<?php
/**
 * tags model
 * @package EMLOG
 * @link https://www.emlog.net
 */

class Tag_Model {

    private $db;

    function __construct() {
        $this->db = Database::getInstance();
    }

    /**
     * 获取标签
     *
     * @param int $blogId
     * @return array
     */
    function getTag($blogId = NULL) {
        $tags = [];

        $tag_ids = $this->getTagIdsFromBlogId($blogId);
        $tag_names = $this->getNamesFromIds($tag_ids);

        foreach ($tag_names as $key => $value) {
            $row = [];
            $row['tagname'] = htmlspecialchars($value);
            $row['tid'] = (int)$key;
            $tags[] = $row;
        }

        return $tags;
    }

    function getOneTag($tagId) {
        $tag = [];
        $row = $this->db->once_fetch_array("SELECT tagname,tid FROM " . DB_PREFIX . "tag WHERE tid=$tagId");
        $tag['tagname'] = htmlspecialchars(trim($row['tagname']));
        $tag['tagid'] = (int)$row['tid'];
        return $tag;
    }

    function getTagByName($tagName) {
        $tagId = $this->getIdFromName($tagName);
        if (!$tagId) {
            return false;
        }
        return $this->getTagById($tagId);
    }

    function getTagById($tagId) {
        $blogs = $this->getBlogIdsFromTagId($tagId);
        $blogIdStr = implode(',', $blogs);
        return $blogIdStr;
    }

    function addTag($tagStr, $blogId) {
        $tagStr = trim($tagStr);
        $tagStr = str_replace('，', ',', $tagStr);

        if (empty($tagStr)) {
            return;
        }

        // 将标签string切割成标签array，并且去重
        $tagNameArray = explode(',', $tagStr);
        $tagNameArray = array_unique($tagNameArray);

        $tags = [];
        foreach ($tagNameArray as $tagName) {
            $tagName = trim($tagName);

            if (empty($tagName)) {
                continue;
            }

            // 从标签名获取到标签Id，如果标签不存在，则创建标签
            $tagId = $this->getIdFromName($tagName);

            if (!$tagId) {
                $tagId = $this->createTag($tagName, $blogId);
            }

            // 将当前文章Id插入到标签里
            $this->addBlogIntoTag($tagId, $blogId);

            $tags[] = $tagId;
        }

        // 保存当前文章关联的标签Id列表
        $tag_string = implode(',', $tags);
        $sql = "UPDATE `" . DB_PREFIX . "blog` SET `tags` = '" . $this->db->escape_string($tag_string) . "' WHERE `gid` = " . $blogId;
        $this->db->query($sql);
    }

    function updateTag($tagStr, $blogId) {
        $tagStr = trim($tagStr);
        $tagStr = str_replace('，', ',', $tagStr);

        // 旧的标签Id列表
        $old_tags = $this->getTagIdsFromBlogId($blogId);

        // 新的标签Id列表
        $new_tags = [];

        // 建立新的标签id数组
        if (!empty($tagStr)) {
            // 将标签string切割成标签array，并且去重
            $tagNameArray = explode(',', $tagStr);
            $tagNameArray = array_unique($tagNameArray);

            foreach ($tagNameArray as $tagName) {
                $tagName = trim($tagName);

                if (empty($tagName)) {
                    continue;
                }

                // 从标签名获取到标签Id，如果标签不存在，则创建标签
                $tagId = $this->getIdFromName($tagName);

                if (!$tagId) {
                    $tagId = $this->createTag($tagName);
                }

                $new_tags[] = $tagId;
            }
        }

        // 如果旧的标签Id在新的标签Id数组里不存在，则从Tag表里删除掉映射
        foreach ($old_tags as $each_tag) {
            if (!in_array($each_tag, $new_tags)) {
                $this->removeBlogIdFromTag($each_tag, $blogId);
            }
        }

        // 如果新的标签Id在旧的标签Id数组里不存在，则在Tag表里建立映射
        foreach ($new_tags as $each_tag) {
            if (!in_array($each_tag, $old_tags)) {
                $this->addBlogIntoTag($each_tag, $blogId);
            }
        }

        // 更新文章Tag映射
        $new_tag_string = implode(',', $new_tags);
        $sql = "UPDATE `" . DB_PREFIX . "blog` SET `tags` = '" . $this->db->escape_string($new_tag_string) . "' WHERE `gid` = " . $blogId;
        $this->db->query($sql);
    }

    function updateTagName($tagId, $tagName) {
        $sql = "UPDATE " . DB_PREFIX . "tag SET tagname='$tagName' WHERE tid=$tagId";
        $this->db->query($sql);
    }

    function deleteTag($tagId) {
        // 要删除一个标签，需要先检查哪些文章有引用这个标签，并把这个标签从那些引用中删除
        $linked_blogs = $this->getBlogIdsFromTagId($tagId);

        foreach ($linked_blogs as $blogId) {
            $this->removeTagIdFromBlog($blogId, $tagId);
        }

        $this->db->query("DELETE FROM " . DB_PREFIX . "tag where tid=$tagId");
    }

    /**
     * 从标签名查找标签ID
     * @param string $tagName 标签名
     * @return int|bool 标签ID | FALSE(未找到标签)
     */
    function getIdFromName($tagName) {
        $sql = "SELECT `tid` FROM `" . DB_PREFIX . "tag` WHERE `tagname` = '" . $tagName . "'";
        $query = $this->db->query($sql);

        if ($this->db->num_rows($query) === 0) {
            return FALSE;
        }

        $result = $this->db->fetch_array($query);
        return $result['tid'];
    }

    /**
     * 从一堆标签名查找一堆标签ID
     * @param string $tagNames 标签名 (以半角逗号分隔)
     * @return array 标签ID
     */
    function getIdsFromNames($tagNames) {
        $result = [];
        $tagNameArray = explode(',', $tagNames);

        foreach ($tagNameArray as $each) {
            $each = trim($each);

            if (empty($each)) {
                continue;
            }

            $each_id = $this->getIdFromName($each);

            if ($each_id !== FALSE) {
                $result[] = $each_id;
            }
        }
        return $result;
    }

    /**
     * 从一堆标签ID查找一堆标签名
     * @param array $tagIds 标签ID
     * @return array
     */
    function getNamesFromIds($tagIds = NULL) {
        $names = [];

        if (!empty($tagIds)) {
            $tag_string = implode(',', $tagIds);
            $sql = "SELECT `tid`, `tagname` FROM `" . DB_PREFIX . "tag` WHERE `tid` IN (" . $this->db->escape_string($tag_string) . ")";
            $query = $this->db->query($sql);

            if ($this->db->num_rows($query) > 0) {
                while ($result = $this->db->fetch_array($query)) {
                    $names[$result['tid']] = $result['tagname'];
                }
            }
        }

        return $names;
    }

    /**
     * 创建一个新的标签
     * @param string $tagName 标签名
     * @param string $blogId
     * @return int 标签ID
     */
    function createTag($tagName, $blogId = '') {
        $existTag = $this->getIdFromName($tagName);

        if (!$existTag) {
            $this->db->query("INSERT INTO `" . DB_PREFIX . "tag` (`tagname`,`gid`) VALUES('" . $this->db->escape_string($tagName) . "', '$blogId')");
            $existTag = $this->db->insert_id();
        }

        return $existTag;
    }

    /**
     * 创建一堆新标签
     * @param mixed $tagNames 标签名 (以半角逗号分隔)
     */
    function createTags($tagNames) {
        $tagNameArray = explode(',', $tagNames);

        foreach ($tagNameArray as $each) {
            $each = trim($each);

            if (empty($each)) {
                continue;
            }

            $this->createTag($each);
        }
    }

    /**
     * 从BlogId获取到TagId列表 (获取到文章所使用的Tag列表)
     * @param int $blogId 文章ID
     * @return array 标签ID列表
     */
    function getTagIdsFromBlogId($blogId = NULL) {
        if (empty($blogId)) {
            return $this->getAllTagIds();
        }

        $tags = [];

        $sql = "SELECT `tags` FROM `" . DB_PREFIX . "blog` WHERE `gid` = " . $blogId;

        $query = $this->db->query($sql);

        if ($this->db->num_rows($query) > 0) {
            $result = $this->db->fetch_array($query);

            if (!empty($result['tags'])) {
                $tags = explode(',', $result['tags']);
            }
        }

        return $tags;
    }

    function getAllTagIds() {
        $tags = [];

        $sql = "SELECT `tid` FROM `" . DB_PREFIX . "tag`";
        $query = $this->db->query($sql);

        if ($this->db->num_rows($query) > 0) {
            while ($result = $this->db->fetch_array($query)) {
                $tags [] = $result['tid'];
            }
        }

        return $tags;
    }

    function getTags($tag_name = '', $page_count = 50, $page = 1) {
        $startId = ($page - 1) * $page_count;
        $limit = "LIMIT $startId, " . $page_count;

        $condition = '';
        if ($tag_name) {
            $condition = " and tagname like '%$tag_name%'";
        }

        $tags = [];

        $sql = "SELECT * FROM `" . DB_PREFIX . "tag`  where 1=1 $condition ORDER BY `tid` DESC $limit";
        $query = $this->db->query($sql);

        if ($this->db->num_rows($query) > 0) {
            while ($result = $this->db->fetch_array($query)) {
                $tags [] = $result;
            }
        }

        return $tags;
    }

    function getTagsCount() {
        $data = $this->db->once_fetch_array("SELECT COUNT(*) AS total FROM " . DB_PREFIX . "tag");
        return $data['total'];
    }


    /**
     * 从TagId获取到BlogId列表 (获取到一个Tag下所有的文章)
     * @param int $tagId 标签ID
     * @return array 文章ID列表
     */
    function getBlogIdsFromTagId($tagId) {
        $blogs = [];

        $sql = "SELECT `gid` FROM `" . DB_PREFIX . "tag` WHERE `tid` = " . $tagId;
        $query = $this->db->query($sql);

        if ($this->db->num_rows($query) > 0) {
            $result = $this->db->fetch_array($query);

            if (!empty($result['gid'])) {
                $blogs = explode(',', $result['gid']);
            }
        }

        return $blogs;
    }

    /**
     * 从Tag表的Tag删除掉一篇文章引用
     * @param int $tagId
     * @param int $blogId
     */
    function removeBlogIdFromTag($tagId, $blogId) {
        $blogs = $this->getBlogIdsFromTagId($tagId);

        if (empty($blogs)) {
            return;
        }

        // 如果blogId存在，则构建一个新的不包含这个blogId的Blog数组，并保存到数据库
        if (in_array($blogId, $blogs)) {
            $new_blogs = [];

            foreach ($blogs as $each) {
                if ($each != $blogId) {
                    $new_blogs[] = $each;
                }
            }

            $blog_string = implode(',', $new_blogs);
            $sql = "UPDATE `" . DB_PREFIX . "tag` SET `gid` = '" . $this->db->escape_string($blog_string) . "' WHERE `tid` = " . $tagId;
            $this->db->query($sql);
        }
    }

    /**
     * 从TagMap表里的gid删除掉一个标签引用
     * @param int $blogId
     * @param int $tagId
     */
    function removeTagIdFromBlog($blogId, $tagId) {
        $tags = $this->getTagIdsFromBlogId($blogId);

        if (empty($tags)) {
            return;
        }

        // 如果tagId存在，则构建一个新的不包含这个TagId的Tag数组，并保存到数据库
        if (in_array($tagId, $tags)) {
            $new_tags = [];

            foreach ($tags as $each) {
                if ($each != $tagId) {
                    $new_tags[] = $each;
                }

                $tag_string = implode(',', $new_tags);
                $sql = "UPDATE `" . DB_PREFIX . "blog` SET `tags` = '" . $this->db->escape_string($tag_string) . "' WHERE `gid` = " . $blogId;
                $this->db->query($sql);
            }
        }
    }

    /**
     * 将BlogId插入到Tag表里
     * @param int $tagId 标签ID
     * @param int $blogId 文章ID
     */
    function addBlogIntoTag($tagId, $blogId) {
        $exist_blogs = $this->getBlogIdsFromTagId($tagId);

        if (!in_array($blogId, $exist_blogs)) {
            $exist_blogs[] = $blogId;

            $blog_string = implode(',', $exist_blogs);
            $sql = "UPDATE `" . DB_PREFIX . "tag` SET `gid` = '" . $this->db->escape_string($blog_string) . "' WHERE `tid` = " . $tagId;
            $this->db->query($sql);
        }
    }
}
