ) {
			return;
		}

		$enabled = get_option( 'adxbyms_ads_txt_enabled', '' );
		$code    = (string) get_option( 'adxbyms_ads_txt_code', '' );
		if ( ! adxbyms_truthy( $enabled ) || '' === trim( $code ) ) {
			return;
		}

		// Clean any existing output buffers before serving ads.txt.
		// This ensures clean output without interfering with WordPress core buffers.
		// We explicitly close buffers with proper checks to follow WordPress best practices.
		if ( function_exists( 'ob_get_level' ) ) {
			$ob_level = ob_get_level();

			// Safety check: ensure level is valid.
			if ( $ob_level < 0 ) {
				$ob_level = 0;
			}

			// Only clean buffers we might have started, not WordPress core buffers.
			// WordPress typically uses 1-2 levels for its own purposes.
			// We'll clean up to 3 levels to be safe, but not aggressively clean all.
			$max_clean_level = 3;
			$clean_attempts  = 0;
			$max_attempts    = 5; // Safety limit to prevent infinite loops.

			while ( $ob_level > 0 && $ob_level <= $max_clean_level && $clean_attempts < $max_attempts ) {
				// Check if buffer is still active before attempting to close.
				if ( ob_get_level() <= 0 ) {
					break;
				}

				// Get buffer contents to verify it's valid before closing.
				$buffer_content = ob_get_contents();
				if ( false === $buffer_content ) {
					// Invalid buffer, stop trying.
					break;
				}

				// Explicitly close the buffer with error suppression.
				// We suppress errors because we're checking validity first.
				@ob_end_clean(); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged

				// Check new level.
				$new_level = ob_get_level();

				// Safety check: if level didn't decrease or is invalid, we've hit a core buffer - stop.
				if ( $new_level >= $ob_level || $new_level < 0 ) {
					break;
				}

				$ob_level = $new_level;
				$clean_attempts++;
			}
		}
		nocache_headers();
		status_header( 200 );
		header( 'Content-Type: text/plain; charset=utf-8' );
		header( 'Cache-Control: no-store, no-cache, must-revalidate, max-age=0' );
		header( 'Pragma: no-cache' );
		header( 'Expires: 0' );
		// ads.txt is a plain text file. Escaping is not required and would break the format.
		echo rtrim( $code, "\r\n" ) . "\n"; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped

		exit;
	},
	0
);