<?php
class Todo {
    private $id;
    private $title;
    private $description;
    private $completed;
    private $createdAt;
    private $updatedAt;
    
    public function __construct($id, $title, $description = '', $completed = false) {
        $this->id = $id;
        $this->title = $title;
        $this->description = $description;
        $this->completed = $completed;
        $this->createdAt = date('Y-m-d H:i:s');
        $this->updatedAt = date('Y-m-d H:i:s');
    }
    
    // Getters
    public function getId() {
        return $this->id;
    }
    
    public function getTitle() {
        return $this->title;
    }
    
    public function getDescription() {
        return $this->description;
    }
    
    public function isCompleted() {
        return $this->completed;
    }
    
    public function getCreatedAt() {
        return $this->createdAt;
    }
    
    public function getUpdatedAt() {
        return $this->updatedAt;
    }
    
    // Setters
    public function setTitle($title) {
        $this->title = $title;
        $this->updateTimestamp();
    }
    
    public function setDescription($description) {
        $this->description = $description;
        $this->updateTimestamp();
    }
    
    public function setCompleted($completed) {
        $this->completed = $completed;
        $this->updateTimestamp();
    }
    
    private function updateTimestamp() {
        $this->updatedAt = date('Y-m-d H:i:s');
    }
    
    public function toArray() {
        return [
            'id' => $this->id,
            'title' => $this->title,
            'description' => $this->description,
            'completed' => $this->completed,
            'created_at' => $this->createdAt,
            'updated_at' => $this->updatedAt
        ];
    }
}
?>