// 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 <memory>

#include "gtest/gtest.h"
#include "src/ast/assignment_statement.h"
#include "src/ast/bool_literal.h"
#include "src/ast/break_statement.h"
#include "src/ast/case_statement.h"
#include "src/ast/fallthrough_statement.h"
#include "src/ast/identifier_expression.h"
#include "src/ast/if_statement.h"
#include "src/ast/int_literal.h"
#include "src/ast/scalar_constructor_expression.h"
#include "src/ast/switch_statement.h"
#include "src/ast/type/bool_type.h"
#include "src/ast/type/i32_type.h"
#include "src/context.h"
#include "src/type_determiner.h"
#include "src/writer/spirv/builder.h"
#include "src/writer/spirv/spv_dump.h"

namespace tint {
namespace writer {
namespace spirv {
namespace {

using BuilderTest = testing::Test;

TEST_F(BuilderTest, Switch_Empty) {
  ast::type::I32Type i32;

  // switch (1) {
  // }
  auto cond = std::make_unique<ast::ScalarConstructorExpression>(
      std::make_unique<ast::IntLiteral>(&i32, 1));

  ast::SwitchStatement expr(std::move(cond), ast::CaseStatementList{});

  Context ctx;
  ast::Module mod;
  TypeDeterminer td(&ctx, &mod);
  ASSERT_TRUE(td.DetermineResultType(&expr)) << td.error();

  Builder b(&mod);
  b.push_function(Function{});

  EXPECT_TRUE(b.GenerateSwitchStatement(&expr)) << b.error();
  EXPECT_EQ(DumpInstructions(b.types()), R"(%2 = OpTypeInt 32 1
%3 = OpConstant %2 1
)");
  EXPECT_EQ(DumpInstructions(b.functions()[0].instructions()),
            R"(OpSelectionMerge %1 None
OpSwitch %3 %4
%4 = OpLabel
OpBranch %1
%1 = OpLabel
)");
}

TEST_F(BuilderTest, Switch_WithCase) {
  ast::type::I32Type i32;

  // switch(a) {
  //   case 1:
  //     v = 1;
  //   case 2:
  //     v = 2;
  // }

  auto v =
      std::make_unique<ast::Variable>("v", ast::StorageClass::kPrivate, &i32);
  auto a =
      std::make_unique<ast::Variable>("a", ast::StorageClass::kPrivate, &i32);

  ast::StatementList case_1_body;
  case_1_body.push_back(std::make_unique<ast::AssignmentStatement>(
      std::make_unique<ast::IdentifierExpression>("v"),
      std::make_unique<ast::ScalarConstructorExpression>(
          std::make_unique<ast::IntLiteral>(&i32, 1))));

  ast::StatementList case_2_body;
  case_2_body.push_back(std::make_unique<ast::AssignmentStatement>(
      std::make_unique<ast::IdentifierExpression>("v"),
      std::make_unique<ast::ScalarConstructorExpression>(
          std::make_unique<ast::IntLiteral>(&i32, 2))));

  ast::CaseSelectorList selector_1;
  selector_1.push_back(std::make_unique<ast::IntLiteral>(&i32, 1));

  ast::CaseSelectorList selector_2;
  selector_2.push_back(std::make_unique<ast::IntLiteral>(&i32, 2));

  ast::CaseStatementList cases;
  cases.push_back(
      std::make_unique<ast::CaseStatement>(std::move(selector_1), std::move(case_1_body)));
  cases.push_back(std::make_unique<ast::CaseStatement>(
      std::move(selector_2), std::move(case_2_body)));

  ast::SwitchStatement expr(std::make_unique<ast::IdentifierExpression>("a"),
                            std::move(cases));

  Context ctx;
  ast::Module mod;
  TypeDeterminer td(&ctx, &mod);
  td.RegisterVariableForTesting(v.get());
  td.RegisterVariableForTesting(a.get());
  ASSERT_TRUE(td.DetermineResultType(&expr)) << td.error();

  ast::Function func("a_func", {}, &i32);

  Builder b(&mod);
  ASSERT_TRUE(b.GenerateGlobalVariable(v.get())) << b.error();
  ASSERT_TRUE(b.GenerateGlobalVariable(a.get())) << b.error();
  ASSERT_TRUE(b.GenerateFunction(&func)) << b.error();

  EXPECT_TRUE(b.GenerateSwitchStatement(&expr)) << b.error();

  EXPECT_EQ(DumpBuilder(b), R"(OpName %1 "v"
OpName %5 "a"
OpName %7 "a_func"
%3 = OpTypeInt 32 1
%2 = OpTypePointer Private %3
%4 = OpConstantNull %3
%1 = OpVariable %2 Private %4
%5 = OpVariable %2 Private %4
%6 = OpTypeFunction %3
%14 = OpConstant %3 1
%15 = OpConstant %3 2
%7 = OpFunction %3 None %6
%8 = OpLabel
%10 = OpLoad %3 %5
OpSelectionMerge %9 None
OpSwitch %10 %11 1 %12 2 %13
%12 = OpLabel
OpStore %1 %14
OpBranch %9
%13 = OpLabel
OpStore %1 %15
OpBranch %9
%11 = OpLabel
OpBranch %9
%9 = OpLabel
OpFunctionEnd
)");
}

TEST_F(BuilderTest, Switch_WithDefault) {
  ast::type::I32Type i32;

  // switch(true) {
  //   default:
  //     v = 1;
  //  }

  auto v =
      std::make_unique<ast::Variable>("v", ast::StorageClass::kPrivate, &i32);
  auto a =
      std::make_unique<ast::Variable>("a", ast::StorageClass::kPrivate, &i32);

  ast::StatementList default_body;
  default_body.push_back(std::make_unique<ast::AssignmentStatement>(
      std::make_unique<ast::IdentifierExpression>("v"),
      std::make_unique<ast::ScalarConstructorExpression>(
          std::make_unique<ast::IntLiteral>(&i32, 1))));

  ast::CaseStatementList cases;
  cases.push_back(
      std::make_unique<ast::CaseStatement>(std::move(default_body)));

  ast::SwitchStatement expr(std::make_unique<ast::IdentifierExpression>("a"),
                            std::move(cases));

  Context ctx;
  ast::Module mod;
  TypeDeterminer td(&ctx, &mod);
  td.RegisterVariableForTesting(v.get());
  td.RegisterVariableForTesting(a.get());
  ASSERT_TRUE(td.DetermineResultType(&expr)) << td.error();

  ast::Function func("a_func", {}, &i32);

  Builder b(&mod);
  ASSERT_TRUE(b.GenerateGlobalVariable(v.get())) << b.error();
  ASSERT_TRUE(b.GenerateGlobalVariable(a.get())) << b.error();
  ASSERT_TRUE(b.GenerateFunction(&func)) << b.error();

  EXPECT_TRUE(b.GenerateSwitchStatement(&expr)) << b.error();

  EXPECT_EQ(DumpBuilder(b), R"(OpName %1 "v"
OpName %5 "a"
OpName %7 "a_func"
%3 = OpTypeInt 32 1
%2 = OpTypePointer Private %3
%4 = OpConstantNull %3
%1 = OpVariable %2 Private %4
%5 = OpVariable %2 Private %4
%6 = OpTypeFunction %3
%12 = OpConstant %3 1
%7 = OpFunction %3 None %6
%8 = OpLabel
%10 = OpLoad %3 %5
OpSelectionMerge %9 None
OpSwitch %10 %11
%11 = OpLabel
OpStore %1 %12
OpBranch %9
%9 = OpLabel
OpFunctionEnd
)");
}

TEST_F(BuilderTest, Switch_WithCaseAndDefault) {
  ast::type::I32Type i32;

  // switch(a) {
  //   case 1:
  //      v = 1;
  //   case 2, 3:
  //      v = 2;
  //   default:
  //      v = 3;
  //  }

  auto v =
      std::make_unique<ast::Variable>("v", ast::StorageClass::kPrivate, &i32);
  auto a =
      std::make_unique<ast::Variable>("a", ast::StorageClass::kPrivate, &i32);

  ast::StatementList case_1_body;
  case_1_body.push_back(std::make_unique<ast::AssignmentStatement>(
      std::make_unique<ast::IdentifierExpression>("v"),
      std::make_unique<ast::ScalarConstructorExpression>(
          std::make_unique<ast::IntLiteral>(&i32, 1))));

  ast::StatementList case_2_body;
  case_2_body.push_back(std::make_unique<ast::AssignmentStatement>(
      std::make_unique<ast::IdentifierExpression>("v"),
      std::make_unique<ast::ScalarConstructorExpression>(
          std::make_unique<ast::IntLiteral>(&i32, 2))));

  ast::StatementList default_body;
  default_body.push_back(std::make_unique<ast::AssignmentStatement>(
      std::make_unique<ast::IdentifierExpression>("v"),
      std::make_unique<ast::ScalarConstructorExpression>(
          std::make_unique<ast::IntLiteral>(&i32, 3))));

  ast::CaseSelectorList selector_1;
  selector_1.push_back(std::make_unique<ast::IntLiteral>(&i32, 1));

  ast::CaseSelectorList selector_2;
  selector_2.push_back(std::make_unique<ast::IntLiteral>(&i32, 2));
  selector_2.push_back(std::make_unique<ast::IntLiteral>(&i32, 3));

  ast::CaseStatementList cases;
  cases.push_back(std::make_unique<ast::CaseStatement>(
      std::move(selector_1), std::move(case_1_body)));
  cases.push_back(std::make_unique<ast::CaseStatement>(
      std::move(selector_2), std::move(case_2_body)));
  cases.push_back(
      std::make_unique<ast::CaseStatement>(std::move(default_body)));

  ast::SwitchStatement expr(std::make_unique<ast::IdentifierExpression>("a"),
                            std::move(cases));

  Context ctx;
  ast::Module mod;
  TypeDeterminer td(&ctx, &mod);
  td.RegisterVariableForTesting(v.get());
  td.RegisterVariableForTesting(a.get());
  ASSERT_TRUE(td.DetermineResultType(&expr)) << td.error();

  ast::Function func("a_func", {}, &i32);

  Builder b(&mod);
  ASSERT_TRUE(b.GenerateGlobalVariable(v.get())) << b.error();
  ASSERT_TRUE(b.GenerateGlobalVariable(a.get())) << b.error();
  ASSERT_TRUE(b.GenerateFunction(&func)) << b.error();

  EXPECT_TRUE(b.GenerateSwitchStatement(&expr)) << b.error();

  EXPECT_EQ(DumpBuilder(b), R"(OpName %1 "v"
OpName %5 "a"
OpName %7 "a_func"
%3 = OpTypeInt 32 1
%2 = OpTypePointer Private %3
%4 = OpConstantNull %3
%1 = OpVariable %2 Private %4
%5 = OpVariable %2 Private %4
%6 = OpTypeFunction %3
%14 = OpConstant %3 1
%15 = OpConstant %3 2
%16 = OpConstant %3 3
%7 = OpFunction %3 None %6
%8 = OpLabel
%10 = OpLoad %3 %5
OpSelectionMerge %9 None
OpSwitch %10 %11 1 %12 2 %13 3 %13
%12 = OpLabel
OpStore %1 %14
OpBranch %9
%13 = OpLabel
OpStore %1 %15
OpBranch %9
%11 = OpLabel
OpStore %1 %16
OpBranch %9
%9 = OpLabel
OpFunctionEnd
)");
}

TEST_F(BuilderTest, Switch_CaseWithFallthrough) {
  ast::type::I32Type i32;

  // switch(a) {
  //   case 1:
  //      v = 1;
  //      fallthrough;
  //   case 2:
  //      v = 2;
  //   default:
  //      v = 3;
  //  }

  auto v =
      std::make_unique<ast::Variable>("v", ast::StorageClass::kPrivate, &i32);
  auto a =
      std::make_unique<ast::Variable>("a", ast::StorageClass::kPrivate, &i32);

  ast::StatementList case_1_body;
  case_1_body.push_back(std::make_unique<ast::AssignmentStatement>(
      std::make_unique<ast::IdentifierExpression>("v"),
      std::make_unique<ast::ScalarConstructorExpression>(
          std::make_unique<ast::IntLiteral>(&i32, 1))));
  case_1_body.push_back(std::make_unique<ast::FallthroughStatement>());

  ast::StatementList case_2_body;
  case_2_body.push_back(std::make_unique<ast::AssignmentStatement>(
      std::make_unique<ast::IdentifierExpression>("v"),
      std::make_unique<ast::ScalarConstructorExpression>(
          std::make_unique<ast::IntLiteral>(&i32, 2))));

  ast::StatementList default_body;
  default_body.push_back(std::make_unique<ast::AssignmentStatement>(
      std::make_unique<ast::IdentifierExpression>("v"),
      std::make_unique<ast::ScalarConstructorExpression>(
          std::make_unique<ast::IntLiteral>(&i32, 3))));

  ast::CaseStatementList cases;
  cases.push_back(std::make_unique<ast::CaseStatement>(
      std::make_unique<ast::IntLiteral>(&i32, 1), std::move(case_1_body)));
  cases.push_back(std::make_unique<ast::CaseStatement>(
      std::make_unique<ast::IntLiteral>(&i32, 2), std::move(case_2_body)));
  cases.push_back(
      std::make_unique<ast::CaseStatement>(std::move(default_body)));

  ast::SwitchStatement expr(std::make_unique<ast::IdentifierExpression>("a"),
                            std::move(cases));

  Context ctx;
  ast::Module mod;
  TypeDeterminer td(&ctx, &mod);
  td.RegisterVariableForTesting(v.get());
  td.RegisterVariableForTesting(a.get());
  ASSERT_TRUE(td.DetermineResultType(&expr)) << td.error();

  ast::Function func("a_func", {}, &i32);

  Builder b(&mod);
  ASSERT_TRUE(b.GenerateGlobalVariable(v.get())) << b.error();
  ASSERT_TRUE(b.GenerateGlobalVariable(a.get())) << b.error();
  ASSERT_TRUE(b.GenerateFunction(&func)) << b.error();

  EXPECT_TRUE(b.GenerateSwitchStatement(&expr)) << b.error();

  EXPECT_EQ(DumpBuilder(b), R"(OpName %1 "v"
OpName %5 "a"
OpName %7 "a_func"
%3 = OpTypeInt 32 1
%2 = OpTypePointer Private %3
%4 = OpConstantNull %3
%1 = OpVariable %2 Private %4
%5 = OpVariable %2 Private %4
%6 = OpTypeFunction %3
%14 = OpConstant %3 1
%15 = OpConstant %3 2
%16 = OpConstant %3 3
%7 = OpFunction %3 None %6
%8 = OpLabel
%10 = OpLoad %3 %5
OpSelectionMerge %9 None
OpSwitch %10 %11 1 %12 2 %13
%12 = OpLabel
OpStore %1 %14
OpBranch %13
%13 = OpLabel
OpStore %1 %15
OpBranch %9
%11 = OpLabel
OpStore %1 %16
OpBranch %9
%9 = OpLabel
OpFunctionEnd
)");
}

TEST_F(BuilderTest, Switch_CaseFallthroughLastStatement) {
  ast::type::I32Type i32;

  // switch(a) {
  //   case 1:
  //      v = 1;
  //      fallthrough;
  //  }

  auto v =
      std::make_unique<ast::Variable>("v", ast::StorageClass::kPrivate, &i32);
  auto a =
      std::make_unique<ast::Variable>("a", ast::StorageClass::kPrivate, &i32);

  ast::StatementList case_1_body;
  case_1_body.push_back(std::make_unique<ast::AssignmentStatement>(
      std::make_unique<ast::IdentifierExpression>("v"),
      std::make_unique<ast::ScalarConstructorExpression>(
          std::make_unique<ast::IntLiteral>(&i32, 1))));
  case_1_body.push_back(std::make_unique<ast::FallthroughStatement>());

  ast::CaseStatementList cases;
  cases.push_back(std::make_unique<ast::CaseStatement>(
      std::make_unique<ast::IntLiteral>(&i32, 1), std::move(case_1_body)));

  ast::SwitchStatement expr(std::make_unique<ast::IdentifierExpression>("a"),
                            std::move(cases));

  Context ctx;
  ast::Module mod;
  TypeDeterminer td(&ctx, &mod);
  td.RegisterVariableForTesting(v.get());
  td.RegisterVariableForTesting(a.get());
  ASSERT_TRUE(td.DetermineResultType(&expr)) << td.error();

  ast::Function func("a_func", {}, &i32);

  Builder b(&mod);
  ASSERT_TRUE(b.GenerateGlobalVariable(v.get())) << b.error();
  ASSERT_TRUE(b.GenerateGlobalVariable(a.get())) << b.error();
  ASSERT_TRUE(b.GenerateFunction(&func)) << b.error();

  EXPECT_FALSE(b.GenerateSwitchStatement(&expr)) << b.error();
  EXPECT_EQ(b.error(), "fallthrough of last case statement is disallowed");
}

// TODO(dsinclair): Implement when parsing is handled for multi-value
// case labels.
TEST_F(BuilderTest, DISABLED_Switch_CaseWithMulitpleLabels) {
  // switch (a) {
  //   case 1, 2, 3:
  //     v = 1;
  // }
  FAIL();
}

TEST_F(BuilderTest, Switch_WithNestedBreak) {
  ast::type::I32Type i32;
  ast::type::BoolType bool_type;

  // switch (a) {
  //   case 1:
  //     if (true) {
  //       break;
  //     }
  //     v = 1;
  //  }

  auto v =
      std::make_unique<ast::Variable>("v", ast::StorageClass::kPrivate, &i32);
  auto a =
      std::make_unique<ast::Variable>("a", ast::StorageClass::kPrivate, &i32);

  ast::StatementList if_body;
  if_body.push_back(std::make_unique<ast::BreakStatement>());

  ast::StatementList case_1_body;
  case_1_body.push_back(std::make_unique<ast::IfStatement>(
      std::make_unique<ast::ScalarConstructorExpression>(
          std::make_unique<ast::BoolLiteral>(&bool_type, true)),
      std::move(if_body)));

  case_1_body.push_back(std::make_unique<ast::AssignmentStatement>(
      std::make_unique<ast::IdentifierExpression>("v"),
      std::make_unique<ast::ScalarConstructorExpression>(
          std::make_unique<ast::IntLiteral>(&i32, 1))));

  ast::CaseSelectorList selector_1;
  selector_1.push_back(std::make_unique<ast::IntLiteral>(&i32, 1));

  ast::CaseStatementList cases;
  cases.push_back(std::make_unique<ast::CaseStatement>(
      std::move(selector_1), std::move(case_1_body)));

  ast::SwitchStatement expr(std::make_unique<ast::IdentifierExpression>("a"),
                            std::move(cases));

  Context ctx;
  ast::Module mod;
  TypeDeterminer td(&ctx, &mod);
  td.RegisterVariableForTesting(v.get());
  td.RegisterVariableForTesting(a.get());
  ASSERT_TRUE(td.DetermineResultType(&expr)) << td.error();

  ast::Function func("a_func", {}, &i32);

  Builder b(&mod);
  ASSERT_TRUE(b.GenerateGlobalVariable(v.get())) << b.error();
  ASSERT_TRUE(b.GenerateGlobalVariable(a.get())) << b.error();
  ASSERT_TRUE(b.GenerateFunction(&func)) << b.error();

  EXPECT_TRUE(b.GenerateSwitchStatement(&expr)) << b.error();

  EXPECT_EQ(DumpBuilder(b), R"(OpName %1 "v"
OpName %5 "a"
OpName %7 "a_func"
%3 = OpTypeInt 32 1
%2 = OpTypePointer Private %3
%4 = OpConstantNull %3
%1 = OpVariable %2 Private %4
%5 = OpVariable %2 Private %4
%6 = OpTypeFunction %3
%13 = OpTypeBool
%14 = OpConstantTrue %13
%17 = OpConstant %3 1
%7 = OpFunction %3 None %6
%8 = OpLabel
%10 = OpLoad %3 %5
OpSelectionMerge %9 None
OpSwitch %10 %11 1 %12
%12 = OpLabel
OpSelectionMerge %15 None
OpBranchConditional %14 %16 %15
%16 = OpLabel
OpBranch %9
%15 = OpLabel
OpStore %1 %17
OpBranch %9
%11 = OpLabel
OpBranch %9
%9 = OpLabel
OpFunctionEnd
)");
}

}  // namespace
}  // namespace spirv
}  // namespace writer
}  // namespace tint