/*
 *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#include "rtc_base/crypto_random.h"

#include <cstdint>
#include <cstring>
#include <memory>
#include <string>
#include <utility>

#include "rtc_base/buffer.h"
#include "test/gmock.h"
#include "test/gtest.h"

namespace webrtc {
namespace {

using ::testing::_;
using ::testing::DoAll;
using ::testing::IsEmpty;
using ::testing::Not;
using ::testing::Return;
using ::testing::WithArg;
using ::testing::WithArgs;

TEST(RandomTest, TestCreateRandomId) {
  CreateRandomId();
}

TEST(RandomTest, TestCreateRandomDouble) {
  for (int i = 0; i < 100; ++i) {
    double r = CreateRandomDouble();
    EXPECT_GE(r, 0.0);
    EXPECT_LT(r, 1.0);
  }
}

TEST(RandomTest, TestCreateNonZeroRandomId) {
  EXPECT_NE(0U, CreateRandomNonZeroId());
}

TEST(RandomTest, TestCreateRandomString) {
  std::string random = CreateRandomString(256);
  EXPECT_EQ(256U, random.size());
  std::string random2;
  EXPECT_TRUE(CreateRandomString(256, &random2));
  EXPECT_NE(random, random2);
  EXPECT_EQ(256U, random2.size());
}

TEST(RandomTest, TestCreateRandomData) {
  static size_t kRandomDataLength = 32;
  std::string random1;
  std::string random2;
  EXPECT_TRUE(CreateRandomData(kRandomDataLength, &random1));
  EXPECT_EQ(kRandomDataLength, random1.size());
  EXPECT_TRUE(CreateRandomData(kRandomDataLength, &random2));
  EXPECT_EQ(kRandomDataLength, random2.size());
  EXPECT_NE(0, memcmp(random1.data(), random2.data(), kRandomDataLength));
}

TEST(RandomTest, TestCreateRandomStringEvenlyDivideTable) {
  static std::string kUnbiasedTable("01234567");
  std::string random;
  EXPECT_TRUE(CreateRandomString(256, kUnbiasedTable, &random));
  EXPECT_EQ(256U, random.size());

  static std::string kBiasedTable("0123456789");
  EXPECT_FALSE(CreateRandomString(256, kBiasedTable, &random));
  EXPECT_EQ(0U, random.size());
}

TEST(RandomTest, TestCreateRandomUuid) {
  std::string random = CreateRandomUuid();
  EXPECT_EQ(36U, random.size());
}

TEST(RandomTest, TestCreateRandomForTest) {
  // Make sure we get the output we expect.
  SetRandomTestMode(true);
  EXPECT_EQ(2154761789U, CreateRandomId());
  EXPECT_EQ("h0ISP4S5SJKH/9EY", CreateRandomString(16));
  EXPECT_EQ("41706e92-cdd3-46d9-a22d-8ff1737ffb11", CreateRandomUuid());
  static size_t kRandomDataLength = 32;
  std::string random;
  EXPECT_TRUE(CreateRandomData(kRandomDataLength, &random));
  EXPECT_EQ(kRandomDataLength, random.size());
  Buffer expected(
      "\xbd\x52\x2a\x4b\x97\x93\x2f\x1c"
      "\xc4\x72\xab\xa2\x88\x68\x3e\xcc"
      "\xa3\x8d\xaf\x13\x3b\xbc\x83\xbb"
      "\x16\xf1\xcf\x56\x0c\xf5\x4a\x8b",
      kRandomDataLength);
  EXPECT_EQ(0, memcmp(expected.data(), random.data(), kRandomDataLength));

  // Reset and make sure we get the same output.
  SetRandomTestMode(true);
  EXPECT_EQ(2154761789U, CreateRandomId());
  EXPECT_EQ("h0ISP4S5SJKH/9EY", CreateRandomString(16));
  EXPECT_EQ("41706e92-cdd3-46d9-a22d-8ff1737ffb11", CreateRandomUuid());
  EXPECT_TRUE(CreateRandomData(kRandomDataLength, &random));
  EXPECT_EQ(kRandomDataLength, random.size());
  EXPECT_EQ(0, memcmp(expected.data(), random.data(), kRandomDataLength));

  // Test different character sets.
  SetRandomTestMode(true);
  std::string str;
  EXPECT_TRUE(CreateRandomString(16, "a", &str));
  EXPECT_EQ("aaaaaaaaaaaaaaaa", str);
  EXPECT_TRUE(CreateRandomString(16, "abcd", &str));
  EXPECT_EQ("dbaaabdaccbcabbd", str);

  // Turn off test mode for other tests.
  SetRandomTestMode(false);
}

class MockRandomGenerator : public RandomGenerator {
 public:
  MOCK_METHOD(void, Die, ());
  ~MockRandomGenerator() override { Die(); }

  MOCK_METHOD(bool, Generate, (void* buf, size_t len), (override));
};

TEST(RandomTest, TestSetRandomGenerator) {
  std::unique_ptr<MockRandomGenerator> will_move =
      std::make_unique<MockRandomGenerator>();
  MockRandomGenerator* generator = will_move.get();
  SetRandomGenerator(std::move(will_move));

  uint32_t id = 4658;
  EXPECT_CALL(*generator, Generate(_, sizeof(uint32_t)))
      .WillOnce(DoAll(
          WithArg<0>([&id](void* p) { std::memcpy(p, &id, sizeof(uint32_t)); }),
          Return(true)));
  EXPECT_EQ(CreateRandomId(), id);

  EXPECT_CALL(*generator, Generate)
      .WillOnce(DoAll(
          WithArgs<0, 1>([](void* p, size_t len) { std::memset(p, 0, len); }),
          Return(true)));
  EXPECT_THAT(CreateRandomUuid(), Not(IsEmpty()));

  // Set the default random generator, and expect that mock generator is
  // not used beyond this point.
  EXPECT_CALL(*generator, Die);
  EXPECT_CALL(*generator, Generate).Times(0);
  SetDefaultRandomGenerator();
  EXPECT_THAT(CreateRandomUuid(), Not(IsEmpty()));
}

}  // namespace
}  // namespace webrtc