/*
 * 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.intellij.psi.impl.compiled;

import com.intellij.openapi.util.AtomicNotNullLazyValue;
import com.intellij.openapi.util.AtomicNullableLazyValue;
import com.intellij.openapi.util.NotNullLazyValue;
import com.intellij.openapi.util.NullableLazyValue;
import com.intellij.psi.*;
import com.intellij.psi.impl.PsiImplUtil;
import com.intellij.psi.impl.PsiJavaParserFacadeImpl;
import com.intellij.psi.impl.cache.TypeInfo;
import com.intellij.psi.impl.source.PsiClassReferenceType;
import com.intellij.psi.impl.source.tree.JavaElementType;
import com.intellij.psi.impl.source.tree.TreeElement;
import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.NotNull;

public class ClsTypeElementImpl extends ClsElementImpl implements PsiTypeElement {
  @NonNls static final char VARIANCE_NONE = '\0';
  @NonNls static final char VARIANCE_EXTENDS = '+';
  @NonNls static final char VARIANCE_SUPER = '-';
  @NonNls static final char VARIANCE_INVARIANT = '*';
  @NonNls static final String VARIANCE_EXTENDS_PREFIX = "? extends ";
  @NonNls static final String VARIANCE_SUPER_PREFIX = "? super ";

  private final PsiElement myParent;
  private final String myTypeText;
  private final char myVariance;
  private final NullableLazyValue<ClsElementImpl> myChild;
  private final NotNullLazyValue<PsiType> myCachedType;

  public ClsTypeElementImpl(@NotNull PsiElement parent, @NotNull String typeText, char variance) {
    myParent = parent;
    myTypeText = TypeInfo.internFrequentType(typeText);
    myVariance = variance;
    myChild = new AtomicNullableLazyValue<ClsElementImpl>() {
      @Override
      protected ClsElementImpl compute() {
        return calculateChild();
      }
    };
    myCachedType = new AtomicNotNullLazyValue<PsiType>() {
      @NotNull
      @Override
      protected PsiType compute() {
        return calculateType();
      }
    };
  }

  @Override
  @NotNull
  public PsiElement[] getChildren() {
    ClsElementImpl child = myChild.getValue();
    return child != null ? new PsiElement[]{child} : PsiElement.EMPTY_ARRAY;
  }

  @Override
  public PsiElement getParent() {
    return myParent;
  }

  @Override
  public String getText() {
    final String shortClassName = PsiNameHelper.getShortClassName(myTypeText);
    return decorateTypeText(shortClassName);
  }

  private String decorateTypeText(final String shortClassName) {
    switch (myVariance) {
      case VARIANCE_NONE:
        return shortClassName;
      case VARIANCE_EXTENDS:
        return VARIANCE_EXTENDS_PREFIX + shortClassName;
      case VARIANCE_SUPER:
        return VARIANCE_SUPER_PREFIX + shortClassName;
      case VARIANCE_INVARIANT:
        return "?";
      default:
        assert false : myVariance;
        return null;
    }
  }

  public String getCanonicalText() {
    return decorateTypeText(myTypeText);
  }

  @Override
  public void appendMirrorText(int indentLevel, @NotNull StringBuilder buffer) {
    buffer.append(decorateTypeText(myTypeText));
  }

  @Override
  public void setMirror(@NotNull TreeElement element) throws InvalidMirrorException {
    setMirrorCheckingType(element, JavaElementType.TYPE);

    ClsElementImpl child = myChild.getValue();
    if (child != null) {
      child.setMirror(element.getFirstChildNode());
    }
  }

  private boolean isArray() {
    return myTypeText.endsWith("[]");
  }

  private boolean isVarArgs() {
    return myTypeText.endsWith("...");
  }

  @Override
  @NotNull
  public PsiType getType() {
    return myCachedType.getValue();
  }

  @Override
  public PsiJavaCodeReferenceElement getInnermostComponentReferenceElement() {
    return null;
  }

  private ClsElementImpl calculateChild() {
    if (PsiJavaParserFacadeImpl.getPrimitiveType(myTypeText) != null) {
      return null;
    }
    if (isArray()) {
      return myVariance == VARIANCE_NONE
             ? new ClsTypeElementImpl(this, myTypeText.substring(0, myTypeText.length() - 2), myVariance)
             : new ClsTypeElementImpl(this, myTypeText, VARIANCE_NONE);
    }
    if (isVarArgs()) {
      return new ClsTypeElementImpl(this, myTypeText.substring(0, myTypeText.length() - 3), myVariance);
    }
    return myVariance == VARIANCE_INVARIANT ? null : new ClsJavaCodeReferenceElementImpl(this, myTypeText);
  }

  @NotNull
  private PsiType calculateType() {
    PsiType result = PsiJavaParserFacadeImpl.getPrimitiveType(myTypeText);
    if (result != null) return result;

    ClsElementImpl childElement = myChild.getValue();
    if (childElement instanceof ClsTypeElementImpl) {
      if (isArray()) {
        switch (myVariance) {
          case VARIANCE_NONE:
            return ((PsiTypeElement)childElement).getType().createArrayType();
          case VARIANCE_EXTENDS:
            return PsiWildcardType.createExtends(getManager(), ((PsiTypeElement)childElement).getType());
          case VARIANCE_SUPER:
            return PsiWildcardType.createSuper(getManager(), ((PsiTypeElement)childElement).getType());
          default:
            assert false : myVariance;
            return null;
        }
      }
      else {
        assert isVarArgs() : this;
        return new PsiEllipsisType(((PsiTypeElement)childElement).getType());
      }
    }
    if (childElement instanceof ClsJavaCodeReferenceElementImpl) {
      PsiClassReferenceType psiClassReferenceType = new PsiClassReferenceType((PsiJavaCodeReferenceElement)childElement, null);
      switch (myVariance) {
        case VARIANCE_NONE:
          return psiClassReferenceType;
        case VARIANCE_EXTENDS:
          return PsiWildcardType.createExtends(getManager(), psiClassReferenceType);
        case VARIANCE_SUPER:
          return PsiWildcardType.createSuper(getManager(), psiClassReferenceType);
        case VARIANCE_INVARIANT:
          return PsiWildcardType.createUnbounded(getManager());
        default:
          assert false : myVariance;
          return null;
      }
    }
    assert childElement == null : this;
    return PsiWildcardType.createUnbounded(getManager());
  }

  @Override
  public void accept(@NotNull PsiElementVisitor visitor) {
    if (visitor instanceof JavaElementVisitor) {
      ((JavaElementVisitor)visitor).visitTypeElement(this);
    }
    else {
      visitor.visitElement(this);
    }
  }

  @Override
  @NotNull
  public PsiAnnotation[] getAnnotations() {
    throw new UnsupportedOperationException();//todo
  }

  @Override
  public PsiAnnotation findAnnotation(@NotNull @NonNls String qualifiedName) {
    return PsiImplUtil.findAnnotation(this, qualifiedName);
  }

  @Override
  @NotNull
  public PsiAnnotation addAnnotation(@NotNull @NonNls String qualifiedName) {
    throw new UnsupportedOperationException();//todo
  }

  @Override
  @NotNull
  public PsiAnnotation[] getApplicableAnnotations() {
    return getAnnotations();
  }

  @Override
  public String toString() {
    return "PsiTypeElement:" + getText();
  }
}