<?php

namespace Kirby\Cms;

use Kirby\Exception\DuplicateException;
use Kirby\Exception\InvalidArgumentException;
use Kirby\Exception\PermissionException;
use Kirby\Filesystem\File as BaseFile;
use Kirby\Toolkit\Str;
use Kirby\Toolkit\V;

/**
 * Validators for all file actions
 *
 * @package   Kirby Cms
 * @author    Bastian Allgeier <bastian@getkirby.com>
 * @link      https://getkirby.com
 * @copyright Bastian Allgeier GmbH
 * @license   https://getkirby.com/license
 */
class FileRules
{
    /**
     * Validates if the filename can be changed
     *
     * @param \Kirby\Cms\File $file
     * @param string $name
     * @return bool
     * @throws \Kirby\Exception\DuplicateException If a file with this name exists
     * @throws \Kirby\Exception\PermissionException If the user is not allowed to rename the file
     */
    public static function changeName(File $file, string $name): bool
    {
        if ($file->permissions()->changeName() !== true) {
            throw new PermissionException([
                'key'  => 'file.changeName.permission',
                'data' => ['filename' => $file->filename()]
            ]);
        }

        if (Str::length($name) === 0) {
            throw new InvalidArgumentException([
                'key' => 'file.changeName.empty'
            ]);
        }

        $parent    = $file->parent();
        $duplicate = $parent->files()->not($file)->findBy('filename', $name . '.' . $file->extension());

        if ($duplicate) {
            throw new DuplicateException([
                'key'  => 'file.duplicate',
                'data' => ['filename' => $duplicate->filename()]
            ]);
        }

        return true;
    }

    /**
     * Validates if the file can be sorted
     *
     * @param \Kirby\Cms\File $file
     * @param int $sort
     * @return bool
     */
    public static function changeSort(File $file, int $sort): bool
    {
        return true;
    }

    /**
     * Validates if the file can be created
     *
     * @param \Kirby\Cms\File $file
     * @param \Kirby\Filesystem\File $upload
     * @return bool
     * @throws \Kirby\Exception\DuplicateException If a file with the same name exists
     * @throws \Kirby\Exception\PermissionException If the user is not allowed to create the file
     */
    public static function create(File $file, BaseFile $upload): bool
    {
        if ($file->exists() === true) {
            if ($file->sha1() !== $upload->sha1()) {
                throw new DuplicateException([
                    'key'  => 'file.duplicate',
                    'data' => [
                        'filename' => $file->filename()
                    ]
                ]);
            }
        }

        if ($file->permissions()->create() !== true) {
            throw new PermissionException('The file cannot be created');
        }

        static::validFile($file, $upload->mime());

        $upload->match($file->blueprint()->accept());
        $upload->validateContents(true);

        return true;
    }

    /**
     * Validates if the file can be deleted
     *
     * @param \Kirby\Cms\File $file
     * @return bool
     * @throws \Kirby\Exception\PermissionException If the user is not allowed to delete the file
     */
    public static function delete(File $file): bool
    {
        if ($file->permissions()->delete() !== true) {
            throw new PermissionException('The file cannot be deleted');
        }

        return true;
    }

    /**
     * Validates if the file can be replaced
     *
     * @param \Kirby\Cms\File $file
     * @param \Kirby\Filesystem\File $upload
     * @return bool
     * @throws \Kirby\Exception\PermissionException If the user is not allowed to replace the file
     * @throws \Kirby\Exception\InvalidArgumentException If the file type of the new file is different
     */
    public static function replace(File $file, BaseFile $upload): bool
    {
        if ($file->permissions()->replace() !== true) {
            throw new PermissionException('The file cannot be replaced');
        }

        static::validMime($file, $upload->mime());

        if (
            (string)$upload->mime() !== (string)$file->mime() &&
            (string)$upload->extension() !== (string)$file->extension()
        ) {
            throw new InvalidArgumentException([
                'key'  => 'file.mime.differs',
                'data' => ['mime' => $file->mime()]
            ]);
        }

        $upload->match($file->blueprint()->accept());
        $upload->validateContents(true);

        return true;
    }

    /**
     * Validates if the file can be updated
     *
     * @param \Kirby\Cms\File $file
     * @param array $content
     * @return bool
     * @throws \Kirby\Exception\PermissionException If the user is not allowed to update the file
     */
    public static function update(File $file, array $content = []): bool
    {
        if ($file->permissions()->update() !== true) {
            throw new PermissionException('The file cannot be updated');
        }

        return true;
    }

    /**
     * Validates the file extension
     *
     * @param \Kirby\Cms\File $file
     * @param string $extension
     * @return bool
     * @throws \Kirby\Exception\InvalidArgumentException If the extension is missing or forbidden
     */
    public static function validExtension(File $file, string $extension): bool
    {
        // make it easier to compare the extension
        $extension = strtolower($extension);

        if (empty($extension) === true) {
            throw new InvalidArgumentException([
                'key'  => 'file.extension.missing',
                'data' => ['filename' => $file->filename()]
            ]);
        }

        if (
            Str::contains($extension, 'php') !== false ||
            Str::contains($extension, 'phar') !== false ||
            Str::contains($extension, 'phtml') !== false
        ) {
            throw new InvalidArgumentException([
                'key'  => 'file.type.forbidden',
                'data' => ['type' => 'PHP']
            ]);
        }

        if (Str::contains($extension, 'htm') !== false) {
            throw new InvalidArgumentException([
                'key'  => 'file.type.forbidden',
                'data' => ['type' => 'HTML']
            ]);
        }

        if (V::in($extension, ['exe', App::instance()->contentExtension()]) !== false) {
            throw new InvalidArgumentException([
                'key'  => 'file.extension.forbidden',
                'data' => ['extension' => $extension]
            ]);
        }

        return true;
    }

    /**
     * Validates the extension, MIME type and filename
     *
     * @param \Kirby\Cms\File $file
     * @param string|null|false $mime If not passed, the MIME type is detected from the file,
     *                                if `false`, the MIME type is not validated for performance reasons
     * @return bool
     * @throws \Kirby\Exception\InvalidArgumentException If the extension, MIME type or filename is missing or forbidden
     */
    public static function validFile(File $file, $mime = null): bool
    {
        if ($mime === false) {
            // request to skip the MIME check for performance reasons
            $validMime = true;
        } else {
            $validMime = static::validMime($file, $mime ?? $file->mime());
        }

        return
            $validMime &&
            static::validExtension($file, $file->extension()) &&
            static::validFilename($file, $file->filename());
    }

    /**
     * Validates the filename
     *
     * @param \Kirby\Cms\File $file
     * @param string $filename
     * @return bool
     * @throws \Kirby\Exception\InvalidArgumentException If the filename is missing or forbidden
     */
    public static function validFilename(File $file, string $filename): bool
    {
        // make it easier to compare the filename
        $filename = strtolower($filename);

        // check for missing filenames
        if (empty($filename)) {
            throw new InvalidArgumentException([
                'key'  => 'file.name.missing'
            ]);
        }

        // Block htaccess files
        if (Str::startsWith($filename, '.ht')) {
            throw new InvalidArgumentException([
                'key'  => 'file.type.forbidden',
                'data' => ['type' => 'Apache config']
            ]);
        }

        // Block invisible files
        if (Str::startsWith($filename, '.')) {
            throw new InvalidArgumentException([
                'key'  => 'file.type.forbidden',
                'data' => ['type' => 'invisible']
            ]);
        }

        return true;
    }

    /**
     * Validates the MIME type
     *
     * @param \Kirby\Cms\File $file
     * @param string|null $mime
     * @return bool
     * @throws \Kirby\Exception\InvalidArgumentException If the MIME type is missing or forbidden
     */
    public static function validMime(File $file, string $mime = null): bool
    {
        // make it easier to compare the mime
        $mime = strtolower($mime);

        if (empty($mime)) {
            throw new InvalidArgumentException([
                'key'  => 'file.mime.missing',
                'data' => ['filename' => $file->filename()]
            ]);
        }

        if (Str::contains($mime, 'php')) {
            throw new InvalidArgumentException([
                'key'  => 'file.type.forbidden',
                'data' => ['type' => 'PHP']
            ]);
        }

        if (V::in($mime, ['text/html', 'application/x-msdownload'])) {
            throw new InvalidArgumentException([
                'key'  => 'file.mime.forbidden',
                'data' => ['mime' => $mime]
            ]);
        }

        return true;
    }
}