use std::{
    path::PathBuf,
    sync::Arc,
    time::{Duration as StdDuration, SystemTime, UNIX_EPOCH},
};

use anyhow::Context;
use db::Db;
use futures::Future;
use lettre::{message::Mailbox, transport::smtp::authentication::Credentials};
use mailer::Mailer;
use push::PushClient;
use rocket::{
    fairing::AdHoc,
    http::{uri::Absolute, ContentType, Header},
    request::{self, FromRequest},
    response::Redirect,
    tokio::{
        spawn,
        task::JoinHandle,
        time::{interval_at, Instant, MissedTickBehavior},
    },
    Request, State,
};
use serde_json::{json, Value};
use time::Duration;
use utils::DeferredActions;

use crate::api::auth::invite::generate_invite_link;

#[macro_use]
extern crate rocket;
#[macro_use]
extern crate anyhow;
#[macro_use]
extern crate lazy_static;

#[macro_use]
pub(crate) mod utils;
pub(crate) mod api;
mod auth;
mod cache;
mod crypto;
pub mod db;
mod js;
mod mailer;
mod push;
pub(crate) mod serde;
mod types;

fn default_push_ttl() -> std::time::Duration {
    std::time::Duration::from_secs(2 * 86400)
}

fn default_task_interval() -> std::time::Duration {
    std::time::Duration::from_secs(5 * 60)
}

#[derive(Debug, ::serde::Deserialize)]
struct Config {
    database_url: String,
    location: Absolute<'static>,
    token_server_location: Absolute<'static>,
    vapid_key: PathBuf,
    vapid_subject: String,
    #[serde(default = "default_push_ttl", with = "humantime_serde")]
    default_push_ttl: std::time::Duration,
    #[serde(default = "default_task_interval", with = "humantime_serde")]
    prune_expired_interval: std::time::Duration,

    mail_from: Mailbox,
    mail_host: Option<String>,
    mail_port: Option<u16>,
    mail_user: Option<String>,
    mail_password: Option<String>,
    #[serde(default)]
    mail_starttls: bool,

    #[serde(default)]
    invite_only: bool,
    #[serde(default)]
    invite_admin_address: String,
}

impl Config {
    pub fn avatars_prefix(&self) -> Absolute<'static> {
        Absolute::parse_owned(format!("{}/avatars", self.location)).unwrap()
    }
}

#[get("/")]
async fn root() -> (ContentType, &'static str) {
    (ContentType::HTML, include_str!("../web/index.html"))
}

#[get("/settings/<_..>")]
async fn settings() -> Redirect {
    Redirect::to(uri!("/#/settings"))
}

#[get("/auth/v1/authorization")]
async fn auth_auth() -> (ContentType, &'static str) {
    root().await
}

#[get("/force_auth")]
async fn force_auth() -> Redirect {
    Redirect::to(uri!("/#/force_auth"))
}

#[derive(Debug)]
struct IsFenix(bool);

#[rocket::async_trait]
impl<'r> FromRequest<'r> for IsFenix {
    type Error = std::convert::Infallible;

    async fn from_request(request: &'r Request<'_>) -> request::Outcome<Self, Self::Error> {
        let ua = request.headers().get_one("user-agent");
        request::Outcome::Success(IsFenix(
            ua.map(|ua| ua.contains("Firefox") && ua.contains("Android")).unwrap_or(false),
        ))
    }
}

#[get("/.well-known/fxa-client-configuration")]
async fn fxa_client_configuration(cfg: &State<Config>, is_fenix: IsFenix) -> Value {
    let base = &cfg.location;
    json!({
        "auth_server_base_url": format!("{base}/auth"),
        "oauth_server_base_url": format!("{base}/oauth"),
        "pairing_server_base_uri": format!("{base}/pairing"),
        "profile_server_base_url": format!("{base}/profile"),
        // NOTE trailing slash is *essential*, otherwise fenix will refuse to sync.
        // likewise firefox desktop seems to misbehave if there *is* a trailing slash.
        "sync_tokenserver_base_url": format!("{}{}", cfg.token_server_location, if is_fenix.0 { "/" } else { "" })
    })
}

// NOTE it looks like firefox does not implement refresh token rotation.
// since it also looks like it doesn't implement MTLS we can't secure
// refresh tokens against being stolen as advised by
// https://datatracker.ietf.org/doc/html/draft-ietf-oauth-security-topics
// section 2.2.2

// NOTE firefox "oldsync" scope is the current version?
// https://github.com/mozilla/fxa/blob/main/packages/fxa-auth-server/docs/oauth/scopes.md
// https://mozilla.github.io/ecosystem-platform/explanation/onepw-protocol
// https://mozilla.github.io/ecosystem-platform/api
// https://github.com/mozilla/fxa/blob/main/packages/fxa-auth-server/docs/device_registration.md
//   -> push for everything
// https://mozilla.github.io/ecosystem-platform/explanation/scoped-keys

#[get("/.well-known/openid-configuration")]
fn oid(cfg: &State<Config>) -> Value {
    let base = &cfg.location;
    json!({
        "authorization_endpoint": format!("{base}/auth/v1/authorization"),
        "introspection_endpoint": format!("{base}/oauth/v1/introspect"),
        "issuer": base.to_string(),
        "jwks_uri": format!("{base}/oauth/v1/jwks"),
        "revocation_endpoint": format!("{base}/oauth/v1/destroy"),
        "token_endpoint": format!("{base}/auth/v1/oauth/token"),
        "userinfo_endpoint": format!("{base}/profile/v1/profile"),
        "claims_supported": ["aud","exp","iat","iss","sub"],
        "id_token_signing_alg_values_supported": ["RS256"],
        "response_types_supported": ["code","token"],
        "scopes_supported": ["openid","profile","email"],
        "subject_types_supported": ["public"],
        "token_endpoint_auth_methods_supported": ["client_secret_post"],
    })
}

fn spawn_periodic<A, P, F>(context: &'static str, t: StdDuration, p: P, f: A) -> JoinHandle<()>
where
    A: Fn(P) -> F + Send + Sync + Sized + 'static,
    P: Clone + Send + Sync + 'static,
    F: Future<Output = anyhow::Result<()>> + Send + Sized,
{
    let mut interval = interval_at(Instant::now() + t, t);
    interval.set_missed_tick_behavior(MissedTickBehavior::Skip);

    spawn(async move {
        loop {
            interval.tick().await;
            info!("starting periodic {context}");
            if let Err(e) = f(p.clone()).await {
                error!("periodic {context} failed: {e}");
            }
        }
    })
}

async fn ensure_invite_admin(db: &Db, cfg: &Config) -> anyhow::Result<()> {
    if !cfg.invite_only {
        return Ok(());
    }

    let tx = db.begin().await?;
    match tx.get_user(&cfg.invite_admin_address).await {
        Err(sqlx::Error::RowNotFound) => {
            let url = generate_invite_link(&tx, cfg, Duration::hours(1)).await?;
            tx.commit().await?;
            warn!("admin user {} does not exist, register at {url}", cfg.invite_admin_address);
            Ok(())
        },
        Err(e) => Err(anyhow!(e)),
        Ok(_) => Ok(()),
    }
}

fn periodic_code_prune(db: &Arc<Db>) -> JoinHandle<()> {
    spawn_periodic("verify code prune", StdDuration::from_secs(5 * 60), Arc::clone(&db), {
        |db| async move {
            let tx = db.begin().await?;
            tx.prune_expired_verify_codes().await?;
            tx.commit().await?;
            Ok(())
        }
    })
}

fn periodic_token_prune(config: &Config, db: &Arc<Db>) -> JoinHandle<()> {
    spawn_periodic("expired token prune", config.prune_expired_interval, Arc::clone(&db), {
        |db| async move {
            let tx = db.begin().await?;
            tx.prune_expired_tokens().await?;
            tx.commit().await?;
            Ok(())
        }
    })
}

pub async fn build(
    base: rocket::Rocket<rocket::Build>,
) -> anyhow::Result<rocket::Rocket<rocket::Build>> {
    let config = base.figment().extract::<Config>().context("reading config")?;
    let db = Arc::new(Db::connect(&config.database_url).await.unwrap());

    db.migrate().await.context("running db migrations")?;

    ensure_invite_admin(&db, &config).await?;
    let push = Arc::new(
        PushClient::new(
            &config.vapid_key,
            &config.vapid_subject,
            config.location.clone(),
            config.default_push_ttl,
        )
        .context("setting up push notifications")?,
    );
    let mailer = Arc::new(
        Mailer::new(
            config.mail_from.clone(),
            config.mail_host.as_deref().unwrap_or("localhost"),
            config.mail_port.unwrap_or(25),
            config.mail_starttls,
            match (config.mail_user.clone(), config.mail_password.clone()) {
                (Some(user), Some(pw)) => Some(Credentials::new(user, pw)),
                _ => None,
            },
            config.location.clone(),
        )
        .context("setting up mail notifications")?,
    );
    let rocket = base
        .manage(config)
        .manage(push)
        .manage(mailer)
        .attach(Arc::clone(&db))
        .attach(DeferredActions)
        .attach(AdHoc::on_ignite("periodic actions", |rocket| async move {
            struct AbortOnDrop<T>(JoinHandle<T>);

            impl<T> Drop for AbortOnDrop<T> {
                fn drop(&mut self) {
                    self.0.abort()
                }
            }

            let config = rocket.state::<Config>().unwrap();
            let code_prune = periodic_code_prune(&db);
            let token_prune = periodic_token_prune(&config, &db);
            rocket.manage((AbortOnDrop(code_prune), AbortOnDrop(token_prune)))
        }))
        .mount("/", routes![root, settings, oid, auth_auth, force_auth, fxa_client_configuration,])
        .register("/auth/v1", catchers![api::auth::catch_all,])
        .mount(
            "/auth/v1",
            routes![
                api::auth::account::create,
                api::auth::account::login,
                api::auth::account::destroy,
                api::auth::account::keys,
                api::auth::account::reset,
                api::auth::oauth::token_authenticated,
                api::auth::oauth::token_unauthenticated,
                api::auth::oauth::destroy,
                api::auth::oauth::scoped_key_data,
                api::auth::device::devices,
                api::auth::device::device,
                api::auth::device::invoke,
                api::auth::device::commands,
                api::auth::session::status,
                api::auth::session::resend_code,
                api::auth::session::verify_code,
                api::auth::session::destroy,
                api::auth::oauth::authorization,
                api::auth::device::destroy,
                api::auth::device::notify,
                api::auth::device::attached_clients,
                api::auth::device::destroy_attached_client,
                api::auth::email::status,
                api::auth::email::verify_code,
                api::auth::email::resend_code,
                api::auth::password::change_start,
                api::auth::password::change_finish,
                api::auth::password::forgot_start,
                api::auth::password::forgot_finish,
            ],
        )
        // slight hack to allow the js auth client to "just work"
        .register("/_invite/v1", catchers![api::auth::catch_all,])
        .mount("/_invite/v1", routes![api::auth::invite::generate,])
        .attach(AdHoc::on_response("/auth Timestamp", |req, resp| {
            Box::pin(async move {
                if req.uri().path().as_str().starts_with("/auth/v1/") {
                    if let Ok(ts) = SystemTime::now().duration_since(UNIX_EPOCH) {
                        resp.set_header(Header::new("timestamp", ts.as_secs().to_string()));
                    }
                }
            })
        }))
        .register("/profile", catchers![api::profile::catch_all,])
        .mount(
            "/profile/v1",
            routes![
                api::profile::profile,
                api::profile::display_name_post,
                api::profile::avatar_get,
                api::profile::avatar_upload,
                api::profile::avatar_delete,
            ],
        )
        .register("/avatars", catchers![api::profile::catch_all,])
        .mount("/avatars", routes![api::profile::avatar_get_img])
        .register("/oauth/v1", catchers![api::oauth::catch_all,])
        .mount("/oauth/v1", routes![api::oauth::destroy, api::oauth::jwks, api::oauth::verify,])
        .mount("/js", routes![js::static_js]);
    Ok(rocket)
}