<?php

namespace Kirby\Filesystem;

use Exception;
use Kirby\Cms\App;
use Kirby\Cms\Page;
use Kirby\Toolkit\Str;
use Throwable;

/**
 * The `Dir` class provides methods
 * for dealing with directories on the
 * file system level, like creating,
 * listing, moving, copying or
 * evaluating directories etc.
 *
 * For the Cms, it includes methods,
 * that handle scanning directories
 * and converting the results into
 * children, files and other page stuff.
 *
 * @package   Kirby Filesystem
 * @author    Bastian Allgeier <bastian@getkirby.com>
 * @link      https://getkirby.com
 * @copyright Bastian Allgeier GmbH
 * @license   https://opensource.org/licenses/MIT
 */
class Dir
{
    /**
     * Ignore when scanning directories
     *
     * @var array
     */
    public static $ignore = [
        '.',
        '..',
        '.DS_Store',
        '.gitignore',
        '.git',
        '.svn',
        '.htaccess',
        'Thumb.db',
        '@eaDir'
    ];

    public static $numSeparator = '_';

    /**
     * Copy the directory to a new destination
     *
     * @param string $dir
     * @param string $target
     * @param bool $recursive
     * @param array $ignore
     * @return bool
     */
    public static function copy(string $dir, string $target, bool $recursive = true, array $ignore = []): bool
    {
        if (is_dir($dir) === false) {
            throw new Exception('The directory "' . $dir . '" does not exist');
        }

        if (is_dir($target) === true) {
            throw new Exception('The target directory "' . $target . '" exists');
        }

        if (static::make($target) !== true) {
            throw new Exception('The target directory "' . $target . '" could not be created');
        }

        foreach (static::read($dir) as $name) {
            $root = $dir . '/' . $name;

            if (in_array($root, $ignore) === true) {
                continue;
            }

            if (is_dir($root) === true) {
                if ($recursive === true) {
                    static::copy($root, $target . '/' . $name, true, $ignore);
                }
            } else {
                F::copy($root, $target . '/' . $name);
            }
        }

        return true;
    }

    /**
     * Get all subdirectories
     *
     * @param string $dir
     * @param array $ignore
     * @param bool $absolute
     * @return array
     */
    public static function dirs(string $dir, array $ignore = null, bool $absolute = false): array
    {
        $result = array_values(array_filter(static::read($dir, $ignore, true), 'is_dir'));

        if ($absolute !== true) {
            $result = array_map('basename', $result);
        }

        return $result;
    }

    /**
     * Checks if the directory exists on disk
     *
     * @param string $dir
     * @return bool
     */
    public static function exists(string $dir): bool
    {
        return is_dir($dir) === true;
    }

    /**
     * Get all files
     *
     * @param string $dir
     * @param array $ignore
     * @param bool $absolute
     * @return array
     */
    public static function files(string $dir, array $ignore = null, bool $absolute = false): array
    {
        $result = array_values(array_filter(static::read($dir, $ignore, true), 'is_file'));

        if ($absolute !== true) {
            $result = array_map('basename', $result);
        }

        return $result;
    }

    /**
     * Read the directory and all subdirectories
     *
     * @param string $dir
     * @param bool $recursive
     * @param array $ignore
     * @param string $path
     * @return array
     */
    public static function index(string $dir, bool $recursive = false, array $ignore = null, string $path = null)
    {
        $result = [];
        $dir    = realpath($dir);
        $items  = static::read($dir);

        foreach ($items as $item) {
            $root     = $dir . '/' . $item;
            $entry    = $path !== null ? $path . '/' . $item: $item;
            $result[] = $entry;

            if ($recursive === true && is_dir($root) === true) {
                $result = array_merge($result, static::index($root, true, $ignore, $entry));
            }
        }

        return $result;
    }

    /**
     * Checks if the folder has any contents
     *
     * @param string $dir
     * @return bool
     */
    public static function isEmpty(string $dir): bool
    {
        return count(static::read($dir)) === 0;
    }

    /**
     * Checks if the directory is readable
     *
     * @param string $dir
     * @return bool
     */
    public static function isReadable(string $dir): bool
    {
        return is_readable($dir);
    }

    /**
     * Checks if the directory is writable
     *
     * @param string $dir
     * @return bool
     */
    public static function isWritable(string $dir): bool
    {
        return is_writable($dir);
    }

    /**
     * Scans the directory and analyzes files,
     * content, meta info and children. This is used
     * in `Kirby\Cms\Page`, `Kirby\Cms\Site` and
     * `Kirby\Cms\User` objects to fetch all
     * relevant information.
     *
     * Don't use outside the Cms context.
     *
     * @internal
     *
     * @param string $dir
     * @param string $contentExtension
     * @param array|null $contentIgnore
     * @param bool $multilang
     * @return array
     */
    public static function inventory(string $dir, string $contentExtension = 'txt', array $contentIgnore = null, bool $multilang = false): array
    {
        $dir = realpath($dir);

        $inventory = [
            'children' => [],
            'files'    => [],
            'template' => 'default',
        ];

        if ($dir === false) {
            return $inventory;
        }

        $items = static::read($dir, $contentIgnore);

        // a temporary store for all content files
        $content = [];

        // sort all items naturally to avoid sorting issues later
        natsort($items);

        foreach ($items as $item) {

            // ignore all items with a leading dot
            if (in_array(substr($item, 0, 1), ['.', '_']) === true) {
                continue;
            }

            $root = $dir . '/' . $item;

            if (is_dir($root) === true) {

                // extract the slug and num of the directory
                if (preg_match('/^([0-9]+)' . static::$numSeparator . '(.*)$/', $item, $match)) {
                    $num  = (int)$match[1];
                    $slug = $match[2];
                } else {
                    $num  = null;
                    $slug = $item;
                }

                $inventory['children'][] = [
                    'dirname' => $item,
                    'model'   => null,
                    'num'     => $num,
                    'root'    => $root,
                    'slug'    => $slug,
                ];
            } else {
                $extension = pathinfo($item, PATHINFO_EXTENSION);

                switch ($extension) {
                    case 'htm':
                    case 'html':
                    case 'php':
                        // don't track those files
                        break;
                    case $contentExtension:
                        $content[] = pathinfo($item, PATHINFO_FILENAME);
                        break;
                    default:
                        $inventory['files'][$item] = [
                            'filename'  => $item,
                            'extension' => $extension,
                            'root'      => $root,
                        ];
                }
            }
        }

        // remove the language codes from all content filenames
        if ($multilang === true) {
            foreach ($content as $key => $filename) {
                $content[$key] = pathinfo($filename, PATHINFO_FILENAME);
            }

            $content = array_unique($content);
        }

        $inventory = static::inventoryContent($inventory, $content);
        $inventory = static::inventoryModels($inventory, $contentExtension, $multilang);

        return $inventory;
    }

    /**
     * Take all content files,
     * remove those who are meta files and
     * detect the main content file
     *
     * @param array $inventory
     * @param array $content
     * @return array
     */
    protected static function inventoryContent(array $inventory, array $content): array
    {

        // filter meta files from the content file
        if (empty($content) === true) {
            $inventory['template'] = 'default';
            return $inventory;
        }

        foreach ($content as $contentName) {

            // could be a meta file. i.e. cover.jpg
            if (isset($inventory['files'][$contentName]) === true) {
                continue;
            }

            // it's most likely the template
            $inventory['template'] = $contentName;
        }

        return $inventory;
    }

    /**
     * Go through all inventory children
     * and inject a model for each
     *
     * @param array $inventory
     * @param string $contentExtension
     * @param bool $multilang
     * @return array
     */
    protected static function inventoryModels(array $inventory, string $contentExtension, bool $multilang = false): array
    {
        // inject models
        if (empty($inventory['children']) === false && empty(Page::$models) === false) {
            if ($multilang === true) {
                $contentExtension = App::instance()->defaultLanguage()->code() . '.' . $contentExtension;
            }

            foreach ($inventory['children'] as $key => $child) {
                foreach (Page::$models as $modelName => $modelClass) {
                    if (file_exists($child['root'] . '/' . $modelName . '.' . $contentExtension) === true) {
                        $inventory['children'][$key]['model'] = $modelName;
                        break;
                    }
                }
            }
        }

        return $inventory;
    }

    /**
     * Create a (symbolic) link to a directory
     *
     * @param string $source
     * @param string $link
     * @return bool
     */
    public static function link(string $source, string $link): bool
    {
        static::make(dirname($link), true);

        if (is_dir($link) === true) {
            return true;
        }

        if (is_dir($source) === false) {
            throw new Exception(sprintf('The directory "%s" does not exist and cannot be linked', $source));
        }

        try {
            return symlink($source, $link) === true;
        } catch (Throwable $e) {
            return false;
        }
    }

    /**
     * Creates a new directory
     *
     * @param string $dir The path for the new directory
     * @param bool $recursive Create all parent directories, which don't exist
     * @return bool True: the dir has been created, false: creating failed
     * @throws \Exception If a file with the provided path already exists or the parent directory is not writable
     */
    public static function make(string $dir, bool $recursive = true): bool
    {
        if (empty($dir) === true) {
            return false;
        }

        if (is_dir($dir) === true) {
            return true;
        }

        if (is_file($dir) === true) {
            throw new Exception(sprintf('A file with the name "%s" already exists', $dir));
        }

        $parent = dirname($dir);

        if ($recursive === true) {
            if (is_dir($parent) === false) {
                static::make($parent, true);
            }
        }

        if (is_writable($parent) === false) {
            throw new Exception(sprintf('The directory "%s" cannot be created', $dir));
        }

        return mkdir($dir);
    }

    /**
     * Recursively check when the dir and all
     * subfolders have been modified for the last time.
     *
     * @param string $dir The path of the directory
     * @param string $format
     * @param string $handler
     * @return int|string
     */
    public static function modified(string $dir, string $format = null, string $handler = 'date')
    {
        $modified = filemtime($dir);
        $items    = static::read($dir);

        foreach ($items as $item) {
            if (is_file($dir . '/' . $item) === true) {
                $newModified = filemtime($dir . '/' . $item);
            } else {
                $newModified = static::modified($dir . '/' . $item);
            }

            $modified = ($newModified > $modified) ? $newModified : $modified;
        }

        return Str::date($modified, $format, $handler);
    }

    /**
     * Moves a directory to a new location
     *
     * @param string $old The current path of the directory
     * @param string $new The desired path where the dir should be moved to
     * @return bool true: the directory has been moved, false: moving failed
     */
    public static function move(string $old, string $new): bool
    {
        if ($old === $new) {
            return true;
        }

        if (is_dir($old) === false || is_dir($new) === true) {
            return false;
        }

        if (static::make(dirname($new), true) !== true) {
            throw new Exception('The parent directory cannot be created');
        }

        return rename($old, $new);
    }

    /**
     * Returns a nicely formatted size of all the contents of the folder
     *
     * @param string $dir The path of the directory
     * @return mixed
     */
    public static function niceSize(string $dir)
    {
        return F::niceSize(static::size($dir));
    }

    /**
     * Reads all files from a directory and returns them as an array.
     * It skips unwanted invisible stuff.
     *
     * @param string $dir The path of directory
     * @param array $ignore Optional array with filenames, which should be ignored
     * @param bool $absolute If true, the full path for each item will be returned
     * @return array An array of filenames
     */
    public static function read(string $dir, array $ignore = null, bool $absolute = false): array
    {
        if (is_dir($dir) === false) {
            return [];
        }

        // create the ignore pattern
        $ignore ??= static::$ignore;
        $ignore   = array_merge($ignore, ['.', '..']);

        // scan for all files and dirs
        $result = array_values((array)array_diff(scandir($dir), $ignore));

        // add absolute paths
        if ($absolute === true) {
            $result = array_map(function ($item) use ($dir) {
                return $dir . '/' . $item;
            }, $result);
        }

        return $result;
    }

    /**
     * Removes a folder including all containing files and folders
     *
     * @param string $dir
     * @return bool
     */
    public static function remove(string $dir): bool
    {
        $dir = realpath($dir);

        if (is_dir($dir) === false) {
            return true;
        }

        if (is_link($dir) === true) {
            return unlink($dir);
        }

        foreach (scandir($dir) as $childName) {
            if (in_array($childName, ['.', '..']) === true) {
                continue;
            }

            $child = $dir . '/' . $childName;

            if (is_link($child) === true) {
                unlink($child);
            } elseif (is_dir($child) === true) {
                static::remove($child);
            } else {
                F::remove($child);
            }
        }

        return rmdir($dir);
    }

    /**
     * Gets the size of the directory
     *
     * @param string $dir The path of the directory
     * @param bool $recursive Include all subfolders and their files
     * @return mixed
     */
    public static function size(string $dir, bool $recursive = true)
    {
        if (is_dir($dir) === false) {
            return false;
        }

        // Get size for all direct files
        $size = F::size(static::files($dir, null, true));

        // if recursive, add sizes of all subdirectories
        if ($recursive === true) {
            foreach (static::dirs($dir, null, true) as $subdir) {
                $size += static::size($subdir);
            }
        }

        return $size;
    }

    /**
     * Checks if the directory or any subdirectory has been
     * modified after the given timestamp
     *
     * @param string $dir
     * @param int $time
     * @return bool
     */
    public static function wasModifiedAfter(string $dir, int $time): bool
    {
        if (filemtime($dir) > $time) {
            return true;
        }

        $content = static::read($dir);

        foreach ($content as $item) {
            $subdir = $dir . '/' . $item;

            if (filemtime($subdir) > $time) {
                return true;
            }

            if (is_dir($subdir) === true && static::wasModifiedAfter($subdir, $time) === true) {
                return true;
            }
        }

        return false;
    }
}