//! Service trait definitions — use-case boundaries for CMS operations.
//!
//! These traits define the public API of the application use-cases.
//! They are implemented by concrete types in the `application` layer
//! and consumed by infrastructure adapters (HTTP handlers, CLI commands).
//!
//! ## Traits
//! - `SettingsService` — load/save settings, update provider config
//! - `ConversationService` — load/save conversations, add messages
//! - `MemoryService` — list/save/delete session memories
//!
//! ## Dependency Inversion
//! Application service implementations accept repository traits as generic
//! type parameters. Infrastructure adapters depend only on these service
//! traits, never on concrete implementations.

use super::conversation::{ChatMessage, Conversation};
use super::error::ServiceError;
use super::memory::Memory;
use super::settings::Settings;

/// Use-cases for application settings.
pub trait SettingsService {
    /// Load the current `Settings` from the default store location.
    fn load_settings(&self) -> Result<Settings, ServiceError>;

    /// Persist updated `Settings` to the default store location.
    fn save_settings(&self, settings: &Settings) -> Result<(), ServiceError>;

    /// Update (or insert) a provider configuration entry.
    fn update_provider(&self, name: &str, config: &super::app_config::ProviderConfig) -> Result<(), ServiceError>;
}

/// Use-cases for conversation (session message) management.
pub trait ConversationService {
    /// Load a `Conversation` for the given session ID.
    fn load_conversation(&self, session_id: &str) -> Result<Conversation, ServiceError>;

    /// Persist a `Conversation` to its session storage.
    fn save_conversation(&self, conv: &Conversation) -> Result<(), ServiceError>;

    /// Append a single `ChatMessage` to the conversation and persist.
    fn add_message(&self, conv: &mut Conversation, msg: ChatMessage) -> Result<(), ServiceError>;
}

/// Use-cases for long-term memory management.
pub trait MemoryService {
    /// List all memory slugs (filenames without extension).
    fn list_memories(&self) -> Result<Vec<String>, ServiceError>;

    /// Save (create or overwrite) a `Memory`.
    fn save_memory(&self, memory: &Memory) -> Result<(), ServiceError>;

    /// Delete a `Memory` by its slug/name.
    fn delete_memory(&self, name: &str) -> Result<(), ServiceError>;
}