// Copyright 2019 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.lowpan;

/// LoWPAN Connectivity State
///
/// This enum describes the level of connectivity being provided
/// by a device.
enum ConnectivityState : int32 {
    /// Inactive state.
    ///
    /// In this state the device is unprovisioned and administratively
    /// disabled (inactive).
    ///
    /// This state can always be explicitly entered by calling `Leave`
    /// followed by `SetActive(false)`.
    INACTIVE = 1;

    /// Ready state.
    ///
    /// In this state the device is provisioned for a network, but is
    /// administratively disabled (inactive).
    ///
    /// This state can be directly entered with the following actions
    /// based on the current connectivity state:
    ///
    /// * `INACTIVE`: by calling `ProvisionNetwork(...)`.
    /// * `ATTACHING`, `ATTACHED`, `ISOLATED`, `COMMISSIONING`: by calling `SetActive(false)`.
    READY = 2;

    /// Offline state.
    ///
    /// In this state the device is administratively enabled (active)
    /// but is not provisioned and thus has no network to attach to.
    ///
    /// This state can be directly entered with the following actions
    /// based on the current connectivity state:
    ///
    /// * `INACTIVE`: by calling `SetActive(true)`.
    /// * `ATTACHING`, `ATTACHED`, `ISOLATED`, `COMMISSIONING`: by calling `Leave()`.
    OFFLINE = 3;

    /// Attaching state.
    ///
    /// In this state the device is administratively enabled
    /// (active) and either provisioned for a network or shortly
    /// about to become provisioned for a network.
    ///
    /// The interface enters this state when it starts the process
    /// of trying to find other nodes so that it can attach to any
    /// pre-existing network fragment, or when it is in the process
    /// of calculating the optimal values for unspecified parameters
    /// when forming a new network.
    ///
    /// This state can be directly entered with the following actions
    /// based on the current connectivity state:
    ///
    /// * `READY`: by calling `SetActive(true)`
    /// * `OFFLINE`, `ATTACHING`, `ATTACHED`, `ISOLATED`, `COMMISSIONING`:
    ///    by calling `ProvisionNetwork(...)`, `FormNetwork(...)`, or `JoinNetwork(...)`
    ATTACHING = 4;

    /// Attached state.
    ///
    /// In this state the device is both administratively enabled
    /// (active) and provisioned for a network. The device is an
    /// active participant on the network and can communicate with
    /// peers.
    ///
    /// This state usually implies that peers are available, but that
    /// may not actually be the case due to current network conditions
    /// or privacy-protecting measures.
    ///
    /// This state cannot generally be entered directly, rather
    /// the device will enter this state automatically from the
    /// `ATTACHING` or `ISOLATED` states once connectivity has been
    /// (re)established.
    ATTACHED = 5;

    /// Isolated state.
    ///
    /// In this state the device is both administratively enabled
    /// (active) and provisioned for a network. However, the device
    /// has no connectivity because there are no peers in range on
    /// the provisioned network.
    ///
    /// Once peer devices on the same network come into range
    /// the connectivity state will eventually switch back to
    /// `ATTACHED`, indicating restored connectivity with at least
    /// one peer.
    ///
    /// This state cannot generally be entered directly, rather
    /// the device may enter this state automatically from the
    /// `ATTACHING` or `ATTACHED` states.
    ISOLATED = 6;

    /// Commissioning state.
    ///
    /// Currently unused, but will later be used to
    /// support in-band commissioning. It is usually appropriate
    /// to consider this as a synonym for the `ATTACHING` state
    /// except that the device remains unprovisioned.
    COMMISSIONING = 7;
};