// Copyright 2021 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/tint/resolver/resolver.h"

#include "gmock/gmock.h"
#include "src/tint/ast/stage_attribute.h"
#include "src/tint/resolver/resolver_test_helper.h"
#include "src/tint/sem/struct.h"

using ::testing::UnorderedElementsAre;

namespace tint::resolver {
namespace {

using ResolverPipelineStageUseTest = ResolverTest;

TEST_F(ResolverPipelineStageUseTest, UnusedStruct) {
  auto* s = Structure("S", {Member("a", ty.f32(), {Location(0)})});

  ASSERT_TRUE(r()->Resolve()) << r()->error();

  auto* sem = TypeOf(s)->As<sem::Struct>();
  ASSERT_NE(sem, nullptr);
  EXPECT_TRUE(sem->PipelineStageUses().empty());
}

TEST_F(ResolverPipelineStageUseTest, StructUsedAsNonEntryPointParam) {
  auto* s = Structure("S", {Member("a", ty.f32(), {Location(0)})});

  Func("foo", {Param("param", ty.Of(s))}, ty.void_(), {}, {});

  ASSERT_TRUE(r()->Resolve()) << r()->error();

  auto* sem = TypeOf(s)->As<sem::Struct>();
  ASSERT_NE(sem, nullptr);
  EXPECT_TRUE(sem->PipelineStageUses().empty());
}

TEST_F(ResolverPipelineStageUseTest, StructUsedAsNonEntryPointReturnType) {
  auto* s = Structure("S", {Member("a", ty.f32(), {Location(0)})});

  Func("foo", {}, ty.Of(s), {Return(Construct(ty.Of(s), Expr(0.f)))}, {});

  ASSERT_TRUE(r()->Resolve()) << r()->error();

  auto* sem = TypeOf(s)->As<sem::Struct>();
  ASSERT_NE(sem, nullptr);
  EXPECT_TRUE(sem->PipelineStageUses().empty());
}

TEST_F(ResolverPipelineStageUseTest, StructUsedAsVertexShaderParam) {
  auto* s = Structure("S", {Member("a", ty.f32(), {Location(0)})});

  Func("main", {Param("param", ty.Of(s))}, ty.vec4<f32>(),
       {Return(Construct(ty.vec4<f32>()))},
       {Stage(ast::PipelineStage::kVertex)},
       {Builtin(ast::Builtin::kPosition)});

  ASSERT_TRUE(r()->Resolve()) << r()->error();

  auto* sem = TypeOf(s)->As<sem::Struct>();
  ASSERT_NE(sem, nullptr);
  EXPECT_THAT(sem->PipelineStageUses(),
              UnorderedElementsAre(sem::PipelineStageUsage::kVertexInput));
}

TEST_F(ResolverPipelineStageUseTest, StructUsedAsVertexShaderReturnType) {
  auto* s = Structure(
      "S", {Member("a", ty.vec4<f32>(), {Builtin(ast::Builtin::kPosition)})});

  Func("main", {}, ty.Of(s), {Return(Construct(ty.Of(s)))},
       {Stage(ast::PipelineStage::kVertex)});

  ASSERT_TRUE(r()->Resolve()) << r()->error();

  auto* sem = TypeOf(s)->As<sem::Struct>();
  ASSERT_NE(sem, nullptr);
  EXPECT_THAT(sem->PipelineStageUses(),
              UnorderedElementsAre(sem::PipelineStageUsage::kVertexOutput));
}

TEST_F(ResolverPipelineStageUseTest, StructUsedAsFragmentShaderParam) {
  auto* s = Structure("S", {Member("a", ty.f32(), {Location(0)})});

  Func("main", {Param("param", ty.Of(s))}, ty.void_(), {},
       {Stage(ast::PipelineStage::kFragment)});

  ASSERT_TRUE(r()->Resolve()) << r()->error();

  auto* sem = TypeOf(s)->As<sem::Struct>();
  ASSERT_NE(sem, nullptr);
  EXPECT_THAT(sem->PipelineStageUses(),
              UnorderedElementsAre(sem::PipelineStageUsage::kFragmentInput));
}

TEST_F(ResolverPipelineStageUseTest, StructUsedAsFragmentShaderReturnType) {
  auto* s = Structure("S", {Member("a", ty.f32(), {Location(0)})});

  Func("main", {}, ty.Of(s), {Return(Construct(ty.Of(s), Expr(0.f)))},
       {Stage(ast::PipelineStage::kFragment)});

  ASSERT_TRUE(r()->Resolve()) << r()->error();

  auto* sem = TypeOf(s)->As<sem::Struct>();
  ASSERT_NE(sem, nullptr);
  EXPECT_THAT(sem->PipelineStageUses(),
              UnorderedElementsAre(sem::PipelineStageUsage::kFragmentOutput));
}

TEST_F(ResolverPipelineStageUseTest, StructUsedAsComputeShaderParam) {
  auto* s = Structure(
      "S",
      {Member("a", ty.u32(), {Builtin(ast::Builtin::kLocalInvocationIndex)})});

  Func("main", {Param("param", ty.Of(s))}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute), WorkgroupSize(1)});

  ASSERT_TRUE(r()->Resolve()) << r()->error();

  auto* sem = TypeOf(s)->As<sem::Struct>();
  ASSERT_NE(sem, nullptr);
  EXPECT_THAT(sem->PipelineStageUses(),
              UnorderedElementsAre(sem::PipelineStageUsage::kComputeInput));
}

TEST_F(ResolverPipelineStageUseTest, StructUsedMultipleStages) {
  auto* s = Structure(
      "S", {Member("a", ty.vec4<f32>(), {Builtin(ast::Builtin::kPosition)})});

  Func("vert_main", {}, ty.Of(s), {Return(Construct(ty.Of(s)))},
       {Stage(ast::PipelineStage::kVertex)});

  Func("frag_main", {Param("param", ty.Of(s))}, ty.void_(), {},
       {Stage(ast::PipelineStage::kFragment)});

  ASSERT_TRUE(r()->Resolve()) << r()->error();

  auto* sem = TypeOf(s)->As<sem::Struct>();
  ASSERT_NE(sem, nullptr);
  EXPECT_THAT(sem->PipelineStageUses(),
              UnorderedElementsAre(sem::PipelineStageUsage::kVertexOutput,
                                   sem::PipelineStageUsage::kFragmentInput));
}

TEST_F(ResolverPipelineStageUseTest, StructUsedAsShaderParamViaAlias) {
  auto* s = Structure("S", {Member("a", ty.f32(), {Location(0)})});
  auto* s_alias = Alias("S_alias", ty.Of(s));

  Func("main", {Param("param", ty.Of(s_alias))}, ty.void_(), {},
       {Stage(ast::PipelineStage::kFragment)});

  ASSERT_TRUE(r()->Resolve()) << r()->error();

  auto* sem = TypeOf(s)->As<sem::Struct>();
  ASSERT_NE(sem, nullptr);
  EXPECT_THAT(sem->PipelineStageUses(),
              UnorderedElementsAre(sem::PipelineStageUsage::kFragmentInput));
}

TEST_F(ResolverPipelineStageUseTest, StructUsedAsShaderReturnTypeViaAlias) {
  auto* s = Structure("S", {Member("a", ty.f32(), {Location(0)})});
  auto* s_alias = Alias("S_alias", ty.Of(s));

  Func("main", {}, ty.Of(s_alias),
       {Return(Construct(ty.Of(s_alias), Expr(0.f)))},
       {Stage(ast::PipelineStage::kFragment)});

  ASSERT_TRUE(r()->Resolve()) << r()->error();

  auto* sem = TypeOf(s)->As<sem::Struct>();
  ASSERT_NE(sem, nullptr);
  EXPECT_THAT(sem->PipelineStageUses(),
              UnorderedElementsAre(sem::PipelineStageUsage::kFragmentOutput));
}

}  // namespace
}  // namespace tint::resolver