#![deny(unsafe_code)]
#![deny(clippy::unwrap_used)]
#![deny(warnings)]
#![doc = include_str!("../README.md")]

use crate::error::Error;
use http::Uri;
use openidconnect::{
    core::{
        CoreAuthDisplay, CoreAuthPrompt, CoreClaimName, CoreClaimType, CoreClientAuthMethod,
        CoreErrorResponseType, CoreGenderClaim, CoreGrantType, CoreJsonWebKey, CoreJsonWebKeyType,
        CoreJsonWebKeyUse, CoreJweContentEncryptionAlgorithm, CoreJweKeyManagementAlgorithm,
        CoreJwsSigningAlgorithm, CoreResponseMode, CoreResponseType, CoreRevocableToken,
        CoreRevocationErrorResponse, CoreSubjectIdentifierType, CoreTokenIntrospectionResponse,
        CoreTokenType,
    },
    reqwest::async_http_client,
    AccessToken, ClientId, ClientSecret, CsrfToken, EmptyExtraTokenFields, IdTokenFields,
    IssuerUrl, Nonce, PkceCodeVerifier, RefreshToken, StandardErrorResponse, StandardTokenResponse,
};
use serde::{de::DeserializeOwned, Deserialize, Serialize};

pub mod error;
mod extractor;
mod middleware;

pub use extractor::{OidcAccessToken, OidcClaims, OidcRpInitiatedLogout};
pub use middleware::{OidcAuthLayer, OidcAuthMiddleware, OidcLoginLayer, OidcLoginMiddleware};

const SESSION_KEY: &str = "axum-oidc";

pub trait AdditionalClaims:
    openidconnect::AdditionalClaims + Clone + Sync + Send + Serialize + DeserializeOwned
{
}

type OidcTokenResponse<AC> = StandardTokenResponse<
    IdTokenFields<
        AC,
        EmptyExtraTokenFields,
        CoreGenderClaim,
        CoreJweContentEncryptionAlgorithm,
        CoreJwsSigningAlgorithm,
        CoreJsonWebKeyType,
    >,
    CoreTokenType,
>;

pub type IdToken<AZ> = openidconnect::IdToken<
    AZ,
    CoreGenderClaim,
    CoreJweContentEncryptionAlgorithm,
    CoreJwsSigningAlgorithm,
    CoreJsonWebKeyType,
>;

type Client<AC> = openidconnect::Client<
    AC,
    CoreAuthDisplay,
    CoreGenderClaim,
    CoreJweContentEncryptionAlgorithm,
    CoreJwsSigningAlgorithm,
    CoreJsonWebKeyType,
    CoreJsonWebKeyUse,
    CoreJsonWebKey,
    CoreAuthPrompt,
    StandardErrorResponse<CoreErrorResponseType>,
    OidcTokenResponse<AC>,
    CoreTokenType,
    CoreTokenIntrospectionResponse,
    CoreRevocableToken,
    CoreRevocationErrorResponse,
>;

type ProviderMetadata = openidconnect::ProviderMetadata<
    AdditionalProviderMetadata,
    CoreAuthDisplay,
    CoreClientAuthMethod,
    CoreClaimName,
    CoreClaimType,
    CoreGrantType,
    CoreJweContentEncryptionAlgorithm,
    CoreJweKeyManagementAlgorithm,
    CoreJwsSigningAlgorithm,
    CoreJsonWebKeyType,
    CoreJsonWebKeyUse,
    CoreJsonWebKey,
    CoreResponseMode,
    CoreResponseType,
    CoreSubjectIdentifierType,
>;

pub type BoxError = Box<dyn std::error::Error + Send + Sync>;

/// OpenID Connect Client
#[derive(Clone)]
pub struct OidcClient<AC: AdditionalClaims> {
    scopes: Vec<String>,
    client_id: String,
    client: Client<AC>,
    application_base_url: Uri,
    end_session_endpoint: Option<Uri>,
}

impl<AC: AdditionalClaims> OidcClient<AC> {
    /// create a new [`OidcClient`] by fetching the required information from the
    /// `/.well-known/openid-configuration` endpoint of the issuer.
    pub async fn discover_new(
        application_base_url: Uri,
        issuer: String,
        client_id: String,
        client_secret: Option<String>,
        scopes: Vec<String>,
    ) -> Result<Self, Error> {
        let provider_metadata =
            ProviderMetadata::discover_async(IssuerUrl::new(issuer)?, async_http_client).await?;
        let end_session_endpoint = provider_metadata
            .additional_metadata()
            .end_session_endpoint
            .clone()
            .map(Uri::from_maybe_shared)
            .transpose()
            .map_err(Error::InvalidEndSessionEndpoint)?;
        let client = Client::from_provider_metadata(
            provider_metadata,
            ClientId::new(client_id.clone()),
            client_secret.map(ClientSecret::new),
        );
        Ok(Self {
            scopes,
            client,
            client_id,
            application_base_url,
            end_session_endpoint,
        })
    }
}

/// an empty struct to be used as the default type for the additional claims generic
#[derive(Deserialize, Serialize, Debug, Clone, Copy, Default)]
pub struct EmptyAdditionalClaims {}
impl AdditionalClaims for EmptyAdditionalClaims {}
impl openidconnect::AdditionalClaims for EmptyAdditionalClaims {}

/// response data of the openid issuer after login
#[derive(Debug, Deserialize)]
struct OidcQuery {
    code: String,
    state: String,
    #[allow(dead_code)]
    session_state: String,
}

/// oidc session
#[derive(Serialize, Deserialize, Debug)]
#[serde(bound = "AC: Serialize + DeserializeOwned")]
struct OidcSession<AC: AdditionalClaims> {
    nonce: Nonce,
    csrf_token: CsrfToken,
    pkce_verifier: PkceCodeVerifier,
    authenticated: Option<AuthenticatedSession<AC>>,
    refresh_token: Option<RefreshToken>,
}

#[derive(Serialize, Deserialize, Debug)]
#[serde(bound = "AC: Serialize + DeserializeOwned")]
struct AuthenticatedSession<AC: AdditionalClaims> {
    id_token: IdToken<AC>,
    access_token: AccessToken,
}

/// additional metadata that is discovered on client creation via the
/// `.well-knwon/openid-configuration` endpoint.
#[derive(Debug, Clone, Serialize, Deserialize)]
struct AdditionalProviderMetadata {
    end_session_endpoint: Option<String>,
}
impl openidconnect::AdditionalProviderMetadata for AdditionalProviderMetadata {}

/// response extension flag to signal the [`OidcAuthLayer`] that the session should be cleared.
#[derive(Clone, Copy)]
pub struct ClearSessionFlag;