// 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 <algorithm>

#include "src/ast/block_statement.h"
#include "src/ast/loop_statement.h"
#include "src/ast/statement.h"
#include "src/debug.h"
#include "src/sem/block_statement.h"
#include "src/sem/statement.h"

TINT_INSTANTIATE_TYPEINFO(tint::sem::Statement);

namespace tint {
namespace sem {

Statement::Statement(const ast::Statement* declaration, const Statement* parent)
    : declaration_(declaration), parent_(parent) {
#ifndef NDEBUG
  if (parent_) {
    auto* block = Block();
    if (parent_ == block) {
      // The parent of this statement is a block. We thus expect the statement
      // to be an element of the block. There is one exception: a loop's
      // continuing block has the loop's body as its parent, but the continuing
      // block is not a statement in the body, so we rule out that case.
      auto& stmts = block->Declaration()->statements();
      if (std::find(stmts.begin(), stmts.end(), declaration) == stmts.end()) {
        bool statement_is_continuing_for_loop = false;
        if (parent_->parent_ != nullptr) {
          if (auto* loop =
                  parent_->parent_->Declaration()->As<ast::LoopStatement>()) {
            if (loop->has_continuing() && Declaration() == loop->continuing()) {
              statement_is_continuing_for_loop = true;
            }
          }
        }
        TINT_ASSERT(statement_is_continuing_for_loop);
      }
    }
  }
#endif  //  NDEBUG
}

const BlockStatement* Statement::Block() const {
  auto* stmt = parent_;
  while (stmt != nullptr) {
    if (auto* block_stmt = stmt->As<BlockStatement>()) {
      return block_stmt;
    }
    stmt = stmt->parent_;
  }
  return nullptr;
}

const ast::Function* Statement::Function() const {
  if (auto* block = Block()) {
    if (auto* fbs = block->FindFirstParent<FunctionBlockStatement>()) {
      return fbs->Function();
    }
  }
  return nullptr;
}

}  // namespace sem
}  // namespace tint