<?php

class Qs_Db extends Zend_Db
{
    const PERCENT_LEFT  = 10;
    const PERCENT_RIGHT = 11;
    const PERCENT_BOTH  = 12;

    /** @var Zend_Db_Adapter_Pdo_Mysql */
    protected static $_instance = null;

    protected static $_tableNames = array();
    protected static $_tables = array();

    /** @var Zend_Config */
    protected static $_config;

    /**
     * @static
     * @param  Zend_Config $config
     * @return Zend_Db_Adapter_Pdo_Mysql
     */
    public static function getInstance($config = null)
    {
        if (null === Qs_Db::$_instance) {
            if (null === $config) {
                $config = Qs_Db::getConfig();
            }
            Qs_Db::$_instance = Zend_Db::factory($config->database->adapter, $config->database->params->toArray());
            Zend_Db_Table::setDefaultAdapter(Qs_Db::$_instance);
        }
        return Qs_Db::$_instance;
    }

    public static function getSelect()
    {
        return static::getInstance()->select();
    }

    /**
     * @static
     * @return Zend_Config | mixed
     * @throws Qs_Db_Exception
     */
    public static function getConfig()
    {
        if (null === Qs_Db::$_config) {
            if (!Zend_Registry::isRegistered('config')) {
                throw new Qs_Db_Exception('config is not registered in Zend_Registry');
            }
            Qs_Db::$_config = Zend_Registry::get('config');
        }
        return Qs_Db::$_config;
    }

    public static function getTableName($shortName)
    {
        if (!isset(Qs_Db::$_tableNames[$shortName])) {
            $dbPrefix = explode('_', $shortName);
            $dbPrefix = reset($dbPrefix);
            $config = Qs_Db::getConfig();
            if (null !== ($additionalDatabases = $config->database->get('additionalDatabases'))) {
                if (null !== ($database = $additionalDatabases->get($dbPrefix))) {
                    $name = substr($shortName, strlen($dbPrefix) + 1);
                    Qs_Db::$_tableNames[$shortName] = $database->name . '.' . $database->tablePrefix . $name;
                } else {
                    Qs_Db::$_tableNames[$shortName] = $config->database->params->dbname . '.'
                                                    . $config->database->tablePrefix
                                                    . $shortName;
                }
            } else {
                Qs_Db::$_tableNames[$shortName] = $config->database->tablePrefix . $shortName;
            }
        }
        return Qs_Db::$_tableNames[$shortName];
    }

    public static function filter(Zend_Db_Select $select, array $filter, $alias)
    {
        if (empty($filter)) {
            return;
        }
        $tableInfo = Qs_Array::get($select->getPart(Zend_Db_Select::FROM), $alias);
        if (null === $tableInfo) {
            throw new Qs_Db_Exception(
                'Alias "' . $alias . '" not found in select "FROM" part'
                . print_r($select->getPart(Zend_Db_Select::FROM), true)
            );
        }
        $table = new Qs_Db_Table(array('name' => $tableInfo['tableName'], 'schema' => $tableInfo['schema']));
        $metaData = $table->getMetaData();
        foreach ($filter as $field => $value) {
            if (!array_key_exists($field, $metaData)) {
                continue;
            }
            $_field = $select->getAdapter()->quoteIdentifier($alias . '.' . $field);
            if (is_null($value)) {
                $_conditionAndValue = 'IS NULL';
            } else {
                $type = Qs_Db::_getMetaTypeToType(Qs_Array::get($metaData, $field . '[DATA_TYPE]'));
                $_condition = is_array($value) ? ' IN (?)' : '= ?';
                $_conditionAndValue = $select->getAdapter()->quoteInto($_condition, $value, $type);
            }
            $select->where($_field . ' ' . $_conditionAndValue);
        }
    }

    /**
     * Modified version of function Zend_Db_Adapter_Abstract->_whereExpr
     *
     * Convert an array, string, or Zend_Db_Expr object
     * into a string to put in a WHERE clause.
     *
     * @param array|string|Zend_Db_Expr $where
     * @return string
     */
    public static function getWhereSql($where)
    {
        if (empty($where)) {
            return 1;
        }
        $db = Qs_Db::getInstance();
        $where = (array) $where;
        foreach ($where as $condition => &$term) {
            if (is_int($condition)) {
                if ($term instanceof Zend_Db_Expr) {
                    $term = $term->__toString();
                }
            } else {
                $condition = (false !== strpos($condition, '?')) ? $condition : $condition . ' = ?';
                $term = $db->quoteInto($condition, $term);
            }
            $term = '(' . $term . ')';
        }
        $where = implode(' AND ', $where);
        return $where;
    }

    protected static function _getMetaTypeToType($type)
    {
        switch (strtolower($type)) {
            case 'mediumint':
                // break was intentionally omitted
            case 'smallint':
                // break was intentionally omitted
            case 'tinyint':
                // break was intentionally omitted
            case 'bit':
                // break was intentionally omitted
            case 'bool':
                // break was intentionally omitted
            case 'boolean':
                // break was intentionally omitted
            case 'int':
                $type = Qs_Db::INT_TYPE;
                break;
            case 'serial':
                // break was intentionally omitted
            case 'bingint':
                $type = Qs_Db::BIGINT_TYPE;
                break;
            case 'decimal':
                // break was intentionally omitted
            case 'double':
                // break was intentionally omitted
            case 'float':
                // break was intentionally omitted
            case 'real':
                $type = Qs_Db::FLOAT_TYPE;
                break;
            default:
                $type = null;
                break;
        }
        return $type;
    }

    public static function getPairExpr($tableAlias, $alias = null)
    {
        $pair = static::getPair($tableAlias, $alias);
        $db = static::getInstance();
        return new Zend_Db_Expr($db->quoteIdentifier(current($pair)) . ' AS ' . $db->quoteIdentifier(key($pair)));
    }

    public static function getPair($tableAlias, $alias = null)
    {
        if (null === $alias) {
            $alias = $tableAlias;
        }
        return array($alias => static::getTableName($tableAlias));
    }

    public static function getField($field, $alias = null)
    {
        return ((null === $alias) ? '' : $alias . '.') . $field;
    }

    public static function quoteField($field, $alias = null)
    {
        return Qs_Db::getInstance()->quoteIdentifier(static::getField($field, $alias));
    }

    public static function getLastQuery()
    {
        return Qs_Db::getInstance()->getProfiler()->getLastQueryProfile()->getQuery();
    }

    /**
     * Method quotes values according to meta data, unknown fields will be removed
     * @static
     * @param array $row
     * @param string|Zend_Db_Table $table Table alias or instance
     * @return array
     * @throws Qs_Db_Exception
     */
    public static function quoteRow(array $row, $table)
    {
        static $metaDataCache = array();

        $table = (is_string($table)) ? new Qs_Db_Table($table) : $table;
        if (!$table instanceof Zend_Db_Table) {
            throw new Qs_Db_Exception('Param $table expected to be "Zend_Db_Table" but "' . get_class($table) . '" found');
        }

        $tableName = $table->getName();
        if (!array_key_exists($tableName, $metaDataCache)) {
            $metaDataCache[$tableName] = $table->info(Zend_Db_Table::METADATA);
        }
        $metaData = $metaDataCache[$tableName];

        $db = static::getInstance();
        $quotedRow = array();
        foreach ($row as $name => $value) {
            if (array_key_exists($name, $metaData)) {
                $colMeta = $metaData[$name];
                $quotedRow[$name] = (null === $value && $colMeta['NULLABLE'])
                    ? 'NULL'
                    : $db->quote($value, static::_getMetaTypeToType($colMeta['DATA_TYPE']));
            }
        }
        return $quotedRow;
    }

    /**
     * Returns quoted list
     * @static
     * @param array $list
     * @param string|Zend_Db_Table $table Table alias or instance
     * @return array
     */
    public static function quoteList(array $list, $table)
    {
        $quotedList = array();
        foreach ($list as $key => $row) {
            $quotedList[$key] = static::quoteRow($row, $table);
        }
        return $quotedList;
    }

    /**
     * @static
     * @param $tableAlias string | array
     * @return bool|string
     */
    public static function getTableModificationTime($tableAlias)
    {
        $tableAlias = (array)$tableAlias;
        $tables = array_map('Qs_Db::getTableName', $tableAlias);
        if (empty($tables)) {
            return false;
        }
        $select = self::getSelect();
        $select->from('information_schema.tables', array('update_time'));
        $select->where('`table_schema` = ?', \Qs_Array::get(self::getInstance()->getConfig(), 'dbname'));
        $select->where('`table_name` IN(?)',  $tables);
        $select->order('update_time DESC');
        $select->limit(1);
        return Qs_Db::getInstance()->fetchOne($select);
    }

    public static function quote($value, $type = null)
    {
        if (is_string($value)) {
            $value = self::_escapeMetaChars($value);
        } elseif (is_array($value)) {
            foreach ($value as &$val) {
                $val = self::_escapeMetaChars($val);
            }
        }

        switch ($type) {
            case self::PERCENT_LEFT:
                $value = '%' . $value;
                $type = null;
                break;
            case self::PERCENT_RIGHT:
                $value = $value . '%';
                $type = null;
                break;
            case self::PERCENT_BOTH:
                $value = '%' . $value . '%';
                $type = null;
                break;
        }

        return Qs_Db::getInstance()->quote($value, $type);

    }

    protected static function _escapeMetaChars($value)
    {
        return str_replace(array('\\', '%', '_'), array('\\\\', '\%', '\_'), (string) $value);
    }

    /**
     * @param array|string $alias alias | [alias, shortAlias]
     * @param array|string $where
     * @return Zend_Db_Expr
     */
    public static function getCountExpr($alias, $where)
    {
        $pair = (is_array($alias))
            ? Qs_Db::getPair(array_shift($alias), array_shift($alias))
            : Qs_Db::getPair($alias);
        $select = Qs_Db::getSelect();
        $select->from($pair, array('COUNT(*)'));
        $select->where(Qs_Db::getWhereSql($where));
        return new \Zend_Db_Expr('(' . $select . ')');
    }

}