namespace as_ohttp_client {
};

[Error]
enum OhttpError {
    "KeyFetchFailed",
    "MalformedKeyConfig",
    "UnsupportedKeyConfig",
    "InvalidSession",
    "RelayFailed",
    "CannotEncodeMessage",
    "MalformedMessage",
    "DuplicateHeaders",
};

/// The decrypted response from the Gateway/Target
dictionary OhttpResponse {
    u16 status_code;
    record<string, string> headers;
    sequence<u8> payload;
};

/// Each OHTTP request-reply exchange needs to create an OhttpSession
/// object to manage encryption state.
interface OhttpSession {
    /// Initialize encryption state based on specific Gateway key config
    [Throws=OhttpError]
    constructor([ByRef] sequence<u8> config);

    /// Encapsulate an HTTP request as Binary HTTP and then encrypt that
    /// payload using HPKE. The caller is responsible for sending the
    /// resulting message to the Relay.
    [Throws=OhttpError]
    sequence<u8> encapsulate([ByRef] string method,
                             [ByRef] string scheme,
                             [ByRef] string server,
                             [ByRef] string endpoint,
                             record<string, string> headers,
                             [ByRef] sequence<u8> payload);

    /// Decypt and unpack the response from the Relay for the previously
    /// encapsulated request. You must use the same OhttpSession that
    /// generated the request message.
    [Throws=OhttpError]
    OhttpResponse decapsulate([ByRef] sequence<u8> encoded);
};

dictionary TestServerRequest {
    string method;
    string scheme;
    string server;
    string endpoint;
    record<string, string> headers;
    sequence<u8> payload;
};

/// A testing interface for decrypting and responding to OHTTP messages. This
/// should only be used for testing.
interface OhttpTestServer {
    constructor();

    /// Return the unique encryption key config for this instance of test server.
    sequence<u8> get_config();

    [Throws=OhttpError]
    TestServerRequest receive([ByRef] sequence<u8> message);

    [Throws=OhttpError]
    sequence<u8> respond(OhttpResponse response);
};