// 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/fuzzers/tint_ast_fuzzer/mutation_finders/delete_statements.h"

#include <memory>

#include "src/tint/fuzzers/tint_ast_fuzzer/jump_tracker.h"
#include "src/tint/fuzzers/tint_ast_fuzzer/mutations/delete_statement.h"
#include "src/tint/fuzzers/tint_ast_fuzzer/util.h"
#include "src/tint/sem/expression.h"
#include "src/tint/sem/statement.h"
#include "src/tint/sem/variable.h"

namespace tint::fuzzers::ast_fuzzer {

MutationList MutationFinderDeleteStatements::FindMutations(const tint::Program& program,
                                                           NodeIdMap* node_id_map,
                                                           ProbabilityContext* /*unused*/) const {
    MutationList result;

    JumpTracker jump_tracker(program);

    // Consider every statement node in the AST.
    for (auto* node : program.ASTNodes().Objects()) {
        auto* statement_node = tint::As<ast::Statement>(node);

        if (!statement_node) {
            continue;
        }

        const auto* statement_sem_node =
            tint::As<sem::Statement>(program.Sem().Get(statement_node));

        // Semantic information for the node is required in order to delete it.
        if (!statement_sem_node) {
            continue;
        }

        // Check that this kind of statement can be deleted.
        if (!MutationDeleteStatement::CanBeDeleted(*statement_node, program, jump_tracker)) {
            continue;
        }

        result.push_back(
            std::make_unique<MutationDeleteStatement>(node_id_map->GetId(statement_node)));
    }

    return result;
}

uint32_t MutationFinderDeleteStatements::GetChanceOfApplyingMutation(
    ProbabilityContext* probability_context) const {
    return probability_context->GetChanceOfDeletingStatements();
}

}  // namespace tint::fuzzers::ast_fuzzer