// 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.

syntax = "proto3";

package tint.fuzzers.ast_fuzzer.protobufs;

message Mutation {
  oneof mutation {
    MutationReplaceIdentifier replace_identifier = 1;
    MutationChangeBinaryOperator change_binary_operator = 2;
    MutationWrapUnaryOperator wrap_unary_operator = 3;
    MutationChangeUnaryOperator change_unary_operator = 4;
    MutationDeleteStatement delete_statement = 5;
  };
}

message MutationSequence {
  repeated Mutation mutation = 1;
}

message MutatorState {
  // Contains the state of the fuzzer.

  // The program that is being fuzzed. This can be either
  // the original program (if mutation sequence is available) or
  // the mutated version (if mutations are being recorded).
  string program = 1;

  // The sequence of mutations that was applied to the `program`.
  // This may not have any mutations if they are not being recorded.
  MutationSequence mutation_sequence = 2;
}

// Keep mutation messages in alphabetical order.

message MutationChangeBinaryOperator {
  // This transformation replaces one binary operator with another.

  // The id of a binary expression in the AST.
  uint32 binary_expr_id = 1;

  // A BinaryOp representing the new binary operator.
  uint32 new_operator = 2;
}

message MutationChangeUnaryOperator {
    // This transformation replaces one unary operator with another.

    // The id of a unary expression in the AST.
    uint32 unary_expr_id = 1;

    // A UnaryOp representing the new unary operator.
    uint32 new_operator = 2;
}

message MutationDeleteStatement {
    // This transformation deletes a statement, as long as doing so does not
    // invalidate the program.

    // The id of a statement to be deleted.
    uint32 statement_id = 1;
}

message MutationReplaceIdentifier {
    // This transformation replaces a use of one variable with another.

    // The id of the use of a variable in the AST.
    uint32 use_id = 1;

    // The id of a definition of a variable to replace the use with.
    uint32 replacement_id = 2;
}

message MutationWrapUnaryOperator {
  // This transformation wraps an expression with a allowed unary
  // expression operator.

  // The id of the expression.
  uint32 expression_id = 1;

  // A fresh id for the created unary expression.
  uint32 fresh_id = 2;

  // The unary operator to wrap the expression with.
  uint32 unary_op_wrapper = 3;
}