use std::cell::RefCell;
use std::collections::HashMap;

use base64::engine::general_purpose::STANDARD as BASE64_STANDARD;
use base64::Engine as _;

use crate::actors::providers_states_actor::ProviderLoginState;
use crate::constants::OIDC_PROVIDERS_LIFETIME;
use crate::data::app_config::AppConfig;
use crate::data::jwt_signer::JsonWebKey;
use crate::data::openid_primitive::{OpenIDUserInfo, TokenResponse};
use crate::data::provider::Provider;
use crate::utils::err::Res;
use crate::utils::time::time;

#[derive(Debug, Clone, serde::Deserialize)]
pub struct ProviderDiscovery {
    pub issuer: String,
    pub authorization_endpoint: String,
    pub token_endpoint: String,
    pub userinfo_endpoint: Option<String>,
    pub jwks_uri: String,
    pub claims_supported: Option<Vec<String>>,
}

#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
pub struct ProviderJWKs {
    pub keys: Vec<JsonWebKey>,
}

/// Provider configuration
#[derive(Debug, Clone)]
pub struct ProviderConfiguration {
    pub discovery: ProviderDiscovery,
    //pub keys: ProviderJWKs,
    pub expire: u64,
}

impl ProviderConfiguration {
    /// Get the URL where a user should be redirected to authenticate
    pub fn auth_url(&self, provider: &Provider, state: &ProviderLoginState) -> String {
        let authorization_url = &self.discovery.authorization_endpoint;
        let client_id = urlencoding::encode(&provider.client_id).to_string();
        let state = urlencoding::encode(&state.state_id).to_string();
        let callback_url = AppConfig::get().oidc_provider_redirect_url();

        format!("{authorization_url}?response_type=code&scope=openid%20profile%20email&client_id={client_id}&state={state}&redirect_uri={callback_url}")
    }

    /// Retrieve the authorization token after a successful authentication, using an authorization code
    pub async fn get_token(
        &self,
        provider: &Provider,
        authorization_code: &str,
    ) -> Res<TokenResponse> {
        let authorization =
            BASE64_STANDARD.encode(format!("{}:{}", provider.client_id, provider.client_secret));

        let redirect_url = AppConfig::get().oidc_provider_redirect_url();

        let mut params = HashMap::new();
        params.insert("grant_type", "authorization_code");
        params.insert("code", authorization_code);
        params.insert("redirect_uri", redirect_url.as_str());

        Ok(reqwest::Client::new()
            .post(&self.discovery.token_endpoint)
            .header("Authorization", format!("Basic {authorization}"))
            .form(&params)
            .send()
            .await?
            .json()
            .await?)
    }

    /// Retrieve information about the user, using given [TokenResponse]
    pub async fn get_userinfo(&self, token: &TokenResponse) -> Res<OpenIDUserInfo> {
        Ok(reqwest::Client::new()
            .get(
                self.discovery
                    .userinfo_endpoint
                    .as_ref()
                    .expect("Userinfo endpoint is required by this implementation!"),
            )
            .header("Authorization", format!("Bearer {}", token.access_token))
            .send()
            .await?
            .json()
            .await?)
    }
}

thread_local! {
    static THREAD_CACHE: RefCell<HashMap<String, ProviderConfiguration>> = RefCell::new(Default::default());
}

pub struct ProviderConfigurationHelper {}

impl ProviderConfigurationHelper {
    /// Get or refresh the configuration for a provider
    pub async fn get_configuration(provider: &Provider) -> Res<ProviderConfiguration> {
        let config = THREAD_CACHE.with(|i| i.borrow().get(&provider.configuration_url).cloned());

        // Refresh config cache if needed
        if config.is_none() || config.as_ref().unwrap().expire < time() {
            let conf = Self::fetch_configuration(provider).await?;

            THREAD_CACHE.with(|i| {
                i.borrow_mut()
                    .insert(provider.configuration_url.clone(), conf.clone())
            });

            return Ok(conf);
        }

        // We can return immediately previously extracted value
        Ok(config.unwrap())
    }

    /// Get fresh configuration from provider
    async fn fetch_configuration(provider: &Provider) -> Res<ProviderConfiguration> {
        let discovery: ProviderDiscovery = reqwest::get(&provider.configuration_url)
            .await?
            .json()
            .await?;

        // let keys: ProviderJWKs = reqwest::get(&discovery.jwks_uri).await?.json().await?;

        Ok(ProviderConfiguration {
            discovery,
            //    keys,
            expire: time() + OIDC_PROVIDERS_LIFETIME,
        })
    }
}