host/frontend/gcastv2/webrtc/include/webrtc/MyWebSocketHandler.h

/*
 * Copyright (C) 2019 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <webrtc/RTPSession.h>
#include <webrtc/RTPSocketHandler.h>
#include <webrtc/SDP.h>
#include <webrtc/ServerState.h>

#include <https/WebSocketHandler.h>
#include <https/RunLoop.h>
#include <source/KeyboardSink.h>
#include <source/TouchSink.h>

#include <memory>
#include <optional>
#include <sstream>
#include <string>
#include <vector>

struct MyWebSocketHandler
    : public WebSocketHandler,
      public std::enable_shared_from_this<MyWebSocketHandler> {

    explicit MyWebSocketHandler(
            std::shared_ptr<RunLoop> runLoop,
            std::shared_ptr<ServerState> serverState,
            size_t handlerId);

    ~MyWebSocketHandler() override;

    int handleMessage(
            uint8_t headerByte, const uint8_t *msg, size_t len) override;

private:
    enum OptionBits : uint32_t {
        disableAudio                        = 1,
        bundleTracks                        = 2,
        enableData                          = 4,
        useSingleCertificateForAllTracks    = 8,
    };

    using TouchSink = android::TouchSink;
    using KeyboardSink = android::KeyboardSink;

    std::shared_ptr<RunLoop> mRunLoop;
    std::shared_ptr<ServerState> mServerState;
    size_t mId;
    uint32_t mOptions;

    // Vector has the same ordering as the media entries in the SDP, i.e.
    // vector index is "mlineIndex". (unless we are bundling, in which case
    // there is only a single session).
    std::vector<std::shared_ptr<RTPSession>> mSessions;

    SDP mOfferedSDP;
    std::vector<std::shared_ptr<RTPSocketHandler>> mRTPs;

    std::shared_ptr<TouchSink> mTouchSink;
    std::shared_ptr<KeyboardSink> mKeyboardSink;

    std::pair<std::shared_ptr<X509>, std::shared_ptr<EVP_PKEY>>
        mCertificateAndKey;

    // Pass -1 for mlineIndex to access the "general" section.
    std::optional<std::string> getSDPValue(
            ssize_t mlineIndex,
            std::string_view key,
            bool fallthroughToGeneralSection) const;

    std::string getRemotePassword(size_t mlineIndex) const;
    std::string getRemoteUFrag(size_t mlineIndex) const;
    std::string getRemoteFingerprint(size_t mlineIndex) const;

    bool getCandidate(int32_t mid);

    static std::pair<std::shared_ptr<X509>, std::shared_ptr<EVP_PKEY>>
        CreateDTLSCertificateAndKey();

    std::pair<std::string, std::string> createUniqueUFragAndPassword();

    void parseOptions(const std::string &pathAndQuery);
    size_t countTracks() const;

    void prepareSessions();

    void emitTrackIceOptionsAndFingerprint(
            std::stringstream &ss, size_t mlineIndex) const;

    // Returns -1 on error.
    ssize_t mlineIndexForMid(int32_t mid) const;

    static void CreateRandomIceCharSequence(char *dst, size_t size);
};