use std::time::Duration;

use anyhow::{bail, ensure};
use http::{Extensions, HeaderMap, HeaderName, StatusCode};

use crate::{status::ConnectStatus, Status};

const GRPC_PREFIX: &str = "grpc-";
const GRPC_TIMEOUT: &str = "grpc-timeout";

// Timeout → "connect-timeout-ms" Timeout-Milliseconds
const CONNECT_TIMEOUT_MS: &str = "connect-timeout-ms";
// Timeout-Milliseconds → {positive integer as ASCII string of at most 10 digits}
const CONNECT_TIMEOUT_MS_MAX: u128 = 9_999_999_999;

pub struct RequestEnvelope {
    pub headers: HeaderMap,
    pub extensions: Extensions,
    pub timeout: Option<Duration>,
}

pub struct ResponseDetails {
    pub status: StatusCode,
    pub headers: HeaderMap,
    pub extensions: Extensions,
}

impl ResponseDetails {
    pub fn from_http_response<T>(response: http::Response<T>) -> (Self, T) {
        let (parts, body) = response.into_parts();
        (
            Self {
                status: parts.status,
                headers: parts.headers,
                extensions: parts.extensions,
            },
            body,
        )
    }

    pub fn into_response<T>(self, message: T) -> Result<crate::Response<T>, Status> {
        let mut extensions = self.extensions;
        let metadata = crate::metadata::from_headers(self.headers, Some(&mut extensions));
        Ok(crate::Response::from_parts(metadata, message, extensions))
    }

    pub fn into_status(self, body: impl AsRef<[u8]>) -> Status {
        let mut status = ConnectStatus::from_body(body.as_ref())
            .unwrap_or_else(|err| {
                tracing::warn!(?err, "failed to deserialize error response body");
                None
            })
            .and_then(|connect_status| {
                connect_status
                    .to_status()
                    .inspect_err(|err| {
                        tracing::warn!(?err, "failed to construct error response details")
                    })
                    .ok()
            })
            .unwrap_or_else(|| Status::new(status_to_code(self.status), ""));
        *status.metadata_mut() = crate::metadata::from_headers(self.headers, None);
        status
    }
}