/*
 * Copyright 2000-2014 JetBrains s.r.o.
 *
 * 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.
 */
package com.jetbrains.python.psi.impl.stubs;

import com.intellij.lang.ASTNode;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiFile;
import com.intellij.psi.stubs.DefaultStubBuilder;
import com.intellij.psi.stubs.StubElement;
import com.jetbrains.python.psi.*;
import com.jetbrains.python.psi.impl.PyEvaluator;
import one.util.streamex.StreamEx;
import org.jetbrains.annotations.NotNull;


public class PyFileStubBuilder extends DefaultStubBuilder {
  @Override
  protected @NotNull StubElement createStubForFile(@NotNull PsiFile file) {
    if (file instanceof PyFile) {
      return new PyFileStubImpl((PyFile)file);
    }

    return super.createStubForFile(file);
  }

  @Override
  public boolean skipChildProcessingWhenBuildingStubs(@NotNull ASTNode parent, @NotNull ASTNode node) {
    PsiElement parentPsi = parent.getPsi();
    if (parentPsi instanceof PyIfStatement && PyUtil.isIfNameEqualsMain((PyIfStatement)parentPsi)) {
      return true;
    }
    if (parentPsi instanceof PyIfStatement ifStatement && node.getPsi() instanceof PyStatementPart part) {
      return isAlwaysUnreachable(ifStatement, part);
    }
    return false;
  }

  private static boolean isAlwaysUnreachable(@NotNull PyIfStatement ifStatement, @NotNull PyStatementPart part) {
    assert part.getParent() == ifStatement;

    for (PyIfPart ifPart : StreamEx.of(ifStatement.getIfPart()).append(ifStatement.getElifParts())) {
      if (ifPart == part) {
        break;
      }
      Boolean result = PyEvaluator.evaluateAsBooleanNoResolve(ifPart.getCondition());
      if (result == Boolean.TRUE) {
        return true;
      }
    }

    if (part instanceof PyIfPart ifPart) {
      Boolean result = PyEvaluator.evaluateAsBooleanNoResolve(ifPart.getCondition());
      if (result == Boolean.FALSE) {
        return true;
      }
    }

    return false;
  }
}
