grammers-client 0.9.0

// Copyright 2020 - developers of the `grammers` project.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use std::num::NonZeroU32;
use std::ops::ControlFlow;
use std::sync::Arc;
use std::time::Duration;

use grammers_mtsender::{InvocationError, SenderPoolFatHandle};
use grammers_tl_types::{self as tl, Deserializable};
use log::info;
use tokio::{sync::Mutex, time::sleep};

use super::{Client, ClientConfiguration, ClientInner, RetryContext};

/// Method implementations directly related with network connectivity.
impl Client {
    /// Creates and returns a new client instance upon successful connection to Telegram.
    ///
    /// If the session in the configuration did not have an authorization key, a new one
    /// will be created and the session will be saved with it.
    ///
    /// The connection will be initialized with the data from the input configuration.
    ///
    /// The [`grammers_mtsender::SenderPoolHandle`] does not keep a reference to the [`grammers_session::Session`]
    /// or `api_id`, but the [`SenderPool`] itself does, so the latter is used as input to guarantee
    /// that the values are correctly shared between the pool and the client handles.
    ///
    /// # Examples
    ///
    /// ```
    /// use std::sync::Arc;
    /// use grammers_client::Client;
    /// use grammers_session::storages::MemorySession; // avoid this storage outside tests!
    /// use grammers_mtsender::SenderPool;
    ///
    /// // Note: these are example values and are not actually valid.
    /// //       Obtain your own with the developer's phone at https://my.telegram.org.
    /// const API_ID: i32 = 932939;
    ///
    /// # async fn f() -> Result<(), Box<dyn std::error::Error>> {
    /// let session = Arc::new(MemorySession::default());
    /// let pool = SenderPool::new(Arc::clone(&session), API_ID);
    /// let client = Client::new(pool.handle);
    /// # Ok(())
    /// # }
    /// ```
    pub fn new(sender_pool: SenderPoolFatHandle) -> Self {
        Self::with_configuration(sender_pool, Default::default())
    }

    /// Like [`Self::new`] but with a custom [`ClientConfiguration`].
    pub fn with_configuration(
        sender_pool: SenderPoolFatHandle,
        configuration: ClientConfiguration,
    ) -> Self {
        // TODO Sender doesn't have a way to handle backpressure yet
        Self(Arc::new(ClientInner {
            session: sender_pool.session,
            api_id: sender_pool.api_id,
            handle: sender_pool.thin,
            configuration,
            auth_copied_to_dcs: Mutex::new(Vec::new()),
        }))
    }

    /// Invoke a raw API call. This directly sends the request to Telegram's servers.
    ///
    /// Using function definitions corresponding to a different layer is likely to cause the
    /// responses to the request to not be understood.
    ///
    /// <div class="warning">
    ///
    /// This method is **not** part of the stability guarantees of semantic
    /// versioning. It **may** break during *minor* version changes (but not on patch version
    /// changes). Use with care.
    ///
    /// </div>
    ///
    /// # Examples
    ///
    /// ```
    /// # async fn f(client: grammers_client::Client) -> Result<(), Box<dyn std::error::Error>> {
    /// use grammers_tl_types as tl;
    ///
    /// dbg!(client.invoke(&tl::functions::Ping { ping_id: 0 }).await?);
    /// # Ok(())
    /// # }
    /// ```
    pub async fn invoke<R: tl::RemoteCall>(
        &self,
        request: &R,
    ) -> Result<R::Return, InvocationError> {
        let dc_id = self.0.session.home_dc_id();
        self.do_invoke_in_dc(dc_id, request.to_bytes())
            .await
            .and_then(|body| R::Return::from_bytes(&body).map_err(|e| e.into()))
    }

    /// Like [`Self::invoke`], but in the specified DC.
    ///
    /// <div class="warning">
    ///
    /// This method is **not** part of the stability guarantees of semantic
    /// versioning. It **may** break during *minor* version changes (but not on patch version
    /// changes). Use with care.
    ///
    /// </div>
    pub async fn invoke_in_dc<R: tl::RemoteCall>(
        &self,
        dc_id: i32,
        request: &R,
    ) -> Result<R::Return, InvocationError> {
        self.do_invoke_in_dc(dc_id, request.to_bytes())
            .await
            .and_then(|body| R::Return::from_bytes(&body).map_err(|e| e.into()))
    }

    async fn do_invoke_in_dc(
        &self,
        dc_id: i32,
        request_body: Vec<u8>,
    ) -> Result<Vec<u8>, InvocationError> {
        let mut retry_context = RetryContext {
            fail_count: NonZeroU32::new(1).unwrap(),
            slept_so_far: Duration::default(),
            error: InvocationError::Dropped,
        };

        loop {
            match self
                .0
                .handle
                .invoke_in_dc(dc_id, request_body.clone())
                .await
            {
                Ok(response) => break Ok(response),
                Err(e) => {
                    retry_context.error = e;
                    match self
                        .0
                        .configuration
                        .retry_policy
                        .should_retry(&retry_context)
                    {
                        ControlFlow::Continue(delay) => {
                            info!(
                                "sleeping on {} for {:?} before retrying",
                                retry_context.error, delay,
                            );
                            sleep(delay).await;
                            retry_context.fail_count = retry_context.fail_count.saturating_add(1);
                            retry_context.slept_so_far += delay;
                            continue;
                        }
                        ControlFlow::Break(()) => break Err(retry_context.error),
                    }
                }
            }
        }
    }

    pub(crate) async fn copy_auth_to_dc(&self, target_dc_id: i32) -> Result<(), InvocationError> {
        let mut auth_copied_to_dcs = self.0.auth_copied_to_dcs.lock().await;
        if auth_copied_to_dcs.contains(&target_dc_id) {
            return Ok(());
        }

        let home_dc_id = self.0.session.home_dc_id();
        if target_dc_id == home_dc_id {
            return Ok(());
        }

        let tl::enums::auth::ExportedAuthorization::Authorization(exported_auth) = self
            .invoke(&tl::functions::auth::ExportAuthorization {
                dc_id: target_dc_id,
            })
            .await?;

        self.invoke_in_dc(
            target_dc_id,
            &tl::functions::auth::ImportAuthorization {
                id: exported_auth.id,
                bytes: exported_auth.bytes,
            },
        )
        .await?;

        auth_copied_to_dcs.push(target_dc_id);

        Ok(())
    }
}