content: /*
   * This file is a part of BSL Language Server.
   *
   * Copyright (c) 2018-2025
   * Alexey Sosnoviy <labotamy@gmail.com>, Nikita Fedkin <nixel2007@gmail.com> and contributors
   *
   * SPDX-License-Identifier: LGPL-3.0-or-later
   *
   * BSL Language Server is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 3.0 of the License, or (at your option) any later version.
   *
   * BSL Language Server is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with BSL Language Server.
   */
  package com.github._1c_syntax.bsl.languageserver.context.computer;
  
  import com.github._1c_syntax.bsl.languageserver.context.DocumentContext;
  import com.github._1c_syntax.bsl.languageserver.context.symbol.RegionSymbol;
  import com.github._1c_syntax.bsl.languageserver.utils.Ranges;
  import com.github._1c_syntax.bsl.parser.BSLParser;
  import com.github._1c_syntax.bsl.parser.BSLParserBaseVisitor;
  import org.antlr.v4.runtime.tree.ParseTree;
  import org.apache.commons.lang3.tuple.Pair;
  import org.eclipse.lsp4j.Range;
  
  import java.util.ArrayDeque;
  import java.util.ArrayList;
  import java.util.Deque;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  
  public final class RegionSymbolComputer
    extends BSLParserBaseVisitor<ParseTree>
    implements Computer<List<RegionSymbol>> {
  
    private final DocumentContext documentContext;
    private final Deque<Pair<RegionSymbol.RegionSymbolBuilder, BSLParser.RegionStartContext>> regionStack =
      new ArrayDeque<>();
    private final Set<RegionSymbol> regions = new HashSet<>();
  
    public RegionSymbolComputer(DocumentContext documentContext) {
      this.documentContext = documentContext;
    }
  
    @Override
    public List<RegionSymbol> compute() {
      regionStack.clear();
      regions.clear();
  
      visitFile(documentContext.getAst());
  
      regionStack.clear();
  
      List<RegionSymbol> result = new ArrayList<>(regions);
      regions.clear();
  
      return result;
    }
  
    @Override
    public ParseTree visitRegionStart(BSLParser.RegionStartContext ctx) {
  
      RegionSymbol.RegionSymbolBuilder builder = RegionSymbol.builder()
        .owner(documentContext)
        .name(ctx.regionName().getText().intern())
        .regionNameRange(Ranges.create(ctx.regionName()))
        .startRange(Ranges.create(ctx));
  
      regionStack.push(Pair.of(builder, ctx));
      return super.visitRegionStart(ctx);
    }
  
    @Override
    public ParseTree visitRegionEnd(BSLParser.RegionEndContext ctx) {
  
      if (regionStack.isEmpty()) {
        return super.visitRegionEnd(ctx);
      }
  
      var pair = regionStack.pop();
  
      RegionSymbol.RegionSymbolBuilder builder = pair.getLeft();
      BSLParser.RegionStartContext regionStartContext = pair.getRight();
  
      Range range = Ranges.create(regionStartContext, ctx);
      builder
        .range(range)
        .endRange(Ranges.create(ctx))
      ;
  
      RegionSymbol region = builder.build();
  
      regions.add(region);
  
      return super.visitRegionEnd(ctx);
    }
  
  }
  