<?php
/**
 * Filesystem helper.
 *
 * @package AceloraSiteAccelerator
 */

namespace Acelora\SiteAccelerator\Includes;

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

/**
 * Handles plugin storage.
 */
class Filesystem {

	/**
	 * Logger.
	 *
	 * @var Logger
	 */
	private $logger;

	/**
	 * WordPress filesystem instance.
	 *
	 * @var \WP_Filesystem_Base|null
	 */
	private $wp_filesystem = null;

	/**
	 * Cached storage information.
	 *
	 * @var array|null
	 */
	private $storage = null;

	/**
	 * Constructor.
	 *
	 * @param Logger $logger Logger.
	 */
	public function __construct( Logger $logger ) {
		$this->logger = $logger;
	}

	/**
	 * Prepare folders and access guards.
	 *
	 * @return void
	 */
	public function prepare() {
		foreach ( $this->directories() as $directory ) {
			if ( ! is_dir( $directory ) ) {
				wp_mkdir_p( $directory );
			}

			$this->write_guard_files( $directory );
		}
	}

	/**
	 * Get plugin-managed directories.
	 *
	 * @return array
	 */
	public function directories() {
		return array(
			$this->storage_dir(),
			$this->storage_dir() . 'cache',
			$this->storage_dir() . 'cache/pages',
			$this->storage_dir() . 'cache/assets',
		);
	}

	/**
	 * Page cache directory.
	 *
	 * @return string
	 */
	public function page_cache_dir() {
		return trailingslashit( $this->storage_dir() . 'cache/pages' );
	}

	/**
	 * Optimized asset directory.
	 *
	 * @return string
	 */
	public function asset_cache_dir() {
		return trailingslashit( $this->storage_dir() . 'cache/assets' );
	}

	/**
	 * Optimized asset URL.
	 *
	 * @return string
	 */
	public function asset_cache_url() {
		return trailingslashit( $this->storage_url() . 'cache/assets' );
	}

	/**
	 * Logs directory.
	 *
	 * @return string
	 */
	public function logs_dir() {
		return trailingslashit( $this->storage_dir() . 'logs' );
	}

	/**
	 * Remove cached files under a controlled root.
	 *
	 * @param string $directory Directory to clear.
	 * @return int Deleted file count.
	 */
	public function clear_directory( $directory ) {
		$real_directory = realpath( $directory );
		$allowed        = realpath( $this->storage_dir() . 'cache' );

		if ( false === $real_directory || false === $allowed || 0 !== strpos( $real_directory, $allowed ) ) {
			return 0;
		}

		$deleted  = 0;
		$iterator = new \RecursiveIteratorIterator(
			new \RecursiveDirectoryIterator( $real_directory, \FilesystemIterator::SKIP_DOTS ),
			\RecursiveIteratorIterator::CHILD_FIRST
		);

		foreach ( $iterator as $item ) {
			if ( $item->isDir() ) {
				$this->remove_directory( $item->getPathname() );
				continue;
			}

			if ( $this->delete_file( $item->getPathname() ) ) {
				++$deleted;
			}
		}

		$this->prepare();

		return $deleted;
	}

	/**
	 * Read a file through the WordPress filesystem API.
	 *
	 * @param string $file File path.
	 * @return string|false
	 */
	public function get_contents( $file ) {
		$wp_filesystem = $this->wp_filesystem();

		return $wp_filesystem ? $wp_filesystem->get_contents( $file ) : false;
	}

	/**
	 * Write a file through the WordPress filesystem API.
	 *
	 * @param string $file     File path.
	 * @param string $contents File contents.
	 * @return bool
	 */
	public function put_contents( $file, $contents ) {
		$directory = dirname( $file );

		if ( ! is_dir( $directory ) ) {
			wp_mkdir_p( $directory );
		}

		$wp_filesystem = $this->wp_filesystem();

		if ( ! $wp_filesystem ) {
			return false;
		}

		return (bool) $wp_filesystem->put_contents( $file, $contents, defined( 'FS_CHMOD_FILE' ) ? FS_CHMOD_FILE : 0644 );
	}

	/**
	 * Delete a file using WordPress' deletion helper.
	 *
	 * @param string $file File path.
	 * @return bool
	 */
	public function delete_file( $file ) {
		if ( ! file_exists( $file ) || is_dir( $file ) ) {
			return false;
		}

		wp_delete_file( $file );

		return ! file_exists( $file );
	}

	/**
	 * Remove a directory through the WordPress filesystem API.
	 *
	 * @param string $directory Directory path.
	 * @return bool
	 */
	public function remove_directory( $directory ) {
		$wp_filesystem = $this->wp_filesystem();

		if ( ! $wp_filesystem || ! is_dir( $directory ) ) {
			return false;
		}

		return (bool) $wp_filesystem->rmdir( $directory, true );
	}

	/**
	 * Count files and bytes.
	 *
	 * @param string $directory Directory.
	 * @return array
	 */
	public function directory_stats( $directory ) {
		$stats = array(
			'files' => 0,
			'bytes' => 0,
		);

		if ( ! is_dir( $directory ) ) {
			return $stats;
		}

		$iterator = new \RecursiveIteratorIterator(
			new \RecursiveDirectoryIterator( $directory, \FilesystemIterator::SKIP_DOTS )
		);

		foreach ( $iterator as $item ) {
			if ( ! $item->isFile() ) {
				continue;
			}

			$stats['files']++;
			$stats['bytes'] += (int) $item->getSize();
		}

		return $stats;
	}

	/**
	 * Write guard files.
	 *
	 * @param string $directory Directory.
	 * @return void
	 */
	private function write_guard_files( $directory ) {
		if ( ! is_dir( $directory ) || ! wp_is_writable( $directory ) ) {
			return;
		}

		$index = trailingslashit( $directory ) . 'index.html';

		if ( ! file_exists( $index ) ) {
			$this->put_contents( $index, '' );
		}
	}

	/**
	 * Base storage directory in uploads.
	 *
	 * @return string
	 */
	private function storage_dir() {
		$storage = $this->storage();

		return $storage['dir'];
	}

	/**
	 * Base storage URL in uploads.
	 *
	 * @return string
	 */
	private function storage_url() {
		$storage = $this->storage();

		return $storage['url'];
	}

	/**
	 * Resolve uploads storage paths.
	 *
	 * @return array
	 */
	private function storage() {
		if ( null !== $this->storage ) {
			return $this->storage;
		}

		$uploads = wp_upload_dir( null, false );
		$base_dir = empty( $uploads['basedir'] ) ? WP_CONTENT_DIR . '/uploads' : $uploads['basedir'];
		$base_url = empty( $uploads['baseurl'] ) ? content_url( 'uploads' ) : $uploads['baseurl'];

		$this->storage = array(
			'dir' => trailingslashit( $base_dir ) . 'acelora-site-accelerator/',
			'url' => trailingslashit( $base_url ) . 'acelora-site-accelerator/',
		);

		return $this->storage;
	}

	/**
	 * Get the WordPress filesystem instance.
	 *
	 * @return \WP_Filesystem_Base|null
	 */
	private function wp_filesystem() {
		global $wp_filesystem;

		if ( $this->wp_filesystem ) {
			return $this->wp_filesystem;
		}

		if ( ! function_exists( 'WP_Filesystem' ) ) {
			require_once ABSPATH . 'wp-admin/includes/file.php';
		}

		if ( ! $wp_filesystem ) {
			WP_Filesystem();
		}

		$this->wp_filesystem = $wp_filesystem;

		return $this->wp_filesystem;
	}
}