// Copyright 2020 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "src/transform/first_index_offset.h"

#include <memory>
#include <utility>
#include <vector>

#include "src/transform/test_helper.h"

namespace tint {
namespace transform {
namespace {

using FirstIndexOffsetTest = TransformTest;

TEST_F(FirstIndexOffsetTest, EmptyModule) {
  auto* src = "";
  auto* expect = "";

  DataMap config;
  config.Add<FirstIndexOffset::BindingPoint>(0, 0);
  auto got = Run<FirstIndexOffset>(src, std::move(config));

  EXPECT_EQ(expect, str(got));

  auto* data = got.data.Get<FirstIndexOffset::Data>();

  ASSERT_NE(data, nullptr);
  EXPECT_EQ(data->has_vertex_index, false);
  EXPECT_EQ(data->has_instance_index, false);
  EXPECT_EQ(data->first_vertex_offset, 0u);
  EXPECT_EQ(data->first_instance_offset, 0u);
}

TEST_F(FirstIndexOffsetTest, BasicModuleVertexIndex) {
  auto* src = R"(
fn test(vert_idx : u32) -> u32 {
  return vert_idx;
}

[[stage(vertex)]]
fn entry([[builtin(vertex_index)]] vert_idx : u32) -> [[builtin(position)]] vec4<f32> {
  ignore(test(vert_idx));
  return vec4<f32>();
}
)";

  auto* expect = R"(
[[block]]
struct tint_symbol {
  first_vertex_index : u32;
};

[[binding(1), group(2)]] var<uniform> tint_symbol_1 : tint_symbol;

fn test(vert_idx : u32) -> u32 {
  return vert_idx;
}

[[stage(vertex)]]
fn entry([[builtin(vertex_index)]] vert_idx : u32) -> [[builtin(position)]] vec4<f32> {
  ignore(test((vert_idx + tint_symbol_1.first_vertex_index)));
  return vec4<f32>();
}
)";

  DataMap config;
  config.Add<FirstIndexOffset::BindingPoint>(1, 2);
  auto got = Run<FirstIndexOffset>(src, std::move(config));

  EXPECT_EQ(expect, str(got));

  auto* data = got.data.Get<FirstIndexOffset::Data>();

  ASSERT_NE(data, nullptr);
  EXPECT_EQ(data->has_vertex_index, true);
  EXPECT_EQ(data->has_instance_index, false);
  EXPECT_EQ(data->first_vertex_offset, 0u);
  EXPECT_EQ(data->first_instance_offset, 0u);
}

TEST_F(FirstIndexOffsetTest, BasicModuleInstanceIndex) {
  auto* src = R"(
fn test(inst_idx : u32) -> u32 {
  return inst_idx;
}

[[stage(vertex)]]
fn entry([[builtin(instance_index)]] inst_idx : u32) -> [[builtin(position)]] vec4<f32> {
  ignore(test(inst_idx));
  return vec4<f32>();
}
)";

  auto* expect = R"(
[[block]]
struct tint_symbol {
  first_instance_index : u32;
};

[[binding(1), group(7)]] var<uniform> tint_symbol_1 : tint_symbol;

fn test(inst_idx : u32) -> u32 {
  return inst_idx;
}

[[stage(vertex)]]
fn entry([[builtin(instance_index)]] inst_idx : u32) -> [[builtin(position)]] vec4<f32> {
  ignore(test((inst_idx + tint_symbol_1.first_instance_index)));
  return vec4<f32>();
}
)";

  DataMap config;
  config.Add<FirstIndexOffset::BindingPoint>(1, 7);
  auto got = Run<FirstIndexOffset>(src, std::move(config));

  EXPECT_EQ(expect, str(got));

  auto* data = got.data.Get<FirstIndexOffset::Data>();

  ASSERT_NE(data, nullptr);
  EXPECT_EQ(data->has_vertex_index, false);
  EXPECT_EQ(data->has_instance_index, true);
  EXPECT_EQ(data->first_vertex_offset, 0u);
  EXPECT_EQ(data->first_instance_offset, 0u);
}

TEST_F(FirstIndexOffsetTest, BasicModuleBothIndex) {
  auto* src = R"(
fn test(instance_idx : u32, vert_idx : u32) -> u32 {
  return instance_idx + vert_idx;
}

struct Inputs {
  [[builtin(instance_index)]] instance_idx : u32;
  [[builtin(vertex_index)]] vert_idx : u32;
};

[[stage(vertex)]]
fn entry(inputs : Inputs) -> [[builtin(position)]] vec4<f32> {
  ignore(test(inputs.instance_idx, inputs.vert_idx));
  return vec4<f32>();
}
)";

  auto* expect = R"(
[[block]]
struct tint_symbol {
  first_vertex_index : u32;
  first_instance_index : u32;
};

[[binding(1), group(2)]] var<uniform> tint_symbol_1 : tint_symbol;

fn test(instance_idx : u32, vert_idx : u32) -> u32 {
  return (instance_idx + vert_idx);
}

struct Inputs {
  [[builtin(instance_index)]]
  instance_idx : u32;
  [[builtin(vertex_index)]]
  vert_idx : u32;
};

[[stage(vertex)]]
fn entry(inputs : Inputs) -> [[builtin(position)]] vec4<f32> {
  ignore(test((inputs.instance_idx + tint_symbol_1.first_instance_index), (inputs.vert_idx + tint_symbol_1.first_vertex_index)));
  return vec4<f32>();
}
)";

  DataMap config;
  config.Add<FirstIndexOffset::BindingPoint>(1, 2);
  auto got = Run<FirstIndexOffset>(src, std::move(config));

  EXPECT_EQ(expect, str(got));

  auto* data = got.data.Get<FirstIndexOffset::Data>();

  ASSERT_NE(data, nullptr);
  EXPECT_EQ(data->has_vertex_index, true);
  EXPECT_EQ(data->has_instance_index, true);
  EXPECT_EQ(data->first_vertex_offset, 0u);
  EXPECT_EQ(data->first_instance_offset, 4u);
}

TEST_F(FirstIndexOffsetTest, NestedCalls) {
  auto* src = R"(
fn func1(vert_idx : u32) -> u32 {
  return vert_idx;
}

fn func2(vert_idx : u32) -> u32 {
  return func1(vert_idx);
}

[[stage(vertex)]]
fn entry([[builtin(vertex_index)]] vert_idx : u32) -> [[builtin(position)]] vec4<f32> {
  ignore(func2(vert_idx));
  return vec4<f32>();
}
)";

  auto* expect = R"(
[[block]]
struct tint_symbol {
  first_vertex_index : u32;
};

[[binding(1), group(2)]] var<uniform> tint_symbol_1 : tint_symbol;

fn func1(vert_idx : u32) -> u32 {
  return vert_idx;
}

fn func2(vert_idx : u32) -> u32 {
  return func1(vert_idx);
}

[[stage(vertex)]]
fn entry([[builtin(vertex_index)]] vert_idx : u32) -> [[builtin(position)]] vec4<f32> {
  ignore(func2((vert_idx + tint_symbol_1.first_vertex_index)));
  return vec4<f32>();
}
)";

  DataMap config;
  config.Add<FirstIndexOffset::BindingPoint>(1, 2);
  auto got = Run<FirstIndexOffset>(src, std::move(config));

  EXPECT_EQ(expect, str(got));

  auto* data = got.data.Get<FirstIndexOffset::Data>();

  ASSERT_NE(data, nullptr);
  EXPECT_EQ(data->has_vertex_index, true);
  EXPECT_EQ(data->has_instance_index, false);
  EXPECT_EQ(data->first_vertex_offset, 0u);
  EXPECT_EQ(data->first_instance_offset, 0u);
}

TEST_F(FirstIndexOffsetTest, MultipleEntryPoints) {
  auto* src = R"(
fn func(i : u32) -> u32 {
  return i;
}

[[stage(vertex)]]
fn entry_a([[builtin(vertex_index)]] vert_idx : u32) -> [[builtin(position)]] vec4<f32> {
  ignore(func(vert_idx));
  return vec4<f32>();
}

[[stage(vertex)]]
fn entry_b([[builtin(vertex_index)]] vert_idx : u32, [[builtin(instance_index)]] inst_idx : u32) -> [[builtin(position)]] vec4<f32> {
  ignore(func(vert_idx + inst_idx));
  return vec4<f32>();
}

[[stage(vertex)]]
fn entry_c([[builtin(instance_index)]] inst_idx : u32) -> [[builtin(position)]] vec4<f32> {
  ignore(func(inst_idx));
  return vec4<f32>();
}
)";

  auto* expect = R"(
[[block]]
struct tint_symbol {
  first_vertex_index : u32;
  first_instance_index : u32;
};

[[binding(1), group(2)]] var<uniform> tint_symbol_1 : tint_symbol;

fn func(i : u32) -> u32 {
  return i;
}

[[stage(vertex)]]
fn entry_a([[builtin(vertex_index)]] vert_idx : u32) -> [[builtin(position)]] vec4<f32> {
  ignore(func((vert_idx + tint_symbol_1.first_vertex_index)));
  return vec4<f32>();
}

[[stage(vertex)]]
fn entry_b([[builtin(vertex_index)]] vert_idx : u32, [[builtin(instance_index)]] inst_idx : u32) -> [[builtin(position)]] vec4<f32> {
  ignore(func(((vert_idx + tint_symbol_1.first_vertex_index) + (inst_idx + tint_symbol_1.first_instance_index))));
  return vec4<f32>();
}

[[stage(vertex)]]
fn entry_c([[builtin(instance_index)]] inst_idx : u32) -> [[builtin(position)]] vec4<f32> {
  ignore(func((inst_idx + tint_symbol_1.first_instance_index)));
  return vec4<f32>();
}
)";

  DataMap config;
  config.Add<FirstIndexOffset::BindingPoint>(1, 2);
  auto got = Run<FirstIndexOffset>(src, std::move(config));

  EXPECT_EQ(expect, str(got));

  auto* data = got.data.Get<FirstIndexOffset::Data>();

  ASSERT_NE(data, nullptr);
  EXPECT_EQ(data->has_vertex_index, true);
  EXPECT_EQ(data->has_instance_index, true);
  EXPECT_EQ(data->first_vertex_offset, 0u);
  EXPECT_EQ(data->first_instance_offset, 4u);
}

}  // namespace
}  // namespace transform
}  // namespace tint