<?php
/**
 * Query class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2012 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\db\dao;

/**
 * Query represents the components in a DB query.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class Query extends CComponent
{
	/**
	 * @var mixed the columns being selected. This refers to the SELECT clause in an SQL
	 * statement. The property can be either a string (column names separated by commas)
	 * or an array of column names. Defaults to '*', meaning all columns.
	 */
	public $select;
	/**
	 * @var string additional option that should be appended to the 'SELECT' keyword. For example,
	 * in MySQL, the option 'SQL_CALC_FOUND_ROWS' can be used.
	 */
	public $selectOption;

	public $from;
	/**
	 * @var boolean whether to select distinct rows of data only. If this is set true,
	 * the SELECT clause would be changed to SELECT DISTINCT.
	 */
	public $distinct;
	/**
	 * @var string query condition. This refers to the WHERE clause in an SQL statement.
	 * For example, <code>age>31 AND team=1</code>.
	 */
	public $where;
	/**
	 * @var integer maximum number of records to be returned. If less than 0, it means no limit.
	 */
	public $limit;
	/**
	 * @var integer zero-based offset from where the records are to be returned. If less than 0, it means starting from the beginning.
	 */
	public $offset;
	/**
	 * @var string how to sort the query results. This refers to the ORDER BY clause in an SQL statement.
	 */
	public $orderBy;
	/**
	 * @var string how to group the query results. This refers to the GROUP BY clause in an SQL statement.
	 * For example, <code>'projectID, teamID'</code>.
	 */
	public $groupBy;
	/**
	 * @var string how to join with other tables. This refers to the JOIN clause in an SQL statement.
	 * For example, <code>'LEFT JOIN users ON users.id=authorID'</code>.
	 */
	public $join;
	/**
	 * @var string the condition to be applied with GROUP-BY clause.
	 * For example, <code>'SUM(revenue)<50000'</code>.
	 */
	public $having;
	/**
	 * @var array list of query parameter values indexed by parameter placeholders.
	 * For example, <code>array(':name'=>'Dan', ':age'=>31)</code>.
	 */
	public $params;

	public $union;


	public function getSql($connection)
	{
		return $connection->getQueryBuilder()->build($this);
	}

	/**
	 * Appends a condition to the existing {@link condition}.
	 * The new condition and the existing condition will be concatenated via the specified operator
	 * which defaults to 'AND'.
	 * The new condition can also be an array. In this case, all elements in the array
	 * will be concatenated together via the operator.
	 * This method handles the case when the existing condition is empty.
	 * After calling this method, the {@link condition} property will be modified.
	 * @param mixed $condition the new condition. It can be either a string or an array of strings.
	 * @param string $operator the operator to join different conditions. Defaults to 'AND'.
	 * @return Query the criteria object itself
	 * @since 1.0.9
	 */
	public function addCondition($condition, $operator = 'AND')
	{
		if (is_array($condition))
		{
			if ($condition === array())
				return $this;
			$condition = '(' . implode(') ' . $operator . ' (', $condition) . ')';
		}
		if ($this->condition === '')
			$this->condition = $condition;
		else
			$this->condition = '(' . $this->condition . ') ' . $operator . ' (' . $condition . ')';
		return $this;
	}

	/**
	 * Appends a search condition to the existing {@link condition}.
	 * The search condition and the existing condition will be concatenated via the specified operator
	 * which defaults to 'AND'.
	 * The search condition is generated using the SQL LIKE operator with the given column name and
	 * search keyword.
	 * @param string $column the column name (or a valid SQL expression)
	 * @param string $keyword the search keyword. This interpretation of the keyword is affected by the next parameter.
	 * @param boolean $escape whether the keyword should be escaped if it contains characters % or _.
	 * When this parameter is true (default), the special characters % (matches 0 or more characters)
	 * and _ (matches a single character) will be escaped, and the keyword will be surrounded with a %
	 * character on both ends. When this parameter is false, the keyword will be directly used for
	 * matching without any change.
	 * @param string $operator the operator used to concatenate the new condition with the existing one.
	 * Defaults to 'AND'.
	 * @param string $like the LIKE operator. Defaults to 'LIKE'. You may also set this to be 'NOT LIKE'.
	 * @return Query the criteria object itself
	 * @since 1.0.10
	 */
	public function addSearchCondition($column, $keyword, $escape = true, $operator = 'AND', $like = 'LIKE')
	{
		if ($keyword == '')
			return $this;
		if ($escape)
			$keyword = '%' . strtr($keyword, array('%' => '\%', '_' => '\_', '\\' => '\\\\')) . '%';
		$condition = $column . " $like " . self::PARAM_PREFIX . self::$paramCount;
		$this->params[self::PARAM_PREFIX . self::$paramCount++] = $keyword;
		return $this->addCondition($condition, $operator);
	}

	/**
	 * Appends an IN condition to the existing {@link condition}.
	 * The IN condition and the existing condition will be concatenated via the specified operator
	 * which defaults to 'AND'.
	 * The IN condition is generated by using the SQL IN operator which requires the specified
	 * column value to be among the given list of values.
	 * @param string $column the column name (or a valid SQL expression)
	 * @param array $values list of values that the column value should be in
	 * @param string $operator the operator used to concatenate the new condition with the existing one.
	 * Defaults to 'AND'.
	 * @return Query the criteria object itself
	 * @since 1.0.10
	 */
	public function addInCondition($column, $values, $operator = 'AND')
	{
		if (($n = count($values)) < 1)
			return $this->addCondition('0=1', $operator); // 0=1 is used because in MSSQL value alone can't be used in WHERE
		if ($n === 1)
		{
			$value = reset($values);
			if ($value === null)
				return $this->addCondition($column . ' IS NULL');
			$condition = $column . '=' . self::PARAM_PREFIX . self::$paramCount;
			$this->params[self::PARAM_PREFIX . self::$paramCount++] = $value;
		}
		else
		{
			$params = array();
			foreach ($values as $value)
			{
				$params[] = self::PARAM_PREFIX . self::$paramCount;
				$this->params[self::PARAM_PREFIX . self::$paramCount++] = $value;
			}
			$condition = $column . ' IN (' . implode(', ', $params) . ')';
		}
		return $this->addCondition($condition, $operator);
	}

	/**
	 * Appends an NOT IN condition to the existing {@link condition}.
	 * The NOT IN condition and the existing condition will be concatenated via the specified operator
	 * which defaults to 'AND'.
	 * The NOT IN condition is generated by using the SQL NOT IN operator which requires the specified
	 * column value to be among the given list of values.
	 * @param string $column the column name (or a valid SQL expression)
	 * @param array $values list of values that the column value should not be in
	 * @param string $operator the operator used to concatenate the new condition with the existing one.
	 * Defaults to 'AND'.
	 * @return Query the criteria object itself
	 * @since 1.1.1
	 */
	public function addNotInCondition($column, $values, $operator = 'AND')
	{
		if (($n = count($values)) < 1)
			return $this;
		if ($n === 1)
		{
			$value = reset($values);
			if ($value === null)
				return $this->addCondition($column . ' IS NOT NULL');
			$condition = $column . '!=' . self::PARAM_PREFIX . self::$paramCount;
			$this->params[self::PARAM_PREFIX . self::$paramCount++] = $value;
		}
		else
		{
			$params = array();
			foreach ($values as $value)
			{
				$params[] = self::PARAM_PREFIX . self::$paramCount;
				$this->params[self::PARAM_PREFIX . self::$paramCount++] = $value;
			}
			$condition = $column . ' NOT IN (' . implode(', ', $params) . ')';
		}
		return $this->addCondition($condition, $operator);
	}

	/**
	 * Appends a condition for matching the given list of column values.
	 * The generated condition will be concatenated to the existing {@link condition}
	 * via the specified operator which defaults to 'AND'.
	 * The condition is generated by matching each column and the corresponding value.
	 * @param array $columns list of column names and values to be matched (name=>value)
	 * @param string $columnOperator the operator to concatenate multiple column matching condition. Defaults to 'AND'.
	 * @param string $operator the operator used to concatenate the new condition with the existing one.
	 * Defaults to 'AND'.
	 * @return Query the criteria object itself
	 * @since 1.0.10
	 */
	public function addColumnCondition($columns, $columnOperator = 'AND', $operator = 'AND')
	{
		$params = array();
		foreach ($columns as $name => $value)
		{
			if ($value === null)
				$params[] = $name . ' IS NULL';
			else
			{
				$params[] = $name . '=' . self::PARAM_PREFIX . self::$paramCount;
				$this->params[self::PARAM_PREFIX . self::$paramCount++] = $value;
			}
		}
		return $this->addCondition(implode(" $columnOperator ", $params), $operator);
	}

	/**
	 * Adds a comparison expression to the {@link condition} property.
	 *
	 * This method is a helper that appends to the {@link condition} property
	 * with a new comparison expression. The comparison is done by comparing a column
	 * with the given value using some comparison operator.
	 *
	 * The comparison operator is intelligently determined based on the first few
	 * characters in the given value. In particular, it recognizes the following operators
	 * if they appear as the leading characters in the given value:
	 * <ul>
	 * <li><code>&lt;</code>: the column must be less than the given value.</li>
	 * <li><code>&gt;</code>: the column must be greater than the given value.</li>
	 * <li><code>&lt;=</code>: the column must be less than or equal to the given value.</li>
	 * <li><code>&gt;=</code>: the column must be greater than or equal to the given value.</li>
	 * <li><code>&lt;&gt;</code>: the column must not be the same as the given value.
	 * Note that when $partialMatch is true, this would mean the value must not be a substring
	 * of the column.</li>
	 * <li><code>=</code>: the column must be equal to the given value.</li>
	 * <li>none of the above: the column must be equal to the given value. Note that when $partialMatch
	 * is true, this would mean the value must be the same as the given value or be a substring of it.</li>
	 * </ul>
	 *
	 * Note that any surrounding white spaces will be removed from the value before comparison.
	 * When the value is empty, no comparison expression will be added to the search condition.
	 *
	 * @param string $column the name of the column to be searched
	 * @param mixed $value the column value to be compared with. If the value is a string, the aforementioned
	 * intelligent comparison will be conducted. If the value is an array, the comparison is done
	 * by exact match of any of the value in the array. If the string or the array is empty,
	 * the existing search condition will not be modified.
	 * @param boolean $partialMatch whether the value should consider partial text match (using LIKE and NOT LIKE operators).
	 * Defaults to false, meaning exact comparison.
	 * @param string $operator the operator used to concatenate the new condition with the existing one.
	 * Defaults to 'AND'.
	 * @param boolean $escape whether the value should be escaped if $partialMatch is true and
	 * the value contains characters % or _. When this parameter is true (default),
	 * the special characters % (matches 0 or more characters)
	 * and _ (matches a single character) will be escaped, and the value will be surrounded with a %
	 * character on both ends. When this parameter is false, the value will be directly used for
	 * matching without any change.
	 * @return Query the criteria object itself
	 * @since 1.1.1
	 */
	public function compare($column, $value, $partialMatch = false, $operator = 'AND', $escape = true)
	{
		if (is_array($value))
		{
			if ($value === array())
				return $this;
			return $this->addInCondition($column, $value, $operator);
		}
		else
			$value = "$value";

		if (preg_match('/^(?:\s*(<>|<=|>=|<|>|=))?(.*)$/', $value, $matches))
		{
			$value = $matches[2];
			$op = $matches[1];
		}
		else
			$op = '';

		if ($value === '')
			return $this;

		if ($partialMatch)
		{
			if ($op === '')
				return $this->addSearchCondition($column, $value, $escape, $operator);
			if ($op === '<>')
				return $this->addSearchCondition($column, $value, $escape, $operator, 'NOT LIKE');
		}
		elseif ($op === '')
			$op = '=';

		$this->addCondition($column . $op . self::PARAM_PREFIX . self::$paramCount, $operator);
		$this->params[self::PARAM_PREFIX . self::$paramCount++] = $value;

		return $this;
	}

	/**
	 * Adds a between condition to the {@link condition} property.
	 *
	 * The new between condition and the existing condition will be concatenated via
	 * the specified operator which defaults to 'AND'.
	 * If one or both values are empty then the condition is not added to the existing condition.
	 * This method handles the case when the existing condition is empty.
	 * After calling this method, the {@link condition} property will be modified.
	 * @param string $column the name of the column to search between.
	 * @param string $valueStart the beginning value to start the between search.
	 * @param string $valueEnd the ending value to end the between search.
	 * @param string $operator the operator used to concatenate the new condition with the existing one.
	 * Defaults to 'AND'.
	 * @return Query the criteria object itself
	 * @since 1.1.2
	 */
	public function addBetweenCondition($column, $valueStart, $valueEnd, $operator = 'AND')
	{
		if ($valueStart === '' || $valueEnd === '')
			return $this;

		$paramStart = self::PARAM_PREFIX . self::$paramCount++;
		$paramEnd = self::PARAM_PREFIX . self::$paramCount++;
		$this->params[$paramStart] = $valueStart;
		$this->params[$paramEnd] = $valueEnd;
		$condition = "$column BETWEEN $paramStart AND $paramEnd";

		if ($this->condition === '')
			$this->condition = $condition;
		else
			$this->condition = '(' . $this->condition . ') ' . $operator . ' (' . $condition . ')';
		return $this;
	}

	/**
	 * Merges with another criteria.
	 * In general, the merging makes the resulting criteria more restrictive.
	 * For example, if both criterias have conditions, they will be 'AND' together.
	 * Also, the criteria passed as the parameter takes precedence in case
	 * two options cannot be merged (e.g. LIMIT, OFFSET).
	 * @param Query $criteria the criteria to be merged with.
	 * @param boolean $useAnd whether to use 'AND' to merge condition and having options.
	 * If false, 'OR' will be used instead. Defaults to 'AND'. This parameter has been
	 * available since version 1.0.6.
	 * @since 1.0.5
	 */
	public function mergeWith($criteria, $useAnd = true)
	{
		$and = $useAnd ? 'AND' : 'OR';
		if (is_array($criteria))
			$criteria = new self($criteria);
		if ($this->select !== $criteria->select)
		{
			if ($this->select === '*')
				$this->select = $criteria->select;
			elseif ($criteria->select !== '*')
			{
				$select1 = is_string($this->select) ? preg_split('/\s*,\s*/', trim($this->select), -1, PREG_SPLIT_NO_EMPTY) : $this->select;
				$select2 = is_string($criteria->select) ? preg_split('/\s*,\s*/', trim($criteria->select), -1, PREG_SPLIT_NO_EMPTY) : $criteria->select;
				$this->select = array_merge($select1, array_diff($select2, $select1));
			}
		}

		if ($this->condition !== $criteria->condition)
		{
			if ($this->condition === '')
				$this->condition = $criteria->condition;
			elseif ($criteria->condition !== '')
				$this->condition = "( {$this->condition}) $and ( {$criteria->condition})";
		}

		if ($this->params !== $criteria->params)
			$this->params = array_merge($this->params, $criteria->params);

		if ($criteria->limit > 0)
			$this->limit = $criteria->limit;

		if ($criteria->offset >= 0)
			$this->offset = $criteria->offset;

		if ($criteria->alias !== null)
			$this->alias = $criteria->alias;

		if ($this->order !== $criteria->order)
		{
			if ($this->order === '')
				$this->order = $criteria->order;
			elseif ($criteria->order !== '')
				$this->order = $criteria->order . ', ' . $this->order;
		}

		if ($this->group !== $criteria->group)
		{
			if ($this->group === '')
				$this->group = $criteria->group;
			elseif ($criteria->group !== '')
				$this->group .= ', ' . $criteria->group;
		}

		if ($this->join !== $criteria->join)
		{
			if ($this->join === '')
				$this->join = $criteria->join;
			elseif ($criteria->join !== '')
				$this->join .= ' ' . $criteria->join;
		}

		if ($this->having !== $criteria->having)
		{
			if ($this->having === '')
				$this->having = $criteria->having;
			elseif ($criteria->having !== '')
				$this->having = "( {$this->having}) $and ( {$criteria->having})";
		}

		if ($criteria->distinct > 0)
			$this->distinct = $criteria->distinct;

		if ($criteria->together !== null)
			$this->together = $criteria->together;

		if ($criteria->index !== null)
			$this->index = $criteria->index;

		if (empty($this->scopes))
			$this->scopes = $criteria->scopes;
		elseif (!empty($criteria->scopes))
		{
			$scopes1 = (array)$this->scopes;
			$scopes2 = (array)$criteria->scopes;
			foreach ($scopes1 as $k => $v)
			{
				if (is_integer($k))
					$scopes[] = $v;
				elseif (isset($scopes2[$k]))
					$scopes[] = array($k => $v);
				else
					$scopes[$k] = $v;
			}
			foreach ($scopes2 as $k => $v)
			{
				if (is_integer($k))
					$scopes[] = $v;
				elseif (isset($scopes1[$k]))
					$scopes[] = array($k => $v);
				else
					$scopes[$k] = $v;
			}
			$this->scopes = $scopes;
		}

		if (empty($this->with))
			$this->with = $criteria->with;
		elseif (!empty($criteria->with))
		{
			$this->with = (array)$this->with;
			foreach ((array)$criteria->with as $k => $v)
			{
				if (is_integer($k))
					$this->with[] = $v;
				elseif (isset($this->with[$k]))
				{
					$excludes = array();
					foreach (array('joinType', 'on') as $opt)
					{
						if (isset($this->with[$k][$opt]))
							$excludes[$opt] = $this->with[$k][$opt];
						if (isset($v[$opt]))
							$excludes[$opt] = ($opt === 'on' && isset($excludes[$opt]) && $v[$opt] !== $excludes[$opt]) ?
								"($excludes[$opt]) AND $v[$opt]" : $v[$opt];
						unset($this->with[$k][$opt]);
						unset($v[$opt]);
					}
					$this->with[$k] = new self($this->with[$k]);
					$this->with[$k]->mergeWith($v, $useAnd);
					$this->with[$k] = $this->with[$k]->toArray();
					if (count($excludes) !== 0)
						$this->with[$k] = CMap::mergeArray($this->with[$k], $excludes);
				}
				else
					$this->with[$k] = $v;
			}
		}
	}

	/**
	 * @return array the array representation of the criteria
	 * @since 1.0.6
	 */
	public function toArray()
	{
		$result = array();
		foreach (array('select', 'condition', 'params', 'limit', 'offset', 'order', 'group', 'join', 'having', 'distinct', 'scopes', 'with', 'alias', 'index', 'together') as $name)
			$result[$name] = $this->$name;
		return $result;
	}
}