feat(application, api-types): use cases with tests and DTOs

crates/application/src/use_cases/login.rs

@@ -0,0 +1,74 @@
+use std::sync::Arc;
+use domain::{
+    entities::User,
+    errors::DomainError,
+    ports::{PasswordHasher, TokenIssuer, UserRepository},
+    value_objects::Email,
+};
+
+pub struct LoginUser {
+    repo: Arc<dyn UserRepository>,
+    hasher: Arc<dyn PasswordHasher>,
+    issuer: Arc<dyn TokenIssuer>,
+}
+
+impl LoginUser {
+    pub fn new(
+        repo: Arc<dyn UserRepository>,
+        hasher: Arc<dyn PasswordHasher>,
+        issuer: Arc<dyn TokenIssuer>,
+    ) -> Self {
+        Self { repo, hasher, issuer }
+    }
+
+    pub async fn execute(&self, email: &str, password: &str) -> Result<(User, String), DomainError> {
+        let email = Email::new(email)?;
+        let user = self.repo.find_by_email(&email).await?
+            .ok_or_else(|| DomainError::Unauthorized("Invalid credentials".to_string()))?;
+        let valid = self.hasher.verify(password, &user.password_hash).await?;
+        if !valid {
+            return Err(DomainError::Unauthorized("Invalid credentials".to_string()));
+        }
+        let token = self.issuer.issue(&user.id, &user.role).await?;
+        Ok((user, token))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::testing::{InMemoryUserRepository, StubPasswordHasher, StubTokenIssuer};
+    use crate::use_cases::register::RegisterUser;
+
+    async fn seeded_repo() -> Arc<InMemoryUserRepository> {
+        let repo = Arc::new(InMemoryUserRepository::new());
+        let r = RegisterUser::new(repo.clone(), Arc::new(StubPasswordHasher));
+        r.execute("user@example.com", "password123").await.unwrap();
+        repo
+    }
+
+    #[tokio::test]
+    async fn login_returns_user_and_token() {
+        let repo = seeded_repo().await;
+        let uc = LoginUser::new(repo, Arc::new(StubPasswordHasher), Arc::new(StubTokenIssuer));
+        let (user, token) = uc.execute("user@example.com", "password123").await.unwrap();
+        assert_eq!(user.email.as_str(), "user@example.com");
+        assert!(token.starts_with("token:"));
+    }
+
+    #[tokio::test]
+    async fn login_rejects_wrong_password() {
+        let repo = seeded_repo().await;
+        let uc = LoginUser::new(repo, Arc::new(StubPasswordHasher), Arc::new(StubTokenIssuer));
+        let result = uc.execute("user@example.com", "wrongpassword").await;
+        assert!(matches!(result, Err(DomainError::Unauthorized(_))));
+    }
+
+    #[tokio::test]
+    async fn login_rejects_unknown_email() {
+        let repo = seeded_repo().await;
+        let uc = LoginUser::new(repo, Arc::new(StubPasswordHasher), Arc::new(StubTokenIssuer));
+        let result = uc.execute("nobody@example.com", "password123").await;
+        assert!(matches!(result, Err(DomainError::Unauthorized(_))));
+    }
+}