<?php

/**
 * DataObject to store versions of uploaded Documents.
 *
 * Versions are only created when replacing a document, not on every save of the
 * DMSDocument dataobject. So, versions store the various versions of the
 * underlying Document, not the DataObject with information about that object.
 *
 * @package dms
 */
class DMSDocument_versions extends DataObject
{

    /**
     * @var bool $enable_versions Flag that turns on or off versions of
     * documents when replacing them
     */
    public static $enable_versions = true;

    private static $db = array(
        'VersionCounter' => 'Int',
        'VersionViewCount' => 'Int'
    );

    private static $has_one = array(
        'Document' => 'DMSDocument'
    );

    private static $defaults = array(
        'VersionCounter' => 0
    );

    private static $display_fields = array(
        'VersionCounter' => 'Version Counter',
        'FilenameWithoutID' => 'Filename',
        'LastEdited' => 'Last Changed'
    );

    private static $summary_fields = array(
        'VersionCounter',
        'FilenameWithoutID'
    );

    private static $field_labels = array(
        'FilenameWithoutID'=>'Filename'
    );

    private static $default_sort = array(
        'LastEdited' => 'DESC'
    );


    /**
     * Creates a new version of a document by moving the current file and
     * renaming it to the versioned filename.
     *
     * This method assumes that the method calling this is just about to upload
     * a new file to replace the old file.
     *
     * @static
     * @param DMSDocument $doc
     *
     * @return bool Success or failure
     */
    public static function create_version(DMSDocument $doc)
    {
        $success = false;

        $existingPath = $doc->getFullPath();
        if (is_file($existingPath)) {
            $docData = $doc->toMap();
            unset($docData['ID']);
            $version = new DMSDocument_versions($docData);  //create a copy of the current DMSDocument as a version

            $previousVersionCounter  = 0;
            $newestExistingVersion = self::get_versions($doc)->sort(array('Created'=>'DESC', 'ID'=>'DESC'))->limit(1);
            if ($newestExistingVersion && $newestExistingVersion->Count() > 0) {
                $previousVersionCounter = $newestExistingVersion->first()->VersionCounter;
            }

            //change the filename field to a field containing the new soon-to-be versioned file
            $version->VersionCounter = $previousVersionCounter + 1; //start versions at 1
            $newFilename = $version->generateVersionedFilename($doc, $version->VersionCounter);
            $version->Filename = $newFilename;

            //add a relation back to the origin ID;
            $version->DocumentID = $doc->ID;
            $id = $version->write();

            if (!empty($id)) {
                rename($existingPath, $version->getFullPath());
                $success = true;
            }
        }

        return $success;
    }

    public function delete()
    {
        $path = $this->getFullPath();

        if (file_exists($path)) {
            unlink($path);
        }

        parent::delete();
    }

    /**
     * Returns a DataList of all previous Versions of a document (check the
     * LastEdited date of each object to find the correct one).
     *
     * @static
     * @param DMSDocument $doc
     *
     * @return DataList List of Document objects
     */
    public static function get_versions(DMSDocument $doc)
    {
        if (!DMSDocument_versions::$enable_versions) {
            user_error("DMSDocument versions are disabled", E_USER_WARNING);
        }
        return DMSDocument_versions::get()->filter(array('DocumentID' => $doc->ID));
    }

    public function __construct($record = null, $isSingleton = false, $model = null)
    {
        //check what the constructor was passed
        $dmsObject = null;
        if ($record && is_subclass_of($record, 'DMSDocumentInterface')) {
            $dmsObject = $record;
            $record = null; //cancel the record creation to just create an empty object
        }

        //create the object
        parent::__construct($record, $isSingleton, $model);

        //copy the DMSDocument object, if passed into the constructor
        if ($dmsObject) {
            foreach (array_keys(DataObject::custom_database_fields($dmsObject->ClassName)) as $key) {
                $this->$key = $dmsObject->$key;
            }
        }
    }

    /**
     * Returns a link to download this document from the DMS store.
     *
     * @return string
     */
    public function getLink()
    {
        return Controller::join_links(Director::baseURL(), 'dmsdocument/version'.$this->ID);
    }

    /**
     * Document versions are always hidden from outside viewing. Only admins can
     * download them.
     *
     * @return bool
     */
    public function isHidden()
    {
        return true;
    }

    /**
     * Returns the full filename of the document stored in this object. Can
     * optionally specify which filename to use at the end.
     *
     * @param string
     *
     * @return string
     */
    public function getFullPath($filename = null)
    {
        if (!$filename) {
            $filename = $this->Filename;
        }
        return DMS::inst()->getStoragePath() . DIRECTORY_SEPARATOR . $this->Folder . DIRECTORY_SEPARATOR . $filename;
    }

    /**
     * @return string
     */
    public function getFilenameWithoutID()
    {
        $filenameParts = explode('~', $this->Filename);
        $filename = array_pop($filenameParts);

        return $filename;
    }

    /**
     * Creates a new filename for the current Document's file when replacing the
     * current file with a new file.
     *
     * @param DMSDocument $filename The original filename
     *
     * @return string The new filename
     */
    protected function generateVersionedFilename(DMSDocument $doc, $versionCounter)
    {
        $filename = $doc->Filename;

        do {
            // Add leading zeros to make sorting accurate up to 10,000 documents
            $versionPaddingString = str_pad($versionCounter, 4, '0', STR_PAD_LEFT);
            $newVersionFilename = preg_replace('/([0-9]+~)(.*?)/', '$1~'.$versionPaddingString.'~$2', $filename);

            // Sanity check for crazy document names
            if ($newVersionFilename == $filename || empty($newVersionFilename)) {
                user_error('Cannot generate new document filename for file: '.$filename, E_USER_ERROR);
            }

            // Increase the counter for the next loop run, if necessary
            $versionCounter++;
        } while (file_exists($this->getFullPath($newVersionFilename)));

        return $newVersionFilename;
    }

    /**
     * Return the extension of the file associated with the document.
     *
     * @return string
     */
    public function getExtension()
    {
        return strtolower(pathinfo($this->Filename, PATHINFO_EXTENSION));
    }

    /**
     * @return string
     */
    public function getSize()
    {
        $size = $this->getAbsoluteSize();

        return ($size) ? File::format_size($size) : false;
    }

    /**
     * Return the size of the file associated with the document.
     *
     * @return string
     */
    public function getAbsoluteSize()
    {
        return filesize($this->getFullPath());
    }

    /**
     * An alias to DMSDocument::getSize()
     *
     * @return string
     */
    public function getFileSizeFormatted()
    {
        return $this->getSize();
    }

    /**
     * @return DMSDocument_versions
     */
    public function trackView()
    {
        if ($this->ID > 0) {
            $this->VersionViewCount++;

            $count = $this->VersionViewCount;

            DB::query("UPDATE \"DMSDocument_versions\" SET \"VersionViewCount\"='$count' WHERE \"ID\"={$this->ID}");
        }

        return $this;
    }
}