#include <gtest/gtest.h>
#include <cstring>
#include <stdexcept>

#include "ship/utils/binarytools/Stream.h"
#include "ship/utils/binarytools/BinaryReader.h"
#include "ship/utils/binarytools/BinaryWriter.h"
#include "ship/utils/binarytools/MemoryStream.h"

// Helper: creates a shared MemoryStream, writes to it via BinaryWriter,
// seeks back to the start, then returns a BinaryReader over the same stream.
static std::pair<std::shared_ptr<Ship::MemoryStream>, Ship::BinaryWriter> MakeWriter() {
    auto stream = std::make_shared<Ship::MemoryStream>();
    return { stream, Ship::BinaryWriter(stream) };
}

// ============================================================
// Round-trip tests (native endianness)
// ============================================================

TEST(BinaryRoundTrip, Int8) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<int8_t>(-42));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadInt8(), static_cast<int8_t>(-42));
}

TEST(BinaryRoundTrip, Int16) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<int16_t>(0x1234));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadInt16(), static_cast<int16_t>(0x1234));
}

TEST(BinaryRoundTrip, Int32) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<int32_t>(0x12345678));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadInt32(), static_cast<int32_t>(0x12345678));
}

TEST(BinaryRoundTrip, Int64) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<int64_t>(0x0102030405060708LL));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadInt64(), static_cast<int64_t>(0x0102030405060708LL));
}

TEST(BinaryRoundTrip, Float) {
    auto [stream, writer] = MakeWriter();
    writer.Write(1.5f);
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_FLOAT_EQ(reader.ReadFloat(), 1.5f);
}

TEST(BinaryRoundTrip, Double) {
    auto [stream, writer] = MakeWriter();
    writer.Write(3.14159265358979);
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_DOUBLE_EQ(reader.ReadDouble(), 3.14159265358979);
}

TEST(BinaryRoundTrip, String) {
    auto [stream, writer] = MakeWriter();
    writer.Write(std::string("hello"));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadString(), "hello");
}

TEST(BinaryRoundTrip, EmptyString) {
    auto [stream, writer] = MakeWriter();
    writer.Write(std::string(""));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadString(), "");
}

// ============================================================
// ReadCString
// ============================================================

TEST(BinaryReadCString, StopsAtNullTerminator) {
    auto [stream, writer] = MakeWriter();
    const char buf[] = "abc\0xyz";
    writer.Write(const_cast<char*>(buf), sizeof(buf));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    // ReadCString reads up to and including the null terminator
    std::string result = reader.ReadCString();
    EXPECT_STREQ(result.c_str(), "abc");
}

TEST(BinaryReadCString, DoesNotOverreadAtEndOfStream) {
    auto [stream, writer] = MakeWriter();
    // Write bytes with no null terminator
    const char buf[] = { 'a', 'b', 'c' };
    writer.Write(const_cast<char*>(buf), sizeof(buf));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    // Should stop at end of stream without crashing
    std::string result = reader.ReadCString();
    EXPECT_EQ(result.size(), 3u);
}

// ============================================================
// NaN throws
// ============================================================

TEST(BinaryReadFloat, NaNThrows) {
    // Write a quiet NaN bit pattern (IEEE 754: 0x7FC00000)
    uint32_t nanBits = 0x7FC00000;
    float nanFloat;
    std::memcpy(&nanFloat, &nanBits, sizeof(float));

    auto [stream, writer] = MakeWriter();
    writer.Write(nanFloat);
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_THROW(reader.ReadFloat(), std::runtime_error);
}

TEST(BinaryReadDouble, NaNThrows) {
    uint64_t nanBits = 0x7FF8000000000000ULL;
    double nanDouble;
    std::memcpy(&nanDouble, &nanBits, sizeof(double));

    auto [stream, writer] = MakeWriter();
    writer.Write(nanDouble);
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_THROW(reader.ReadDouble(), std::runtime_error);
}

// ============================================================
// Endianness
// ============================================================

TEST(BinaryEndianness, WriteBigReadBigRoundTrips) {
    auto [stream, writer] = MakeWriter();
    writer.SetEndianness(Ship::Endianness::Big);
    writer.Write(static_cast<int32_t>(0x01020304));

    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    reader.SetEndianness(Ship::Endianness::Big);
    EXPECT_EQ(reader.ReadInt32(), static_cast<int32_t>(0x01020304));
}

TEST(BinaryEndianness, WriteBigReadNativeGivesByteSwappedValue) {
    // On a little-endian machine:
    //   Writing 0x01020304 as Big swaps to 0x04030201 on the wire.
    //   Reading as Native (LE) gives back 0x04030201.
    // On a big-endian machine both Native and Big are the same, so no swap occurs.
    auto [stream, writer] = MakeWriter();
    writer.SetEndianness(Ship::Endianness::Big);
    writer.Write(static_cast<int32_t>(0x01020304));

    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    reader.SetEndianness(Ship::Endianness::Native);
    int32_t result = reader.ReadInt32();

#ifdef IS_BIGENDIAN
    EXPECT_EQ(result, static_cast<int32_t>(0x01020304));
#else
    EXPECT_EQ(result, static_cast<int32_t>(0x04030201));
#endif
}

// ============================================================
// Seek
// ============================================================

TEST(BinarySeek, SeekFromStart) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<int32_t>(0xAAAA));
    writer.Write(static_cast<int32_t>(0xBBBB));

    stream->Seek(4, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadInt32(), static_cast<int32_t>(0xBBBB));
}

TEST(BinarySeek, SeekToBeginningAndReread) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<int32_t>(0xDEAD));

    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    int32_t first = reader.ReadInt32();
    stream->Seek(0, Ship::SeekOffsetType::Start);
    int32_t second = reader.ReadInt32();
    EXPECT_EQ(first, second);
}

// ============================================================
// Unsigned type round-trips
// ============================================================

TEST(BinaryRoundTrip, UByte) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<uint8_t>(200));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadUByte(), static_cast<uint8_t>(200));
}

TEST(BinaryRoundTrip, UInt16) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<uint16_t>(0xABCD));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadUInt16(), static_cast<uint16_t>(0xABCD));
}

TEST(BinaryRoundTrip, UInt32) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<uint32_t>(0xDEADBEEF));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadUInt32(), static_cast<uint32_t>(0xDEADBEEF));
}

TEST(BinaryRoundTrip, UInt64) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<uint64_t>(0xDEADBEEFCAFEBABEULL));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadUInt64(), static_cast<uint64_t>(0xDEADBEEFCAFEBABEULL));
}

TEST(BinaryRoundTrip, Char) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<int8_t>('Z'));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadChar(), 'Z');
}

// ============================================================
// BinaryWriter::Write(int32_t, int32_t)
// ============================================================

TEST(BinaryWriterDualWrite, WritesTwoInt32s) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<int32_t>(0x11111111), static_cast<int32_t>(0x22222222));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadInt32(), static_cast<int32_t>(0x11111111));
    EXPECT_EQ(reader.ReadInt32(), static_cast<int32_t>(0x22222222));
}

// ============================================================
// BinaryWriter::GetLength / GetBaseAddress
// ============================================================

TEST(BinaryWriterMeta, GetLengthAfterWrite) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<int32_t>(0));
    EXPECT_EQ(writer.GetLength(), sizeof(int32_t));
}

TEST(BinaryWriterMeta, GetBaseAddressAfterWrite) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<int32_t>(0));
    EXPECT_EQ(writer.GetBaseAddress(), sizeof(int32_t));
}

// ============================================================
// BinaryReader::Read(char*, int32_t) — raw buffer read
// ============================================================

TEST(BinaryReaderRawRead, ReadIntoBuffer) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<int8_t>(0x01));
    writer.Write(static_cast<int8_t>(0x02));
    writer.Write(static_cast<int8_t>(0x03));

    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    char buf[3] = {};
    reader.Read(buf, 3);
    EXPECT_EQ(static_cast<uint8_t>(buf[0]), 0x01);
    EXPECT_EQ(static_cast<uint8_t>(buf[1]), 0x02);
    EXPECT_EQ(static_cast<uint8_t>(buf[2]), 0x03);
}

// ============================================================
// BinaryReader / BinaryWriter ToVector
// ============================================================

TEST(BinaryToVector, WriterAndReaderMatchVectors) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<int32_t>(0x12345678));

    auto writerVec = writer.ToVector();
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    auto readerVec = reader.ToVector();

    ASSERT_EQ(writerVec.size(), readerVec.size());
    for (size_t i = 0; i < writerVec.size(); i++) {
        EXPECT_EQ(writerVec[i], readerVec[i]);
    }
}

// ============================================================
// MemoryStream — seek modes: Current and End
// ============================================================

TEST(MemoryStreamSeek, SeekFromCurrent) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<int32_t>(0xAAAA));
    writer.Write(static_cast<int32_t>(0xBBBB));
    // Position is now at 8; seek back 4 from current
    stream->Seek(-4, Ship::SeekOffsetType::Current);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadInt32(), static_cast<int32_t>(0xBBBB));
}

TEST(MemoryStreamSeek, SeekFromEnd) {
    auto [stream, writer] = MakeWriter();
    writer.Write(static_cast<int32_t>(0xAAAA));
    writer.Write(static_cast<int32_t>(0xBBBB));
    // MemoryStream::Seek(End) uses formula: mBufferSize - 1 - offset.
    // With 8 bytes total: 8 - 1 - 3 = 4, which is the start of the second int32.
    stream->Seek(3, Ship::SeekOffsetType::End);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadInt32(), static_cast<int32_t>(0xBBBB));
}

// ============================================================
// MemoryStream — constructors
// ============================================================

TEST(MemoryStreamCtor, RawBufferConstructor) {
    char buf[] = { 0x01, 0x02, 0x03 };
    Ship::BinaryReader reader(buf, sizeof(buf));
    EXPECT_EQ(reader.ReadInt8(), static_cast<int8_t>(0x01));
    EXPECT_EQ(reader.ReadInt8(), static_cast<int8_t>(0x02));
    EXPECT_EQ(reader.ReadInt8(), static_cast<int8_t>(0x03));
}

TEST(MemoryStreamCtor, SharedVectorConstructor) {
    auto vec = std::make_shared<std::vector<char>>(std::initializer_list<char>{ 0x0A, 0x0B, 0x0C });
    auto stream = std::make_shared<Ship::MemoryStream>(vec);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadInt8(), static_cast<int8_t>(0x0A));
    EXPECT_EQ(reader.ReadInt8(), static_cast<int8_t>(0x0B));
    EXPECT_EQ(reader.ReadInt8(), static_cast<int8_t>(0x0C));
}

TEST(MemoryStreamCtor, SharedVectorWithOffsetConstructor) {
    // First byte is padding at index 0; reader starts at offset 1
    auto vec = std::make_shared<std::vector<char>>(std::initializer_list<char>{ 0x00, 0x0A, 0x0B, 0x0C });
    auto stream = std::make_shared<Ship::MemoryStream>(vec, 1);
    Ship::BinaryReader reader(stream);
    EXPECT_EQ(reader.ReadInt8(), static_cast<int8_t>(0x0A));
    EXPECT_EQ(reader.ReadInt8(), static_cast<int8_t>(0x0B));
    EXPECT_EQ(reader.ReadInt8(), static_cast<int8_t>(0x0C));
}

// ============================================================
// Endianness — unsigned types
// ============================================================

TEST(BinaryEndianness, UInt16BigRoundTrip) {
    auto [stream, writer] = MakeWriter();
    writer.SetEndianness(Ship::Endianness::Big);
    writer.Write(static_cast<uint16_t>(0xABCD));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    reader.SetEndianness(Ship::Endianness::Big);
    EXPECT_EQ(reader.ReadUInt16(), static_cast<uint16_t>(0xABCD));
}

TEST(BinaryEndianness, UInt64BigRoundTrip) {
    auto [stream, writer] = MakeWriter();
    writer.SetEndianness(Ship::Endianness::Big);
    writer.Write(static_cast<uint64_t>(0x0102030405060708ULL));
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    reader.SetEndianness(Ship::Endianness::Big);
    EXPECT_EQ(reader.ReadUInt64(), static_cast<uint64_t>(0x0102030405060708ULL));
}

TEST(BinaryEndianness, FloatBigRoundTrip) {
    auto [stream, writer] = MakeWriter();
    writer.SetEndianness(Ship::Endianness::Big);
    writer.Write(2.5f);
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    reader.SetEndianness(Ship::Endianness::Big);
    EXPECT_FLOAT_EQ(reader.ReadFloat(), 2.5f);
}

TEST(BinaryEndianness, DoubleBigRoundTrip) {
    auto [stream, writer] = MakeWriter();
    writer.SetEndianness(Ship::Endianness::Big);
    writer.Write(2.718281828459045);
    stream->Seek(0, Ship::SeekOffsetType::Start);
    Ship::BinaryReader reader(stream);
    reader.SetEndianness(Ship::Endianness::Big);
    EXPECT_DOUBLE_EQ(reader.ReadDouble(), 2.718281828459045);
}