<?php
/**
 * Phinx
 *
 * (The MIT license)
 * Copyright (c) 2015 Rob Morgan
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated * documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * @package    Phinx
 * @subpackage Phinx\Db\Adapter
 */
namespace Phinx\Db\Adapter;

use Phinx\Db\Table;
use Phinx\Db\Table\Column;
use Phinx\Db\Table\Index;
use Phinx\Db\Table\ForeignKey;

/**
 * Phinx SqlServer Adapter.
 *
 * @author Rob Morgan <robbym@gmail.com>
 */
class SqlServerAdapter extends PdoAdapter implements AdapterInterface
{
    protected $schema = 'dbo';

    protected $signedColumnTypes = array('integer' => true, 'biginteger' => true, 'float' => true, 'decimal' => true);

    /**
     * {@inheritdoc}
     */
    public function connect()
    {
        if (null === $this->connection) {
            if (!class_exists('PDO') || !in_array('sqlsrv', \PDO::getAvailableDrivers(), true)) {
                // try our connection via freetds (Mac/Linux)
                return $this->connectDblib();
            }

            $db = null;
            $options = $this->getOptions();

            // if port is specified use it, otherwise use the SqlServer default
            if (empty($options['port'])) {
                $dsn = 'sqlsrv:server=' . $options['host'] . ';database=' . $options['name'];
            } else {
                $dsn = 'sqlsrv:server=' . $options['host'] . ',' . $options['port'] . ';database=' . $options['name'];
            }
            $dsn .= ';MultipleActiveResultSets=false';

            $driverOptions = array(\PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION);

            // charset support
            if (isset($options['charset'])) {
                $driverOptions[\PDO::SQLSRV_ATTR_ENCODING] = $options['charset'];
            }

            // support arbitrary \PDO::SQLSRV_ATTR_* driver options and pass them to PDO
            // http://php.net/manual/en/ref.pdo-sqlsrv.php#pdo-sqlsrv.constants
            foreach ($options as $key => $option) {
                if (strpos($key, 'sqlsrv_attr_') === 0) {
                    $driverOptions[constant('\PDO::' . strtoupper($key))] = $option;
                }
            }

            try {
                $db = new \PDO($dsn, $options['user'], $options['pass'], $driverOptions);
            } catch (\PDOException $exception) {
                throw new \InvalidArgumentException(sprintf(
                    'There was a problem connecting to the database: %s',
                    $exception->getMessage()
                ));
            }

            $this->setConnection($db);
        }
    }

    /**
     * Connect to MSSQL using dblib/freetds.
     *
     * The "sqlsrv" driver is not available on Unix machines.
     *
     * @throws \InvalidArgumentException
     */
    protected function connectDblib()
    {
        if (!class_exists('PDO') || !in_array('dblib', \PDO::getAvailableDrivers(), true)) {
            // @codeCoverageIgnoreStart
            throw new \RuntimeException('You need to enable the PDO_Dblib extension for Phinx to run properly.');
            // @codeCoverageIgnoreEnd
        }

        $options = $this->getOptions();

        // if port is specified use it, otherwise use the SqlServer default
        if (empty($options['port'])) {
            $dsn = 'dblib:host=' . $options['host'] . ';dbname=' . $options['name'];
        } else {
            $dsn = 'dblib:host=' . $options['host'] . ':' . $options['port'] . ';dbname=' . $options['name'];
        }

        $driverOptions = array(\PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION);


        try {
            $db = new \PDO($dsn, $options['user'], $options['pass'], $driverOptions);
        } catch (\PDOException $exception) {
            throw new \InvalidArgumentException(sprintf(
                'There was a problem connecting to the database: %s',
                $exception->getMessage()
            ));
        }

        $this->setConnection($db);
    }

    /**
     * {@inheritdoc}
     */
    public function disconnect()
    {
        $this->connection = null;
    }

    /**
     * {@inheritdoc}
     */
    public function hasTransactions()
    {
        return true;
    }

    /**
     * {@inheritdoc}
     */
    public function beginTransaction()
    {
        $this->execute('BEGIN TRANSACTION');
    }

    /**
     * {@inheritdoc}
     */
    public function commitTransaction()
    {
        $this->execute('COMMIT TRANSACTION');
    }

    /**
     * {@inheritdoc}
     */
    public function rollbackTransaction()
    {
        $this->execute('ROLLBACK TRANSACTION');
    }

    /**
     * {@inheritdoc}
     */
    public function quoteTableName($tableName)
    {
        return str_replace('.', '].[', $this->quoteColumnName($tableName));
    }

    /**
     * {@inheritdoc}
     */
    public function quoteColumnName($columnName)
    {
        return '[' . str_replace(']', '\]', $columnName) . ']';
    }

    /**
     * {@inheritdoc}
     */
    public function hasTable($tableName)
    {
        $result = $this->fetchRow(sprintf('SELECT count(*) as [count] FROM information_schema.tables WHERE table_name = \'%s\';', $tableName));
        return $result['count'] > 0;
    }

    /**
     * {@inheritdoc}
     */
    public function createTable(Table $table)
    {
        $this->startCommandTimer();

        $options = $table->getOptions();

        // Add the default primary key
        $columns = $table->getPendingColumns();
        if (!isset($options['id']) || (isset($options['id']) && $options['id'] === true)) {
            $column = new Column();
            $column->setName('id')
                   ->setType('integer')
                   ->setIdentity(true);

            array_unshift($columns, $column);
            $options['primary_key'] = 'id';

        } elseif (isset($options['id']) && is_string($options['id'])) {
            // Handle id => "field_name" to support AUTO_INCREMENT
            $column = new Column();
            $column->setName($options['id'])
                   ->setType('integer')
                   ->setIdentity(true);

            array_unshift($columns, $column);
            $options['primary_key'] = $options['id'];
        }

        $sql = 'CREATE TABLE ';
        $sql .= $this->quoteTableName($table->getName()) . ' (';
        $sqlBuffer = array();
        $columnsWithComments = array();
        foreach ($columns as $column) {
            $sqlBuffer[] = $this->quoteColumnName($column->getName()) . ' ' . $this->getColumnSqlDefinition($column);

            // set column comments, if needed
            if ($column->getComment()) {
                $columnsWithComments[] = $column;
            }
        }

        // set the primary key(s)
        if (isset($options['primary_key'])) {
            $pkSql = sprintf('CONSTRAINT PK_%s PRIMARY KEY (', $table->getName());
            if (is_string($options['primary_key'])) { // handle primary_key => 'id'
                $pkSql .= $this->quoteColumnName($options['primary_key']);
            } elseif (is_array($options['primary_key'])) { // handle primary_key => array('tag_id', 'resource_id')
                // PHP 5.4 will allow access of $this, so we can call quoteColumnName() directly in the anonymous function,
                // but for now just hard-code the adapter quotes
                $pkSql .= implode(
                    ',',
                    array_map(
                        function ($v) {
                            return '[' . $v . ']';
                        },
                        $options['primary_key']
                    )
                );
            }
            $pkSql .= ')';
            $sqlBuffer[] = $pkSql;
        }

        // set the foreign keys
        $foreignKeys = $table->getForeignKeys();
        if (!empty($foreignKeys)) {
            foreach ($foreignKeys as $foreignKey) {
                $sqlBuffer[] = $this->getForeignKeySqlDefinition($foreignKey, $table->getName());
            }
        }

        $sql .= implode(', ', $sqlBuffer);
        $sql .= ');';

        // process column comments
        if (!empty($columnsWithComments)) {
            foreach ($columnsWithComments as $column) {
                $sql .= $this->getColumnCommentSqlDefinition($column, $table->getName());
            }
        }

        // set the indexes
        $indexes = $table->getIndexes();
        if (!empty($indexes)) {
            foreach ($indexes as $index) {
                $sql .= $this->getIndexSqlDefinition($index, $table->getName());
            }
        }

        // execute the sql
        $this->writeCommand('createTable', array($table->getName()));
        $this->execute($sql);
        $this->endCommandTimer();
    }

    /**
     * Gets the SqlServer Column Comment Defininition for a column object.
     *
     * @param Column $column    Column
     * @param string $tableName Table name
     *
     * @return string
     */
    protected function getColumnCommentSqlDefinition(Column $column, $tableName)
    {
        // passing 'null' is to remove column comment
        $currentComment = $this->getColumnComment($tableName, $column->getName());

        $comment = (strcasecmp($column->getComment(), 'NULL') !== 0) ? $this->getConnection()->quote($column->getComment()) : '\'\'';
        $command = $currentComment === false ? 'sp_addextendedproperty' : 'sp_updateextendedproperty';
        return sprintf(
            "EXECUTE %s N'MS_Description', N%s, N'SCHEMA', N'%s', N'TABLE', N'%s', N'COLUMN', N'%s';",
            $command,
            $comment,
            $this->schema,
            $tableName,
            $column->getName()
        );
    }

    /**
     * {@inheritdoc}
     */
    public function renameTable($tableName, $newTableName)
    {
        $this->startCommandTimer();
        $this->writeCommand('renameTable', array($tableName, $newTableName));
        $this->execute(sprintf('EXEC sp_rename \'%s\', \'%s\'', $tableName, $newTableName));
        $this->endCommandTimer();
    }

    /**
     * {@inheritdoc}
     */
    public function dropTable($tableName)
    {
        $this->startCommandTimer();
        $this->writeCommand('dropTable', array($tableName));
        $this->execute(sprintf('DROP TABLE %s', $this->quoteTableName($tableName)));
        $this->endCommandTimer();
    }

    public function getColumnComment($tableName, $columnName)
    {
        $sql = sprintf("SELECT cast(extended_properties.[value] as nvarchar(4000)) comment
  FROM sys.schemas
 INNER JOIN sys.tables
    ON schemas.schema_id = tables.schema_id
 INNER JOIN sys.columns
    ON tables.object_id = columns.object_id
 INNER JOIN sys.extended_properties
    ON tables.object_id = extended_properties.major_id
   AND columns.column_id = extended_properties.minor_id
   AND extended_properties.name = 'MS_Description'
   WHERE schemas.[name] = '%s' AND tables.[name] = '%s' AND columns.[name] = '%s'", $this->schema, $tableName, $columnName);
        $row = $this->fetchRow($sql);

        if ($row) {
            return $row['comment'];
        }

        return false;
    }

    /**
     * {@inheritdoc}
     */
    public function getColumns($tableName)
    {
        $columns = array();
        $sql = sprintf(
            "SELECT DISTINCT TABLE_SCHEMA AS [schema], TABLE_NAME as [table_name], COLUMN_NAME AS [name], DATA_TYPE AS [type],
            IS_NULLABLE AS [null], COLUMN_DEFAULT AS [default],
            CHARACTER_MAXIMUM_LENGTH AS [char_length],
            NUMERIC_PRECISION AS [precision],
            NUMERIC_SCALE AS [scale], ORDINAL_POSITION AS [ordinal_position],
            COLUMNPROPERTY(object_id(TABLE_NAME), COLUMN_NAME, 'IsIdentity') as [identity]
        FROM INFORMATION_SCHEMA.COLUMNS
        WHERE TABLE_NAME = '%s'
        ORDER BY ordinal_position",
            $tableName
        );
        $rows = $this->fetchAll($sql);
        foreach ($rows as $columnInfo) {
            $column = new Column();
            $column->setName($columnInfo['name'])
                   ->setType($this->getPhinxType($columnInfo['type']))
                   ->setNull($columnInfo['null'] !== 'NO')
                   ->setDefault($this->parseDefault($columnInfo['default']))
                   ->setIdentity($columnInfo['identity'] === '1')
                   ->setComment($this->getColumnComment($columnInfo['table_name'], $columnInfo['name']));

            if (!empty($columnInfo['char_length'])) {
                $column->setLimit($columnInfo['char_length']);
            }

            $columns[$columnInfo['name']] = $column;
        }

        return $columns;
    }

    protected function parseDefault($default)
    {
        $default = preg_replace(array("/\('(.*)'\)/", "/\(\((.*)\)\)/", "/\((.*)\)/"), '$1', $default);

        if (strtoupper($default) === 'NULL') {
            $default = null;
        } elseif (is_numeric($default)) {
            $default = (int) $default;
        }

        return $default;
    }

    /**
     * {@inheritdoc}
     */
    public function hasColumn($tableName, $columnName, $options = array())
    {
        $sql = sprintf(
            "SELECT count(*) as [count]
             FROM information_schema.columns
             WHERE table_name = '%s' AND column_name = '%s'",
            $tableName,
            $columnName
        );
        $result = $this->fetchRow($sql);

        return $result['count'] > 0;
    }

    /**
     * {@inheritdoc}
     */
    public function addColumn(Table $table, Column $column)
    {
        $this->startCommandTimer();
        $sql = sprintf(
            'ALTER TABLE %s ADD %s %s',
            $this->quoteTableName($table->getName()),
            $this->quoteColumnName($column->getName()),
            $this->getColumnSqlDefinition($column)
        );

        $this->writeCommand('addColumn', array($table->getName(), $column->getName(), $column->getType()));
        $this->execute($sql);
        $this->endCommandTimer();
    }

    /**
     * {@inheritdoc}
     */
    public function renameColumn($tableName, $columnName, $newColumnName)
    {
        $this->startCommandTimer();

        if (!$this->hasColumn($tableName, $columnName)) {
            throw new \InvalidArgumentException("The specified column does not exist: $columnName");
        }
        $this->writeCommand('renameColumn', array($tableName, $columnName, $newColumnName));
        $this->renameDefault($tableName, $columnName, $newColumnName);
        $this->execute(
             sprintf(
                 "EXECUTE sp_rename N'%s.%s', N'%s', 'COLUMN' ",
                 $tableName,
                 $columnName,
                 $newColumnName
             )
        );
        $this->endCommandTimer();
    }

    protected function renameDefault($tableName, $columnName, $newColumnName)
    {
        $oldConstraintName = "DF_{$tableName}_{$columnName}";
        $newConstraintName = "DF_{$tableName}_{$newColumnName}";
        $sql = <<<SQL
IF (OBJECT_ID('$oldConstraintName', 'D') IS NOT NULL)
BEGIN
     EXECUTE sp_rename N'%s', N'%s', N'OBJECT'
END
SQL;
        $this->execute(sprintf(
            $sql,
            $oldConstraintName,
            $newConstraintName
        ));
    }

    public function changeDefault($tableName, Column $newColumn)
    {
        $constraintName = "DF_{$tableName}_{$newColumn->getName()}";
        $default = $newColumn->getDefault();

        if ($default === null) {
            $default = 'DEFAULT NULL';
        } else {
            $default = $this->getDefaultValueDefinition($default);
        }

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

        $this->execute(sprintf(
            'ALTER TABLE %s ADD CONSTRAINT %s %s FOR %s',
            $this->quoteTableName($tableName),
            $constraintName,
            $default,
            $this->quoteColumnName($newColumn->getName())
        ));
    }

    /**
     * {@inheritdoc}
     */
    public function changeColumn($tableName, $columnName, Column $newColumn)
    {
        $this->startCommandTimer();
        $this->writeCommand('changeColumn', array($tableName, $columnName, $newColumn->getType()));
        $columns = $this->getColumns($tableName);
        $changeDefault = $newColumn->getDefault() !== $columns[$columnName]->getDefault() || $newColumn->getType() !== $columns[$columnName]->getType();
        if ($columnName !== $newColumn->getName()) {
            $this->renameColumn($tableName, $columnName, $newColumn->getName());
        }

        if ($changeDefault) {
            $this->dropDefaultConstraint($tableName, $newColumn->getName());
        }

        $this->execute(
            sprintf(
                'ALTER TABLE %s ALTER COLUMN %s %s',
                $this->quoteTableName($tableName),
                $this->quoteColumnName($newColumn->getName()),
                $this->getColumnSqlDefinition($newColumn, false)
            )
        );
        // change column comment if needed
        if ($newColumn->getComment()) {
            $sql = $this->getColumnCommentSqlDefinition($newColumn, $tableName);
            $this->execute($sql);
        }

        if ($changeDefault) {
            $this->changeDefault($tableName, $newColumn);
        }
        $this->endCommandTimer();
    }

    /**
     * {@inheritdoc}
     */
    public function dropColumn($tableName, $columnName)
    {
        $this->startCommandTimer();
        $this->writeCommand('dropColumn', array($tableName, $columnName));
        $this->dropDefaultConstraint($tableName, $columnName);

        $this->execute(
            sprintf(
                'ALTER TABLE %s DROP COLUMN %s',
                $this->quoteTableName($tableName),
                $this->quoteColumnName($columnName)
            )
        );
        $this->endCommandTimer();
    }

    protected function dropDefaultConstraint($tableName, $columnName)
    {
        $defaultConstraint = $this->getDefaultConstraint($tableName, $columnName);

        if (!$defaultConstraint) {
            return;
        }

        $this->dropForeignKey($tableName, $columnName, $defaultConstraint);
    }

    protected function getDefaultConstraint($tableName, $columnName)
    {
        $sql = "SELECT
    default_constraints.name
FROM
    sys.all_columns

        INNER JOIN
    sys.tables
        ON all_columns.object_id = tables.object_id

        INNER JOIN
    sys.schemas
        ON tables.schema_id = schemas.schema_id

        INNER JOIN
    sys.default_constraints
        ON all_columns.default_object_id = default_constraints.object_id

WHERE
        schemas.name = 'dbo'
    AND tables.name = '{$tableName}'
    AND all_columns.name = '{$columnName}'";

        $rows = $this->fetchAll($sql);
        return empty($rows) ? false : $rows[0]['name'];
    }

    protected function getIndexColums($tableId, $indexId)
    {
        $sql = "SELECT AC.[name] AS [column_name]
FROM sys.[index_columns] IC
  INNER JOIN sys.[all_columns] AC ON IC.[column_id] = AC.[column_id]
WHERE AC.[object_id] = {$tableId} AND IC.[index_id] = {$indexId}  AND IC.[object_id] = {$tableId}
ORDER BY IC.[key_ordinal];";

        $rows = $this->fetchAll($sql);
        $columns = array();
        foreach($rows as $row) {
            $columns[] = strtolower($row['column_name']);
        }
        return $columns;
    }

    /**
     * Get an array of indexes from a particular table.
     *
     * @param string $tableName Table Name
     * @return array
     */
    public function getIndexes($tableName)
    {
        $indexes = array();
        $sql = "SELECT I.[name] AS [index_name], I.[index_id] as [index_id], T.[object_id] as [table_id]
FROM sys.[tables] AS T
  INNER JOIN sys.[indexes] I ON T.[object_id] = I.[object_id]
WHERE T.[is_ms_shipped] = 0 AND I.[type_desc] <> 'HEAP'  AND T.[name] = '{$tableName}'
ORDER BY T.[name], I.[index_id];";

        $rows = $this->fetchAll($sql);
        foreach ($rows as $row) {
            $columns = $this->getIndexColums($row['table_id'], $row['index_id']);
            $indexes[$row['index_name']] = array('columns' => $columns);
        }

        return $indexes;
    }

    /**
     * {@inheritdoc}
     */
    public function hasIndex($tableName, $columns)
    {
        if (is_string($columns)) {
            $columns = array($columns); // str to array
        }

        $columns = array_map('strtolower', $columns);
        $indexes = $this->getIndexes($tableName);

        foreach ($indexes as $index) {
            $a = array_diff($columns, $index['columns']);

            if (empty($a)) {
                return true;
            }
        }

        return false;
    }

    /**
     * {@inheritdoc}
     */
    public function hasIndexByName($tableName, $indexName)
    {
        $indexes = $this->getIndexes($tableName);

        foreach ($indexes as $name => $index) {
            if ($name === $indexName) {
                 return true;
            }
        }

        return false;
    }

    /**
     * {@inheritdoc}
     */
    public function addIndex(Table $table, Index $index)
    {
        $this->startCommandTimer();
        $this->writeCommand('addIndex', array($table->getName(), $index->getColumns()));
        $sql = $this->getIndexSqlDefinition($index, $table->getName());
        $this->execute($sql);
        $this->endCommandTimer();
    }

    /**
     * {@inheritdoc}
     */
    public function dropIndex($tableName, $columns)
    {
        $this->startCommandTimer();
        if (is_string($columns)) {
            $columns = array($columns); // str to array
        }

        $this->writeCommand('dropIndex', array($tableName, $columns));
        $indexes = $this->getIndexes($tableName);
        $columns = array_map('strtolower', $columns);

        foreach ($indexes as $indexName => $index) {
            $a = array_diff($columns, $index['columns']);
            if (empty($a)) {
                $this->execute(
                    sprintf(
                        'DROP INDEX %s ON %s',
                        $this->quoteColumnName($indexName),
                        $this->quoteTableName($tableName)
                    )
                );
                $this->endCommandTimer();
                return;
            }
        }
    }

    /**
     * {@inheritdoc}
     */
    public function dropIndexByName($tableName, $indexName)
    {
        $this->startCommandTimer();

        $this->writeCommand('dropIndexByName', array($tableName, $indexName));
        $indexes = $this->getIndexes($tableName);

        foreach ($indexes as $name => $index) {
            if ($name === $indexName) {
                $this->execute(
                    sprintf(
                        'DROP INDEX %s ON %s',
                        $this->quoteColumnName($indexName),
                        $this->quoteTableName($tableName)
                    )
                );
                $this->endCommandTimer();
                return;
            }
        }
    }

    /**
     * {@inheritdoc}
     */
    public function hasForeignKey($tableName, $columns, $constraint = null)
    {
        if (is_string($columns)) {
            $columns = array($columns); // str to array
        }
        $foreignKeys = $this->getForeignKeys($tableName);
        if ($constraint) {
            if (isset($foreignKeys[$constraint])) {
                return !empty($foreignKeys[$constraint]);
            }
            return false;
        } else {
            foreach ($foreignKeys as $key) {
                $a = array_diff($columns, $key['columns']);
                if (empty($a)) {
                    return true;
                }
            }
            return false;
        }
    }

    /**
     * Get an array of foreign keys from a particular table.
     *
     * @param string $tableName Table Name
     * @return array
     */
    protected function getForeignKeys($tableName)
    {
        $foreignKeys = array();
        $rows = $this->fetchAll(sprintf(
            "SELECT
                    tc.constraint_name,
                    tc.table_name, kcu.column_name,
                    ccu.table_name AS referenced_table_name,
                    ccu.column_name AS referenced_column_name
                FROM
                    information_schema.table_constraints AS tc
                    JOIN information_schema.key_column_usage AS kcu ON tc.constraint_name = kcu.constraint_name
                    JOIN information_schema.constraint_column_usage AS ccu ON ccu.constraint_name = tc.constraint_name
                WHERE constraint_type = 'FOREIGN KEY' AND tc.table_name = '%s'
                ORDER BY kcu.ordinal_position",
            $tableName
        ));
        foreach ($rows as $row) {
            $foreignKeys[$row['constraint_name']]['table'] = $row['table_name'];
            $foreignKeys[$row['constraint_name']]['columns'][] = $row['column_name'];
            $foreignKeys[$row['constraint_name']]['referenced_table'] = $row['referenced_table_name'];
            $foreignKeys[$row['constraint_name']]['referenced_columns'][] = $row['referenced_column_name'];
        }

        return $foreignKeys;
    }

    /**
     * {@inheritdoc}
     */
    public function addForeignKey(Table $table, ForeignKey $foreignKey)
    {
        $this->startCommandTimer();
        $this->writeCommand('addForeignKey', array($table->getName(), $foreignKey->getColumns()));
        $this->execute(
            sprintf(
                'ALTER TABLE %s ADD %s',
                $this->quoteTableName($table->getName()),
                $this->getForeignKeySqlDefinition($foreignKey, $table->getName())
            )
        );
        $this->endCommandTimer();
    }

    /**
     * {@inheritdoc}
     */
    public function dropForeignKey($tableName, $columns, $constraint = null)
    {
        $this->startCommandTimer();
        if (is_string($columns)) {
            $columns = array($columns); // str to array
        }

        $this->writeCommand('dropForeignKey', array($tableName, $columns));

        if ($constraint) {
            $this->execute(
                sprintf(
                    'ALTER TABLE %s DROP CONSTRAINT %s',
                    $this->quoteTableName($tableName),
                    $constraint
                )
            );
            $this->endCommandTimer();
            return;
        } else {
            foreach ($columns as $column) {
                $rows = $this->fetchAll(sprintf(
                    "SELECT
                    tc.constraint_name,
                    tc.table_name, kcu.column_name,
                    ccu.table_name AS referenced_table_name,
                    ccu.column_name AS referenced_column_name
                FROM
                    information_schema.table_constraints AS tc
                    JOIN information_schema.key_column_usage AS kcu ON tc.constraint_name = kcu.constraint_name
                    JOIN information_schema.constraint_column_usage AS ccu ON ccu.constraint_name = tc.constraint_name
                WHERE constraint_type = 'FOREIGN KEY' AND tc.table_name = '%s' and ccu.column_name='%s'
                ORDER BY kcu.ordinal_position",
                    $tableName,
                    $column
                ));
                foreach ($rows as $row) {
                    $this->dropForeignKey($tableName, $columns, $row['constraint_name']);
                }
            }
        }
        $this->endCommandTimer();
    }

    /**
     * {@inheritdoc}
     */
    public function getSqlType($type, $limit = null)
    {
        switch ($type) {
            case static::PHINX_TYPE_STRING:
                return array('name' => 'nvarchar', 'limit' => 255);
                break;
            case static::PHINX_TYPE_CHAR:
                return array('name' => 'nchar', 'limit' => 255);
                break;
            case static::PHINX_TYPE_TEXT:
                return array('name' => 'ntext');
                break;
            case static::PHINX_TYPE_INTEGER:
                return array('name' => 'int');
                break;
            case static::PHINX_TYPE_BIG_INTEGER:
                return array('name' => 'bigint');
                break;
            case static::PHINX_TYPE_FLOAT:
                return array('name' => 'float');
                break;
            case static::PHINX_TYPE_DECIMAL:
                return array('name' => 'decimal');
                break;
            case static::PHINX_TYPE_DATETIME:
            case static::PHINX_TYPE_TIMESTAMP:
                return array('name' => 'datetime');
                break;
            case static::PHINX_TYPE_TIME:
                return array('name' => 'time');
                break;
            case static::PHINX_TYPE_DATE:
                return array('name' => 'date');
                break;
            case static::PHINX_TYPE_BLOB:
            case static::PHINX_TYPE_BINARY:
                return array('name' => 'varbinary');
                break;
            case static::PHINX_TYPE_BOOLEAN:
                return array('name' => 'bit');
                break;
            case static::PHINX_TYPE_UUID:
                return array('name' => 'uniqueidentifier');
            case static::PHINX_TYPE_FILESTREAM:
                return array('name' => 'varbinary', 'limit' => 'max');
            // Geospatial database types
            case static::PHINX_TYPE_GEOMETRY:
            case static::PHINX_TYPE_POINT:
            case static::PHINX_TYPE_LINESTRING:
            case static::PHINX_TYPE_POLYGON:
                // SQL Server stores all spatial data using a single data type.
                // Specific types (point, polygon, etc) are set at insert time.
                return array('name' => 'geography');
                break;
            default:
                throw new \RuntimeException('The type: "' . $type . '" is not supported.');
        }
    }

    /**
     * Returns Phinx type by SQL type
     *
     * @param $sqlTypeDef
     * @throws \RuntimeException
     * @internal param string $sqlType SQL type
     * @returns string Phinx type
     */
    public function getPhinxType($sqlType)
    {
        switch ($sqlType) {
            case 'nvarchar':
            case 'varchar':
                return static::PHINX_TYPE_STRING;
            case 'char':
            case 'nchar':
                return static::PHINX_TYPE_CHAR;
            case 'text':
            case 'ntext':
                return static::PHINX_TYPE_TEXT;
            case 'int':
            case 'integer':
                return static::PHINX_TYPE_INTEGER;
            case 'decimal':
            case 'numeric':
            case 'money':
                return static::PHINX_TYPE_DECIMAL;
            case 'bigint':
                return static::PHINX_TYPE_BIG_INTEGER;
            case 'real':
            case 'float':
                return static::PHINX_TYPE_FLOAT;
            case 'binary':
            case 'image':
            case 'varbinary':
                return static::PHINX_TYPE_BINARY;
                break;
            case 'time':
                return static::PHINX_TYPE_TIME;
            case 'date':
                return static::PHINX_TYPE_DATE;
            case 'datetime':
            case 'timestamp':
                return static::PHINX_TYPE_DATETIME;
            case 'bit':
                return static::PHINX_TYPE_BOOLEAN;
            case 'uniqueidentifier':
                return static::PHINX_TYPE_UUID;
            case 'filestream':
                return static::PHINX_TYPE_FILESTREAM;
            default:
                throw new \RuntimeException('The SqlServer type: "' . $sqlType . '" is not supported');
        }
    }

    /**
     * {@inheritdoc}
     */
    public function createDatabase($name, $options = array())
    {
        $this->startCommandTimer();
        $this->writeCommand('createDatabase', array($name));

        if (isset($options['collation'])) {
            $this->execute(sprintf('CREATE DATABASE [%s] COLLATE [%s]', $name, $options['collation']));
        } else {
            $this->execute(sprintf('CREATE DATABASE [%s]', $name));
        }
        $this->execute(sprintf('USE [%s]', $name));
        $this->endCommandTimer();
    }

    /**
     * {@inheritdoc}
     */
    public function hasDatabase($name)
    {
        $result = $this->fetchRow(
            sprintf(
                'SELECT count(*) as [count] FROM master.dbo.sysdatabases WHERE [name] = \'%s\'',
                $name
            )
        );

        return $result['count'] > 0;
    }

    /**
     * {@inheritdoc}
     */
    public function dropDatabase($name)
    {
        $this->startCommandTimer();
        $this->writeCommand('dropDatabase', array($name));
        $sql = <<<SQL
USE master;
IF EXISTS(select * from sys.databases where name=N'$name')
ALTER DATABASE [$name] SET SINGLE_USER WITH ROLLBACK IMMEDIATE;
DROP DATABASE [$name];
SQL;
        $this->execute($sql);
        $this->endCommandTimer();
    }

    /**
     * Get the defintion for a `DEFAULT` statement.
     *
     * @param  mixed $default
     * @return string
     */
    protected function getDefaultValueDefinition($default)
    {
        if (is_string($default) && 'CURRENT_TIMESTAMP' !== $default) {
            $default = $this->getConnection()->quote($default);
        } elseif (is_bool($default)) {
            $default = $this->castToBool($default);
        }
        return isset($default) ? ' DEFAULT ' . $default : '';
    }

    /**
     * Gets the SqlServer Column Definition for a Column object.
     *
     * @param Column $column Column
     * @return string
     */
    protected function getColumnSqlDefinition(Column $column, $create = true)
    {
        $buffer = array();

        $sqlType = $this->getSqlType($column->getType());
        $buffer[] = strtoupper($sqlType['name']);
        // integers cant have limits in SQlServer
        $noLimits = array(
            'bigint',
            'int',
            'tinyint'
        );
        if (!in_array($sqlType['name'], $noLimits) && ($column->getLimit() || isset($sqlType['limit']))) {
            $buffer[] = sprintf('(%s)', $column->getLimit() ? $column->getLimit() : $sqlType['limit']);
        }
        if ($column->getPrecision() && $column->getScale()) {
            $buffer[] = '(' . $column->getPrecision() . ',' . $column->getScale() . ')';
        }

        $properties = $column->getProperties();
        $buffer[] = $column->getType() === 'filestream' ? 'FILESTREAM' : '';
        $buffer[] = isset($properties['rowguidcol']) ? 'ROWGUIDCOL' : '';

        $buffer[] = $column->isNull() ? 'NULL' : 'NOT NULL';

        if ($create === true) {
            if ($column->getDefault() === null && $column->isNull()) {
                $buffer[] = ' DEFAULT NULL';
            } else {
                $buffer[] = $this->getDefaultValueDefinition($column->getDefault());
            }
        }

        if ($column->isIdentity()) {
            $buffer[] = 'IDENTITY(1, 1)';
        }

        return implode(' ', $buffer);
    }

    /**
     * Gets the SqlServer Index Definition for an Index object.
     *
     * @param Index $index Index
     * @return string
     */
    protected function getIndexSqlDefinition(Index $index, $tableName)
    {
        if (is_string($index->getName())) {
            $indexName = $index->getName();
        } else {
            $columnNames = $index->getColumns();
            if (is_string($columnNames)) {
                $columnNames = array($columnNames);
            }
            $indexName = sprintf('%s_%s', $tableName, implode('_', $columnNames));
        }
        $def = sprintf(
            "CREATE %s INDEX %s ON %s (%s);",
            ($index->getType() === Index::UNIQUE ? 'UNIQUE' : ''),
            $indexName,
            $this->quoteTableName($tableName),
            '[' . implode('],[', $index->getColumns()) . ']'
        );

        return $def;
    }

    /**
     * Gets the SqlServer Foreign Key Definition for an ForeignKey object.
     *
     * @param ForeignKey $foreignKey
     * @return string
     */
    protected function getForeignKeySqlDefinition(ForeignKey $foreignKey, $tableName)
    {
        $def = ' CONSTRAINT "';
        $def .= $tableName . '_' . implode('_', $foreignKey->getColumns());
        $def .= '" FOREIGN KEY ("' . implode('", "', $foreignKey->getColumns()) . '")';
        $def .= " REFERENCES {$this->quoteTableName($foreignKey->getReferencedTable()->getName())} (\"" . implode('", "', $foreignKey->getReferencedColumns()) . '")';
        if ($foreignKey->getOnDelete()) {
            $def .= " ON DELETE {$foreignKey->getOnDelete()}";
        }
        if ($foreignKey->getOnUpdate()) {
            $def .= " ON UPDATE {$foreignKey->getOnUpdate()}";
        }

        return $def;
    }

    /**
     * {@inheritdoc}
     */
    public function getColumnTypes()
    {
        return array_merge(parent::getColumnTypes(), array('filestream'));
    }
}
