// Copyright 2022 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/lang/wgsl/reader/parser/helper_test.h"

namespace tint::wgsl::reader {
namespace {

TEST_F(WGSLParserTest, MathExpression_Parses_Multiplicative) {
    auto p = parser("a * b");
    auto lhs = p->unary_expression();
    auto e = p->expect_math_expression_post_unary_expression(lhs.value);
    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(core::BinaryOp::kMultiply, rel->op);

    ASSERT_TRUE(rel->lhs->Is<ast::IdentifierExpression>());
    auto* ident_expr = rel->lhs->As<ast::IdentifierExpression>();
    EXPECT_EQ(ident_expr->identifier->symbol, p->builder().Symbols().Get("a"));

    ASSERT_TRUE(rel->rhs->Is<ast::IdentifierExpression>());
    ident_expr = rel->rhs->As<ast::IdentifierExpression>();
    EXPECT_EQ(ident_expr->identifier->symbol, p->builder().Symbols().Get("b"));
}

TEST_F(WGSLParserTest, MathExpression_Parses_Mixed_MultiplicativeStart) {
    auto p = parser("a * b + c");
    auto lhs = p->unary_expression();
    auto e = p->expect_math_expression_post_unary_expression(lhs.value);
    EXPECT_FALSE(e.errored);
    EXPECT_FALSE(p->has_error()) << p->error();
    ASSERT_NE(e.value, nullptr);

    ASSERT_TRUE(e->Is<ast::BinaryExpression>());
    // lhs: a * b
    // op: +
    // rhs: c
    auto* rel = e->As<ast::BinaryExpression>();
    EXPECT_EQ(core::BinaryOp::kAdd, rel->op);

    ASSERT_TRUE(rel->rhs->Is<ast::IdentifierExpression>());
    auto* ident_expr = rel->rhs->As<ast::IdentifierExpression>();
    EXPECT_EQ(ident_expr->identifier->symbol, p->builder().Symbols().Get("c"));

    ASSERT_TRUE(rel->lhs->Is<ast::BinaryExpression>());
    // lhs: a
    // op: *
    // rhs: b
    rel = rel->lhs->As<ast::BinaryExpression>();
    EXPECT_EQ(core::BinaryOp::kMultiply, rel->op);

    ASSERT_TRUE(rel->lhs->Is<ast::IdentifierExpression>());
    ident_expr = rel->lhs->As<ast::IdentifierExpression>();
    EXPECT_EQ(ident_expr->identifier->symbol, p->builder().Symbols().Get("a"));

    ASSERT_TRUE(rel->rhs->Is<ast::IdentifierExpression>());
    ident_expr = rel->rhs->As<ast::IdentifierExpression>();
    EXPECT_EQ(ident_expr->identifier->symbol, p->builder().Symbols().Get("b"));
}

TEST_F(WGSLParserTest, MathExpression_Parses_Additive) {
    auto p = parser("a + b");
    auto lhs = p->unary_expression();
    auto e = p->expect_math_expression_post_unary_expression(lhs.value);
    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(core::BinaryOp::kAdd, rel->op);

    ASSERT_TRUE(rel->lhs->Is<ast::IdentifierExpression>());
    auto* ident_expr = rel->lhs->As<ast::IdentifierExpression>();
    EXPECT_EQ(ident_expr->identifier->symbol, p->builder().Symbols().Get("a"));

    ASSERT_TRUE(rel->rhs->Is<ast::IdentifierExpression>());
    ident_expr = rel->rhs->As<ast::IdentifierExpression>();
    EXPECT_EQ(ident_expr->identifier->symbol, p->builder().Symbols().Get("b"));
}

TEST_F(WGSLParserTest, MathExpression_Parses_Mixed_AdditiveStart) {
    auto p = parser("a + b * c");
    auto lhs = p->unary_expression();
    auto e = p->expect_math_expression_post_unary_expression(lhs.value);
    EXPECT_FALSE(e.errored);
    EXPECT_FALSE(p->has_error()) << p->error();
    ASSERT_NE(e.value, nullptr);

    ASSERT_TRUE(e->Is<ast::BinaryExpression>());
    // lhs: a
    // op: +
    // rhs: b * c
    auto* rel = e->As<ast::BinaryExpression>();
    EXPECT_EQ(core::BinaryOp::kAdd, rel->op);

    ASSERT_TRUE(rel->lhs->Is<ast::IdentifierExpression>());
    auto* ident_expr = rel->lhs->As<ast::IdentifierExpression>();
    EXPECT_EQ(ident_expr->identifier->symbol, p->builder().Symbols().Get("a"));

    ASSERT_TRUE(rel->rhs->Is<ast::BinaryExpression>());
    // lhs: b
    // op: *
    // rhs: c
    rel = rel->rhs->As<ast::BinaryExpression>();
    EXPECT_EQ(core::BinaryOp::kMultiply, rel->op);

    ASSERT_TRUE(rel->lhs->Is<ast::IdentifierExpression>());
    ident_expr = rel->lhs->As<ast::IdentifierExpression>();
    EXPECT_EQ(ident_expr->identifier->symbol, p->builder().Symbols().Get("b"));

    ASSERT_TRUE(rel->rhs->Is<ast::IdentifierExpression>());
    ident_expr = rel->rhs->As<ast::IdentifierExpression>();
    EXPECT_EQ(ident_expr->identifier->symbol, p->builder().Symbols().Get("c"));
}

TEST_F(WGSLParserTest, MathExpression_NoMatch_ReturnLHS) {
    auto p = parser("a if");
    auto lhs = p->unary_expression();
    auto e = p->expect_math_expression_post_unary_expression(lhs.value);
    EXPECT_FALSE(e.errored);
    EXPECT_FALSE(p->has_error()) << p->error();
    ASSERT_NE(e.value, nullptr);
    EXPECT_EQ(lhs.value, e.value);
}

TEST_F(WGSLParserTest, MathExpression_InvalidRHS) {
    auto p = parser("a * if");
    auto lhs = p->unary_expression();
    auto e = p->expect_math_expression_post_unary_expression(lhs.value);
    EXPECT_TRUE(e.errored);
    EXPECT_TRUE(p->has_error());
    ASSERT_EQ(e.value, nullptr);
    EXPECT_EQ("1:5: unable to parse right side of * expression", p->error());
}

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