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<?php

namespace WPGMZA;

class Query
{
    private $_type;
    private $_table;
    
    private $_fields;
    
    private $_join;
    private $_where;
    private $_groupBy;
    private $_orderBy;
    private $_having;
    
    private $_limit;
    
    private $_params;
    
    public function __construct($parts=null)
    {
        $this->_type = null;
        $this->_table = null;
        
        $this->_fields  = new QueryFragment();

        $this->_join    = new QueryFragment();
        $this->_where   = new QueryFragment();
        $this->_groupBy = new QueryFragment();
        $this->_orderBy = new QueryFragment();
        $this->_having  = new QueryFragment();
        
        $this->_placeholders = array();
        $this->_params  = new QueryFields();
    }
    
    public function __get($name)
    {
        if(isset($this->{"_$name"}))
        {
            if($this->{"_$name"} instanceof QueryFragment)
                return $this->{"_$name"};
            
            return $this->{"_$name"};
        }
        
        return $this->{$name};
    }
    
    public function __set($name, $value)
    {
        if(isset($this->{"_$name"}) && is_array($this->{"_$name"}) && $name != 'fields' && $name != 'limit')
            throw new \Exception('Property is read only');
        
        switch($name)
        {
            case 'type':
                $value = strtoupper($value);
                $this->{"_$name"} = $value;
                
                $this->assertTypeValid();
                
                break;
            
            case 'table':
                $this->{"_$name"} = $value;
                
                $this->assertTableValid();
                
                break;
                
            case 'fields':
                if(!is_array($value))
                    throw new \Exception('Fields must be an array');
                
                foreach($value as $k => $v)
                    $this->_fields->{$k} = $v;

                break;
                
            case 'limit':
                if(!preg_match('/\d+\s*,\s*\d+/', $value))
                    throw new \Exception('Invalid SQL limit');
            
                $this->_limit = $value;

                break;
                
            default:
                $this->{$name} = $value;
                break;
        }
        
    }
    
    private function assertTypeValid()
    {
        switch($this->_type)
        {
            case 'INSERT':
            case 'SELECT':
            case 'UPDATE':
            case 'DELETE':
                break;
            
            default:
                throw new \Exception('Invalid query type');
                break;
        }
    }
    
    private function assertTableValid()
    {
        if(!is_string($this->_table) || empty($this->_table))
            throw new \Exception('Invalid table');
    }
    
    public function in($field, $set, $placeholder='%d')
    {
        if(!is_string($field))
            throw new \Exception('Invalid field name');
        
        if(!is_array($set))
            throw new \Exception('Set must be an array');
        
        if(empty($set))
            return;
        
        $count = count($set);
        
        $placeholders = implode(', ', array_fill(0, $count, $placeholder));
        
        $this->_where[] = "$field IN ($placeholders)";
        
        foreach($set as $item)
            $this->_params[] = $item;
        
        return $this;
    }
    
    public function build()
    {
        global $wpdb;
        
        $this->assertTypeValid();
        $this->assertTableValid();
        
        $qstr = $this->_type;
        
        switch($this->_type)
        {
            case 'SELECT':
                if(empty($this->_fields))
                    throw new \Exception('You must specify fields to select');
                
                $arr = $this->_fields->toArray();
                
                if(!empty($arr))
                    $str = implode(', ', $arr);
                else
                    $str = '*';
            
                $qstr .= " $str FROM";
                break;
            
            case 'INSERT':
                $qstr .= " INTO";
                break;
                
            case 'DELETE':
                $qstr .= " FROM";
                break;
        }
        
        $qstr .= " " . $this->_table;
        
        if(!empty($this->_join))
        {
            $qstr .= ' ';
            
            foreach($this->_join as $join)
                $qstr .= 'JOIN ' . $join;
        }
        
        $where = $this->_where->toArray();
        if(!empty($where))
            $qstr .= " WHERE " . implode(' AND ', $where);
        
        if(!empty($this->_limit))
            $qstr .= " LIMIT {$this->_limit}";
        
        $params = $this->_params->toArray();
        
        if(empty($params))
            return $qstr;
        
        return $wpdb->prepare($qstr, $params);
    }
}