<?php

class DB_Record extends Object {
    protected $table;
    protected $primaryKey;
    protected $primaryId;
    protected $columns;

    public function __construct($table) {
        $this->table = $table;
        $stm = db::query("DESCRIBE `{$this->table}`");
        $rows = $stm->fetchAll(PDO::FETCH_OBJ);
        // echo '<pre>';
        // var_dump($rows);
        // echo '</pre>';
        foreach ($rows as $row) {
            if ($row->Key == 'PRI') {
                $this->primaryKey = $row->Field;
            }
            $this->columns[] = $row->Field;
        }
    }

    public function load($id) {
        if (preg_match('/^[1-9]\d*$/', $id)) {
            $stm = db::query("SELECT * FROM `{$this->table}` WHERE `{$this->primaryKey}`=$id");
            $data = $stm->fetch(PDO::FETCH_ASSOC);
            if (count($data)) {
                $this->data = $data;
                $this->primaryId = $id;
                return true;
            }
        }
        return false;
    }

    public function save() {
        $data = $this->matchColumns();
        if ($this->primaryId) {
            $sql = "UPDATE `{$this->table}` SET ";
            $parts = array();
            foreach ($data as $k => $v) {
                $parts[] = "`$k`=:$k";
            }
            $sql .= implode(',', $parts) . " WHERE `{$this->primaryKey}`={$this->primaryId}";
            // echo $sql . '<br>';
            $stm = db::prepare($sql);
            $stm->execute($data);
            return (bool) $stm->rowCount();
        }
        $sql = "INSERT INTO `{$this->table}`";
        $sql .= ' (`' . implode('`,`', array_keys($data)) . '`)';
        $sql .= ' VALUES (' . substr(str_repeat('?,', count($data)), 0 , -1) . ')';
        // echo $sql . '<br>';
        $stm = db::prepare($sql);
        $stm->execute(array_values($data));
        return db::lastInsertId();
    }

    protected function matchColumns() {
        $ret = array();
        foreach ($this->columns as $column) {
            if (isset($this->data[$column])) {
                $ret[$column] = $this->data[$column];
            }
        }
        return $ret;
    }
}