// 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, ShouldRunEmptyModule) {
  auto* src = R"()";

  EXPECT_FALSE(ShouldRun<FirstIndexOffset>(src));
}

TEST_F(FirstIndexOffsetTest, ShouldRunFragmentStage) {
  auto* src = R"(
[[stage(fragment)]]
fn entry() {
  return;
}
)";

  EXPECT_FALSE(ShouldRun<FirstIndexOffset>(src));
}

TEST_F(FirstIndexOffsetTest, ShouldRunVertexStage) {
  auto* src = R"(
[[stage(vertex)]]
fn entry() -> [[builtin(position)]] vec4<f32> {
  return vec4<f32>();
}
)";

  EXPECT_TRUE(ShouldRun<FirstIndexOffset>(src));
}

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>();

  EXPECT_EQ(data, nullptr);
}

TEST_F(FirstIndexOffsetTest, BasicVertexShader) {
  auto* src = R"(
@stage(vertex)
fn entry() -> @builtin(position) vec4<f32> {
  return vec4<f32>();
}
)";
  auto* expect = src;

  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> {
  test(vert_idx);
  return vec4<f32>();
}
)";

  auto* expect = R"(
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> {
  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> {
  test(inst_idx);
  return vec4<f32>();
}
)";

  auto* expect = R"(
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> {
  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> {
  test(inputs.instance_idx, inputs.vert_idx);
  return vec4<f32>();
}
)";

  auto* expect = R"(
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> {
  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> {
  func2(vert_idx);
  return vec4<f32>();
}
)";

  auto* expect = R"(
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> {
  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> {
  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> {
  func(vert_idx + inst_idx);
  return vec4<f32>();
}

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

  auto* expect = R"(
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> {
  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> {
  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> {
  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