// Copyright 2024 The Dawn & Tint Authors
//
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#include "src/tint/utils/bytes/buffer_reader.h"

#include <array>
#include <span>

#include "gtest/gtest.h"

namespace tint::bytes {
namespace {

template <typename... ARGS>
auto Data(ARGS... args) {
    return std::array{std::byte{static_cast<uint8_t>(args)}...};
}

TEST(BufferReaderTest, IntegerBigEndian) {
    auto data = Data(0x10, 0x20, 0x30, 0x40);

    BufferReader u32_reader{data};
    EXPECT_FALSE(u32_reader.IsEOF());
    auto u32 = u32_reader.Int<uint32_t>(Endianness::kBig);
    EXPECT_EQ(u32, 0x10203040u);
    EXPECT_TRUE(u32_reader.IsEOF());

    BufferReader i32_reader{data};
    EXPECT_FALSE(i32_reader.IsEOF());
    auto i32 = i32_reader.Int<int32_t>(Endianness::kBig);
    EXPECT_EQ(i32, 0x10203040);
    EXPECT_TRUE(i32_reader.IsEOF());
}

TEST(BufferReaderTest, IntegerBigEndian_TooShort) {
    auto data = Data(0x10, 0x20);

    BufferReader u32_reader{data};
    EXPECT_FALSE(u32_reader.IsEOF());
    auto u32 = u32_reader.Int<uint32_t>(Endianness::kBig);
    EXPECT_NE(u32, Success);
    EXPECT_TRUE(u32_reader.IsEOF());

    BufferReader i32_reader{data};
    EXPECT_FALSE(i32_reader.IsEOF());
    auto i32 = i32_reader.Int<int32_t>(Endianness::kBig);
    EXPECT_NE(i32, Success);
    EXPECT_TRUE(i32_reader.IsEOF());
}

TEST(BufferReaderTest, IntegerLittleEndian) {
    auto data = Data(0x10, 0x20, 0x30, 0x40);

    BufferReader u32_reader{data};
    EXPECT_FALSE(u32_reader.IsEOF());
    auto u32 = u32_reader.Int<uint32_t>(Endianness::kLittle);
    EXPECT_EQ(u32, 0x40302010u);
    EXPECT_TRUE(u32_reader.IsEOF());

    BufferReader i32_reader{data};
    EXPECT_FALSE(i32_reader.IsEOF());
    auto i32 = i32_reader.Int<int32_t>(Endianness::kLittle);
    EXPECT_EQ(i32, 0x40302010);
    EXPECT_TRUE(i32_reader.IsEOF());
}

TEST(BufferReaderTest, IntegerLittleEndian_TooShort) {
    auto data = Data(0x30, 0x40);

    BufferReader u32_reader{data};
    EXPECT_FALSE(u32_reader.IsEOF());
    auto u32 = u32_reader.Int<uint32_t>(Endianness::kLittle);
    EXPECT_NE(u32, Success);
    EXPECT_TRUE(u32_reader.IsEOF());

    BufferReader i32_reader{data};
    EXPECT_FALSE(i32_reader.IsEOF());
    auto i32 = i32_reader.Int<int32_t>(Endianness::kLittle);
    EXPECT_NE(i32, Success);
    EXPECT_TRUE(i32_reader.IsEOF());
}

TEST(BufferReaderTest, Float) {
    auto data = Data(0x00, 0x00, 0x08, 0x41);

    BufferReader f32_reader{data};
    EXPECT_FALSE(f32_reader.IsEOF());
    auto f32 = f32_reader.Float<float>();
    ASSERT_EQ(f32, Success);
    EXPECT_EQ(f32.Get(), 8.5f);
    EXPECT_TRUE(f32_reader.IsEOF());
}

TEST(BufferReaderTest, Float_TooShort) {
    auto data = Data(0x08, 0x41);

    BufferReader f32_reader{data};
    EXPECT_FALSE(f32_reader.IsEOF());
    auto f32 = f32_reader.Float<float>();
    EXPECT_NE(f32, Success);
    EXPECT_TRUE(f32_reader.IsEOF());
}

}  // namespace
}  // namespace tint::bytes