// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

library fuchsia.bluetooth.bredr;

using fuchsia.bluetooth;
using zx;

/// The RFCOMM channel ID used when requesting to open a channel.
/// This is known as a ServerChannel in RFCOMM. It must be within the
/// range [1,30] (inclusive). See RFCOMM 5.4.
alias RfcommChannel = uint8;

/// The parameters associated with a connection over the RFCOMM protocol.
table RfcommParameters {
    /// Required. RFCOMM channel for the connection.
    1: RfcommChannel channel;
};

/// The parameters associated with a connection over the L2CAP protocol.
table L2capParameters {
    /// Required. Dynamic PSM for the connection. See the defined PSMs in `service.fidl`.
    1: uint16 psm;

    /// Optional. L2CAP channel parameters.
    2: ChannelParameters parameters;
};

/// The channel and relevant parameters for a connection.
union ConnectParameters {
    /// An L2CAP connection.
    1: L2capParameters l2cap;

    /// An RFCOMM connection.
    2: RfcommParameters rfcomm;
};

/// Authentication and permission requirements to access an advertised service.
table SecurityRequirements {
    /// If present and true, the physical link must be authenticated with man-in-the-middle attack
    /// protection to access this service.  If missing, authentication is not required.
    1: bool authentication_required;

    /// If present and true, the physical link must be encrypted with a Secure Connections key to
    /// access this service if the host is capable.  Advertisement will fail if the host does not
    /// support Secure Connections.  See Bluetooth Spec v5.2, Vol 3, Part C, Sec 5.2.2.8.
    2: bool secure_connections_required;
};

/// Used to specify preferred and accepted L2CAP channel modes.  If the peer rejects a non-BASIC
/// mode, the Bluetooth system will attempt to open the channel in BASIC mode instead.  For a
/// description of each mode, see Bluetooth Spec v5.2, Vol 3, Part A, Sec 2.4.
enum ChannelMode {
    BASIC = 1;
    ENHANCED_RETRANSMISSION = 2;
};

/// Used to specify preferred L2CAP channel parameters.
table ChannelParameters {
    /// Optional. If not provided, BASIC will be used.
    1: ChannelMode channel_mode;
    /// Maximum SDU size this profile is capable of accepting. Must be >= 48.  Optional. If not
    /// provided, the size will be determined by the Bluetooth system.  No guarantees are given
    /// regarding the size selected.
    2: uint16 max_rx_sdu_size;
    /// Minimum security requirements a link must have before this channel can be created.
    /// The requirements provided here will be attempted with the peer before the channel is
    /// established. If a peer cannot provide the requirements, the channel is closed.
    /// Optional. If not provided, then the only security property guaranteed is encryption.
    3: SecurityRequirements security_requirements;
    /// The flush timeout indicates the maximum amount of time a data packet should be buffered
    /// in the controller before it is dropped. A flush timeout of infinity can be used to mark
    /// packets as flushable without any particular flush timeout.
    /// Range: 1ms - 1,279ms (or ∞). Rounded down.
    /// Optional. If not provided, no flush timeout and packets are not flushable.
    4: zx.duration flush_timeout;
};

/// A channel opened to a peer.
resource table Channel {
    /// Socket interface for sending/receiving SDUs on the channel.
    /// Always present.
    1: zx.handle:SOCKET socket;
    /// Channel mode accepted by the peer.
    /// Always present.
    2: ChannelMode channel_mode;
    /// Maximum SDU size the peer is capable of accepting.
    /// Always present.
    3: uint16 max_tx_sdu_size;
    /// Audio Direction priority extension. See `AudioDirectionExt`.
    /// Present only if supported by the host.
    4: AudioDirectionExt ext_direction;
    // Duration after which packets are dropped from the controller.
    // Present only if a flush timeout was successfully configured.
    5: zx.duration flush_timeout;
    /// L2CAP parameter extension. See `L2capParametersExt`.
    /// Always present for L2CAP Channels, never present for other Channels.
    6: L2capParametersExt ext_l2cap;
};

/// A2DP packet priority used in `AudioDirectionExt`. `NORMAL` should be used whenever audio is not
/// streaming, and `SOURCE`/`SINK` should match the direction audio is being streamed.
enum A2dpDirectionPriority {
    NORMAL = 1;
    SOURCE = 2;
    SINK = 3;
};

/// Audio Priority Direction extension.
/// Used to put the channel in a mode where A2DP packets are prioritized over other packets in the
/// source or sink direction.
protocol AudioDirectionExt {
    SetPriority(A2dpDirectionPriority priority) -> () error fuchsia.bluetooth.ErrorCode;
};

/// L2CAP Parameters Extension. Used to configure L2CAP channel parameters on an open channel.
protocol L2capParametersExt {
    /// Request a L2CAP channel parameter update. `request` indicates the
    /// desired parameters, and `new` indicates the new parameters
    /// (which may differ from the requested parameters if they are
    /// rejected/modified).
    /// Currently only the following parameters can be changed:
    /// - flush_timeout
    RequestParameters(ChannelParameters request) -> (ChannelParameters new);
};

/// Represents a service which is registered by this profile.  Closing this protocol will remove the
/// service registration.
protocol ConnectionReceiver {
    /// Called when a peer connects to this service.  The channel connected is delivered
    /// with parameters in `channel`.
    /// `protocol` will contain a protocol list up to the point connected (for example, if
    /// L2CAP is connected, it will contain the L2CAP protocol and specify the PSM connected)
    Connected(fuchsia.bluetooth.PeerId peer_id, Channel channel, ProtocolDescriptorList protocol);
};

/// Maximum number of attributes returned or allowed in a search request.
const uint16 MAX_ATTRIBUTES = 512;

/// Represents an active search which can produce results when peers are connected.  Closing this
/// protocol will result in the associated search not being performed on new connected peers.
protocol SearchResults {
    /// Called when a search this client added finds a matching service on a peer.
    /// `peer_id` is the peer the service was found on.
    /// `protocol` includes the ProtocolDescriptorList in the service record if it exists
    /// (it is also included in `attributes`.)
    /// `attributes` contains all attributes requested from the search that are present on the
    /// peer record.  It may also include additional attributes.
    /// Each ServiceFound call should be acknowledged by replying.
    /// A limited amount of unacknowledged results will be sent on the channel. Results may be
    /// dropped if results are received while too many results are unacknowledged.
    ServiceFound(fuchsia.bluetooth.PeerId peer_id, ProtocolDescriptorList? protocol,
                 vector<Attribute>:MAX_ATTRIBUTES attributes) -> ();
};

/// Maximum service records that can be advertised at once.
const uint8 MAX_SERVICES_PER_ADVERTISEMENT = 32;

/// Service provides Bluetooth BR/EDR profiles a way to register a service definition, making a
/// profile discoverable by peers. Registered services can receive L2CAP connections made to the
/// advertised records, and can open new connections on peers.
[Discoverable] protocol Profile {
    /// Register a set of services.
    ///
    /// The call will resolve when the service advertisement terminates or if there was an error
    /// when advertising.
    ///
    /// These services will be discoverable via Service Discovery Protocol server.
    /// All services advertising the same channel must be added at once - if services are already
    /// registered on any channel advertised, registration will fail, the receiver will be closed
    /// with ZX_ERR_ALREADY_BOUND and an error will be returned.
    /// The ConnectionReceiver will get calls for connections to the channels included in the
    /// `protocol_descriptor` or `alternative_protocol_descriptors` in the services advertised.
    /// The receiver will be closed if there are any errors advertising.
    ///
    /// If the advertisement cannot be made for any reason, an error of `INVALID_ARGUMENTS`
    /// will be returned and the receiver will be closed with a suitable epitaph.
    Advertise(vector<ServiceDefinition>:MAX_SERVICES_PER_ADVERTISEMENT services,
              ChannelParameters parameters, ConnectionReceiver receiver)
        -> () error fuchsia.bluetooth.ErrorCode;

    /// Register a search for services on newly connected peers.  The SearchResults protocol will be
    /// used to report results for this search.  Any service result with a service matching
    /// `service_uuid` will be returned with the additional attributes in `attr_ids`.  If `attr_ids`
    /// is empty, all attributes will be requested.  The additional attribute
    /// BLUETOOTH_PROTOCOL_DESCRIPTOR_LIST is always requested.  See the Bluetooth Spec v5.2, Vol 3,
    /// Part B, Section 5) and relevant profile specification documents.
    Search(ServiceClassProfileIdentifier service_uuid, vector<uint16>:MAX_ATTRIBUTES attr_ids,
           SearchResults results);

    /// Connect an L2CAP or RFCOMM channel to the connected peer identified by `peer_id` using the
    /// desired `connection` parameters listed.  Dynamic PSMs can be specified in `connection`.
    ///
    /// Returns the channel connected once established, or an error code if the channel could not
    /// be connected.
    Connect(fuchsia.bluetooth.PeerId peer_id, ConnectParameters connection)
        -> (Channel channel) error fuchsia.bluetooth.ErrorCode;

    /// Attempt to establish a synchronous connection to `peer_id` configured using `params`.
    /// If `initiator` is true, a connection request will be sent. If `initiator` is false, the host will
    /// attempt to accept the next connection request.
    /// The result of the connection attempt will be returned with `receiver`. Dropping `receiver` will cancel the request.
    ConnectSco(fuchsia.bluetooth.PeerId peer_id, bool initiator, ScoConnectionParameters params, ScoConnectionReceiver receiver);
};