// Copyright 2025 The NativeLink Authors. All rights reserved.

//

// Licensed under the Functional Source License, Version 1.1, Apache 2.0 Future License (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//    See LICENSE file for details

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

use core::future::Future;

use core::pin::Pin;

use core::task::{Context, Poll};

use std::sync::Arc;

use aws_config::retry::ErrorKind::TransientError;

use aws_smithy_runtime_api::client::http::{

    HttpClient as SmithyHttpClient, HttpConnector as SmithyHttpConnector, HttpConnectorFuture,

    HttpConnectorSettings, SharedHttpConnector,

};

use aws_smithy_runtime_api::client::orchestrator::HttpRequest;

use aws_smithy_runtime_api::client::result::ConnectorError;

use aws_smithy_runtime_api::client::runtime_components::RuntimeComponents;

use aws_smithy_runtime_api::http::Response;

use aws_smithy_types::body::SdkBody;

use bytes::{Bytes, BytesMut};

use futures::Stream;

use http_body::{Frame, SizeHint};

use http_body_util::BodyExt;

use hyper::{Method, Request};

use hyper_rustls::{HttpsConnector, HttpsConnectorBuilder};

use hyper_util::client::legacy::Client as LegacyClient;

use hyper_util::client::legacy::connect::HttpConnector as LegacyHttpConnector;

use hyper_util::rt::TokioExecutor;

use nativelink_config::stores::CommonObjectSpec;

// Note: S3 store should be very careful about the error codes it returns

// when in a retryable wrapper. Always prefer Code::Aborted or another

// retryable code over Code::InvalidArgument or make_input_err!().

// ie: Don't import make_input_err!() to help prevent this.

use nativelink_error::{Code, make_err};

use nativelink_util::buf_channel::DropCloserReadHalf;

use nativelink_util::fs;

use nativelink_util::retry::{Retrier, RetryResult};

use tokio::time::sleep;

pub(crate) fn install_default_rustls_crypto_provider() {

    drop(rustls::crypto::ring::default_provider().install_default());

}

#[derive(Clone)]

pub struct TlsClient {

    client: LegacyClient<HttpsConnector<LegacyHttpConnector>, SdkBody>,

    retrier: Retrier,

}

impl TlsClient {

    #[must_use]

    pub fn new(common: &CommonObjectSpec) -> Self {

        install_default_rustls_crypto_provider();

        let connector_with_roots = HttpsConnectorBuilder::new().with_platform_verifier();

        let connector_with_schemes = if common.insecure_allow_http {

            connector_with_roots.https_or_http()

        } else {

            connector_with_roots.https_only()

        };

        let connector = if common.disable_http2 {

            connector_with_schemes.enable_http1().build()

        } else {

            connector_with_schemes.enable_http1().enable_http2().build()

        };

        Self::with_https_connector(common, connector)

    }

    pub fn with_https_connector(

        common: &CommonObjectSpec,

        connector: HttpsConnector<LegacyHttpConnector>,

    ) -> Self {

        install_default_rustls_crypto_provider();

        let client = LegacyClient::builder(TokioExecutor::new()).build(connector);

        Self {

            client,

            retrier: Retrier::new(

                Arc::new(|duration| 
Box::pin0
(
sleep0
(
duration0
))),

                common.retry.make_jitter_fn(),

                common.retry.clone(),

            ),

        }

    }

}

impl core::fmt::Debug for TlsClient {

    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> Result<(), core::fmt::Error> {

        f.debug_struct("TlsClient").finish_non_exhaustive()

    }

}

impl SmithyHttpClient for TlsClient {

    fn http_connector(

        &self,

        _settings: &HttpConnectorSettings,

        _components: &RuntimeComponents,

    ) -> SharedHttpConnector {

        SharedHttpConnector::new(self.clone())

    }

}

struct RequestBuilder<'a> {

    components: &'a RequestComponents,

}

impl<'a> RequestBuilder<'a> {

    #[inline]

    const fn new(components: &'a RequestComponents) -> Self {

        Self { components }

    }

    #[inline]

    #[allow(unused_qualifications, reason = "false positive on hyper::http::Error")]

    fn build(&self) -> Result<Request<SdkBody>, hyper::http::Error> {

        let mut req_builder = Request::builder()

            .method(self.components.method.clone())

            .uri(self.components.uri.clone())

            .version(self.components.version);

        let headers_map = req_builder.headers_mut().unwrap();

        for (name, value) in 
&self.components.headers6
 {

            headers_map.insert(name, value.clone());

        }

        match &self.components.body_data {

            BufferedBodyState::Cloneable(body) => {

                let cloned_body = body.try_clone().expect("Body should be cloneable");

                req_builder.body(cloned_body)

            }

            BufferedBodyState::Buffered(bytes) => req_builder.body(SdkBody::from(bytes.clone())),

            BufferedBodyState::Empty => req_builder.body(SdkBody::empty()),

        }

    }

}

mod execution {

    use super::conversions::ResponseExt;

    use super::{

        Code, HttpsConnector, LegacyClient, LegacyHttpConnector, RequestBuilder, RequestComponents,

        Response, RetryResult, SdkBody, fs, make_err,

    };

    #[inline]

    pub(crate) async fn execute_request(

        client: LegacyClient<HttpsConnector<LegacyHttpConnector>, SdkBody>,

        components: &RequestComponents,

    ) -> RetryResult<Response<SdkBody>> {

        let _permit = match fs::get_permit().await {

            Ok(permit) => permit,

            Err(e) => {

                return RetryResult::Retry(make_err!(

                    Code::Unavailable,

                    "Failed to acquire permit: {e}"

                ));

            }

        };

        let request = match RequestBuilder::new(components).build() {

            Ok(req) => req,

            Err(e) => {

                return RetryResult::Err(make_err!(

                    Code::Internal,

                    "Failed to create request: {e}",

                ));

            }

        };

        match client.request(request).await {

            Ok(resp) => RetryResult::Ok(resp.into_smithy_response()),

            Err(e) => RetryResult::Retry(make_err!(

                Code::Unavailable,

                "Failed request in S3Store: {e}"

            )),

        }

    }

    #[inline]

    pub(crate) fn create_retry_stream(

        client: LegacyClient<HttpsConnector<LegacyHttpConnector>, SdkBody>,

        components: RequestComponents,

    ) -> impl futures::Stream<Item = RetryResult<Response<SdkBody>>> {

        futures::stream::unfold(components, move |components| {

            let client_clone = client.clone();

            async move {

                let result = execute_request(client_clone, &components).await;

                Some((result, components))

            }

        })

    }

}

enum BufferedBodyState {

    Cloneable(SdkBody),

    Buffered(Bytes),

    Empty,

}

mod body_processing {

    use super::{BodyExt, BufferedBodyState, BytesMut, ConnectorError, SdkBody, TransientError};

    /// Buffer a request body fully into memory.

    ///

    /// TODO(aaronmondal): This could lead to OOMs in extremely constrained

    ///                    environments. Probably better to implement something

    ///                    like a rewindable stream logic.

    #[inline]

    pub(crate) async fn buffer_body(body: SdkBody) -> Result<BufferedBodyState, ConnectorError> {

        let mut bytes = BytesMut::new();

        let mut body_stream = body;

        while let Some(frame) = body_stream.frame().await {

            match frame {

                Ok(frame) => {

                    if let Some(data) = frame.data_ref() {

                        bytes.extend_from_slice(data);

                    }

                }

                Err(e) => {

                    return Err(ConnectorError::other(

                        format!("Failed to read request body: {e}").into(),

                        Some(TransientError),

                    ));

                }

            }

        }

        Ok(BufferedBodyState::Buffered(bytes.freeze()))

    }

}

pub(crate) struct RequestComponents {

    method: Method,

    uri: hyper::Uri,

    version: hyper::Version,

    headers: hyper::HeaderMap,

    body_data: BufferedBodyState,

}

mod conversions {

    use super::{

        BufferedBodyState, ConnectorError, Future, HttpRequest, Method, RequestComponents,

        Response, SdkBody, TransientError, body_processing,

    };

    pub(crate) trait RequestExt {

        fn into_components(self)

        -> impl Future<Output = Result<RequestComponents, ConnectorError>>;

    }

    impl RequestExt for HttpRequest {

        async fn into_components(self) -> Result<RequestComponents, ConnectorError> {

            // Note: This does *not* refer the the HTTP protocol, but to the

            //       version of the http crate.

            let hyper_req = self.try_into_http1x().map_err(|e| 
{0

                ConnectorError::other(

                    format!("Failed to convert to HTTP request: {e}").into(),

                    Some(TransientError),

                )

            })?;

            let method = hyper_req.method().clone();

            let uri = hyper_req.uri().clone();

            let version = hyper_req.version();

            let headers = hyper_req.headers().clone();

            let body = hyper_req.into_body();

            // Only buffer bodies for methods likely to have payloads.

            let needs_buffering = 
matches!0
(method, Method::POST | Method::PUT);

            // Preserve the body in case we need to retry.

            let body_data = if needs_buffering {

                if let Some(cloneable_body) = body.try_clone() {

                    BufferedBodyState::Cloneable(cloneable_body)

                } else {

                    body_processing::buffer_body(body).await?

                }

            } else {

                BufferedBodyState::Empty

            };

            Ok(RequestComponents {

                method,

                uri,

                version,

                headers,

                body_data,

            })

        }

    }

    pub(crate) trait ResponseExt {

        fn into_smithy_response(self) -> Response<SdkBody>;

    }

    impl ResponseExt for hyper::Response<hyper::body::Incoming> {

        fn into_smithy_response(self) -> Response<SdkBody> {

            let (parts, body) = self.into_parts();

            let sdk_body = SdkBody::from_body_1_x(body);

            let mut smithy_resp = Response::new(parts.status.into(), sdk_body);

            let header_pairs: Vec<(String, String)> = parts

                .headers

                .iter()

                .filter_map(|(name, value)| {

                    value

                        .to_str()

                        .ok()

                        .map(|value_str| (name.as_str().to_owned(), value_str.to_owned()))

                })

                .collect();

            for (name, value) in header_pairs {

                smithy_resp.headers_mut().insert(name, value);

            }

            smithy_resp

        }

    }

}

impl SmithyHttpConnector for TlsClient {

    fn call(&self, req: HttpRequest) -> HttpConnectorFuture {

        use conversions::RequestExt;

        let client = self.client.clone();

        let retrier = self.retrier.clone();

        HttpConnectorFuture::new(Box::pin(async move {

            let components = req.into_components().await
?0
;

            let retry_stream = execution::create_retry_stream(client, components);

            match retrier.retry(retry_stream).await {

                Ok(response) => Ok(response),

                Err(e) => Err(ConnectorError::other(

                    format!("Connection failed after retries: {e}").into(),

                    Some(TransientError),

                )),

            }

        }))

    }

}

#[derive(Debug)]

pub struct BodyWrapper {

    pub reader: DropCloserReadHalf,

    pub size: u64,

}

impl http_body::Body for BodyWrapper {

    type Data = Bytes;

    type Error = std::io::Error;

    fn poll_frame(

        self: Pin<&mut Self>,

        cx: &mut Context<'_>,

    ) -> Poll<Option<Result<Frame<Self::Data>, Self::Error>>> {

        let reader = Pin::new(&mut Pin::get_mut(self).reader);

        reader

            .poll_next(cx)

            .map(|maybe_bytes_res| 
maybe_bytes_res58
.
map58
(|res| 
res50
.
map50
(Frame::data)))

    }

    fn size_hint(&self) -> SizeHint {

        SizeHint::with_exact(self.size)

    }

}