<?php
namespace CacheShark;

defined( 'ABSPATH' ) || exit;

/**
 * Apache / LiteSpeed rules: GZIP compression and browser caching for static files.
 *
 * Every directive is wrapped in <IfModule>, so a server missing a module ignores
 * the rule instead of returning a 500 error. The block is clearly marked and is
 * the only part of .htaccess this plugin ever edits.
 */
class Htaccess {

	const BEGIN = '# BEGIN Cache Shark';
	const END   = '# END Cache Shark';

	public static function path(): string {
		return ABSPATH . '.htaccess';
	}

	/** True on Apache and LiteSpeed (WordPress sets $is_apache for both). */
	public static function is_supported(): bool {
		global $is_apache;
		return ! empty( $is_apache );
	}

	/** The marked block, ready to write. */
	public static function block(): string {
		$rules = array(
			self::BEGIN,
			'# Rules between BEGIN and END are generated by Cache Shark. Do not edit by hand.',
			'<IfModule mod_deflate.c>',
			'	AddOutputFilterByType DEFLATE text/html text/plain text/xml text/css text/javascript',
			'	AddOutputFilterByType DEFLATE application/javascript application/x-javascript application/json',
			'	AddOutputFilterByType DEFLATE application/xml application/xhtml+xml application/rss+xml application/atom+xml',
			'	AddOutputFilterByType DEFLATE image/svg+xml font/ttf font/otf application/vnd.ms-fontobject',
			'</IfModule>',
			'<IfModule mod_expires.c>',
			'	ExpiresActive On',
			'	ExpiresByType image/jpeg "access plus 1 year"',
			'	ExpiresByType image/png "access plus 1 year"',
			'	ExpiresByType image/gif "access plus 1 year"',
			'	ExpiresByType image/webp "access plus 1 year"',
			'	ExpiresByType image/avif "access plus 1 year"',
			'	ExpiresByType image/svg+xml "access plus 1 year"',
			'	ExpiresByType image/x-icon "access plus 1 year"',
			'	ExpiresByType font/woff2 "access plus 1 year"',
			'	ExpiresByType font/woff "access plus 1 year"',
			'	ExpiresByType font/ttf "access plus 1 year"',
			'	ExpiresByType font/otf "access plus 1 year"',
			'	ExpiresByType text/css "access plus 1 month"',
			'	ExpiresByType text/javascript "access plus 1 month"',
			'	ExpiresByType application/javascript "access plus 1 month"',
			'</IfModule>',
			self::END,
		);
		return implode( "\n", $rules ) . "\n";
	}

	/** Pure: return $src with our block (re)placed at the top. */
	public static function with_block( string $src, string $block ): string {
		$src = self::without_block( $src );
		return $block . ( '' === trim( $src ) ? '' : "\n" . $src );
	}

	/** Pure: return $src with our block removed. */
	public static function without_block( string $src ): string {
		$pattern = '/^' . preg_quote( self::BEGIN, '/' ) . '.*?^' . preg_quote( self::END, '/' ) . '[ \t]*\R?\R?/ms';
		return (string) preg_replace( $pattern, '', $src );
	}

	public static function insert(): bool {
		if ( ! self::is_supported() ) {
			return false;
		}
		$path = self::path();
		$src  = file_exists( $path ) ? (string) file_get_contents( $path ) : ''; // phpcs:ignore WordPress.WP.AlternativeFunctions
		return self::write( $path, self::with_block( $src, self::block() ) );
	}

	public static function remove(): bool {
		$path = self::path();
		if ( ! file_exists( $path ) ) {
			return true;
		}
		$src = (string) file_get_contents( $path ); // phpcs:ignore WordPress.WP.AlternativeFunctions
		if ( false === strpos( $src, self::BEGIN ) ) {
			return true;
		}
		$new = self::without_block( $src );
		if ( '' === trim( $new ) ) {
			return Fs::delete( $path ); // The file held only our block.
		}
		return self::write( $path, $new );
	}

	/** Atomic write that keeps the existing permissions. */
	private static function write( string $path, string $contents ): bool {
		$exists = file_exists( $path );
		if ( $exists ? ! is_writable( $path ) : ! is_writable( dirname( $path ) ) ) { // phpcs:ignore WordPress.WP.AlternativeFunctions
			return false;
		}
		if ( $exists && ! is_writable( dirname( $path ) ) ) { // phpcs:ignore WordPress.WP.AlternativeFunctions
			return false; // rename() needs a writable directory.
		}
		$tmp = $path . '.vc-tmp';
		if ( false === file_put_contents( $tmp, $contents, LOCK_EX ) ) { // phpcs:ignore WordPress.WP.AlternativeFunctions
			return false;
		}
		Fs::chmod( $tmp, $exists ? ( fileperms( $path ) & 0777 ) : 0644 );
		if ( ! Fs::move( $tmp, $path ) ) {
			Fs::delete( $tmp );
			return false;
		}
		return true;
	}
}