<?php

/**
 * $header
 * @copyright Copyright 2007, Peter Goodman
 * @package valkyrie
 * @subpackage Database.activerecord
 * @author Peter Goodman
 */

if(!defined('IN_VALKYRIE')) {
	exit;
}

/**
 * Class to handle table-level operations. This is a decorator class to the database
 * abstraction layer that gives a more intuitive interface to finding rows in the database.
 */
class DatabaseFinder implements VK_Finder {
	
	/**
	 * A reference to the current database abstraction layer.
	 * @see Database
	 */
	protected $dba;
	
	/**
	 * A reference to a table driver for this database.
	 */
	private $table;
	
	/**
	 * A reference to a model definition for this table.
	 * @see DatabaseModelDefinition
	 */
	private $definition;
	
	/**
	 * An array of transactions currently going on.
	 * @see Database::begin(), Database::end(), Database::commit(), Database::rollback()
	 * @internal
	 */
	private $transactions = array();
	
	/**
	 * Constructor, bring in the database layer and model definition.
	 * @param mixed $dba The database abstraction layer.
	 * @param mixed $model The model definition for the table that we're working with.
	 * @see Database, DatabaseModelDefinition
	 */
	public function __construct(DatabaseDriver $dba, DatabaseModelDefinition $definition) {
		
		$this->dba = $dba;
		$this->definition = $definition;
		
		// bring in the table driver for table-level operations
		$table_driver = $this->dba->layer . 'Table';
		$this->table = new $table_driver($this->dba, $this->definition);
	}
	
	/**
	 * Find a single row in the database by the value of its primary key.
	 * @param mixed $primary_key The value of a row's primary key.
	 * @return A new VK_DatabaseRecord
	 */
	public function find($primary_key = '') {
		return $this->findBy($this->definition->getPrimaryKey(), $primary_key);
	}
	
	/**
	 * Find a single row in the database given a table column name and a corresponding value.
	 * @param string $col The column name.
	 * @param mixed $val The value corresponding to the column name.
	 * @return A new VK_DatabaseRecord
	 */
	public function findBy($col = '', $val = '') {
		return $this->findWhere($col .'=?', array($val));
	}
	
	/**
	 * Find a single row in the database given conditions.
	 * @param string $where Everything that goes into a SQL WHERE clause.
	 * @param array $args Values to substitute into the SQL query for every question mark.
	 * @return A new VK_DatabaseRecord
	 */
	public function findWhere($where = '', array $args = array()) {
		return $this->findByQuery($this->buildQuery('*', $where, '', 1), $args);
	}
	
	/**
	 * Find the most recent entry into the db for this table.
	 */
	public function findLast() {
		return $this->findByQuery("SELECT * FROM ". $this->definition->getTable('name') ." GROUP BY ". $this->definition->getPrimaryKey() ." HAVING MAX(". $this->definition->getPrimaryKey() .") LIMIT 1");
	}
	
	public function findLastWhere($table, $value) {
		return $this->findByQuery("SELECT * FROM ". $this->definition->getTable('name') ." WHERE ". $table ."=". $value ." GROUP BY ". $this->definition->getPrimaryKey() ." HAVING MAX(". $this->definition->getPrimaryKey() .") LIMIT 1");
	}
	
	/**
	 * Find a single row in the databse by a query.
	 * @param string $stmt The query to execute.
	 * @param array $args Values to substitute into the SQL query for every question mark.
	 * @return A new VK_DatabaseRecord
	 */
	public function findByQuery($stmt = '', array $args = array()) {
		$record = $this->definition->getName() .'Record';
		
		if(!class_exists($record, FALSE)) {
			$record = 'VK_DatabaseRecord';
		}
		
		// add in any custom select things
		if($stmt instanceof VK_SelectQuery) {
			$this->definition->prepareSelect($stmt);
			$stmt = $stmt->getSql();
		}
		
		$result = $this->dba->select($stmt, $args)->fetch();
		$ret = NULL;
		
		if(!empty($result)) {
			$ret = new $record($result, $this->dba, $this->definition);
		}
		
		return $ret;
	}
	
	/**
	 * Find all rows
	 */
	public function findAll($limit = '', $order = '') {
		if($this->definition->getPrimaryKey() && $this->definition->getPrimaryKey() != '') {
			$order = $this->definition->getPrimaryKey() .' DESC';
		}
		
		return $this->findAllWhere('', array(), $order, $limit);
	}
	
	/**
	 * Find multiple rows in the database given a column name and a value for it.
	 * @param string $col The column name.
	 * @param mixed $val The value corresponding to the column name.
	 * @return A new VK_DatabaseRecordSet
	 */
	public function findAllBy($col = '', $val = '', $order = '', $limit = '') {
		return $this->findAllWhere($col .'=?', array($val), $order, $limit);
	}
	
	/**
	 * Find multiple rows in the database given conditions.
	 * @param string $where Everything that goes into a SQL WHERE clause.
	 * @param array $args Values to substitute into the SQL query for every question mark.
	 * @param string $order Everything that goes in the SQL ORDER BY clause
	 * @param string $limit Everything that goes in the SQL LIMIT clause
	 * @return A new VK_DatabaseRecordSet
	 */
	public function findAllWhere($where = '',$args = array(), $order = '', $limit = '') {
		return $this->findAllByQuery($this->buildQuery('*', $where, $order, $limit), $args);
	}
	
	/**
	 * Find multiple rows in the databse by a query.
	 * @param string $stmt The query to execute.
	 * @param array $args Values to substitute into the SQL query for every question mark.
	 * @return A new VK_DatabaseRecordSet
	 */
	public function findAllByQuery($stmt, array $args = array()) {
		
		// add in any custom select things
		if($stmt instanceof VK_SelectQuery) {
			$this->definition->prepareSelect($stmt);
			$stmt = $stmt->getSql();
		}
		
		$record = $this->definition->getName() .'RecordSet';
		
		if(!class_exists($record, FALSE)) {
			$record = 'VK_DatabaseRecordSet';
		}
		$result = $this->dba->select($stmt, $args);
		$ret = NULL;
		
		if($result->valid()) {
			$ret = new $record($result, $this->dba, $this->definition);
		}
		
		return $ret;
	}
	
	/**
	 * Find a single row in the databse given conditions and the columns that are to be selected.
	 * @param string $select A comma separated list of the columns that are to be selected.
	 * @param string $where Everything that goes into a SQL WHERE clause.
	 * @param array $args Values to substitute into the SQL query for every question mark.
	 * @param string $order Everything that goes in the SQL ORDER BY clause
	 * @param string $limit Everything that goes in the SQL LIMIT clause
	 * @return A new VK_DatabaseRecord
	 */
	public function selectWhere($select = '', $where = '', array $args = array(), $order = '') {
		return $this->findByQuery($this->buildQuery($select, $where, $order, 1), $args);
	}
	
	/**
	 * Find multiple rows in the databse given conditions and the columns that are to be selected.
	 * @param string $select A comma separated list of the columns that are to be selected.
	 * @param string $where Everything that goes into a SQL WHERE clause.
	 * @param array $args Values to substitute into the SQL query for every question mark.
	 * @param string $order Everything that goes in the SQL ORDER BY clause
	 * @param string $limit Everything that goes in the SQL LIMIT clause
	 * @return A new VK_DatabaseRecordSet
	 */
	public function selectAllWhere($select = '', $where = '', array $args = array(), $order = '', $limit = '') {
		return $this->findAllByQuery($this->buildQuery($select, $where, $order, $limit), $args);
	}
	
	/**
	 * Build a SQL query given all sorts of stuff.
	 * @param string $select A comma separated list of the columns that are to be selected.
	 * @param string $where Everything that goes into a SQL WHERE clause.
	 * @param array $args Values to substitute into the SQL query for every question mark.
	 * @param string $order Everything that goes in the SQL ORDER BY clause
	 * @param string $limit Everything that goes in the SQL LIMIT clause
	 * @return string A SQL query.
	 * @internal
	 */
	private function buildQuery($select = '', $where = '', $order = '', $limit = '') {
		$query = new VK_SelectQuery($select, $this->definition->getTable('name'), $where);
		
		$query->addOrderBy($order, '')
			  ->addLimit($limit);
			
		$this->definition->prepareSelect($query);
		
		return $query;
	}
	
	/**
	 * Create the SQL table.
	 */
	public function create() {
		return $this->table->create();
	}
	
	/**
	 * Drop this SQL table.
	 */
	public function drop() {
		return $this->table->drop();
	}
	
	/**
	 * Optimize this SQL table.
	 */
	public function optimize() {
		return $this->table->optimize();
	}
	
	/**
	 * Create a new database record.
	 * @return mixed A new VK_DatabaseRecord object.
	 */
	public function createRecord() {
		$record = $this->definition->getName() .'Record';
		
		if(!class_exists($record, FALSE)) {
			$record = 'VK_DatabaseRecord';
		}
		
		return new $record(array(), $this->dba, $this->definition);
	}
	
	/**
	 * Insert a row into a database.
	 * @param array $keys An array of column names of this table that will be used in the insert.
	 * @param array $vals An array of corresponding values to the column names.
	 * @return boolean
	 */
	public function insert(array $keys = array(), array $vals = array()) {
		
		// for convenience
		if(!empty($keys) && empty($vals)) {
			$keys = array_keys($keys);
			$vals = array_values($keys);
		}
		
		return $this->dba->update($this->dba->buildInsert($this->definition->getTable('name'), $keys, $vals), $vals);
	}
	
	/**
	 * Insert multiple rows into a database.
	 * @param array $keys An array of column names of this table that will be used in the insert.
	 * @param array $vals A miltidimensional array of corresponding values to the column names.
	 * @return boolean
	 */
	public function insertMany(array $keys = array(), array $vals = array()) {
		
		if(!$this->definition->extended_inserts) {
			foreach($vals as $val_set) {
				$this->insertOne($keys, $vals);
			}
		} else {
			$sql = $this->dba->buildInsert($this->definition->getTable('name'), $keys, $vals[0]);
			$sql .= str_repeat(',(' . substr(str_repeat('?,', count($keys)), 0, -1) . ')', count($vals) - 1);
			
			$this->dba->update($sql, array_flatten($vals));
		}
	}
	
	/**
	 * Begin a new SQL Transaction. If the transaction exists, return it. The return part of this is useful
	 * for if you are modifying the same transaction over multiple functions.
	 * @param string $id The ID of this transaction.
	 * @param string $type The type of this transaction. (deferred, immediate, exclusive)
	 * @param string $on_conflict The conflict algorithm to use. Defaults to ROLLBACK
	 */
	final public function beginTransaction($id = '', $on_conflict = 'ROLLBACK') {
		
		if(!isset($this->transactions[$id])) {
			$class = $this->dba->layer .'QueryTransaction';
		
			$this->transactions[$id] = new $class($this->dba, $this->definition, $id, $on_conflict);
		}
		
		return $this->transactions[$id];
	}
}

?>