<?php

use Vn\Lib;
use Vn\Web\Security;
use Vn\Lib\Type;

class Query extends Vn\Web\JsonRequest
{
	const PARAMS = ['sql'];
	const SECURITY = Security::INVOKER;

	function run ($db)
	{
		$results = [];

		try {
			$db->multiQuery ($_REQUEST['sql']);

			do {
				$result = $db->storeResult ();

				if ($result !== FALSE)
				{
					$results[] = $this->transformResult ($result);
					$result->free ();
				}
				else
					$results[] = TRUE;
			}
			while ($db->moreResults () && $db->nextResult ());
		
			// Checks for warnings
		
			if ($db->checkWarnings ()
			&& ($result = $db->query ('SHOW WARNINGS')))
			{
				$sql = 'SELECT description, @warn code '.
					'FROM sql_message WHERE code = @warn';

				while ($row = $result->fetch_assoc ())
				{
					if ($row['Code'] == 1265
					&& ($warning = $db->getRow ($sql)))
						trigger_error ("{$warning['code']}: {$warning['description']}", E_USER_WARNING);
					else
						trigger_error ("{$row['Code']}: {$row['Message']}", E_USER_WARNING);
				}
			}
		
			// Checks for errors

			$db->checkError ();
		}
		catch (Vn\Db\Exception $e)
		{
			$row = NULL;
			$code = $e->getCode ();
			$message = $e->getMessage ();

			switch ($code)
			{
				case 1644: // ER_SIGNAL_EXCEPTION
				{
					$sql = 'SELECT description, #code code '.
						'FROM sql_message WHERE code = #code';
					$row = $db->getRow ($sql, ['code' => $message]);
					break;
				}
				case 1305: // ER_SP_DOES_NOT_EXIST
				{
					if (strpos ($message, 'EXCEPTION') === FALSE)
						break;

					$sql = 'SELECT description, @err code '.
						'FROM sql_message WHERE code = @err';
					$row = $db->getRow ($sql);
					break;
				}
			}

			if ($row)
				throw new Lib\UserException ($row['description'], $row['code']);
			else
				throw $e;
		}

		return $results;
	}

	/**
	 * Transforms the database result into a JSON parseable object.
	 **/
	function transformResult ($result)
	{
		$tableMap = [];
		$columns = $result->fetch_fields ();

		$resultMap =
		[
			'data'    => [],
			'columns' => [],
			'tables'  => []
		];
	
		for ($i = 0; $i < $result->field_count; $i++)
		{
			$column = $columns[$i];
		
			switch ($column->type)
			{
				case MYSQLI_TYPE_BIT:
					$type = Type::BOOLEAN;
					break;
				case MYSQLI_TYPE_TINY:
				case MYSQLI_TYPE_SHORT:
				case MYSQLI_TYPE_LONG:
				case MYSQLI_TYPE_LONGLONG:
				case MYSQLI_TYPE_INT24:
				case MYSQLI_TYPE_YEAR:
					$type = Type::INTEGER;
					break;
				case MYSQLI_TYPE_FLOAT:
				case MYSQLI_TYPE_DOUBLE:
				case MYSQLI_TYPE_DECIMAL:	
				case MYSQLI_TYPE_NEWDECIMAL:
					$type = Type::DOUBLE;
					break;
				case MYSQLI_TYPE_DATE:	
					$type = Type::DATE;
					break;
				case MYSQLI_TYPE_DATETIME:
				case MYSQLI_TYPE_TIMESTAMP:
					$type = Type::DATE_TIME;
					break;
				default;
					$type = Type::STRING;
			}

			if (!isset ($tableMap[$column->table]))
			{
				$resultMap['tables'][] =
				[
					'name'     => $column->table,
					'orgname'  => $column->orgtable,
					'schema'   => $column->db,
					'pks'      => []
				];
				$tableIndex = count ($resultMap['tables']) - 1;
				$tableMap[$column->table] = $tableIndex;	 
			}
			else
				$tableIndex = $tableMap[$column->table];
		
			if ($column->flags & MYSQLI_PRI_KEY_FLAG)
				$resultMap['tables'][$tableIndex]['pks'][] = $i;
		
			$default = $this->castValue ($column->def, $type);

			$resultMap['columns'][] =
			[
				'type'     => $type,
				'flags'    => $column->flags,
				'def'      => $default,
				'name'     => $column->name,
				'orgname'  => $column->orgname,
				'table'    => $tableIndex
			];
		}
	
		$columns = $resultMap['columns'];

		while ($row = $result->fetch_row ())
		{
			for ($j = 0; $j < $result->field_count; $j++)
				$row[$j] = $this->castValue ($row[$j], $columns[$j]['type']);

			$resultMap['data'][] = $row;
		}

		return $resultMap;
	}

	/**
	 * Transforms the database value into a JSON parseable value.
	 **/
	function castValue ($value, $type)
	{
		if ($value !== NULL)
		switch ($type)
		{
			case Type::BOOLEAN:
				return (bool) $value;
			case Type::INTEGER:
				return (int) $value;
			case Type::DOUBLE:
				return (float) $value;
			case Type::DATE:	
			case Type::DATE_TIME:				
				return mktime
				(
					 substr ($value, 11 , 2)
					,substr ($value, 14 , 2)
					,substr ($value, 17 , 2)
					,substr ($value, 5 , 2)
					,substr ($value, 8 , 2)
					,substr ($value, 0 , 4)
				);
				break;
		}
		
		return $value;
	}

}