mod data;
use std::{
    borrow::Borrow,
    collections::{HashMap, HashSet},
    hash::{Hash, Hasher},
    str::FromStr,
    sync::{Arc, RwLock},
    time::{Duration, SystemTime, UNIX_EPOCH},
};

use crate::{
    api::client_server::TOKEN_LENGTH,
    config::{sso::ProviderConfig as Config, IdpConfig},
    utils, Error, Result,
};
pub use data::Data;
use email_address::EmailAddress;
use futures_util::future::{self};
use mas_oidc_client::{
    http_service::{hyper, HttpService},
    jose::jwk::PublicJsonWebKeySet,
    requests::{
        authorization_code::{self, AuthorizationRequestData, AuthorizationValidationData},
        discovery,
        jose::{self, JwtVerificationData},
        userinfo,
    },
    types::{
        iana::jose::JsonWebSignatureAlg, oidc::VerifiedProviderMetadata,
        requests::AccessTokenResponse, IdToken,
    },
};
use rand::SeedableRng;
use ruma::{api::client::error::ErrorKind, MilliSecondsSinceUnixEpoch, OwnedUserId, UserId};
use serde::{Deserialize, Serialize};
use serde_json::Value;
use tokio::sync::{oneshot, OnceCell};
use tracing::error;
use url::Url;

use crate::services;

pub use data::Data;

pub const SSO_AUTH_EXPIRATION_SECS: u64 = 60 * 60;
pub const SSO_TOKEN_EXPIRATION_SECS: u64 = 60 * 2;
pub const SSO_SESSION_COOKIE: &str = "sso-auth";

pub struct Service {
    db: &'static dyn Data,
    service: HttpService,
    providers: OnceCell<HashSet<Provider>>,
}

impl Service {
    pub fn build(db: &'static dyn Data) -> Result<Arc<Self>> {
        Ok(Arc::new(Self {
            db,
            service: HttpService::new(hyper::hyper_service()),
            providers: OnceCell::new(),
        }))
    }

    pub fn service(&self) -> &HttpService {
        &self.service
    }

    pub async fn start_handler(&self) -> Result<()> {
        let providers = services().globals.config.idps.iter();

        self.providers
            .get_or_try_init(|| {
                future::try_join_all(providers.map(Provider::fetch_metadata))
                    .await
                    .map(Vec::into_iter)
                    .map(HashSet::from_iter)
            })
            .await?;

        Ok(())
    }

    pub fn get(&self, provider: &str) -> Option<&Provider> {
        let providers = self.providers.get().expect("");

        providers.get(provider)
    }

    pub fn user_from_subject(&self, provider: &str, subject: &str) -> Result<Option<OwnedUserId>> {
        self.db.user_from_subject(provider, subject)
    }
}

#[derive(Clone, Debug)]
pub struct Provider {
    pub config: &'static IdpConfig,
    pub metadata: VerifiedProviderMetadata,
}

impl Provider {
    pub async fn fetch_metadata(config: &'static IdpConfig) -> Result<Self> {
        discovery::discover(services().sso.service(), &config.issuer)
            .await
            .map(|metadata| Provider { config, metadata })
            .map_err(|e| {
                error!(
                    "Failed to fetch identity provider metadata ({}): {}",
                    &config.inner.id, e
                );

                Error::bad_config("Failed to fetch identity provider metadata.")
            })
    }

    async fn fetch_signing_keys(&self) -> Result<PublicJsonWebKeySet> {
        jose::fetch_jwks(&services().sso.service, self.metadata.jwks_uri())
            .await
            .map_err(|e| {
                error!("Failed to fetch signing keys for token endpoint: {}", e);

                Error::bad_config("Failed to fetch signing keys for token endpoint.")
            })
    }

    pub async fn fetch_access_token(
        &self,
        auth_code: String,
        validation_data: AuthorizationValidationData,
    ) -> Result<(AccessTokenResponse, Option<IdToken<'_>>)> {
    }

    pub async fn fetch_userinfo(
        &self,
        access_token: &str,
        id_token: &IdToken<'_>,
    ) -> Result<Option<HashMap<String, Value>>> {
    }
}

impl Borrow<str> for Provider {
    fn borrow(&self) -> &str {
        self.config.borrow()
    }
}

impl PartialEq for Provider {
    fn eq(&self, other: &Self) -> bool {
        self.config == other.config
    }
}

impl Eq for Provider {}

impl Hash for Provider {
    fn hash<H: Hasher>(&self, hasher: &mut H) {
        self.config.hash(hasher)
    }
}

#[derive(Clone, Debug, Deserialize, Serialize)]
pub struct RegistrationToken {
    pub info: RegistrationInfo,
    pub provider_id: String,
    pub unique_claim: String,
    pub redirect_uri: Url,
    pub expires_at: MilliSecondsSinceUnixEpoch,
}

impl RegistrationToken {
    pub fn new(
        provider_id: String,
        unique_claim: String,
        redirect_uri: Url,
        info: RegistrationInfo,
    ) -> Self {
        let expires_at = MilliSecondsSinceUnixEpoch::from_system_time(
            UNIX_EPOCH
                .checked_add(Duration::from_secs(REGISTRATION_EXPIRATION_SECS))
                .expect("SystemTime should not overflow"),
        )
        .expect("MilliSecondsSinceUnixEpoch is not too large");

        Self {
            info,
            provider_id,
            unique_claim,
            redirect_uri,
            expires_at,
        }
    }
}

#[derive(Clone, Debug, Default, Deserialize, Serialize)]
pub struct RegistrationInfo {
    pub username: String,
    pub displayname: Option<String>,
    pub avatar_url: Option<Url>,
    pub email: Option<EmailAddress>,
}

impl RegistrationInfo {
    pub fn new(
        claims: &HashMap<String, Value>,
        username: &str,
        displayname: &str,
        avatar_url: &str,
        email: &str,
    ) -> Self {
        Self {
            username: claims
                .get(username)
                .and_then(|v| v.as_str())
                .map(ToOwned::to_owned)
                .unwrap_or_default(),
            displayname: claims
                .get(displayname)
                .and_then(|v| v.as_str())
                .map(ToOwned::to_owned),
            avatar_url: claims
                .get(avatar_url)
                .and_then(|v| v.as_str())
                .map(Url::parse)
                .and_then(Result::ok),
            email: claims
                .get(email)
                .and_then(|v| v.as_str())
                .map(EmailAddress::from_str)
                .and_then(Result::ok),
        }
    }
}

#[derive(Clone, Deserialize, Serialize)]
pub struct LoginToken {
    pub inner: String,
    pub provider_id: String,
    pub user_id: OwnedUserId,

    #[serde(rename = "exp")]
    expires_at: u64,
}

impl LoginToken {
    pub fn new(provider_id: String, user_id: OwnedUserId) -> Self {
        let expires_at = SystemTime::now()
            .checked_add(Duration::from_secs(LOGIN_TOKEN_EXPIRATION_SECS))
            .expect("SystemTime should not overflow")
            .duration_since(UNIX_EPOCH)
            .expect("SystemTime went backwards")
            .as_secs();

        Self {
            inner: utils::random_string(TOKEN_LENGTH),
            provider_id,
            user_id,
            expires_at,
        }
    }
}

#[derive(Clone, Debug, Deserialize, Serialize)]
pub struct ValidationData {
    pub provider: String,
    #[serde(flatten, with = "AuthorizationValidationDataDef")]
    pub inner: AuthorizationValidationData,
}

impl ValidationData {
    pub fn new(provider: String, inner: AuthorizationValidationData) -> Self {
        Self { provider, inner }
    }
}

#[derive(Clone, Debug, Deserialize, Serialize)]
#[serde(remote = "AuthorizationValidationData")]
pub struct AuthorizationValidationDataDef {
    pub state: String,
    pub nonce: String,
    pub redirect_uri: Url,
    pub code_challenge_verifier: Option<String>,
}

impl From<AuthorizationValidationData> for AuthorizationValidationDataDef {
    fn from(
        AuthorizationValidationData {
            state,
            nonce,
            redirect_uri,
            code_challenge_verifier,
        }: AuthorizationValidationData,
    ) -> Self {
        Self {
            state,
            nonce,
            redirect_uri,
            code_challenge_verifier,
        }
    }
}