use aws_config::default_provider::credentials::DefaultCredentialsChain;
use aws_config::imds;
use aws_smithy_types::retry::{RetryConfig, RetryConfigBuilder};
use aws_types::region::Region;
use aws_types::SdkConfig;
use snafu::{ResultExt, Snafu};
use std::time::Duration;

// Max request retry attempts; Retry many many times and let the caller decide when to terminate
const MAX_ATTEMPTS: u32 = 100;
const IMDS_CONNECT_TIMEOUT: Duration = Duration::from_secs(3);

#[derive(Debug, Snafu)]
pub(super) enum Error {
    #[snafu(display("Failed to build IMDS client: {}", source))]
    SdkImds {
        source: imds::client::error::BuildError,
    },
}

type Result<T> = std::result::Result<T, Error>;

async fn sdk_imds_client() -> Result<imds::Client> {
    imds::Client::builder()
        .max_attempts(MAX_ATTEMPTS)
        .connect_timeout(IMDS_CONNECT_TIMEOUT)
        .build()
        .await
        .context(SdkImdsSnafu)
}

fn sdk_retry_config() -> RetryConfig {
    RetryConfigBuilder::new().max_attempts(MAX_ATTEMPTS).build()
}

pub(crate) async fn sdk_config(region: &str) -> Result<SdkConfig> {
    let provider = DefaultCredentialsChain::builder()
        .imds_client(sdk_imds_client().await?)
        .build()
        .await;
    Ok(aws_config::from_env()
        .region(Region::new(region.to_owned()))
        .credentials_provider(provider)
        .retry_config(sdk_retry_config())
        .load()
        .await)
}