<?php
/**
 * Interface for a DMSDocument used in the Document Management System. A DMSDocument is create by storing a File object in an
 * instance of the DMSInterface. All write operations on the DMSDocument create a new relation, so we never need to
 * explicitly call the write() method on the DMSDocument DataObject
 */
interface DMSDocumentInterface
{

    /**
     * Deletes the DMSDocument, its underlying file, as well as any tags related to this DMSDocument.
     *
     * @todo Can't be applied to classes which already implement the DataObjectInterface (naming conflict)
     *
     * @abstract
     * @return null
     */
    // function delete();

    /**
     * Associates this DMSDocument with a Page. This method does nothing if the association already exists.
     * This could be a simple wrapper around $myDoc->Pages()->add($myPage) to add a many_many relation
     * @abstract
     * @param $pageObject Page object to associate this DMSDocument with
     * @return null
     *
     * @deprecated 2.0 Will be removed in future in favour of document sets
     */
    public function addPage($pageObject);

    /**
     * Associates this DMSDocument with a set of Pages. This method loops through a set of page ids, and then associates this
     * DMSDocument with the individual Page with the each page id in the set
     * @abstract
     * @param $pageIDs array of page ids used for the page objects associate this DMSDocument with
     * @return null
     *
     * @deprecated 2.0 Will be removed in future in favour of document sets
     */
    public function addPages($pageIDs);

    /**
     * Removes the association between this DMSDocument and a Page. This method does nothing if the association does not exist.
     * @abstract
     * @param $pageObject Page object to remove the association to
     * @return mixed
     */
    public function removePage($pageObject);

    /**
     * Returns a list of the Page objects associated with this DMSDocument
     * @abstract
     * @return DataList
     *
     * @deprecated 2.0 Will be removed in future in favour of document sets
     */
    public function getPages();

    /**
     * Removes all associated Pages from the DMSDocument
     * @abstract
     * @return null
     *
     * @deprecated 2.0 Will be removed in future in favour of document sets
     */
    public function removeAllPages();

    /**
     * Adds a metadata tag to the DMSDocument. The tag has a category and a value.
     * Each category can have multiple values by default. So: addTag("fruit","banana") addTag("fruit", "apple") will add two items.
     * However, if the third parameter $multiValue is set to 'false', then all updates to a category only ever update a single value. So:
     * addTag("fruit","banana") addTag("fruit", "apple") would result in a single metadata tag: fruit->apple.
     * Can could be implemented as a key/value store table (although it is more like category/value, because the
     * same category can occur multiple times)
     * @abstract
     * @param $category String of a metadata category to add (required)
     * @param $value String of a metadata value to add (required)
     * @param bool $multiValue Boolean that determines if the category is multi-value or single-value (optional)
     * @return null
     *
     * @deprecated 2.0 Will be removed in future in favour of using silverstripe/taxonomy
     */
    public function addTag($category, $value, $multiValue = true);

    /**
     * Fetches all tags associated with this DMSDocument within a given category. If a value is specified this method
     * tries to fetch that specific tag.
     * @abstract
     * @param $category String of the metadata category to get
     * @param null $value String of the value of the tag to get
     * @return array of Strings of all the tags or null if there is no match found
     *
     * @deprecated 2.0 Will be removed in future in favour of using silverstripe/taxonomy
     */
    public function getTagsList($category, $value = null);

    /**
     * Removes a tag from the DMSDocument. If you only set a category, then all values in that category are deleted.
     * If you specify both a category and a value, then only that single category/value pair is deleted.
     * Nothing happens if the category or the value do not exist.
     * @abstract
     * @param $category Category to remove (required)
     * @param null $value Value to remove (optional)
     * @return null
     *
     * @deprecated 2.0 Will be removed in future in favour of using silverstripe/taxonomy
     */
    public function removeTag($category, $value = null);

    /**
     * Deletes all tags associated with this DMSDocument.
     * @abstract
     * @return null
     *
     * @deprecated 2.0 Will be removed in future in favour of using silverstripe/taxonomy
     */
    public function removeAllTags();

    /**
     * Returns a link to download this DMSDocument from the DMS store
     * @abstract
     * @return String
     */
    public function getLink();

    /**
     * Return the extension of the file associated with the document
     */
    public function getExtension();

    /**
     * Returns the size of the file type in an appropriate format.
     *
     * @return string
     */
    public function getSize();

    /**
     * Return the size of the file associated with the document, in bytes.
     *
     * @return int
     */
    public function getAbsoluteSize();


    /**
     * Takes a File object or a String (path to a file) and copies it into the DMS, replacing the original document file
     * but keeping the rest of the document unchanged.
     * @param $file File object, or String that is path to a file to store
     * @return DMSDocumentInstance Document object that we replaced the file in
     */
    public function replaceDocument($file);

    /**
     * Hides the DMSDocument, so it does not show up when getByPage($myPage) is called
     * (without specifying the $showEmbargoed = true parameter). This is similar to expire, except that this method
     * should be used to hide DMSDocuments that have not yet gone live.
     * @abstract
     * @return null
     */
    public function embargoIndefinitely();

    /**
     * Returns if this is DMSDocument is embargoed or expired.
     * @abstract
     * @return bool True or False depending on whether this DMSDocument is embargoed or expired
     */
    public function isHidden();


    /**
     * Returns if this is DMSDocument is embargoed.
     * @abstract
     * @return bool True or False depending on whether this DMSDocument is embargoed
     */
    public function isEmbargoed();

    /**
     * Hides the DMSDocument, so it does not show up when getByPage($myPage) is called. Automatically un-hides the
     * DMSDocument at a specific date.
     * @abstract
     * @param $datetime String date time value when this DMSDocument should expire
     * @return null
     */
    public function embargoUntilDate($datetime);

    /**
     * Hides the document until any page it is linked to is published
     * @return null
     */
    public function embargoUntilPublished();

    /**
     * Clears any previously set embargos, so the DMSDocument always shows up in all queries.
     * @abstract
     * @return null
     */
    public function clearEmbargo();

    /**
     * Returns if this is DMSDocument is expired.
     * @abstract
     * @return bool True or False depending on whether this DMSDocument is expired
     */
    public function isExpired();

    /**
     * Hides the DMSDocument at a specific date, so it does not show up when getByPage($myPage) is called.
     * @abstract
     * @param $datetime String date time value when this DMSDocument should expire
     * @return null
     */
    public function expireAtDate($datetime);

    /**
     * Clears any previously set expiry.
     * @abstract
     * @return null
     */
    public function clearExpiry();

    /*---- FROM HERE ON: optional API features ----*/

    /**
     * Returns a DataList of all previous Versions of this DMSDocument (check the LastEdited date of each
     * object to find the correct one)
     * @abstract
     * @return DataList List of DMSDocument objects
     */
    public function getVersions();
}