/*
 *  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/byte_buffer.h"

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

#include "absl/strings/string_view.h"
#include "rtc_base/buffer.h"
#include "rtc_base/byte_order.h"
#include "test/gmock.h"
#include "test/gtest.h"

namespace webrtc {

using ::testing::ElementsAre;
using ::testing::ElementsAreArray;

TEST(ByteBufferTest, WriterAccessors) {
  // To be changed into ByteBufferWriter when base type is converted.
  ByteBufferWriterT<BufferT<uint8_t>> buffer;
  buffer.WriteString("abc");
  EXPECT_EQ(buffer.Length(), 3U);
  EXPECT_THAT(buffer.DataView(), ElementsAre('a', 'b', 'c'));
  EXPECT_EQ(absl::string_view("abc"), buffer.DataAsStringView());

  buffer.WriteUInt8(0);
  EXPECT_STREQ(buffer.DataAsCharPointer(), "abc");
  EXPECT_STREQ(reinterpret_cast<const char*>(buffer.Data()), "abc");
}

TEST(ByteBufferTest, TestByteOrder) {
  uint16_t n16 = 1;
  uint32_t n32 = 1;
  uint64_t n64 = 1;

  EXPECT_EQ(n16, NetworkToHost16(HostToNetwork16(n16)));
  EXPECT_EQ(n32, NetworkToHost32(HostToNetwork32(n32)));
  EXPECT_EQ(n64, NetworkToHost64(HostToNetwork64(n64)));

  if (IsHostBigEndian()) {
    // The host is the network (big) endian.
    EXPECT_EQ(n16, HostToNetwork16(n16));
    EXPECT_EQ(n32, HostToNetwork32(n32));
    EXPECT_EQ(n64, HostToNetwork64(n64));

    // GetBE converts big endian to little endian here.
    EXPECT_EQ(n16 >> 8, GetBE16(std::span<const uint8_t>(
                            reinterpret_cast<const uint8_t*>(&n16), 2)));
    EXPECT_EQ(n32 >> 24, GetBE32(std::span<const uint8_t>(
                             reinterpret_cast<const uint8_t*>(&n32), 4)));
    EXPECT_EQ(n64 >> 56, GetBE64(std::span<const uint8_t>(
                             reinterpret_cast<const uint8_t*>(&n64), 8)));
  } else {
    // The host is little endian.
    EXPECT_NE(n16, HostToNetwork16(n16));
    EXPECT_NE(n32, HostToNetwork32(n32));
    EXPECT_NE(n64, HostToNetwork64(n64));

    // GetBE converts little endian to big endian here.
    EXPECT_EQ(GetBE16(std::span<const uint8_t>(
                  reinterpret_cast<const uint8_t*>(&n16), 2)),
              HostToNetwork16(n16));
    EXPECT_EQ(GetBE32(std::span<const uint8_t>(
                  reinterpret_cast<const uint8_t*>(&n32), 4)),
              HostToNetwork32(n32));
    EXPECT_EQ(GetBE64(std::span<const uint8_t>(
                  reinterpret_cast<const uint8_t*>(&n64), 8)),
              HostToNetwork64(n64));

    // GetBE converts little endian to big endian here.
    EXPECT_EQ(n16 << 8, GetBE16(std::span<const uint8_t>(
                            reinterpret_cast<const uint8_t*>(&n16), 2)));
    EXPECT_EQ(n32 << 24, GetBE32(std::span<const uint8_t>(
                             reinterpret_cast<const uint8_t*>(&n32), 4)));
    EXPECT_EQ(n64 << 56, GetBE64(std::span<const uint8_t>(
                             reinterpret_cast<const uint8_t*>(&n64), 8)));
  }
}

TEST(ByteBufferTest, TestBufferLength) {
  ByteBufferWriter buffer;
  size_t size = 0;
  EXPECT_EQ(size, buffer.Length());

  buffer.WriteUInt8(1);
  ++size;
  EXPECT_EQ(size, buffer.Length());

  buffer.WriteUInt16(1);
  size += 2;
  EXPECT_EQ(size, buffer.Length());

  buffer.WriteUInt24(1);
  size += 3;
  EXPECT_EQ(size, buffer.Length());

  buffer.WriteUInt32(1);
  size += 4;
  EXPECT_EQ(size, buffer.Length());

  buffer.WriteUInt64(1);
  size += 8;
  EXPECT_EQ(size, buffer.Length());
}

TEST(ByteBufferTest, TestReadWriteBuffer) {
  ByteBufferWriter buffer;
  ByteBufferReader read_buf(std::span<const uint8_t>{});
  uint8_t ru8;
  EXPECT_FALSE(read_buf.ReadUInt8(&ru8));

  // Write and read uint8_t.
  uint8_t wu8 = 1;
  buffer.WriteUInt8(wu8);
  ByteBufferReader read_buf1(buffer);
  EXPECT_TRUE(read_buf1.ReadUInt8(&ru8));
  EXPECT_EQ(wu8, ru8);
  EXPECT_EQ(read_buf1.Length(), 0U);
  buffer.Clear();

  // Write and read uint16_t.
  uint16_t wu16 = (1 << 8) + 1;
  buffer.WriteUInt16(wu16);
  ByteBufferReader read_buf2(buffer);
  uint16_t ru16;
  EXPECT_TRUE(read_buf2.ReadUInt16(&ru16));
  EXPECT_EQ(wu16, ru16);
  EXPECT_EQ(read_buf2.Length(), 0U);
  buffer.Clear();

  // Write and read uint24.
  uint32_t wu24 = (3 << 16) + (2 << 8) + 1;
  buffer.WriteUInt24(wu24);
  ByteBufferReader read_buf3(buffer);
  uint32_t ru24;
  EXPECT_TRUE(read_buf3.ReadUInt24(&ru24));
  EXPECT_EQ(wu24, ru24);
  EXPECT_EQ(read_buf3.Length(), 0U);
  buffer.Clear();

  // Write and read uint32_t.
  uint32_t wu32 = (4 << 24) + (3 << 16) + (2 << 8) + 1;
  buffer.WriteUInt32(wu32);
  ByteBufferReader read_buf4(buffer);
  uint32_t ru32;
  EXPECT_TRUE(read_buf4.ReadUInt32(&ru32));
  EXPECT_EQ(wu32, ru32);
  EXPECT_EQ(read_buf3.Length(), 0U);
  buffer.Clear();

  // Write and read uint64_t.
  uint32_t another32 = (8 << 24) + (7 << 16) + (6 << 8) + 5;
  uint64_t wu64 = (static_cast<uint64_t>(another32) << 32) + wu32;
  buffer.WriteUInt64(wu64);
  ByteBufferReader read_buf5(buffer);
  uint64_t ru64;
  EXPECT_TRUE(read_buf5.ReadUInt64(&ru64));
  EXPECT_EQ(wu64, ru64);
  EXPECT_EQ(read_buf5.Length(), 0U);
  buffer.Clear();

  // Write and read string.
  std::string write_string("hello");
  buffer.WriteString(write_string);
  ByteBufferReader read_buf6(buffer);
  std::string read_string;
  EXPECT_TRUE(read_buf6.ReadString(&read_string, write_string.size()));
  EXPECT_EQ(write_string, read_string);
  EXPECT_EQ(read_buf6.Length(), 0U);
  buffer.Clear();

  // Write and read bytes
  uint8_t write_bytes[] = {3, 2, 1};
  buffer.Write(std::span<const uint8_t>(write_bytes, 3));
  ByteBufferReader read_buf7(buffer);
  uint8_t read_bytes[3];
  EXPECT_TRUE(read_buf7.ReadBytes(read_bytes));
  EXPECT_THAT(read_bytes, ElementsAreArray(write_bytes));
  EXPECT_EQ(read_buf7.Length(), 0U);
  buffer.Clear();

  // Write and read reserved buffer space
  uint8_t* write_dst = buffer.ReserveWriteBuffer(3);
  memcpy(write_dst, write_bytes, 3);
  ByteBufferReader read_buf8(buffer);
  memset(read_bytes, 0, 3);
  EXPECT_TRUE(read_buf8.ReadBytes(read_bytes));
  EXPECT_THAT(read_bytes, ElementsAreArray(write_dst, 3));
  EXPECT_EQ(read_buf8.Length(), 0U);
  buffer.Clear();

  // Write and read in order.
  buffer.WriteUInt8(wu8);
  buffer.WriteUInt16(wu16);
  buffer.WriteUInt24(wu24);
  buffer.WriteUInt32(wu32);
  buffer.WriteUInt64(wu64);
  ByteBufferReader read_buf9(buffer);
  EXPECT_TRUE(read_buf9.ReadUInt8(&ru8));
  EXPECT_EQ(wu8, ru8);
  EXPECT_TRUE(read_buf9.ReadUInt16(&ru16));
  EXPECT_EQ(wu16, ru16);
  EXPECT_TRUE(read_buf9.ReadUInt24(&ru24));
  EXPECT_EQ(wu24, ru24);
  EXPECT_TRUE(read_buf9.ReadUInt32(&ru32));
  EXPECT_EQ(wu32, ru32);
  EXPECT_TRUE(read_buf9.ReadUInt64(&ru64));
  EXPECT_EQ(wu64, ru64);
  EXPECT_EQ(read_buf9.Length(), 0U);
  buffer.Clear();
}

TEST(ByteBufferTest, TestWriteCArray) {
  // Write and read data
  const uint8_t write_data[3] = {3, 2, 1};
  ByteBufferWriter buffer;
  buffer.Write(write_data);
  EXPECT_EQ(buffer.Length(), 3U);
  ByteBufferReader read_buf10(buffer);
  uint8_t read_bytes[3] = {};
  EXPECT_TRUE(read_buf10.ReadBytes(read_bytes));
  EXPECT_THAT(read_bytes, ElementsAreArray(write_data));
  EXPECT_EQ(read_buf10.Length(), 0U);
}

TEST(ByteBufferTest, TestWriteBuffer) {
  const uint8_t write_data[3] = {3, 2, 1};
  // Write and read buffer
  Buffer write_buffer(write_data);
  ByteBufferWriter buffer;
  buffer.Write(write_buffer);
  ByteBufferReader read_buf11(buffer);
  uint8_t read_bytes[3] = {};
  EXPECT_TRUE(read_buf11.ReadBytes(read_bytes));
  EXPECT_THAT(read_bytes, ElementsAreArray(write_buffer));
  EXPECT_EQ(read_buf11.Length(), 0U);
}

TEST(ByteBufferTest, TestWriteSpan) {
  const uint8_t write_data[3] = {3, 2, 1};
  // Write and read std::span
  std::span<const uint8_t> write_view(write_data);
  ByteBufferWriter buffer;
  buffer.Write(write_view);
  ByteBufferReader read_buf12(buffer);
  uint8_t read_bytes[3] = {};
  EXPECT_TRUE(read_buf12.ReadBytes(read_bytes));
  EXPECT_THAT(read_bytes, ElementsAreArray(write_view));
  EXPECT_EQ(read_buf12.Length(), 0U);
}

TEST(ByteBufferTest, TestWriteConsume) {
  ByteBufferWriter writer;
  // Write and read uint8_t.
  uint8_t wu8 = 1;
  writer.WriteUInt8(wu8);
  Buffer consumed = std::move(writer).Extract();
  EXPECT_THAT(consumed, ElementsAre(wu8));
}

TEST(ByteBufferTest, TestReadStringView) {
  const absl::string_view tests[] = {"hello", " ", "string_view"};
  std::string buffer;
  for (const auto& test : tests)
    buffer += test;

  std::span<const uint8_t> bytes(reinterpret_cast<const uint8_t*>(&buffer[0]),
                                 buffer.size());

  ByteBufferReader read_buf(bytes);
  size_t consumed = 0;
  for (const auto& test : tests) {
    absl::string_view sv;
    EXPECT_TRUE(read_buf.ReadStringView(&sv, test.length()));
    EXPECT_EQ(sv.compare(test), 0);
    // The returned string view should point directly into the original
    // string.
    EXPECT_EQ(&sv[0], &buffer[0 + consumed]);
    consumed += sv.size();
  }
}

TEST(ByteBufferTest, TestReadWriteUVarint) {
  ByteBufferWriter write_buffer;
  size_t size = 0;
  EXPECT_EQ(size, write_buffer.Length());

  write_buffer.WriteUVarint(1u);
  ++size;
  EXPECT_EQ(size, write_buffer.Length());

  write_buffer.WriteUVarint(2u);
  ++size;
  EXPECT_EQ(size, write_buffer.Length());

  write_buffer.WriteUVarint(27u);
  ++size;
  EXPECT_EQ(size, write_buffer.Length());

  write_buffer.WriteUVarint(149u);
  size += 2;
  EXPECT_EQ(size, write_buffer.Length());

  write_buffer.WriteUVarint(68719476736u);
  size += 6;
  EXPECT_EQ(size, write_buffer.Length());

  ByteBufferReader read_buffer(write_buffer);
  EXPECT_EQ(size, read_buffer.Length());
  uint64_t val1, val2, val3, val4, val5;

  ASSERT_TRUE(read_buffer.ReadUVarint(&val1));
  EXPECT_EQ(val1, 1U);
  --size;
  EXPECT_EQ(size, read_buffer.Length());

  ASSERT_TRUE(read_buffer.ReadUVarint(&val2));
  EXPECT_EQ(val2, 2U);
  --size;
  EXPECT_EQ(size, read_buffer.Length());

  ASSERT_TRUE(read_buffer.ReadUVarint(&val3));
  EXPECT_EQ(val3, 27U);
  --size;
  EXPECT_EQ(size, read_buffer.Length());

  ASSERT_TRUE(read_buffer.ReadUVarint(&val4));
  EXPECT_EQ(val4, 149U);
  size -= 2;
  EXPECT_EQ(size, read_buffer.Length());

  ASSERT_TRUE(read_buffer.ReadUVarint(&val5));
  EXPECT_EQ(val5, 68719476736U);
  size -= 6;
  EXPECT_EQ(size, read_buffer.Length());
}

TEST(ByteBufferTest, ReadFromSpan) {
  const uint8_t buf[] = {'a', 'b', 'c'};
  std::span<const uint8_t> view(buf, 3);

  ByteBufferReader read_buffer(view);
  uint8_t val;
  EXPECT_TRUE(read_buffer.ReadUInt8(&val));
  EXPECT_EQ(val, 'a');
  EXPECT_TRUE(read_buffer.ReadUInt8(&val));
  EXPECT_EQ(val, 'b');
  EXPECT_TRUE(read_buffer.ReadUInt8(&val));
  EXPECT_EQ(val, 'c');
  EXPECT_FALSE(read_buffer.ReadUInt8(&val));
}

TEST(ByteBufferTest, ReadToSpan) {
  const uint8_t buf[] = {'a', 'b', 'c'};
  std::span<const uint8_t> stored_view(buf, 3);
  ByteBufferReader read_buffer(stored_view);
  uint8_t result[] = {'1', '2', '3'};
  EXPECT_TRUE(read_buffer.ReadBytes(std::span(result, 2)));
  EXPECT_EQ(result[0], 'a');
  EXPECT_EQ(result[1], 'b');
  EXPECT_EQ(result[2], '3');
  EXPECT_TRUE(read_buffer.ReadBytes(std::span(&result[2], 1)));
  EXPECT_EQ(result[2], 'c');
  EXPECT_FALSE(read_buffer.ReadBytes(std::span(result, 1)));
}

}  // namespace webrtc