// 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/else_statement.h"
#include "src/ast/identifier_expression.h"
#include "src/ast/if_statement.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, IfStmt) {
  auto p = parser("if (a == 4) { a = b; c = d; }");
  auto e = p->if_stmt();
  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::IfStatement>());
  ASSERT_NE(e->condition(), nullptr);
  ASSERT_TRUE(e->condition()->Is<ast::BinaryExpression>());
  EXPECT_EQ(e->body()->size(), 2u);
  EXPECT_EQ(e->else_statements().size(), 0u);
}

TEST_F(ParserImplTest, IfStmt_WithElse) {
  auto p = parser("if (a == 4) { a = b; c = d; } elseif(c) { d = 2; } else {}");
  auto e = p->if_stmt();
  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::IfStatement>());
  ASSERT_NE(e->condition(), nullptr);
  ASSERT_TRUE(e->condition()->Is<ast::BinaryExpression>());
  EXPECT_EQ(e->body()->size(), 2u);

  ASSERT_EQ(e->else_statements().size(), 2u);
  ASSERT_NE(e->else_statements()[0]->condition(), nullptr);
  ASSERT_TRUE(
      e->else_statements()[0]->condition()->Is<ast::IdentifierExpression>());
  EXPECT_EQ(e->else_statements()[0]->body()->size(), 1u);

  ASSERT_EQ(e->else_statements()[1]->condition(), nullptr);
  EXPECT_EQ(e->else_statements()[1]->body()->size(), 0u);
}

TEST_F(ParserImplTest, IfStmt_InvalidCondition) {
  auto p = parser("if (a = 3) {}");
  auto e = p->if_stmt();
  EXPECT_FALSE(e.matched);
  EXPECT_TRUE(e.errored);
  EXPECT_EQ(e.value, nullptr);
  EXPECT_TRUE(p->has_error());
  EXPECT_EQ(p->error(), "1:7: expected ')'");
}

TEST_F(ParserImplTest, IfStmt_MissingCondition) {
  auto p = parser("if {}");
  auto e = p->if_stmt();
  EXPECT_FALSE(e.matched);
  EXPECT_TRUE(e.errored);
  EXPECT_EQ(e.value, nullptr);
  EXPECT_TRUE(p->has_error());
  EXPECT_EQ(p->error(), "1:4: expected '('");
}

TEST_F(ParserImplTest, IfStmt_InvalidBody) {
  auto p = parser("if (a) { fn main() -> void {}}");
  auto e = p->if_stmt();
  EXPECT_FALSE(e.matched);
  EXPECT_TRUE(e.errored);
  EXPECT_EQ(e.value, nullptr);
  EXPECT_TRUE(p->has_error());
  EXPECT_EQ(p->error(), "1:10: expected '}'");
}

TEST_F(ParserImplTest, IfStmt_MissingBody) {
  auto p = parser("if (a)");
  auto e = p->if_stmt();
  EXPECT_FALSE(e.matched);
  EXPECT_TRUE(e.errored);
  EXPECT_EQ(e.value, nullptr);
  EXPECT_TRUE(p->has_error());
  EXPECT_EQ(p->error(), "1:7: expected '{'");
}

TEST_F(ParserImplTest, IfStmt_InvalidElseif) {
  auto p = parser("if (a) {} elseif (a) { fn main() -> a{}}");
  auto e = p->if_stmt();
  EXPECT_FALSE(e.matched);
  EXPECT_TRUE(e.errored);
  EXPECT_EQ(e.value, nullptr);
  EXPECT_TRUE(p->has_error());
  EXPECT_EQ(p->error(), "1:24: expected '}'");
}

TEST_F(ParserImplTest, IfStmt_InvalidElse) {
  auto p = parser("if (a) {} else { fn main() -> a{}}");
  auto e = p->if_stmt();
  EXPECT_FALSE(e.matched);
  EXPECT_TRUE(e.errored);
  EXPECT_EQ(e.value, nullptr);
  EXPECT_TRUE(p->has_error());
  EXPECT_EQ(p->error(), "1:18: expected '}'");
}

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