<?php

abstract class Qs_Sys_Db extends Zend_Db
{
    /** @var Zend_Db_Adapter_Pdo_Mssql */
    protected static $_instance = null;
    protected static $_tableNames = array();
    protected static $_tables = array();
    protected static $_config;

    /**
     * @static
     * @param  Zend_Config $config
     * @return Zend_Db_Adapter_Pdo_Mssql
     */
    public static function getInstance($config = null)
    {
        if (null === Qs_Db::$_instance) {
            if (null === $config) {
                $config = Qs_Db::getConfig();
            }
            Qs_Db::$_instance = Zend_Db::factory($config->database->adapter, $config->database->params->toArray());
            Qs_Db::$_instance->getConnection()->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
            if (isset($config->database->initCommands)) {
                foreach ($config->database->initCommands->toArray() as $sql) {
                    Qs_Db::$_instance->query($sql);
                }
            }
        }
        return Qs_Db::$_instance;
    }
    
    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, $isService = false)
    {
        if (!isset(Qs_Db::$_tableNames[(int) $isService][$shortName])) {
            $config = Qs_Db::getConfig();
            Qs_Db::$_tableNames[(int) $isService][$shortName] = $config->database->tablePrefix
                                                              . (($isService) ? $config->database->servicePrefix : '')
                                                              . $shortName;
        }
        return Qs_Db::$_tableNames[(int) $isService][$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 {
                $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)
    {
        $pair = self::getPair($tableAlias, $alias);
        $db = self::getInstance();
        return new Zend_Db_Expr($db->quoteIdentifier(current($pair)) . ' AS ' . $db->quoteIdentifier(key($pair)));
    }

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

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

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