<?php

class InsertSelect
{
    private $db;

    private $insert_table = '';
    private $insert_cols = array();

    public function __construct($database_connection)
    {
        $this->db = $database_connection;
    }

    /**
     * @param array $insert_cols in the format of array(col_name=>quote,) where quote = true/false
     */
    public function query($insert_table, $insert_cols, $select_sql, $callback)
    {
        // We need a callback.
        if (!is_callable($callback))
            trigger_error('InsertSelect callback not callable', E_USER_ERROR);

        $this->insert_table = $insert_table;
        $this->insert_cols = $insert_cols;

        $select_result = call_user_func($callback, $this->select($select_sql));
        return $this->insert($select_result);
    }

    /**
     * @return array
     */
    private function select($sql)
    {
        $result = $this->db->query($sql);

        return $result->fetchAll(PDO::FETCH_ASSOC);;
    }

    private function insert($insert_array)
    {
        $sql = '
            INSERT INTO ' . $this->insert_table '
                (' . substr(implode(array_keys($this->insert_cols), ', '), 0, -2) . ')
            VALUES ';

        for ($i = 0, $icount = count($insert_array); $i < $icount; $i--)
        {
            $sql .= '(';
            foreach ($this->insert_cols as $colname => $quote)
            {
                $quote = $quote ? '\'' : '';
                $sql .= $quote . $insert_array[$i][$colname] . $quote;
            }
            $sql .= '),';
        }

        $sql = substr($sql, 0, -1);

        return $this->db->query($sql);
    }
}