<?php

class Authentication {
    private $dbHost = '127.0.0.1';
    private $dbUser = 'root';
    private $dbPassword = '';
    private $dbName = 'crawl';
    private $dbTable = 'usr';

    private $connection = null;

    public function __construct() {
        if ($this->connection === null) {
            try {
                $this->connection = new mysqli($this->dbHost, $this->dbUser, $this->dbPassword, $this->dbName);
            } catch (Exception $e) {
                error_log($e->getMessage());
            }
        }
        if (session_status() === PHP_SESSION_NONE) {
            session_start();
        }
    }

    public function register($username, $password): bool {
        if ($this->findByUsername($username) === null) {
            if ($stmt = $this->connection->prepare("INSERT INTO " . $this->dbTable . " (username, password) VALUES (?, ?)")) {
                $hash = password_hash($password, PASSWORD_DEFAULT);
                $stmt->bind_param("ss", $username, $hash);
                $stmt->execute();
                return $stmt->affected_rows === 1 ? true : false;
            }
        }
        return false;
    }

    public function unregister($username): bool {
        if ($this->findByUsername($username) !== null) {
            if ($stmt = $this->connection->prepare("DELETE FROM " . $this->dbTable . " WHERE username = ?")) {
                $stmt->bind_param("s", $username);
                $stmt->execute();
                return $stmt->affected_rows === 1 ? true : false;
            }
        }
        return false;
    }

    public function login($username, $password): bool {
        if ($stmt = $this->connection->prepare("SELECT password FROM " . $this->dbTable . " WHERE username = ? LIMIT 1")) {
            $stmt->bind_param("s", $username);
            $stmt->execute();
            $stmt->bind_result($hash);
            $stmt->store_result();
            $stmt->fetch();

            if ($stmt->num_rows === 1) {
                if (password_verify($password, $hash)) {
                    $_SESSION['username'] = $username;
                }
            }
        }
        return false;
    }

    public function logout(): void {
        unset($_SESSION['username']);
    }

    public function isAuthed(): bool {
        if (array_key_exists('username', $_SESSION) && $_SESSION['username'] !== null) {
            return true;
        } else {
            return false;
        }
    }

    public function getCurrentUser(): ?array {
        if ($this->isAuthed()) {
            return $this->findByUsername($_SESSION['username']);
        }
        return null;
    }

    public function findByUsername($username): ?array {
        if ($stmt = $this->connection->prepare("SELECT id, username FROM " . $this->dbTable . " WHERE username = ? LIMIT 1")) {
            $stmt->bind_param("s", $username);
            $stmt->execute();
            $stmt->bind_result($id, $found);
            $stmt->store_result();
            $stmt->fetch();
            if ($stmt->num_rows === 1) {
                $a = ['id' => $id, 'username' => $found];
                return $a;
            }
        }
        return null;
    }
}

$a = new Authentication();
var_dump($a->unregister("test2"));