//! PasswordService port — password hashing and verification abstraction.
//!
//! Defines the trait that password-hashing adapters (argon2, bcrypt, etc.)
//! implement. The application layer depends only on this trait, never on
//! a concrete hashing library.

use anyhow::Result;
use std::future::Future;

/// Abstraction for password hashing and verification.
///
/// Implementors handle the actual hashing algorithm (argon2, bcrypt, etc.)
/// and parameter selection. The trait is `Send + Sync` for use in async
/// service layers.
pub trait PasswordService: Send + Sync {
    /// Hash a plaintext password and return the encoded hash string
    /// (suitable for storage in a credential store).
    fn hash(&self, password: &str) -> impl Future<Output = Result<String>> + Send;

    /// Verify a plaintext password against a previously-hashed string.
    ///
    /// Returns `true` if the password matches the hash, `false` otherwise.
    fn verify(&self, password: &str, hash: &str) -> impl Future<Output = Result<bool>> + Send;
}