mod types;
mod msa;
mod mcservices;

use std::error::Error;
use std::fmt::{Display, Formatter};
use std::future::Future;
use std::ops::Add;
use std::time::{Duration, Instant, SystemTime};
use chrono::{DateTime, NaiveDateTime, TimeDelta, Utc};
use log::debug;
use oauth2::{AccessToken, AuthType, AuthUrl, ClientId, DeviceAuthorizationResponse, DeviceAuthorizationUrl, DeviceCodeErrorResponse, EmptyExtraDeviceAuthorizationFields, EndpointNotSet, EndpointSet, HttpClientError, RefreshToken, RequestTokenError, Scope, StandardDeviceAuthorizationResponse, StandardRevocableToken, StandardTokenResponse, TokenResponse, TokenUrl};
use oauth2::basic::{BasicErrorResponse, BasicErrorResponseType, BasicRevocationErrorResponse, BasicTokenIntrospectionResponse, BasicTokenResponse};
use reqwest::{IntoUrl, Method, RequestBuilder};
pub use types::*;
use crate::auth::msa::{XSTS_RP_MINECRAFT_SERVICES, XSTS_RP_XBOX_LIVE};
use crate::util::USER_AGENT;

#[derive(Debug)]
pub enum AuthError {
    // An unexpected error happened while performing a request
    Request { what: &'static str, error: reqwest::Error },
    OAuthRequestToken { what: &'static str, error: RequestTokenError<HttpClientError<reqwest::Error>, BasicErrorResponse> },
    OAuthRequestDeviceCode { what: &'static str, error: RequestTokenError<HttpClientError<reqwest::Error>, DeviceCodeErrorResponse> },

    // Some internal auth error (unrecoverable)
    Internal(String),

    // Device code auth was cancelled
    Cancel(Option<Box<dyn Error>>),

    // Device code auth timed out
    Timeout,

    // Requires interactive authentication
    RequireInteractive(&'static str),

    // XSTS error
    AuthXError { what: &'static str, x_error: u64, message: Option<String> },

    // You don't own the game!
    EntitlementError
}

impl Display for AuthError {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        match self {
            AuthError::Request { what, error } => write!(f, "auth request error ({}): {}", what, error),
            AuthError::OAuthRequestToken { what, error } => write!(f, "oauth error requesting token ({what}): {error}"),
            AuthError::OAuthRequestDeviceCode { what, error } => write!(f, "oauth error with device code ({what}): {error}"),
            AuthError::Internal(msg) => write!(f, "internal auth error: {}", msg),
            AuthError::Cancel(Some(error)) => write!(f, "operation cancelled: {error}"),
            AuthError::Cancel(None) => f.write_str("operation cancelled"),
            AuthError::Timeout => f.write_str("interactive authentication timed out"),
            AuthError::RequireInteractive(why) => write!(f, "user must log in interactively: {why}"),
            AuthError::AuthXError { what, x_error, message } => write!(f, "XSTS error: {what} ({x_error} -> {})", message.as_ref().map_or("<no message>", |s| s.as_str())),
            AuthError::EntitlementError => f.write_str("no minecraft entitlement (do you own the game?)")
        }
    }
}

impl Error for AuthError {
    fn source(&self) -> Option<&(dyn Error + 'static)> {
        match self {
            AuthError::Request { error, .. } => Some(error),
            AuthError::OAuthRequestToken { error, .. } => Some(error),
            AuthError::OAuthRequestDeviceCode { error, .. } => Some(error),
            AuthError::Cancel(Some(error)) => Some(error.as_ref()),
            _ => None
        }
    }
}

impl Token {
    fn is_expired(&self, now: DateTime<Utc>) -> bool {
        self.expire.is_some_and(|exp| now >= exp)
    }
}

macro_rules! create_oauth_client {
    ($is_azure_client_id:expr, $client_id:expr) => {
        oauth2::Client::new($client_id)
            .set_token_uri(TokenUrl::new(if $is_azure_client_id { AZURE_TOKEN_URL.into() } else { NON_AZURE_TOKEN_URL.into() }).expect("hardcoded url"))
            .set_device_authorization_url(DeviceAuthorizationUrl::new(if $is_azure_client_id { AZURE_DEVICE_CODE_URL.into() } else { NON_AZURE_DEVICE_CODE_URL.into() }).expect("hardcoded url"))
        as oauth2::Client<BasicErrorResponse, BasicTokenResponse, BasicTokenIntrospectionResponse, StandardRevocableToken, BasicRevocationErrorResponse,
                          EndpointNotSet, EndpointSet, EndpointNotSet, EndpointNotSet, EndpointSet>
    }
}

const AZURE_TOKEN_URL: &str = "https://login.microsoftonline.com/consumers/oauth2/v2.0/token";
const AZURE_DEVICE_CODE_URL: &str = "https://login.microsoftonline.com/consumers/oauth2/v2.0/token";
const NON_AZURE_TOKEN_URL: &str = "https://login.live.com/oauth20_token.srf";
const NON_AZURE_DEVICE_CODE_URL: &str = "https://login.live.com/oauth20_connect.srf";

const AZURE_LOGIN_SCOPES: &[&str] = ["XboxLive.signin", "offline_access"].as_slice();
const NON_AZURE_LOGIN_SCOPES: &[&str] = ["service::user.auth.xboxlive.com::MBI_SSL"].as_slice();

fn build_json_request(client: &reqwest::Client, url: impl IntoUrl, method: Method) -> RequestBuilder {
    client.request(method, url)
        .header(reqwest::header::USER_AGENT, USER_AGENT)
        .header(reqwest::header::ACCEPT, "application/json")
}

impl MsaUser {
    pub fn create_client() -> reqwest::Client {
        reqwest::ClientBuilder::new()
            .redirect(reqwest::redirect::Policy::none())
            .build().expect("building client should succeed")
    }

    fn scopes_iter(&self) -> impl Iterator<Item = Scope> {
        let to_scope = |f: &&str| Scope::new(String::from(*f));

        if self.is_azure_client_id {
            AZURE_LOGIN_SCOPES.iter().map(to_scope)
        } else {
            NON_AZURE_LOGIN_SCOPES.iter().map(to_scope)
        }
    }

    // uses an access token from, for example, a device code grant logs into xbox live
    async fn xbl_login(&mut self, client: &reqwest::Client, token: &AccessToken) -> Result<(), AuthError> {
        debug!("Logging into xbox live using access token");
        self.xbl_token = Some(msa::xbox_live_login(client, token, self.is_azure_client_id).await?);

        Ok(())
    }

    // logs into xbox live using a refresh token
    // (panics if no refresh token present)
    async fn xbl_login_refresh(&mut self, client: &reqwest::Client) -> Result<(), AuthError> {
        debug!("Using refresh token for XBL login");
        let oauth_client = create_oauth_client!(self.is_azure_client_id, self.client_id.clone());
        let refresh_token = self.refresh_token.as_ref().expect("refresh_access_token called with no refresh token");

        let tokenres: BasicTokenResponse = oauth_client
            .exchange_refresh_token(refresh_token)
            .add_scopes(self.scopes_iter())
            .add_extra_param("response_type", "device_code")
            .request_async(client)
            .await.map_err(|e| AuthError::OAuthRequestToken { what: "refresh", error: e })?;

        self.refresh_token = tokenres.refresh_token().cloned();

        self.xbl_login(client, tokenres.access_token()).await
    }

    async fn xbl_login_device<D, DF>(&mut self, client: &reqwest::Client, handle_device: D) -> Result<(), AuthError>
    where
        D: FnOnce(StandardDeviceAuthorizationResponse) -> DF,
        DF: Future<Output = ()>
    {
        debug!("Using device authorization for XBL login");
        let oauth_client = create_oauth_client!(self.is_azure_client_id, self.client_id.clone());
        let device_auth: StandardDeviceAuthorizationResponse = oauth_client.exchange_device_code()
            .add_scopes(self.scopes_iter())
            .add_extra_param("response_type", "device_code")
            .request_async(client)
            .await.map_err(|e| AuthError::OAuthRequestToken { what: "device code", error: e })?;

        handle_device(device_auth.clone()).await;

        let tokenres = oauth_client.exchange_device_access_token(&device_auth)
            .set_max_backoff_interval(Duration::from_secs(20u64))
            .request_async(client, tokio::time::sleep, None)
            .await.map_err(|e| AuthError::OAuthRequestDeviceCode { what: "device access code", error: e })?;

        self.refresh_token = tokenres.refresh_token().cloned();

        self.xbl_login(client, tokenres.access_token()).await
    }

    // ensure we have an xbox live token for this person
    // tasks for this function:
    //  - check if the XBL token is valid/not expired
    //  - if it is expired, try to use refresh token to get a new one
    //    - get rid of auth token if yeah
    async fn ensure_xbl(&mut self, client: &reqwest::Client, now: DateTime<Utc>) -> Result<(), AuthError> {
        if self.xbl_token.as_ref().is_some_and(|tok| !tok.is_expired(now)) {
            debug!("XBL token valid. Using it.");
            return Ok(())
        }

        if self.refresh_token.is_none() {
            return Err(AuthError::RequireInteractive("no refresh token"));
        }

        debug!("XBL token expired. Trying to refresh it.");
        self.xbl_login_refresh(client).await
            .map_err(|e| match &e {
                AuthError::OAuthRequestToken { error, .. } => match error {
                    RequestTokenError::ServerResponse(res) => match res.error() {
                        BasicErrorResponseType::Extension(s) if s == "interaction_required" || s == "consent_required" => {
                            AuthError::RequireInteractive("msa requested interactive logon")
                        },
                        _ => e
                    },
                    _ => e
                },
                _ => e
            })?;

        self.mc_token = None;

        Ok(())
    }

    // function's tasks:
    // - if the minecraft services token invalid/expired/missing, do the following
    //   - get minecraftservices xsts token
    //   - use minecraftservices to get mojang token with that xsts token
    async fn ensure_mc_token(&mut self, client: &reqwest::Client, now: DateTime<Utc>) -> Result<(), AuthError> {
        if self.mc_token.as_ref().is_some_and(|tok| !tok.is_expired(now)) {
            debug!("Mojang token valid. Using it.");
            return Ok(())
        }

        debug!("Mojang token has expired. Must log in again.");
        let xbl_token = self.xbl_token.as_ref().expect("ensure_mc_token requires xbl token").value.as_str();
        let (user_hash, mc_xsts_tok) = match msa::xsts_request(client, xbl_token, XSTS_RP_MINECRAFT_SERVICES).await? {
            msa::XSTSAuthResponse::Success(res) => {
                let user_hash = res.get_user_hash()
                    .map_or(Err(AuthError::Internal("malformed response: no user hash".into())), |h| Ok(h.to_owned()))?;
                (user_hash, res.into_token())
            },
            msa::XSTSAuthResponse::Error(e) => return Err(e.into())
        };

        debug!("Got MinecraftServices XSTS, logging in.");
        self.mc_token = Some(mcservices::login_with_xbox(client, mc_xsts_tok.as_str(), user_hash.as_str()).await?);

        Ok(())
    }

    async fn load_xbox_info(&mut self, client: &reqwest::Client) -> Result<(), AuthError> {
        debug!("Loading Xbox info...");
        let xbl_token = self.xbl_token.as_ref().expect("xbl token missing").value.as_str();

        let res = match msa::xsts_request(client, xbl_token, XSTS_RP_XBOX_LIVE).await? {
            msa::XSTSAuthResponse::Success(res) => res,
            msa::XSTSAuthResponse::Error(e) => return Err(e.into())
        };

        let Some(xuid) = res.get_xuid() else {
            return Err(AuthError::Internal("missing xuid for user".into()));
        };

        self.xuid = Some(xuid);
        self.gamertag = res.get_gamertag().map(|s| s.to_owned());

        debug!("Xbox info loaded: (xuid {xuid}, gamertag {})", res.get_gamertag().unwrap_or("<none>"));

        Ok(())
    }

    async fn load_profile(&mut self, client: &reqwest::Client) -> Result<(), AuthError> {
        self.load_xbox_info(client).await?;

        let mc_token = self.mc_token.as_ref().expect("minecraft token missing").value.as_str();

        if !mcservices::owns_the_game(client, mc_token).await? {
            return Err(AuthError::EntitlementError);
        }

        let player_info = mcservices::get_player_info(client, mc_token).await?;
        let player_profile = mcservices::get_player_profile(client, player_info.id).await
            .map_err(|e| AuthError::Request { what: "looking up profile", error: e })?;

        self.player_info = Some(player_info);
        self.player_profile = Some(player_profile);

        Ok(())
    }

    async fn log_in_silent(&mut self, client: &reqwest::Client) -> Result<(), AuthError> {
        let now: DateTime<Utc> = DateTime::from(SystemTime::now()) + TimeDelta::hours(12);

        self.ensure_xbl(client, now).await?;
        self.ensure_mc_token(client, now).await?;
        self.load_profile(client).await?;

        Ok(())
    }
}

#[cfg(test)]
mod test {
    use reqwest::Client;
    use super::*;

    #[tokio::test]
    async fn abc() {
        simple_logger::SimpleLogger::new().with_colors(true).with_level(log::LevelFilter::Trace).init().unwrap();

        let mut user = match tokio::fs::read_to_string("test_stuff/test.json").await {
            Ok(s) => serde_json::from_str::<MsaUser>(&s).unwrap(),
            Err(e) if e.kind() == tokio::io::ErrorKind::NotFound => {
                MsaUser {
                    player_profile: None,
                    xuid: None,
                    gamertag: None,
                    player_info: None,
                    client_id: ClientId::new("00000000402b5328".into()),
                    is_azure_client_id: false,
                    mc_token: None,
                    xbl_token: None,
                    refresh_token: None
                }
            },
            Err(e) => panic!("i/o error: {}", e)
        };

        let client = MsaUser::create_client();

        loop {
            match user.log_in_silent(&client).await {
                Ok(_) => break,
                Err(AuthError::RequireInteractive(s)) => {
                    debug!("Requires interactive auth: {s}")
                },
                Err(e) => {
                    panic!("{}", e);
                }
            }

            user.xbl_login_device(&client, |d| async move {
                let d = dbg!(d);
                debug!("User code: {}", d.user_code().secret());
                ()
            }).await.unwrap()
        }

        debug!("User: {user:?}");

        let user_str = serde_json::to_string_pretty(&user).unwrap();
        tokio::fs::write("test_stuff/test.json", user_str.as_str()).await.unwrap();
    }
}