<?php
/**
 * @file src/Model/FileTag.php
 */

namespace Friendica\Model;

use Friendica\Core\L10n;
use Friendica\Core\PConfig;
use Friendica\Database\DBA;

/**
 * @brief This class handles FileTag related functions
 */
class FileTag
{
    // post categories and "save to file" use the same item.file table for storage.
    // We will differentiate the different uses by wrapping categories in angle brackets
    // and save to file categories in square brackets.
    // To do this we need to escape these characters if they appear in our tag.

    /**
     * @brief URL encode &lt, &gt, left and right brackets
     * 
     * @param string $s String to be URL encoded.
     * 
     * @return string   The URL encoded string.
     */
    public static function encode($s)
    {
        return str_replace(['<', '>', '[', ']'], ['%3c', '%3e', '%5b', '%5d'], $s);
    }

    /**
     * @brief URL decode &lt, &gt, left and right brackets
     * 
     * @param string $s The URL encoded string to be decoded
     * 
     * @return string   The decoded string.
     */
    public static function decode($s)
    {
        return str_replace(['%3c', '%3e', '%5b', '%5d'], ['<', '>', '[', ']'], $s);
    }

    /**
     * @brief Query files for tag
     * 
     * @param string $table The table to be queired.
     * @param string $s     The search term
     * @param string $type  Optional file type.
     * 
     * @return string       Query string.
     */
    public static function fileQuery($table, $s, $type = 'file')
    {
        if ($type == 'file') {
            $str = preg_quote('[' . str_replace('%', '%%', self::encode($s)) . ']');
        } else {
            $str = preg_quote('<' . str_replace('%', '%%', self::encode($s)) . '>');
        }

        return " AND " . (($table) ? DBA::escape($table) . '.' : '') . "file regexp '" . DBA::escape($str) . "' ";
    }

    /**
     * @brief Get file tags from list
     * 
     * ex. given music,video return <music><video> or [music][video]
     * @param string $list  A comma delimited list of tags.
     * @param string $type  Optional file type.
     * 
     * @return string       A list of file tags.
     */
    public static function listToFile($list, $type = 'file')
    {
        $tag_list = '';
        if (strlen($list)) {
            $list_array = explode(",", $list);
            if ($type == 'file') {
                $lbracket = '[';
                $rbracket = ']';
            } else {
                $lbracket = '<';
                $rbracket = '>';
            }

            foreach ($list_array as $item)
            {
                if (strlen($item))
                {
                    $tag_list .= $lbracket . self::encode(trim($item))  . $rbracket;
                }
            }
        }

        return $tag_list;
    }

    /**
     * @brief Get list from file tags
     * 
     * ex. given <music><video>[friends], return music,video or friends
     * @param string $file  File tags
     * @param string $type  Optional file type.
     * 
     * @return string       Comma delimited list of tag names.
     */
    public static function fileToList($file, $type = 'file')
    {
        $matches = false;
        $list = '';

        if ($type == 'file') {
            $cnt = preg_match_all('/\[(.*?)\]/', $file, $matches, PREG_SET_ORDER);
        } else {
            $cnt = preg_match_all('/<(.*?)>/', $file, $matches, PREG_SET_ORDER);
        }

        if ($cnt)
        {
            foreach ($matches as $mtch)
            {
                if (strlen($list))
                {
                    $list .= ',';
                }

                $list .= self::decode($mtch[1]);
            }
        }

        return $list;
    }

	/**
	 * @brief Update file tags in PConfig
	 *
	 * @param int    $uid      Unique Identity.
	 * @param string $file_old Categories previously associated with an item
	 * @param string $file_new New list of categories for an item
	 * @param string $type     Optional file type.
	 *
	 * @return boolean          A value indicating success or failure.
	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
	 */
    public static function updatePconfig($uid, $file_old, $file_new, $type = 'file')
    {
        if (!intval($uid)) {
            return false;
        } elseif ($file_old == $file_new) {
            return true;
        }

        $saved = PConfig::get($uid, 'system', 'filetags');

        if (strlen($saved))
        {
            if ($type == 'file') {
                $lbracket = '[';
                $rbracket = ']';
                $termtype = TERM_FILE;
            } else {
                $lbracket = '<';
                $rbracket = '>';
                $termtype = TERM_CATEGORY;
            }

            $filetags_updated = $saved;

            // check for new tags to be added as filetags in pconfig
            $new_tags = [];
            $check_new_tags = explode(",", self::fileToList($file_new, $type));

            foreach ($check_new_tags as $tag)
            {
                if (!stristr($saved,$lbracket . self::encode($tag) . $rbracket)) {
                    $new_tags[] = $tag;
                }
            }

            $filetags_updated .= self::listToFile(implode(",", $new_tags), $type);

            // check for deleted tags to be removed from filetags in pconfig
            $deleted_tags = [];
            $check_deleted_tags = explode(",", self::fileToList($file_old, $type));

            foreach ($check_deleted_tags as $tag)
            {
                if (!stristr($file_new,$lbracket . self::encode($tag) . $rbracket)) {
                    $deleted_tags[] = $tag;
                }
            }

            foreach ($deleted_tags as $key => $tag)
            {
                $r = q("SELECT `oid` FROM `term` WHERE `term` = '%s' AND `otype` = %d AND `type` = %d AND `uid` = %d",
                    DBA::escape($tag),
                    intval(TERM_OBJ_POST),
                    intval($termtype),
                    intval($uid));

                if (DBA::isResult($r)) {
                    unset($deleted_tags[$key]);
                } else {
                    $filetags_updated = str_replace($lbracket . self::encode($tag) . $rbracket, '', $filetags_updated);
                }
            }

            if ($saved != $filetags_updated)
            {
                PConfig::set($uid, 'system', 'filetags', $filetags_updated);
            }

            return true;
        } elseif (strlen($file_new)) {
            PConfig::set($uid, 'system', 'filetags', $file_new);
        }

        return true;
    }

	/**
	 * @brief Add tag to file
	 *
	 * @param int    $uid     Unique identity.
	 * @param int    $item_id Item identity.
	 * @param string $file    File tag.
	 *
	 * @return boolean      A value indicating success or failure.
	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
	 */
    public static function saveFile($uid, $item_id, $file)
    {
        if (!intval($uid))
        {
            return false;
        }

        $item = Item::selectFirst(['file'], ['id' => $item_id, 'uid' => $uid]);
        if (DBA::isResult($item))
        {
            if (!stristr($item['file'], '[' . self::encode($file) . ']'))
            {
                $fields = ['file' => $item['file'] . '[' . self::encode($file) . ']'];
                Item::update($fields, ['id' => $item_id]);
            }

            $saved = PConfig::get($uid, 'system', 'filetags');

            if (!strlen($saved) || !stristr($saved, '[' . self::encode($file) . ']'))
            {
                PConfig::set($uid, 'system', 'filetags', $saved . '[' . self::encode($file) . ']');
            }

            info(L10n::t('Item filed'));
        }

        return true;
    }

	/**
	 * @brief Remove tag from file
	 *
	 * @param int     $uid     Unique identity.
	 * @param int     $item_id Item identity.
	 * @param string  $file    File tag.
	 * @param boolean $cat     Optional value indicating the term type (i.e. Category or File)
	 *
	 * @return boolean      A value indicating success or failure.
	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
	 */
    public static function unsaveFile($uid, $item_id, $file, $cat = false)
    {
        if (!intval($uid))
        {
            return false;
        }

        if ($cat == true) {
            $pattern = '<' . self::encode($file) . '>';
            $termtype = TERM_CATEGORY;
        } else {
            $pattern = '[' . self::encode($file) . ']';
            $termtype = TERM_FILE;
        }

        $item = Item::selectFirst(['file'], ['id' => $item_id, 'uid' => $uid]);

        if (!DBA::isResult($item))
        {
            return false;
        }

        $fields = ['file' => str_replace($pattern, '', $item['file'])];

        Item::update($fields, ['id' => $item_id]);

        $r = q("SELECT `oid` FROM `term` WHERE `term` = '%s' AND `otype` = %d AND `type` = %d AND `uid` = %d",
            DBA::escape($file),
            intval(TERM_OBJ_POST),
            intval($termtype),
            intval($uid)
        );

        if (!DBA::isResult($r))
        {
            $saved = PConfig::get($uid, 'system', 'filetags');
            PConfig::set($uid, 'system', 'filetags', str_replace($pattern, '', $saved));
        }

        return true;
    }
}
