use std::ops::Add;
use std::sync::Arc;

use actix_jwt_authc::*;
use actix_web::web::{Data, Form, ServiceConfig};
use actix_web::{get, post, HttpResponse};
use askama_actix::Template;
use autometrics::autometrics;
use futures::channel::{mpsc, mpsc::Sender};
use futures::stream::Stream;
use futures::SinkExt;
use jsonwebtoken::*;
use oswilno_view::{Lang, TranslationStorage};
use ring::rand::SystemRandom;
use ring::signature::{Ed25519KeyPair, KeyPair};
use sea_orm::DatabaseConnection;
use serde::{Deserialize, Serialize};
use time::ext::*;
use time::OffsetDateTime;
use tokio::sync::Mutex;

mod hashing;

pub use oswilno_view::filters;

pub type UserSession = Authenticated<Claims>;

#[derive(Clone, Copy)]
pub struct JWTTtl(time::Duration);

#[derive(Debug, Serialize, Deserialize, Clone, Eq, PartialEq)]
enum Audience {
    Web,
}

#[derive(Debug, Serialize, Deserialize, Clone, Eq, PartialEq)]
pub struct Claims {
    #[serde(rename = "exp")]
    expires_at: usize,
    #[serde(rename = "iat")]
    issues_at: usize,
    #[serde(rename = "sub")]
    subject: String,
    #[serde(rename = "aud")]
    audience: Audience,
    #[serde(rename = "jti")]
    jwt_id: uuid::Uuid,
}

#[derive(Serialize, Deserialize)]
pub struct EmptyResponse {}

#[derive(Debug, Serialize, Deserialize)]
pub struct LoginResponse {
    bearer_token: String,
    claims: Claims,
}

const JWT_SIGNING_ALGO: Algorithm = Algorithm::EdDSA;

#[derive(Clone)]
pub struct SessionConfigurator {
    jwt_ttl: Data<JWTTtl>,
    invalidated_jwts_store: Data<InvalidatedJWTStore>,
    encoding_key: Data<EncodingKey>,
    factory: AuthenticateMiddlewareFactory<Claims>,
}

impl SessionConfigurator {
    pub fn app_data(self, config: &mut ServiceConfig) {
        config
            .app_data(self.invalidated_jwts_store)
            .app_data(self.encoding_key)
            .app_data(self.jwt_ttl)
            .service(login)
            .service(login_view)
            .service(logout)
            .service(session_info)
            .service(register)
            .service(register_view);
    }

    pub fn factory(&self) -> AuthenticateMiddlewareFactory<Claims> {
        self.factory.clone()
    }

    pub fn translations(&self, l10n: &mut oswilno_view::TranslationStorage) {
        l10n
            // English
            .with_lang(oswilno_view::Lang::En)
            .add("Sign in", "Sign in")
            .add("Sign up", "Sign up")
            .add("Bad credentials", "Bad credentials")
            .done()
            // Polish
            .with_lang(oswilno_view::Lang::Pl)
            .add("Sign in", "Logowanie")
            .add("Sign up", "Rejestracja")
            .add("Bad credentials", "Złe dane uwierzytelniające")
            .add("Login already taken", "Login jest zajęty")
            .add(
                "Login or email already taken",
                "Login lub adres e-mail jest zajęty",
            )
            .add("Submit", "Wyślij")
            .done();
    }

    pub fn new() -> Self {
        let jwt_ttl = JWTTtl(31.days());
        let jwt_signing_keys = JwtSigningKeys::generate().unwrap();
        let validator = Validation::new(JWT_SIGNING_ALGO);
        let auth_middleware_settings = AuthenticateMiddlewareSettings {
            jwt_decoding_key: jwt_signing_keys.decoding_key,
            jwt_authorization_header_prefixes: Some(vec!["Bearer".to_string()]),
            jwt_validator: validator,
            jwt_session_key: None,
        };
        let (invalidated_jwts_store, stream) = InvalidatedJWTStore::new_with_stream();
        let auth_middleware_factory =
            AuthenticateMiddlewareFactory::<Claims>::new(stream, auth_middleware_settings.clone());

        Self {
            invalidated_jwts_store: Data::new(invalidated_jwts_store.clone()),
            encoding_key: Data::new(jwt_signing_keys.encoding_key.clone()),
            jwt_ttl: Data::new(jwt_ttl.clone()),
            factory: auth_middleware_factory,
        }
    }
}

#[derive(Template)]
#[template(path = "./sign-in/full.html")]
struct SignInTemplate {
    form: SignInPayload,
    lang: Lang,
    t: Arc<TranslationStorage>,
}

#[derive(Template)]
#[template(path = "./sign-in/partial.html")]
struct SignInPartialTemplate {
    form: SignInPayload,
    lang: Lang,
    t: Arc<TranslationStorage>,
}

#[derive(Debug, Serialize, Deserialize, Clone, Eq, PartialEq, Default)]
pub struct SignInPayload {
    #[serde(skip, default)]
    errors: Vec<String>,

    login: String,
    #[serde(skip, default)]
    login_errors: Vec<String>,

    password: String,
    #[serde(skip, default)]
    password_errors: Vec<String>,
}

#[get("/login")]
async fn login_view(t: Data<TranslationStorage>) -> SignInTemplate {
    SignInTemplate {
        form: SignInPayload::default(),
        lang: Lang::Pl,
        t: t.into_inner(),
    }
}

#[autometrics]
#[post("/login")]
async fn login(
    jwt_encoding_key: Data<EncodingKey>,
    jwt_ttl: Data<JWTTtl>,
    db: Data<DatabaseConnection>,
    payload: Form<SignInPayload>,
    t: Data<oswilno_view::TranslationStorage>,
) -> Result<HttpResponse, Error> {
    let t = t.into_inner();
    match login_inner(jwt_encoding_key, jwt_ttl, db, payload).await {
        Ok(res) => Ok(HttpResponse::Ok().json(res)),
        Err(form) => Ok(HttpResponse::Ok().body(
            SignInPartialTemplate {
                form,
                lang: Lang::Pl,
                t,
            }
            .render()
            .unwrap(),
        )),
    }
}

async fn login_inner(
    jwt_encoding_key: Data<EncodingKey>,
    jwt_ttl: Data<JWTTtl>,
    db: Data<DatabaseConnection>,
    payload: Form<SignInPayload>,
) -> Result<LoginResponse, SignInPayload> {
    let db = db.into_inner();
    let mut payload = payload.into_inner();

    let iat = OffsetDateTime::now_utc().unix_timestamp() as usize;
    let expires_at = OffsetDateTime::now_utc().add(jwt_ttl.0);
    let exp = expires_at.unix_timestamp() as usize;

    use sea_orm::*;
    let account = match oswilno_contract::accounts::Entity::find()
        .filter(oswilno_contract::accounts::Column::Login.eq(payload.login.as_str()))
        .one(&*db)
        .await
    {
        Ok(Some(a)) => a,
        Ok(None) => {
            payload.errors.push("Bad credentials".into());
            return Err(payload);
        }
        Err(e) => {
            tracing::warn!("Failed to find account: {e}");
            payload.errors.push("Bad credentials".into());
            return Err(payload);
        }
    };
    if hashing::verify(account.pass_hash.as_str(), payload.password.as_str()).is_err() {
        payload.errors.push("Bad credentials".into());
        return Err(payload);
    }

    let jwt_claims = Claims {
        issues_at: iat,
        subject: format!("account-{}", account.id),
        expires_at: exp,
        audience: Audience::Web,
        jwt_id: uuid::Uuid::new_v4(),
    };
    let jwt_token = encode(
        &Header::new(JWT_SIGNING_ALGO),
        &jwt_claims,
        &jwt_encoding_key,
    )
    .map_err(|_| {
        payload.errors.push("Bad credentials".into());
        payload
    })?;
    Ok(LoginResponse {
        bearer_token: jwt_token,
        claims: jwt_claims,
    })
}

#[autometrics]
#[get("/session")]
async fn session_info(authenticated: UserSession) -> Result<HttpResponse, Error> {
    Ok(HttpResponse::Ok().json(authenticated))
}

#[autometrics]
#[get("/logout")]
async fn logout(
    invalidated_jwts: Data<InvalidatedJWTStore>,
    authenticated: Authenticated<Claims>,
) -> Result<HttpResponse, Error> {
    invalidated_jwts.add_to_invalidated(authenticated).await;
    Ok(HttpResponse::Ok().json(EmptyResponse {}))
}

#[derive(Debug, Default, Serialize, Deserialize, Clone, Eq, PartialEq)]
struct AccountInfo {
    #[serde(skip)]
    errors: Vec<String>,
    login: String,
    #[serde(skip)]
    login_errors: Vec<String>,
    email: String,
    #[serde(skip)]
    email_errors: Vec<String>,
    password: String,
    #[serde(skip)]
    password_errors: Vec<String>,
}

#[derive(askama_actix::Template)]
#[template(path = "./register/full.html")]
struct RegisterTemplate {
    form: AccountInfo,
    t: Arc<TranslationStorage>,
    lang: Lang,
}

#[get("/register")]
async fn register_view(t: Data<TranslationStorage>) -> RegisterTemplate {
    RegisterTemplate {
        form: AccountInfo::default(),
        t: t.into_inner(),
        lang: Lang::Pl,
    }
}

#[derive(askama_actix::Template)]
#[template(path = "./register/partial.html")]
struct RegisterPartialTemplate {
    form: AccountInfo,
    t: Arc<TranslationStorage>,
    lang: Lang,
}

#[autometrics]
#[post("/register")]
async fn register(
    db: Data<DatabaseConnection>,
    payload: Form<AccountInfo>,
    t: Data<oswilno_view::TranslationStorage>,
) -> Result<HttpResponse, Error> {
    let t = t.into_inner();
    Ok(
        match register_internal(db.into_inner(), payload.into_inner(), t.clone()).await {
            Ok(res) => res,
            Err(p) => HttpResponse::BadRequest().body(
                RegisterPartialTemplate {
                    form: p,
                    t,
                    lang: Lang::Pl,
                }
                .render()
                .unwrap(),
            ),
        },
    )
}

async fn register_internal(
    db: Arc<DatabaseConnection>,
    mut p: AccountInfo,
    t: Arc<TranslationStorage>,
) -> Result<HttpResponse, AccountInfo> {
    use oswilno_contract::accounts::*;
    use sea_orm::*;

    let pass = match hashing::encrypt(p.password.as_str()) {
        Ok(p) => p,
        Err(e) => {
            tracing::warn!("{e}");
            return Ok(HttpResponse::InternalServerError().body(""));
        }
    };

    match Entity::find()
        .filter(Column::Login.eq(&p.login))
        .one(&*db)
        .await
    {
        Ok(None) | Err(_) => {
            p.login_errors.push("Login already taken".into());
            return Err(p);
        }
        _ => (),
    };

    let model = match (ActiveModel {
        id: NotSet,
        login: Set(p.login.to_string()),
        // email: Set(p.email.to_string()),
        pass_hash: Set(pass),
        ..Default::default()
    })
    .save(&*db)
    .await
    {
        Ok(model) => model,
        Err(e) => {
            tracing::warn!("{e}");
            p.login_errors
                .push(t.to_lang(Lang::Pl, "Login or email already taken"));
            return Err(p);
        }
    };

    tracing::info!("{model:?}");

    Ok(HttpResponse::SeeOther()
        .append_header(("Location", "/login"))
        .json(EmptyResponse {}))
}

#[derive(Clone)]
struct InvalidatedJWTStore {
    // store: Arc<DashSet<JWT>>,
    tx: Arc<Mutex<Sender<InvalidatedTokensEvent>>>,
}

impl InvalidatedJWTStore {
    /// Returns a [InvalidatedJWTStore] with a Stream of [InvalidatedTokensEvent]s
    fn new_with_stream() -> (
        InvalidatedJWTStore,
        impl Stream<Item = InvalidatedTokensEvent>,
    ) {
        // let invalidated = Arc::new(DashSet::new());
        let (tx, rx) = mpsc::channel(100);
        let tx_to_hold = Arc::new(Mutex::new(tx));
        (
            InvalidatedJWTStore {
                // store: invalidated,
                tx: tx_to_hold,
            },
            rx,
        )
    }

    async fn add_to_invalidated(&self, authenticated: Authenticated<Claims>) {
        // self.store.insert(authenticated.jwt.clone());
        let mut tx = self.tx.lock().await;
        if let Err(_e) = tx
            .send(InvalidatedTokensEvent::Add(authenticated.jwt))
            .await
        {
            #[cfg(feature = "tracing")]
            error!(error = ?_e, "Failed to send update on adding to invalidated")
        }
    }
}

struct JwtSigningKeys {
    encoding_key: EncodingKey,
    decoding_key: DecodingKey,
}

impl JwtSigningKeys {
    fn generate() -> Result<Self, Box<dyn std::error::Error>> {
        let doc = Ed25519KeyPair::generate_pkcs8(&SystemRandom::new())?;
        let keypair = Ed25519KeyPair::from_pkcs8(doc.as_ref())?;
        let encoding_key = EncodingKey::from_ed_der(doc.as_ref());
        let decoding_key = DecodingKey::from_ed_der(keypair.public_key().as_ref());
        Ok(JwtSigningKeys {
            encoding_key,
            decoding_key,
        })
    }
}