use std::io::ErrorKind;
use std::sync::Arc;

use actix_web::web;
use uuid::Uuid;
use webauthn_rs::{Webauthn, WebauthnBuilder};
use webauthn_rs::prelude::{CreationChallengeResponse, Passkey, PublicKeyCredential, RegisterPublicKeyCredential, RequestChallengeResponse};

use crate::constants::{WEBAUTHN_LOGIN_CHALLENGE_EXPIRE, WEBAUTHN_REGISTER_CHALLENGE_EXPIRE};
use crate::data::app_config::AppConfig;
use crate::data::crypto_wrapper::CryptoWrapper;
use crate::data::user::{User, UserID};
use crate::utils::err::Res;
use crate::utils::time::time;

#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
pub struct WebauthnPubKey {
    creds: Passkey,
}

pub struct RegisterKeyRequest {
    pub opaque_state: String,
    pub creation_challenge: CreationChallengeResponse,
}

#[derive(Debug, serde::Serialize, serde::Deserialize)]
struct RegisterKeyOpaqueData {
    registration_state: String,
    user_id: UserID,
    expire: u64,
}

pub struct AuthRequest {
    pub opaque_state: String,
    pub login_challenge: RequestChallengeResponse,
}

#[derive(Debug, serde::Serialize, serde::Deserialize)]
struct AuthStateOpaqueData {
    authentication_state: String,
    user_id: UserID,
    expire: u64,
}


pub type WebAuthManagerReq = web::Data<Arc<WebAuthManager>>;

pub struct WebAuthManager {
    core: Webauthn,
    crypto_wrapper: CryptoWrapper,
}

impl WebAuthManager {
    pub fn init(conf: &AppConfig) -> Self {
        Self {
            core: WebauthnBuilder::new(
                conf.domain_name().split_once(':')
                    .map(|s| s.0)
                    .unwrap_or_else(|| conf.domain_name()),
                &url::Url::parse(&conf.website_origin)
                    .expect("Failed to parse configuration origin!"))
                .expect("Invalid Webauthn configuration")
                .build()
                .expect("Failed to build webauthn")

            ,
            crypto_wrapper: CryptoWrapper::new_random(),
        }
    }

    pub fn start_register(&self, user: &User) -> Res<RegisterKeyRequest> {
        let (creation_challenge, registration_state)
            = self.core.start_passkey_registration(
            Uuid::parse_str(&user.uid.0).expect("Failed to parse user id"),
            &user.username,
            &user.full_name(),
            None,
        )?;

        Ok(RegisterKeyRequest {
            opaque_state: self.crypto_wrapper.encrypt(&RegisterKeyOpaqueData {
                registration_state: serde_json::to_string(&registration_state)?,
                user_id: user.uid.clone(),
                expire: time() + WEBAUTHN_REGISTER_CHALLENGE_EXPIRE,
            })?,
            creation_challenge,
        })
    }

    pub fn finish_registration(&self, user: &User, opaque_state: &str,
                               pub_cred: RegisterPublicKeyCredential) -> Res<WebauthnPubKey> {
        let state: RegisterKeyOpaqueData = self.crypto_wrapper.decrypt(opaque_state)?;
        if state.user_id != user.uid {
            return Err(Box::new(
                std::io::Error::new(ErrorKind::Other, "Invalid user for pubkey!")));
        }

        if state.expire < time() {
            return Err(Box::new(
                std::io::Error::new(ErrorKind::Other, "Challenge has expired!")));
        }

        let res = self.core
            .finish_passkey_registration(&pub_cred, &serde_json::from_str(&state.registration_state)?)?;

        Ok(WebauthnPubKey { creds: res })
    }

    pub fn start_authentication(&self, user_id: &UserID, key: &WebauthnPubKey) -> Res<AuthRequest> {
        let (login_challenge, authentication_state) = self.core.start_passkey_authentication(&vec![
            key.creds.clone()
        ])?;

        Ok(AuthRequest {
            opaque_state: self.crypto_wrapper.encrypt(&AuthStateOpaqueData {
                authentication_state: serde_json::to_string(&authentication_state)?,
                user_id: user_id.clone(),
                expire: time() + WEBAUTHN_LOGIN_CHALLENGE_EXPIRE,
            })?,
            login_challenge,
        })
    }

    pub fn finish_authentication(&self, user_id: &UserID, opaque_state: &str,
                                 pub_cred: &PublicKeyCredential) -> Res {
        let state: AuthStateOpaqueData = self.crypto_wrapper.decrypt(opaque_state)?;
        if &state.user_id != user_id {
            return Err(Box::new(
                std::io::Error::new(ErrorKind::Other, "Invalid user for pubkey!")));
        }

        if state.expire < time() {
            return Err(Box::new(
                std::io::Error::new(ErrorKind::Other, "Challenge has expired!")));
        }

        self.core.finish_passkey_authentication(pub_cred,
                                                &serde_json::from_str(&state.authentication_state)?)?;

        Ok(())
    }
}