<?php
/* -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
# ***** BEGIN LICENSE BLOCK *****
# This file is part of Plume Framework, a simple PHP Application Framework.
# Copyright (C) 2001-2007 Loic d'Anterroches and contributors.
#
# Plume Framework is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# Plume Framework is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#
# ***** END LICENSE BLOCK ***** */

/**
 * Generate the WHERE SQL clause in an easy and SQL proof way.
 */
class Pluf_SQL
{

    protected $db;
    protected $where = '';
    public $ands = array();

    /**
     * Construct the constructor with a default condition.
     */
    function __construct($base='', $args=array())
    {
        $this->db = Pluf::db();
        if (strlen($base) > 0) {
            $this->Q($base, $args);
        }
    }

    /**
     * Returns the where clause.
     *
     * @return string Where clause without the WHERE
     */
    function gen()
    {
        return implode(' AND ', $this->ands);
    }

    /**
     * Add a condition.
     *
     * @param string String to 'interpolate'
     * @param mixed String or array of parameters (array())
     */
    function Q($base, $args=array()) 
    {
        $escaped = array();
        if (!is_array($args)) {
            $args = array($args);
        }
        foreach ($args as $arg) {
            $escaped[] = $this->db->esc($arg);
        }
        $this->ands[] = vsprintf($base, $escaped);
        return $this;
    }

    /**
     * Add another SQL as a AND.
     *
     * @param Pluf_SQL Other object to add to the current.
     */
    function SAnd($sql)
    {
        return $this->SDef($sql);
    }

    /**
     * Add another SQL as a OR
     *
     * @param Pluf_SQL Other object to add to the current.
     */
    function SOr($sql)
    {
        return $this->SDef($sql, 'OR');
    }

    /**
     * Add another SQL to the current
     *
     * @param Pluf_SQL Other object to add to the current.
     * @param string Type of addition
     */
    function SDef($sql, $k='AND')
    {
        if (empty($this->ands)) {
            $this->ands = $sql->ands;
        } else {
            $othersql = $sql->gen();
            $current = $this->gen();
            if (strlen($othersql)) {
                $this->ands = array();
                $this->ands[] = '('.$current.') '.$k.' ('.$othersql.')';
            }
        }
        return $this;
    }

    /**
     * Get keywords.
     *
     * Considering a query string, explode the query string in
     * keywords given a defined delimiter.
     *
     * @param string Query string
     * @param string delimiter (' ')
     * @return array Array of keywords
     */
    function keywords($string, $del=' ')
    {
        $keys = array();
        $args = explode($del, $string);
        foreach ($args as $arg) {
            $arg = trim($arg);
            if (strlen($arg) > 0) {
                $keys[] = $arg;
            }
        }
        return $keys;
    }
}