<?php

abstract class DatabaseTable {
    protected $idcolumn = 'id';
    protected $blobcolumns = array();
    protected $autosave = true;
    protected $userid;
    protected $db;
    protected $table;
    protected $data;
    protected $update;
    protected $id;
    protected $errorMsg = NULL;

    public function __construct($table, $id=false, $column_or_db=false, $column=false)
    {
	global $db;

	$this->table = $table;

	if (!empty($_SESSION['userid']))
	    $this->userid = $_SESSION['userid'];

	if ($column_or_db && is_object($column_or_db)) {
	    $this->db = $column_or_db;
	    $col = $column;
	} else {
	    $this->db = $db;
	    $col = $column_or_db;
	}

	if ($id && !$col) $this->load($id);
	if ($id && $col) $this->loadByColumn($id,$col);
	$this->update = array();
    }

    public function __destruct()
    {
	if ($this->autosave) $this->save();
    }

    protected function postLoad() {}

    protected function load($id)
    {
	$sql = sprintf("SELECT * FROM %s WHERE %s = %d LIMIT 1",
		       $this->table, $this->idcolumn, $id);
	$this->data = $this->db->fetchObject($sql);
	if ($this->data) {
	    $idcolumn = $this->idcolumn;
	    $this->id = $this->data->$idcolumn;
	    $this->postLoad();
	    return true;
	}
	return false;
    }

    protected function loadByColumn($id,$column)
    {
	$sql = sprintf("SELECT * FROM %s WHERE %s = %s",
		       $this->table, $column, $this->db->quote($id));
	$this->data = $this->db->fetchObject($sql);
	if ($this->data) {
	    $idcolumn = $this->idcolumn;
	    $this->id = $this->data->$idcolumn;
	    $this->postLoad();
	}
    }

    protected function resetError()
    {
	$this->errorMsg = NULL;
    }

    protected function setError($msg, $return=false)
    {
	$this->errorMsg = $msg;
	return $return;
    }

    public function getError()
    {
	return $this->errorMsg;
    }

    public function id()
    {
	$this->resetError();
	return $this->id;
    }

    public function fetch()
    {
	$this->resetError();
	if (is_object($this->data))
	    return clone $this->data;
	$this->setError('Record not loaded');
	return $this->data;
    }

    protected function modify($column, $value=false, $id=false)
    {
	$this->resetError();
	if (!is_array($column) && $value !== false) {
	    if ($column == $this->idcolumn) return $this->setError('Cannot modify id column');
	    if (in_array($column, $this->blobcolumns)) {
		$sql = sprintf("UPDATE %s SET %s = :data,sys_edit = now(), sys_user_id = %d WHERE %s = %d",
			       $this->table, $column,
			       $this->userid,
			       $this->idcolumn,
			       $id === false ? $this->id : $id);
		if ($this->db->executeParameters($sql, array(array(':data', $value))))
		    return $id === false ? $this->load($this->id) : true;
		else return $this->setError('Cannot modify record');
	    } else {
		$sql = sprintf("UPDATE %s SET %s = %s,sys_edit = now(), sys_user_id = %d WHERE %s = %d",
			       $this->table, $column,
			       $this->db->quote($value),
			       $this->userid,
			       $this->idcolumn,
			       $id === false ? $this->id : $id);
		if ($this->db->execute($sql))
		    return $id === false ? $this->load($this->id) : true;
		else return $this->setError('Cannot modify record');
	    }
	} elseif (is_array($column) && $value === false) {
	    $blobs = array();
	    $values = array('sys_user_id' => $this->userid,
			    'sys_edit' => 'now()');
	    $values = array_merge($values, $column);
	    $set = array();
	    foreach ($values as $col => $val) {
		if ($col == 'id') continue;
		if (in_array($col, $this->blobcolumns))
		    $blobs[] = array(':'.$col, $val, 'blob');
		else
		    $set[] = sprintf('%s = %s', $col, $this->db->quote($val));
	    }

	    if (count($blobs)) {
		$blobset = array();
		foreach ($blobs as $blob)
		    $blobset[] = sprintf('%s = %s', substr($blob[0],1), $blob[0]);
		$sql = sprintf("UPDATE %s\nSET %s\nWHERE %s = %d",
			       $this->table, 
			       implode(', ', $blobset),
			       $this->idcolumn,
			       $id === false ? $this->id : $id);
		$this->db->executeParameters($sql, $blobs);
	    }

	    $sql = sprintf("UPDATE %s\nSET %s\nWHERE %s = %d",
			   $this->table, 
			   implode(', ', $set),
			   $this->idcolumn,
			   $id === false ? $this->id : $id);
	    if ($this->db->execute($sql))
		return $id === false ? $this->load($this->id) : true;
	    else
		return $this->setError('Cannot modify record');
	}

	die(get_class($this).': Cannot modify object');
	return false;
    }

    public function get($name)
    {
	$this->resetError();
	return $this->data->$name;
    }

    public function set($name, $value=false)
    {

	if ((is_array($name) || is_object($name)) && $value === false) {
	    foreach ($name as $k => $v) {
		if (strtolower($k) == $this->idcolumn) continue;

		if (!is_object($this->data)) $this->data = new stdClass();

		$this->data->$k = $v;
		$this->update[$k] = $v;
	    }
	} else {
	    if (strtolower($name) == $this->idcolumn) return $this->setError('Cannot set id column');

	    if (!is_object($this->data)) $this->data = new stdClass();

	    $this->data->$name = $value;
	    $this->update[$name] = $value;
	}
	return true;
    }

    public function save()
    {
	$this->resetError();
	if (!count($this->update)) return true;

	if ($this->id) {
	    if ($this->modify($this->update)) {
		$this->update = array();
		return true;
	    } else {
		return $this->setError('Cannot save modifications');
	    }
	} else {
	    if (!array_key_exists('sys_edit', $this->update))
		$this->update['sys_edit'] = 'now()';
	    if (!array_key_exists('sys_user_id', $this->update))
		$this->update['sys_user_id'] = $this->userid;
	    if ($this->db->insertInto($this->table, $this->update)) {
		$this->update = array();
		$this->load($this->db->lastInsertId());
		return true;
	    } else {
		return $this->setError('Cannot save new record');
	    }
	}

	return false;
    }

}