// 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 "gtest/gtest.h"
#include "src/ast/binary_expression.h"
#include "src/ast/bool_literal.h"
#include "src/ast/identifier_expression.h"
#include "src/ast/scalar_constructor_expression.h"
#include "src/reader/wgsl/parser_impl.h"
#include "src/reader/wgsl/parser_impl_test_helper.h"

namespace tint {
namespace reader {
namespace wgsl {
namespace {

TEST_F(ParserImplTest, EqualityExpression_Parses_Equal) {
  auto p = parser("a == true");
  auto e = p->equality_expression();
  EXPECT_TRUE(e.matched);
  EXPECT_FALSE(e.errored);
  EXPECT_FALSE(p->has_error()) << p->error();
  ASSERT_NE(e.value, nullptr);

  ASSERT_TRUE(e->Is<ast::BinaryExpression>());
  auto* rel = e->As<ast::BinaryExpression>();
  EXPECT_EQ(ast::BinaryOp::kEqual, rel->op());

  ASSERT_TRUE(rel->lhs()->Is<ast::IdentifierExpression>());
  auto* ident = rel->lhs()->As<ast::IdentifierExpression>();
  EXPECT_EQ(ident->symbol(), p->get_program().RegisterSymbol("a"));

  ASSERT_TRUE(rel->rhs()->Is<ast::ConstructorExpression>());
  ASSERT_TRUE(rel->rhs()->Is<ast::ScalarConstructorExpression>());
  auto* init = rel->rhs()->As<ast::ScalarConstructorExpression>();
  ASSERT_TRUE(init->literal()->Is<ast::BoolLiteral>());
  ASSERT_TRUE(init->literal()->As<ast::BoolLiteral>()->IsTrue());
}

TEST_F(ParserImplTest, EqualityExpression_Parses_NotEqual) {
  auto p = parser("a != true");
  auto e = p->equality_expression();
  EXPECT_TRUE(e.matched);
  EXPECT_FALSE(e.errored);
  EXPECT_FALSE(p->has_error()) << p->error();
  ASSERT_NE(e.value, nullptr);

  ASSERT_TRUE(e->Is<ast::BinaryExpression>());
  auto* rel = e->As<ast::BinaryExpression>();
  EXPECT_EQ(ast::BinaryOp::kNotEqual, rel->op());

  ASSERT_TRUE(rel->lhs()->Is<ast::IdentifierExpression>());
  auto* ident = rel->lhs()->As<ast::IdentifierExpression>();
  EXPECT_EQ(ident->symbol(), p->get_program().RegisterSymbol("a"));

  ASSERT_TRUE(rel->rhs()->Is<ast::ConstructorExpression>());
  ASSERT_TRUE(rel->rhs()->Is<ast::ScalarConstructorExpression>());
  auto* init = rel->rhs()->As<ast::ScalarConstructorExpression>();
  ASSERT_TRUE(init->literal()->Is<ast::BoolLiteral>());
  ASSERT_TRUE(init->literal()->As<ast::BoolLiteral>()->IsTrue());
}

TEST_F(ParserImplTest, EqualityExpression_InvalidLHS) {
  auto p = parser("if (a) {} == true");
  auto e = p->equality_expression();
  EXPECT_FALSE(e.matched);
  EXPECT_FALSE(e.errored);
  EXPECT_FALSE(p->has_error()) << p->error();
  EXPECT_EQ(e.value, nullptr);
}

TEST_F(ParserImplTest, EqualityExpression_InvalidRHS) {
  auto p = parser("true == if (a) {}");
  auto e = p->equality_expression();
  EXPECT_FALSE(e.matched);
  EXPECT_TRUE(e.errored);
  EXPECT_EQ(e.value, nullptr);
  EXPECT_TRUE(p->has_error());
  EXPECT_EQ(p->error(), "1:9: unable to parse right side of == expression");
}

TEST_F(ParserImplTest, EqualityExpression_NoOr_ReturnsLHS) {
  auto p = parser("a true");
  auto e = p->equality_expression();
  EXPECT_TRUE(e.matched);
  EXPECT_FALSE(e.errored);
  EXPECT_FALSE(p->has_error()) << p->error();
  ASSERT_NE(e.value, nullptr);
  ASSERT_TRUE(e->Is<ast::IdentifierExpression>());
}

}  // namespace
}  // namespace wgsl
}  // namespace reader
}  // namespace tint