// 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.mem;
using fuchsia.ui.views;

using Url = string;

// TODO(WEB-29): Consider using fuchsia.logger.LogLevelFilter if possible.
enum ConsoleLogLevel : int32 {
    /// No logging.
    NONE = 100;

    /// Outputs messages from console.debug() and above levels.
    DEBUG = -1;

    /// Outputs messages from console.log(), console.info() and above levels.
    INFO = 0;

    /// Outputs messages from console.warn() and console.error().
    WARN = 1;

    /// Outputs messages from console.error().
    ERROR = 2;
};

/// Represents the return status of a Frame method.
enum FrameError : int32 {
    /// An internal error occured.
    INTERNAL_ERROR = 1;

    /// The provided buffer is not UTF-8 encoded.
    BUFFER_NOT_UTF8 = 2;

    /// The Frame's URL does not match any of the origins provided by the
    /// caller.
    INVALID_ORIGIN = 3;

    /// The required |data| property is missing from a WebMessage
    NO_DATA_IN_MESSAGE = 4;
};

protocol Frame {
    /// Creates a new view using the specified |view_token|. Caller should pass
    /// the other end of the token to CreateViewHolderCmd() to attach the new
    /// view to a the view tree.
    ///
    /// |view_token|: Token for the new view.
    CreateView(fuchsia.ui.views.ViewToken view_token);

    /// Returns an interface through which the frame may be navigated to
    /// a desired URL, reloaded, etc.
    ///
    /// |controller|: An asynchronous interface request for the Frame's
    /// NavigationController.
    GetNavigationController(request<NavigationController> controller);

    /// Executes a UTF-8 encoded |script| in the frame if the frame's URL has
    /// an origin which matches entries in |origins|.
    /// At least one |origins| entry must be specified.
    /// If a wildcard "*" is specified in |origins|, then the script will be
    /// evaluated unconditionally.
    ///
    /// Note that scripts share the same execution context as the document,
    /// meaning that document may modify variables, classes, or objects set by
    /// the script in arbitrary or unpredictable ways.
    ///
    /// If an error occured, the FrameError will be set to one of these values:
    /// BUFFER_NOT_UTF8: |script| is not UTF-8 encoded.
    /// INVALID_ORIGIN: The Frame's current URL does not match any of the
    ///                 values in |origins| or |origins| is an empty vector.
    // TODO(crbug.com/900391): Investigate if we can run the scripts in
    // isolated JS worlds.
    ExecuteJavaScriptNoResult(
        vector<Url> origins,
        fuchsia.mem.Buffer script)
        -> () error FrameError;

    /// Executes a UTF-8 encoded |script| for every subsequent page load where
    /// the frame's URL has an origin reflected in |origins|. The script is
    /// executed early, prior to the execution of the document's scripts.
    ///
    /// Scripts are identified by a client-managed identifier |id|. Any
    /// script previously injected using the same |id| will be replaced.
    ///
    /// The order in which multiple bindings are executed is the same as the
    /// order in which the bindings were Added. If a script is added which
    /// clobbers an existing script of the same |id|, the previous script's
    /// precedence in the injection order will be preserved.
    ///
    /// At least one |origins| entry must be specified.
    /// If a wildcard "*" is specified in |origins|, then the script will be
    /// evaluated for all documents.
    ///
    /// If an error occured, the FrameError will be set to one of these values:
    /// BUFFER_NOT_UTF8: |script| is not UTF-8 encoded.
    /// INVALID_ORIGIN: |origins| is an empty vector.
    AddBeforeLoadJavaScript(
        uint64 id,
        vector<Url> origins,
        fuchsia.mem.Buffer script)
        -> () error FrameError;

    /// Removes a previously added JavaScript snippet identified by |id|.
    /// This is a no-op if there is no JavaScript snippet identified by |id|.
    RemoveBeforeLoadJavaScript(uint64 id);

    /// Posts a message to the frame's onMessage handler.
    ///
    /// |target_origin| restricts message delivery to the specified origin.
    /// If |target_origin| is "*", then the message will be sent to the
    /// document regardless of its origin.
    /// See html.spec.whatwg.org/multipage/web-messaging.html sect. 9.4.3
    /// for more details on how the target origin policy is applied.
    ///
    /// If an error occured, the FrameError will be set to one of these values:
    /// INTERNAL_ERROR: The WebEngine failed to create a message pipe.
    /// BUFFER_NOT_UTF8: The script in |message|'s |data| property is not
    ///                  UTF-8 encoded.
    /// INVALID_ORIGIN: |origins| is an empty vector.
    /// NO_DATA_IN_MESSAGE: The |data| property is missing in |message|.
    PostMessage(Url target_origin, WebMessage message)
        -> () error FrameError;

    /// Sets the listener for handling page navigation events.
    ///
    /// |listener|: The observer to use. Unregisters any existing listener if
    ///             null.
    SetNavigationEventListener(NavigationEventListener? listener);

    /// If set to a value other than NONE, allows web content to log messages
    /// to the system logger using the console APIs (debug(), log(), info(),
    /// warn() and error()).
    /// When logged to the system logger:
    /// * debug(), log() and info() logs are logged with LogLevelFilter.INFO
    ///   severity level.
    /// * warn() logs are logged with LogLevelFilter.WARN severity level.
    /// * error() logs are logged with LogLevelFilter.ERROR severity level.
    SetJavaScriptLogLevel(ConsoleLogLevel level);

    /// Used at runtime to enable or disable user input processing
    /// (e.g. keyboard, mouse, touch) on a Frame.
    /// Input is enabled by default.
    SetEnableInput(bool enable_input);
};

table WebMessage {
    /// The message payload, encoded as an UTF-8 string. This is a required
    /// property.
    1: fuchsia.mem.Buffer data;

    /// Optional list of objects transferred into the MessagePort from the FIDL
    /// client.
    2: vector<IncomingTransferable> incoming_transfer;

    /// Optional list of objects transferred out of the MessagePort to the FIDL
    /// client.
    3: vector<OutgoingTransferable> outgoing_transfer;
};

xunion OutgoingTransferable {
    request<MessagePort> message_port;
};

xunion IncomingTransferable {
    MessagePort message_port;
};

/// Represents one end of an HTML5 MessageChannel. Can be used to send
/// and exchange Messages with the peered MessagePort in the Frame's script
/// context. The port is destroyed when either end of the MessagePort channel
/// is torn down.
protocol MessagePort {
    /// Sends a WebMessage to the peer. These are processed in order, one at a
    /// time. It is not necessary for the caller to wait for the completion
    /// callback before calling PostMessage() again.
    ///
    /// If an error occured, the FrameError will be set to this value:
    /// BUFFER_NOT_UTF8: The script in |message|'s |data| property is not
    ///                  UTF-8 encoded.
    /// NO_DATA_IN_MESSAGE: The |data| property is missing in |message|.
    PostMessage(WebMessage message) -> () error FrameError;

    /// Asynchronously reads the next message from the channel.
    /// The client should invoke the callback when it is ready to process
    /// another message.
    /// Unreceived messages are buffered on the sender's side and bounded
    /// by its available resources.
    ReceiveMessage() -> (WebMessage message);
};