use std::collections::HashMap;
use std::future::Future;

use actix_web::cookie::time::Duration;

use crate::error::SessionError;
use crate::key::SessionKey;

pub type SessionState = HashMap<String, String>;

#[derive(Debug, Clone, Default, PartialEq, Eq)]
pub struct SessionDiff {
    pub set: HashMap<String, String>,
    pub removed: Vec<String>,
}

impl SessionDiff {
    pub fn is_empty(&self) -> bool {
        self.set.is_empty() && self.removed.is_empty()
    }
}

pub trait SessionStore {
    fn load(
        &self,
        session_key: &SessionKey,
    ) -> impl Future<Output = Result<Option<(SessionState, Duration)>, SessionError>>;

    fn save(
        &self,
        session_state: SessionState,
        ttl: &Duration,
    ) -> impl Future<Output = Result<SessionKey, SessionError>>;

    fn update(
        &self,
        session_key: SessionKey,
        diff: SessionDiff,
        ttl: &Duration,
        previous_user_id: Option<i64>,
        user_id: Option<i64>,
    ) -> impl Future<Output = Result<SessionKey, SessionError>>;

    fn rotate(
        &self,
        session_key: SessionKey,
        diff: SessionDiff,
        ttl: &Duration,
        previous_user_id: Option<i64>,
        user_id: Option<i64>,
    ) -> impl Future<Output = Result<Option<SessionKey>, SessionError>>;

    fn update_ttl(
        &self,
        session_key: &SessionKey,
        ttl: &Duration,
        user_id: Option<i64>,
    ) -> impl Future<Output = Result<(), SessionError>>;

    fn delete(
        &self,
        session_key: &SessionKey,
        user_id: Option<i64>,
    ) -> impl Future<Output = Result<(), SessionError>>;

    fn revoke_user(&self, user_id: i64) -> impl Future<Output = Result<usize, SessionError>>;
}

pub fn generate_session_key() -> SessionKey {
    SessionKey::generate()
}