durable-streams-server 0.2.0-beta.1

use crate::protocol::{
    headers::names,
    problem::{Result, request_instance},
    stream_name::StreamName,
};
use crate::storage::Storage;
use axum::{
    extract::{OriginalUri, State},
    http::{HeaderMap, HeaderValue, StatusCode},
    response::{IntoResponse, Response},
};
use chrono::Utc;
use std::sync::Arc;

/// HEAD handler for stream metadata
///
/// Returns stream metadata in headers without a body.
///
/// # Errors
///
/// Returns 404 if stream doesn't exist or has expired.
///
/// # Panics
///
/// Panics if validated header values fail to parse into `HeaderValue`,
/// which should never happen with valid inputs.
pub async fn stream_metadata<S: Storage>(
    State(storage): State<Arc<S>>,
    StreamName(name): StreamName,
    original_uri: OriginalUri,
) -> Result<Response> {
    let instance = request_instance(&original_uri);
    let result = (|| -> Result<Response> {
        // Get stream metadata
        let metadata = storage.head(&name)?;

        // Build response headers
        let mut headers = HeaderMap::new();
        headers.insert(
            "content-type",
            metadata.config.content_type.parse().unwrap(),
        );
        headers.insert(
            names::STREAM_NEXT_OFFSET,
            HeaderValue::from_bytes(metadata.next_offset.as_str().as_bytes()).unwrap(),
        );
        // Include Stream-Closed if stream is closed
        if metadata.closed {
            headers.insert(names::STREAM_CLOSED, "true".parse().unwrap());
        }

        // Include TTL metadata if applicable
        if let Some(expires_at) = metadata.config.expires_at {
            // Calculate remaining TTL
            let now = Utc::now();
            let remaining_seconds = (expires_at - now).num_seconds();

            // Only include if not expired (positive remaining time)
            if remaining_seconds > 0 {
                headers.insert(
                    names::STREAM_TTL,
                    remaining_seconds.to_string().parse().unwrap(),
                );
                headers.insert(
                    names::STREAM_EXPIRES_AT,
                    expires_at.to_rfc3339().parse().unwrap(),
                );
            }
        }

        Ok((StatusCode::OK, headers).into_response())
    })();

    result.map_err(|problem| problem.with_instance(instance))
}