// 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.web;

using fuchsia.net.http;

/// Interface supplied by the embedder for receiving notifications about
/// navigation events in a Frame.
protocol NavigationEventListener {
    /// Called when user-visible navigation state has changed since Frame
    /// creation or the last acknowledgement callback, whichever occurred last.
    /// |change| will contain all the differences in navigation state since the
    /// last acknowledgement. Any unchanged properties will be left unset in
    /// |change|.
    /// Implementer must call the acknowledgement callback to receive new
    /// navigation events.
    OnNavigationStateChanged(NavigationState change) -> ();
};

/// Represents the return status of a NavigationController method.
enum NavigationControllerError : int32 {
    /// The provided URL is invalid.
    INVALID_URL = 1;
};

/// Provides methods for controlling and querying the navigation state
/// of a Frame.
protocol NavigationController {
    /// Tells the Frame to navigate to a |url|.
    ///
    /// |url|:    The address to navigate to.
    /// |params|: Additional parameters that affect how the resource will be
    ///           loaded (e.g. cookies, HTTP headers, etc.)
    ///
    /// If an error occured, the NavigationControllerError will be set:
    /// INVALID_URL: The |url| parameter is invalid.
    LoadUrl(Url url, LoadUrlParams params)
        -> () error NavigationControllerError;

    GoBack();

    GoForward();

    Stop();

    Reload(ReloadType type);

    /// Returns information for the currently visible content regardless of
    /// loading state, or an empty entry if no content is being displayed.
    GetVisibleEntry() -> (NavigationState entry);
};

/// Additional parameters for modifying the behavior of LoadUrl().
table LoadUrlParams {
    /// Provides a hint to the browser UI about how LoadUrl was triggered.
    1: LoadUrlReason type;

    /// The URL that linked to the resource being requested.
    2: Url referrer_url;

    /// Should be set to true to propagate user activation to the frame. User
    /// activation implies that the user is interacting with the web frame. It
    /// enables some web features that are not available otherwise. For example
    /// autoplay will work only when this flag is set to true.
    3: bool was_user_activated;

    /// Custom HTTP headers.
    4: vector<fuchsia.net.http.Header> headers;
};

/// Contains information about the Frame's navigation state.
table NavigationState {
    /// The page's URL.
    1: Url url;

    /// The user-visible page title.
    2: string title;

    /// Indicates whether this was a navigation to an error page.
    3: PageType page_type;

    /// Indicates if there is a following navigation.
    4: bool can_go_forward;

    /// Indicates if there is a previous navigation.
    5: bool can_go_back;

    /// Indicates that the main document's statically declared resources have
    /// been loaded.
    6: bool is_main_document_loaded;
};

/// Characterizes the type of reload.
enum ReloadType : uint32 {
    /// Reloads the current entry, bypassing the cache for the main resource.
    PARTIAL_CACHE = 0;

    /// Reloads the current entry, bypassing the cache entirely.
    NO_CACHE = 1;
};

/// Characterizes the origin of a LoadUrl request.
enum LoadUrlReason : uint32 {
    /// Navigation was initiated by the user following a link.
    LINK = 0;

    /// Navigation was initiated by a user-provided URL.
    TYPED = 1;
};

/// Characterizes the page type in a NavigationState.
enum PageType {
    /// Regular web page.
    NORMAL = 0;

    /// Error page.
    ERROR = 1;
};