/*
 * Copyright 2000-2013 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 org.jetbrains.plugins.javaFX.fxml.refs;

import com.intellij.openapi.util.TextRange;
import com.intellij.openapi.util.text.StringUtil;
import com.intellij.psi.*;
import com.intellij.psi.util.PsiTreeUtil;
import com.intellij.psi.util.TypeConversionUtil;
import com.intellij.psi.xml.XmlAttribute;
import com.intellij.psi.xml.XmlAttributeValue;
import com.intellij.psi.xml.XmlTag;
import com.intellij.util.ArrayUtil;
import com.intellij.util.ProcessingContext;
import com.intellij.xml.XmlAttributeDescriptor;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.jetbrains.plugins.javaFX.fxml.FxmlConstants;
import org.jetbrains.plugins.javaFX.fxml.JavaFxPsiUtil;

import java.util.*;

/**
* User: anna
*/
class JavaFxComponentIdReferenceProvider extends PsiReferenceProvider {
  @NotNull
  @Override
  public PsiReference[] getReferencesByElement(@NotNull PsiElement element,
                                               @NotNull ProcessingContext context) {
    final XmlAttributeValue xmlAttributeValue = (XmlAttributeValue)element;
    final XmlTag currentTag = PsiTreeUtil.getParentOfType(xmlAttributeValue, XmlTag.class);
    final String value = xmlAttributeValue.getValue();
    final boolean startsWithDollar = value.startsWith("$");
    final String referencesId = startsWithDollar ? value.substring(1) : value;
    final Map<String, XmlAttributeValue> fileIds = new HashMap<String, XmlAttributeValue>();
    xmlAttributeValue.getContainingFile().accept(new XmlRecursiveElementVisitor() {
      @Override
      public void visitXmlTag(XmlTag tag) {
        super.visitXmlTag(tag);
        if (currentTag != tag) {
          final XmlAttribute attribute = tag.getAttribute(FxmlConstants.FX_ID);
          if (attribute != null) {
            fileIds.put(attribute.getValue(), attribute.getValueElement());
          }
        }
      }
    });

    if (JavaFxPsiUtil.isExpressionBinding(value)) {
      final String expressionText = referencesId.substring(1, referencesId.length() - 1);
      final String newId = StringUtil.getPackageName(expressionText);
      final String fieldRef = StringUtil.getShortName(expressionText);

      final PsiReferenceBase idReferenceBase;

      final PsiClass controllerClass = JavaFxPsiUtil.getControllerClass(element.getContainingFile());
      final PsiField controllerField = controllerClass != null ? controllerClass.findFieldByName(newId, false) : null;
      if (controllerField == null) {
        idReferenceBase = new JavaFxIdReferenceBase(xmlAttributeValue, fileIds, newId);
      } else {
        idReferenceBase = new JavaFxFieldIdReferenceProvider.JavaFxControllerFieldRef(xmlAttributeValue, controllerField, controllerClass); 
      }

      final TextRange range = idReferenceBase.getRangeInElement();
      final int startOffset = range.getStartOffset() + 2;
      final int endOffset = startOffset + newId.length();
      idReferenceBase.setRangeInElement(new TextRange(startOffset, endOffset));
      if (fileIds.containsKey(newId)) {
        final XmlAttributeValue attributeValue = fileIds.get(newId);
        final PsiClass tagClass = JavaFxPsiUtil.getTagClass(attributeValue);
        if (tagClass != null) {
          final JavaFxExpressionReferenceBase referenceBase = new JavaFxExpressionReferenceBase(xmlAttributeValue, tagClass, fieldRef);
          final TextRange textRange = referenceBase.getRangeInElement();
          referenceBase.setRangeInElement(new TextRange(endOffset + 1, textRange.getEndOffset() - 1));
          return new PsiReference[] {idReferenceBase, referenceBase};
        }
      }
      return new PsiReference[] {idReferenceBase};
    }
    if (startsWithDollar) {
      final JavaFxIdReferenceBase idReferenceBase = new JavaFxIdReferenceBase(xmlAttributeValue, fileIds, referencesId);
      final TextRange rangeInElement = idReferenceBase.getRangeInElement();
      idReferenceBase.setRangeInElement(new TextRange(rangeInElement.getStartOffset() + 1, rangeInElement.getEndOffset()));
      return new PsiReference[]{idReferenceBase};
    } else {
      final Set<String> acceptableIds = new HashSet<String>();
      if (currentTag != null) {
        final XmlTag parentTag = currentTag.getParentTag();
        for (final String id : fileIds.keySet()) {
          final XmlAttributeValue resolvedAttrValue = fileIds.get(id);
          if (JavaFxPsiUtil.isClassAcceptable(parentTag, JavaFxPsiUtil.getTagClass(resolvedAttrValue)) == null) {
            acceptableIds.add(id);
          }
        }
      }
      JavaFxIdReferenceBase idReferenceBase = new JavaFxIdReferenceBase(xmlAttributeValue, fileIds, acceptableIds, referencesId);
      return new PsiReference[]{idReferenceBase};
    }
  }

  private static class JavaFxIdReferenceBase extends PsiReferenceBase<XmlAttributeValue> {
    private final Map<String, XmlAttributeValue> myFileIds;
    private final Set<String> myAcceptableIds;
    private final String myReferencesId;

    private JavaFxIdReferenceBase(XmlAttributeValue element,
                                  Map<String, XmlAttributeValue> fileIds, 
                                  Set<String> acceptableIds, 
                                  String referencesId) {
      super(element);
      myFileIds = fileIds;
      myAcceptableIds = acceptableIds;
      myReferencesId = referencesId;
    }

    public JavaFxIdReferenceBase(XmlAttributeValue xmlAttributeValue,
                                 Map<String, XmlAttributeValue> fileIds,
                                 String referencesId) {
      super(xmlAttributeValue);
      myFileIds = fileIds;
      myReferencesId = referencesId;
      myAcceptableIds = myFileIds.keySet();
    }

    @Nullable
    @Override
    public PsiElement resolve() {
      return myFileIds.get(myReferencesId);
    }

    @NotNull
    @Override
    public Object[] getVariants() {
      return ArrayUtil.toStringArray(myAcceptableIds);
    }
  }

  private static class JavaFxExpressionReferenceBase extends PsiReferenceBase<XmlAttributeValue> {
    private final PsiClass myTagClass;
    private final String myFieldName;

    public JavaFxExpressionReferenceBase(XmlAttributeValue xmlAttributeValue, PsiClass tagClass, String fieldName) {
      super(xmlAttributeValue);
      myTagClass = tagClass;
      myFieldName = fieldName;
    }

    @Nullable
    @Override
    public PsiElement resolve() {
      return myTagClass.findFieldByName(myFieldName, true);
    }

    @NotNull
    @Override
    public Object[] getVariants() {
      final PsiElement parent = getElement().getParent();
      if (parent instanceof XmlAttribute) {
        final XmlAttributeDescriptor descriptor = ((XmlAttribute)parent).getDescriptor();
        if (descriptor != null) {
          final PsiElement declaration = descriptor.getDeclaration();
          if (declaration instanceof PsiField) {
            return collectProperties((PsiField)declaration);
          }
        }
      }
      return ArrayUtil.EMPTY_OBJECT_ARRAY;
    }

    private Object[] collectProperties(@NotNull PsiField psiField) {
      final PsiType type = psiField.getType();
      final PsiType propertyType = JavaFxPsiUtil.getPropertyType(type, psiField.getProject());
      final List<PsiField> objs = new ArrayList<PsiField>();
      for (PsiField field : myTagClass.getAllFields()) {
        if (field.hasModifierProperty(PsiModifier.STATIC)) continue;
        final PsiType fieldType = field.getType();
        if (TypeConversionUtil.isAssignable(type, fieldType) || (propertyType != null && TypeConversionUtil.isAssignable(propertyType, fieldType))) {
          objs.add(field);
        }
      }
      return ArrayUtil.toObjectArray(objs);
    }
  }
}