<?php
class PasswordManager {
    private $cost = 12;
    
    public function hashPassword($password) {
        $hash = password_hash($password, PASSWORD_BCRYPT, ["cost" => $this->cost]);
        if ($hash === false) {
            throw new Exception("Password hashing failed");
        }
        return $hash;
    }
    
    public function verifyPassword($password, $hash) {
        if (password_verify($password, $hash)) {
            if (password_needs_rehash($hash, PASSWORD_BCRYPT, ["cost" => $this->cost])) {
                return ["valid" => true, "needs_rehash" => true];
            }
            return ["valid" => true, "needs_rehash" => false];
        }
        return ["valid" => false, "needs_rehash" => false];
    }
    
    public function getPasswordStrength($password) {
        $score = 0;
        $feedback = [];
        
        if (strlen($password) >= 8) $score += 25;
        else $feedback[] = "At least 8 characters";
        
        if (preg_match("/[A-Z]/", $password)) $score += 25;
        else $feedback[] = "Add uppercase letters";
        
        if (preg_match("/[a-z]/", $password)) $score += 25;
        else $feedback[] = "Add lowercase letters";
        
        if (preg_match("/[0-9]/", $password)) $score += 15;
        else $feedback[] = "Add numbers";
        
        if (preg_match("/[^a-zA-Z0-9]/", $password)) $score += 10;
        else $feedback[] = "Add special characters";
        
        $strength = "Weak";
        if ($score >= 80) $strength = "Strong";
        elseif ($score >= 50) $strength = "Medium";
        
        return ["score" => $score, "strength" => $strength, "feedback" => $feedback];
    }
}