<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\db\cubrid;

use yii\db\Expression;
use yii\db\TableSchema;
use yii\db\ColumnSchema;

/**
 * Schema is the class for retrieving metadata from a CUBRID database (version 9.1.x and higher).
 *
 * @author Carsten Brandt <mail@cebe.cc>
 * @since 2.0
 */
class Schema extends \yii\db\Schema
{
	/**
	 * @var array mapping from physical column types (keys) to abstract column types (values)
	 * Please refer to [CUBRID manual](http://www.cubrid.org/manual/91/en/sql/datatype.html) for
	 * details on data types.
	 */
	public $typeMap = array(
		// Numeric data types
		'short' => self::TYPE_SMALLINT,
		'smallint' => self::TYPE_SMALLINT,
		'int' => self::TYPE_INTEGER,
		'integer' => self::TYPE_INTEGER,
		'bigint' => self::TYPE_BIGINT,
		'numeric' => self::TYPE_DECIMAL,
		'decimal' => self::TYPE_DECIMAL,
		'float' => self::TYPE_FLOAT,
		'real' => self::TYPE_FLOAT,
		'double' => self::TYPE_FLOAT,
		'double precision' => self::TYPE_FLOAT,
		'monetary' => self::TYPE_MONEY,
		// Date/Time data types
		'date' => self::TYPE_DATE,
		'time' => self::TYPE_TIME,
		'timestamp' => self::TYPE_TIMESTAMP,
		'datetime' => self::TYPE_DATETIME,
		// String data types
		'char' => self::TYPE_STRING,
		'varchar' => self::TYPE_STRING,
		'char varying' => self::TYPE_STRING,
		'nchar' => self::TYPE_STRING,
		'nchar varying' => self::TYPE_STRING,
		'string' => self::TYPE_STRING,
		// BLOB/CLOB data types
		'blob' => self::TYPE_BINARY,
		'clob' => self::TYPE_BINARY,
		// Bit string data types
//		'bit' => self::TYPE_STRING,
//		'bit varying' => self::TYPE_STRING,
		// Collection data types (TODO are considered strings for now, naybe support conversion?)
//		'set' => self::TYPE_STRING,
//		'multiset' => self::TYPE_STRING,
//		'list' => self::TYPE_STRING,
//		'sequence' => self::TYPE_STRING,
//		'enum' => self::TYPE_STRING,
	);

	/**
	 * Quotes a table name for use in a query.
	 * A simple table name has no schema prefix.
	 * @param string $name table name
	 * @return string the properly quoted table name
	 */
	public function quoteSimpleTableName($name)
	{
		return strpos($name, "`") !== false ? $name : "`" . $name . "`";
	}

	/**
	 * Quotes a column name for use in a query.
	 * A simple column name has no prefix.
	 * @param string $name column name
	 * @return string the properly quoted column name
	 */
	public function quoteSimpleColumnName($name)
	{
		return strpos($name, '`') !== false || $name === '*' ? $name : '`' . $name . '`';
	}

	/**
	 * Creates a query builder for the CUBRID database.
	 * @return QueryBuilder query builder instance
	 */
	public function createQueryBuilder()
	{
		return new QueryBuilder($this->db);
	}

	/**
	 * Loads the metadata for the specified table.
	 * @param string $name table name
	 * @return TableSchema driver dependent table metadata. Null if the table does not exist.
	 */
	protected function loadTableSchema($name)
	{
		$this->db->open();
		$tableInfo = $this->db->pdo->cubrid_schema(\PDO::CUBRID_SCH_TABLE, $name);

		if (isset($tableInfo[0]['NAME'])) {
			$table = new TableSchema();
			$table->name = $tableInfo[0]['NAME'];

			$sql = 'SHOW FULL COLUMNS FROM ' . $this->quoteSimpleTableName($table->name);
			$columns = $this->db->createCommand($sql)->queryAll();

			foreach ($columns as $info) {
				$column = $this->loadColumnSchema($info);
				$table->columns[$column->name] = $column;
				if ($column->isPrimaryKey) {
					$table->primaryKey[] = $column->name;
					if ($column->autoIncrement) {
						$table->sequenceName = '';
					}
				}
			}

			$foreignKeys = $this->db->pdo->cubrid_schema(\PDO::CUBRID_SCH_IMPORTED_KEYS, $table->name);
			foreach($foreignKeys as $key) {
				$table->foreignKeys[] = array(
					$key['PKTABLE_NAME'],
					$key['FKCOLUMN_NAME'] => $key['PKCOLUMN_NAME']
					// TODO support composite foreign keys
				);
			}

			return $table;
		} else {
			return null;
		}
	}

	/**
	 * Loads the column information into a [[ColumnSchema]] object.
	 * @param array $info column information
	 * @return ColumnSchema the column schema object
	 */
	protected function loadColumnSchema($info)
	{
		$column = new ColumnSchema();

		$column->name = $info['Field'];
		$column->allowNull = $info['Null'] === 'YES';
		$column->isPrimaryKey = strpos($info['Key'], 'PRI') !== false;
		$column->autoIncrement = stripos($info['Extra'], 'auto_increment') !== false;

		$column->dbType = strtolower($info['Type']);
		$column->unsigned = strpos($column->dbType, 'unsigned') !== false;

		$column->type = self::TYPE_STRING;
		if (preg_match('/^([\w ]+)(?:\(([^\)]+)\))?/', $column->dbType, $matches)) {
			$type = $matches[1];
			if (isset($this->typeMap[$type])) {
				$column->type = $this->typeMap[$type];
			}
			if (!empty($matches[2])) {
				if ($type === 'enum') {
					$values = explode(',', $matches[2]);
					foreach ($values as $i => $value) {
						$values[$i] = trim($value, "'");
					}
					$column->enumValues = $values;
				} else {
					$values = explode(',', $matches[2]);
					$column->size = $column->precision = (int)$values[0];
					if (isset($values[1])) {
						$column->scale = (int)$values[1];
					}
					if ($type === 'bit' || $type === 'bit varying') {
						if ($column->size === 1) {
							$column->type = self::TYPE_BOOLEAN;
						} elseif ($column->size > 32) {
							$column->type = self::TYPE_BIGINT;
						} elseif ($column->size === 32) {
							$column->type = self::TYPE_INTEGER;
						}
					}
				}
			}
		}

		$column->phpType = $this->getColumnPhpType($column);

		if ($column->type === 'timestamp' && $info['Default'] === 'CURRENT_TIMESTAMP' ||
			$column->type === 'datetime' && $info['Default'] === 'SYS_DATETIME' ||
			$column->type === 'date' && $info['Default'] === 'SYS_DATE' ||
			$column->type === 'time' && $info['Default'] === 'SYS_TIME') {
			$column->defaultValue = new Expression($info['Default']);
		} else {
			$column->defaultValue = $column->typecast($info['Default']);
		}

		return $column;
	}

	/**
	 * Returns all table names in the database.
	 * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
	 * @return array all table names in the database. The names have NO schema name prefix.
	 */
	protected function findTableNames($schema = '')
	{
		$this->db->open();
		$tables = $this->db->pdo->cubrid_schema(\PDO::CUBRID_SCH_TABLE);
		$tableNames = array();
		foreach($tables as $table) {
			// do not list system tables
			if ($table['TYPE'] !== 0) {
				$tableNames[] = $table['NAME'];
			}
		}
		return $tableNames;
	}
}