// Copyright 2024 Google LLC

//

// 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

//

//     https://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 "parser/macro_expr_factory.h"

#include <utility>

#include <vector>

#include "absl/functional/overload.h"

#include "absl/types/optional.h"

#include "absl/types/variant.h"

#include "common/constant.h"

#include "common/expr.h"

namespace cel {

Expr MacroExprFactory::Copy(const Expr& expr) {

  // Copying logic is recursive at the moment, we alter it to be iterative in

  // the future.

  return absl::visit(

      absl::Overload(

          [this, &expr](const UnspecifiedExpr&) -> Expr {

            return NewUnspecified(CopyId(expr));

          },

          [this, &expr](const Constant& const_expr) -> Expr {

            return NewConst(CopyId(expr), const_expr);

          },

          [this, &expr](const IdentExpr& ident_expr) -> Expr {

            return NewIdent(CopyId(expr), ident_expr.name());

          },

          [this, &expr](const SelectExpr& select_expr) -> Expr {

            const auto id = CopyId(expr);

            return select_expr.test_only()

                       ? NewPresenceTest(id, Copy(select_expr.operand()),

                                         select_expr.field())

                       : NewSelect(id, Copy(select_expr.operand()),

                                   select_expr.field());

          },

          [this, &expr](const CallExpr& call_expr) -> Expr {

            const auto id = CopyId(expr);

            absl::optional<Expr> target;

            if (call_expr.has_target()) {

              target = Copy(call_expr.target());

            }

            std::vector<Expr> args;

            args.reserve(call_expr.args().size());

            for (const auto& arg : call_expr.args()) {

              args.push_back(Copy(arg));

            }

            return target.has_value()

                       ? NewMemberCall(id, call_expr.function(),

                                       std::move(*target), std::move(args))

                       : NewCall(id, call_expr.function(), std::move(args));

          },

          [this, &expr](const ListExpr& list_expr) -> Expr {

            const auto id = CopyId(expr);

            std::vector<ListExprElement> elements;

            elements.reserve(list_expr.elements().size());

            for (const auto& element : list_expr.elements()) {

              elements.push_back(Copy(element));

            }

            return NewList(id, std::move(elements));

          },

          [this, &expr](const StructExpr& struct_expr) -> Expr {

            const auto id = CopyId(expr);

            std::vector<StructExprField> fields;

            fields.reserve(struct_expr.fields().size());

            for (const auto& field : struct_expr.fields()) {

              fields.push_back(Copy(field));

            }

            return NewStruct(id, struct_expr.name(), std::move(fields));

          },

          [this, &expr](const MapExpr& map_expr) -> Expr {

            const auto id = CopyId(expr);

            std::vector<MapExprEntry> entries;

            entries.reserve(map_expr.entries().size());

            for (const auto& entry : map_expr.entries()) {

              entries.push_back(Copy(entry));

            }

            return NewMap(id, std::move(entries));

          },

          [this, &expr](const ComprehensionExpr& comprehension_expr) -> Expr {

            const auto id = CopyId(expr);

            auto iter_range = Copy(comprehension_expr.iter_range());

            auto accu_init = Copy(comprehension_expr.accu_init());

            auto loop_condition = Copy(comprehension_expr.loop_condition());

            auto loop_step = Copy(comprehension_expr.loop_step());

            auto result = Copy(comprehension_expr.result());

            return NewComprehension(

                id, comprehension_expr.iter_var(), std::move(iter_range),

                comprehension_expr.accu_var(), std::move(accu_init),

                std::move(loop_condition), std::move(loop_step),

                std::move(result));

          }),

      expr.kind());

}

ListExprElement MacroExprFactory::Copy(const ListExprElement& element) {

  return NewListElement(Copy(element.expr()), element.optional());

}

StructExprField MacroExprFactory::Copy(const StructExprField& field) {

  auto field_id = CopyId(field.id());

  auto field_value = Copy(field.value());

  return NewStructField(field_id, field.name(), std::move(field_value),

                        field.optional());

}

MapExprEntry MacroExprFactory::Copy(const MapExprEntry& entry) {

  auto entry_id = CopyId(entry.id());

  auto entry_key = Copy(entry.key());

  auto entry_value = Copy(entry.value());

  return NewMapEntry(entry_id, std::move(entry_key), std::move(entry_value),

                     entry.optional());

}

}  // namespace cel