// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "modules/peerconnection/RTCDataChannel.h"

#include "bindings/core/v8/ExceptionState.h"
#include "core/dom/DOMArrayBuffer.h"
#include "core/dom/DOMException.h"
#include "core/events/Event.h"
#include "platform/heap/Heap.h"
#include "public/platform/WebRTCDataChannelHandler.h"
#include "public/platform/WebVector.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "wtf/PtrUtil.h"
#include "wtf/RefPtr.h"
#include "wtf/text/WTFString.h"

namespace blink {
namespace {

class MockHandler final : public WebRTCDataChannelHandler {
 public:
  MockHandler()
      : m_client(0),
        m_state(WebRTCDataChannelHandlerClient::ReadyStateConnecting),
        m_bufferedAmount(0) {}
  void setClient(WebRTCDataChannelHandlerClient* client) override {
    m_client = client;
  }
  WebString label() override { return WebString(""); }
  bool ordered() const override { return true; }
  unsigned short maxRetransmitTime() const override { return 0; }
  unsigned short maxRetransmits() const override { return 0; }
  WebString protocol() const override { return WebString(""); }
  bool negotiated() const override { return false; }
  unsigned short id() const override { return 0; }

  WebRTCDataChannelHandlerClient::ReadyState state() const override {
    return m_state;
  }
  unsigned long bufferedAmount() override { return m_bufferedAmount; }
  bool sendStringData(const WebString& s) override {
    m_bufferedAmount += s.length();
    return true;
  }
  bool sendRawData(const char* data, size_t length) override {
    m_bufferedAmount += length;
    return true;
  }
  void close() override {}

  // Methods for testing.
  void changeState(WebRTCDataChannelHandlerClient::ReadyState state) {
    m_state = state;
    if (m_client) {
      m_client->didChangeReadyState(m_state);
    }
  }
  void drainBuffer(unsigned long bytes) {
    unsigned long oldBufferedAmount = m_bufferedAmount;
    m_bufferedAmount -= bytes;
    if (m_client) {
      m_client->didDecreaseBufferedAmount(oldBufferedAmount);
    }
  }

 private:
  WebRTCDataChannelHandlerClient* m_client;
  WebRTCDataChannelHandlerClient::ReadyState m_state;
  unsigned long m_bufferedAmount;
};

}  // namespace

TEST(RTCDataChannelTest, BufferedAmount) {
  MockHandler* handler = new MockHandler();
  RTCDataChannel* channel = RTCDataChannel::create(0, WTF::wrapUnique(handler));

  handler->changeState(WebRTCDataChannelHandlerClient::ReadyStateOpen);
  String message(std::string(100, 'A').c_str());
  channel->send(message, IGNORE_EXCEPTION_FOR_TESTING);
  EXPECT_EQ(100U, channel->bufferedAmount());
}

TEST(RTCDataChannelTest, BufferedAmountLow) {
  MockHandler* handler = new MockHandler();
  RTCDataChannel* channel = RTCDataChannel::create(0, WTF::wrapUnique(handler));

  // Add and drain 100 bytes
  handler->changeState(WebRTCDataChannelHandlerClient::ReadyStateOpen);
  String message(std::string(100, 'A').c_str());
  channel->send(message, IGNORE_EXCEPTION_FOR_TESTING);
  EXPECT_EQ(100U, channel->bufferedAmount());
  EXPECT_EQ(1U, channel->m_scheduledEvents.size());

  handler->drainBuffer(100);
  EXPECT_EQ(0U, channel->bufferedAmount());
  EXPECT_EQ(2U, channel->m_scheduledEvents.size());
  EXPECT_EQ(
      "bufferedamountlow",
      std::string(channel->m_scheduledEvents.back()->type().utf8().data()));

  // Add and drain 1 byte
  channel->send("A", IGNORE_EXCEPTION_FOR_TESTING);
  EXPECT_EQ(1U, channel->bufferedAmount());
  EXPECT_EQ(2U, channel->m_scheduledEvents.size());

  handler->drainBuffer(1);
  EXPECT_EQ(0U, channel->bufferedAmount());
  EXPECT_EQ(3U, channel->m_scheduledEvents.size());
  EXPECT_EQ(
      "bufferedamountlow",
      std::string(channel->m_scheduledEvents.back()->type().utf8().data()));

  // Set the threshold to 99 bytes, add 101, and drain 1 byte at a time.
  channel->setBufferedAmountLowThreshold(99U);
  channel->send(message, IGNORE_EXCEPTION_FOR_TESTING);
  EXPECT_EQ(100U, channel->bufferedAmount());

  channel->send("A", IGNORE_EXCEPTION_FOR_TESTING);
  EXPECT_EQ(101U, channel->bufferedAmount());

  handler->drainBuffer(1);
  EXPECT_EQ(100U, channel->bufferedAmount());
  EXPECT_EQ(3U, channel->m_scheduledEvents.size());  // No new events.

  handler->drainBuffer(1);
  EXPECT_EQ(99U, channel->bufferedAmount());
  EXPECT_EQ(4U, channel->m_scheduledEvents.size());  // One new event.
  EXPECT_EQ(
      "bufferedamountlow",
      std::string(channel->m_scheduledEvents.back()->type().utf8().data()));

  handler->drainBuffer(1);
  EXPECT_EQ(98U, channel->bufferedAmount());

  channel->setBufferedAmountLowThreshold(97U);
  EXPECT_EQ(4U, channel->m_scheduledEvents.size());  // No new events.

  handler->drainBuffer(1);
  EXPECT_EQ(97U, channel->bufferedAmount());
  EXPECT_EQ(5U, channel->m_scheduledEvents.size());  // New event.
  EXPECT_EQ(
      "bufferedamountlow",
      std::string(channel->m_scheduledEvents.back()->type().utf8().data()));
}

}  // namespace blink