<?php

abstract class ORM_Abstract {
    public $pdo;
    protected $_tablePrefix;
    protected $_statementCache = [];

    abstract public function quoteName($name);

    abstract public function getMeta($table);

    public function __construct(PDO $pdo, $table_prefix='') {
        $this->pdo = $pdo;
        $this->_tablePrefix = $table_prefix;
    }

    public function record($table, $id=null) {
        $meta = $this->getmeta($table);
        $rec = new ORM_Record($this, $table);

        if (func_num_args() > 1 && !$rec->load($id))
            return false;

        return $rec;
    }

    public function load($table, $id) {
        $o = $this->disponse($table);
        return $o->load($id) ? $o: false;
    }

    public function query($query, array $bindings=[]) {
        // '?_' автоматически заменяется на преффикс для таблиц.
        $query = str_replace('?_', $this->_tablePrefix, $query);
        echo dump($query);
        $h = md5($query);
        if (isset($this->_statementCache[$h])) {
            list($s, $t) = $this->_statementCache[$h];
        }
        else {
            $s = $this->pdo->prepare($query);
            preg_match('/^\s*(\w+)/', $query, $m);
            $t = strtolower($m[1]);
            $this->_statementCache[$h] = [$s, $t];
        }

        $s->execute($bindings);

        if ($t == 'update' or $t == 'delete')
            return $s->rowCount();

        if ($t == 'insert')
            return $this->lastInsertId();

        return $s;
    }

    public function get($query, array $bindings=[],
                        $fetch_type=ORM::FETCH_ALL) {
        $r = $this->query($query, $bindings);

        if ($fetch_type & ORM::FETCH_COLUMN)
            return $r->fetchColumn();

        if ($fetch_type & ORM::FETCH_ROW)
            return $r->fetch(PDO::FETCH_ASSOC);

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

    public function row($query, array $bindings=[]) {
        return $this->get($query, $bindings, ORM::FETCH_ROW);
    }

    public function column($query, array $bindings=[]) {
        return $this->get($query, $bindings, ORM::FETCH_COLUMN);
    }

    public function count($table, $where=1, array $bindings=[]) {
        $tbl = $this->fulltablename($table);
        $q = "SELECT COUNT(*) FROM $tbl WHERE $where";
        return (int) $this->column($q, $bindings);
    }

    public function insert($table, array $data) {
        if (!$data)
            return false;

        $t = $this;
        $keys = array_keys($data);

        foreach ($keys as $v) {
            $columns[] = $t->quotename($v);
            $values[] = ":$v";
        }

        $columns = implode(',', $columns);
        $values = implode(',', $values);
        $tbl = $t->fulltablename($table);
        $q = "INSERT INTO $tbl ($columns) VALUES ($values)";
        return $t->query($q, $data);
    }

    public function update($table, array $data, $where=1,
                           array $bindings=[]) {
        if (!$data)
            return false;

        $t = $this;
        $is_l = is_list($bindings);
        $bindings = array_merge($is_l ? array_values($data) : $data,
                                $bindings);
        $keys = array_keys($data);

        foreach ($keys as $v) {
            $set[] = $t->quotename($v) . '=' . ($is_l ? '?' : ":$v");
        }

        $set = implode(',', $set);
        $tbl = $t->fulltablename($table);
        return $t->query("UPDATE $tbl SET $set WHERE $where", $bindings);
    }

    public function delete($table, $where=1, array $bindings=[]) {
        $tbl = $this->fulltablename($table);
        return $this->query("DELETE FROM $tbl WHERE $where", $bindings);
    }

    public function commit() {
        return $this->pdo->commit();
    }

    public function rollback() {
        return $this->pdo->rollback();
    }

    public function lastInsertId() {
        return $this->pdo->lastInsertId();
    }

    public function fullTableName($table) {
        return $this->quotename($this->_tablePrefix . $table);
    }
}

/* ---------------------------- 78 characters ----------------------------- */

<?php

class ORM_Record extends object {
    protected $_db;
    protected $_table;
    protected $_primaryKey;
    protected $_columns;
    protected $_relations;
    protected $_primaryId;


    public function __construct(ORM_Abstract $db, $table,
                                $columns, $relations) {
        $t = $this;
        $t->_db = $db;
        $t->_table = $table;
        $t->_columns = $columns;
        $t->_relations = $relations;
    }

    public function load($id) {
        $t = $this;
        $tbl = $t->_db->fulltablename($t->_table);
        $k = $t->_db->quotename($t->_primaryKey);
        $r = $t->_db->row("SELECT * FROM $tbl WHERE $k=?", [$id,]);

        if ($r) {
            $t->_data = $r;
            $t->_primaryId = $id;
            return true;
        }

        /*
        array (
          'columns' =>
          array (
            0 => 'id',
            1 => 'cat_id',
            2 => 'author_id',
            3 => 'title',
            4 => 'body',
          ),
          'primary_key' => 'id',
          'relations' =>
          array (
            0 =>
            array (
              'foreign_alias' => 'category',
              'foreign_key' => 'cat_id',
              'ref_table' => 'categories',
              'ref_key' => 'id',
            ),
          ),
        ) */

        foreach ($t->_relations as $rel) {
            $t->_data[  ]
        }

        return false;
    }

    public function save() {
        $t = $this;
        $a = $t->_matchcolumns();

        if ($t->_primaryId) {
            $k = $t->_db->quotename($t->_primaryKey);
            $c = $t->_db->update($t->_table, $a, "$k=?", [$t->_primaryId,]);
            return (bool) $c;
        }

        $id = $t->_db->insert($t->_table, $a);

        if (!$id)
            return fase;

        $t->_primaryId = $id;
        return true;
    }

    public function trash() {
        $t = $this;
        $k = $t->_db->quotename($t->_primaryKey);
        $c = $t->_db->delete($t->_table, "$k=?", [$t->_primaryId,]);

        if ($c)
            $t->_data = null;

        return (bool) $c;
    }

    protected function _matchColumns() {
        $t = $this;
        $r = array();

        foreach ($t->_columns as $v) {
            if (isset($t->_data[$v])) {
                $r[$v] = $t->_data[$v];
            }
        }

        return $r;
    }
}