LegacyApp

<?php

require_once("todo_conf.php");

// Caching Service
class TodoCache {
    private $cache;

    public function __construct() { $this->cache = array(); }
    public function set($key, $val) { $this->cache[$key] = $val; }
    public function get($key) { return $this->cache[$key]; }
    public function hasEntry($key) { return isset($this->cache[$key]); }
}

// Todo_Backend
class Todo {
    private $list;

    public function __construct() {
        $this->dbConn = $this->getDbConn();
        $this->cache = new TodoCache();
    }

    private function logger($log_msg) {
        echo $log_msg;
    }

    private function getDbConn() {
        $db = new PDO("pgsql:host=".DBHOST.";port=".DBPORT."; dbname='".DBNAME."'; user=".DBUSER." password=".DBPASS);
        $db->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
        return $db;
    }

    private function getOwnerId($owner) {
        $stmt = $this->dbConn->prepare("SELECT id FROM owners WHERE owner = :owner");
        $stmt->execute(array(':owner'=>$owner));
        return $stmt->fetchColumn(\PDO::FETCH_ASSOC);
    }

    private function addItem($owner_id, $item) {
        $this->logger("Adding $item for owner with id $owner_id\n");
        $stmt = $this->dbConn->prepare("INSERT INTO todo (owner_id, item) VALUES (:owner_id,
            :item)");
        $stmt->execute(array(':owner_id'=>$owner_id, ':item'=>$item));
        return $stmt->fetch(\PDO::FETCH_ASSOC);
    }

    private function createOwnerAddItem($owner, $item) {
        // entire body done in a transaction of course
        $this->logger("Add $owner to the owner's list\n");
        $stmt = $this->dbConn->prepare("INSERT INTO owners (owner) VALUES (:owner) RETURNING id");
        $stmt->execute(array(':owner'=>$owner));
        $res = $stmt->fetch(\PDO::FETCH_ASSOC);
        $owner_id = $res['id'];
        $this->addItem($owner_id, $item);
    }

    public function add($owner, $item) {
        $owner_id = $this->getOwnerId($owner);
        if ($owner_id === false || is_null($owner_id)) {
            $this->createOwnerAddItem($owner, $item);
        } else {
            $this->addItem($owner_id, $item);
        }
    }

    private function getOwnersItems($owner) {
        if ($this->cache->hasEntry($owner)) {
            return $this->cache->get($owner);
        }
        $stmt = $this->dbConn->prepare("SELECT item FROM todo t
        JOIN owners o ON o.id = t.owner_id WHERE o.owner = :owner");
        $stmt->execute(array(':owner'=>$owner));
        $res = $stmt->fetchAll(\PDO::FETCH_ASSOC);
        $this->cache->set($owner, $res);
        return $res;
    }

    public function display($owner) {
        $rows = $this->getOwnersItems($owner);
        foreach ($rows as $row) {
            echo "$owner -> ${row['item']}\n";
        }
    }

}

// Consumer, Frontend/Controller
$c = new Todo();
$c->add('Adam', 'Buy bread');
$c->add('Adam', 'Buy butter');
$c->add('Jane', 'Visit Paris');
$c->add('Jane', 'Fix car');
$c->add('Adam', 'Fix Bike');
$c->display('Jane');
$c->display('Adam');
$c->add('Adam', 'Yoga');
$c->display('Adam');


class TodoRestAPI {
    public function POST_add($owner, $item) { }
    public function GET_items($owner) { }
}