// Copyright 2019 Google LLC. All Rights Reserved. This file and proprietary
// source code may only be used and distributed under the Widevine Master
// License Agreement.

#include "test_sleep.h"

#include <unistd.h>

#include <chrono>

#include "clock.h"

namespace wvcdm {

bool TestSleep::real_sleep_ = true;
TestSleep::CallBack* TestSleep::callback_ = nullptr;

void TestSleep::Sleep(unsigned int seconds) {
  int64_t milliseconds = 1000 * seconds;
  if (real_sleep_) {
    // This next bit of logic is to avoid slow drift apart of the real clock and
    // the fake clock.  We compute how far from the real clock has advanced in
    // total since the start, and then compare to a running total of sleep
    // calls. We sleep for approximately x second, and then advance the clock by
    // the amount of time that has actually passed.
    static auto start_real = std::chrono::steady_clock().now();
    static int64_t fake_clock = 0;
    sleep(seconds);
    auto now_real = std::chrono::steady_clock().now();
    int64_t total_real = (now_real - start_real) / std::chrono::milliseconds(1);
    // We want to advance the fake clock by the difference between the real
    // clock, and the previous value on the fake clock.
    milliseconds = total_real - fake_clock;
    fake_clock += milliseconds;
  }
  if (callback_ != nullptr) callback_->ElapseTime(milliseconds);
}

void TestSleep::SyncFakeClock() {
  // Syncing can be done by sleeping 0 seconds.
  Sleep(0);
}

}  // namespace wvcdm