/*
 * Copyright 2013-2017 consulo.io
 *
 * 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 consulo.csharp.lang.psi.impl.source;

import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import com.intellij.lang.ASTNode;
import com.intellij.openapi.util.text.CharFilter;
import com.intellij.openapi.util.text.StringUtil;
import com.intellij.psi.PsiElement;
import com.intellij.psi.util.CachedValueProvider;
import com.intellij.psi.util.CachedValuesManager;
import com.intellij.psi.util.PsiModificationTracker;
import com.intellij.util.ArrayFactory;
import consulo.annotations.RequiredReadAction;
import consulo.csharp.lang.psi.CSharpElementVisitor;
import consulo.csharp.lang.psi.CSharpNamespaceDeclaration;
import consulo.csharp.lang.psi.CSharpStubElements;
import consulo.csharp.lang.psi.CSharpTokens;
import consulo.csharp.lang.psi.CSharpUsingNamespaceStatement;
import consulo.csharp.lang.psi.impl.stub.CSharpWithStringValueStub;
import consulo.dotnet.psi.DotNetReferenceExpression;
import consulo.dotnet.resolve.DotNetNamespaceAsElement;
import consulo.dotnet.resolve.DotNetPsiSearcher;

/**
 * @author VISTALL
 * @since 28.11.13.
 */
public class CSharpUsingNamespaceStatementImpl extends CSharpStubElementImpl<CSharpWithStringValueStub<CSharpUsingNamespaceStatement>> implements CSharpUsingNamespaceStatement
{
	public static final CSharpUsingNamespaceStatementImpl[] EMPTY_ARRAY = new CSharpUsingNamespaceStatementImpl[0];

	public static ArrayFactory<CSharpUsingNamespaceStatementImpl> ARRAY_FACTORY = new ArrayFactory<CSharpUsingNamespaceStatementImpl>()
	{
		@NotNull
		@Override
		public CSharpUsingNamespaceStatementImpl[] create(int count)
		{
			return count == 0 ? EMPTY_ARRAY : new CSharpUsingNamespaceStatementImpl[count];
		}
	};

	public CSharpUsingNamespaceStatementImpl(@NotNull ASTNode node)
	{
		super(node);
	}

	public CSharpUsingNamespaceStatementImpl(@NotNull CSharpWithStringValueStub<CSharpUsingNamespaceStatement> stub)
	{
		super(stub, CSharpStubElements.USING_NAMESPACE_STATEMENT);
	}

	@RequiredReadAction
	@NotNull
	@Override
	public PsiElement getUsingKeywordElement()
	{
		return findNotNullChildByType(CSharpTokens.USING_KEYWORD);
	}

	@RequiredReadAction
	@Override
	@Nullable
	public String getReferenceText()
	{
		CSharpWithStringValueStub<CSharpUsingNamespaceStatement> stub = getStub();
		if(stub != null)
		{
			return stub.getReferenceText();
		}

		DotNetReferenceExpression namespaceReference = getNamespaceReference();
		return namespaceReference == null ? null : namespaceReference.getText();
	}

	@RequiredReadAction
	@Override
	@Nullable
	public DotNetNamespaceAsElement resolve()
	{
		return CachedValuesManager.getManager(getProject()).createCachedValue(() -> CachedValueProvider.Result.create(resolveInner(), PsiModificationTracker.OUT_OF_CODE_BLOCK_MODIFICATION_COUNT),
				false).getValue();
	}

	@Nullable
	@RequiredReadAction
	private DotNetNamespaceAsElement resolveInner()
	{
		String referenceText = getReferenceText();
		if(referenceText == null)
		{
			return null;
		}

		final String qName = StringUtil.strip(referenceText, CharFilter.NOT_WHITESPACE_FILTER);

		PsiElement parent = getParent();
		DotNetPsiSearcher psiSearcher = DotNetPsiSearcher.getInstance(getProject());
		if(parent instanceof CSharpNamespaceDeclaration)
		{
			String newNamespaceName = ((CSharpNamespaceDeclaration) parent).getPresentableQName() + "." + qName;
			DotNetNamespaceAsElement namespace = psiSearcher.findNamespace(newNamespaceName, getResolveScope());
			if(namespace != null)
			{
				return namespace;
			}
		}

		return psiSearcher.findNamespace(qName, getResolveScope());
	}

	@Override
	public DotNetReferenceExpression getNamespaceReference()
	{
		return findChildByClass(DotNetReferenceExpression.class);
	}

	@Override
	public void accept(@NotNull CSharpElementVisitor visitor)
	{
		visitor.visitUsingNamespaceStatement(this);
	}

	@RequiredReadAction
	@Nullable
	@Override
	public PsiElement getReferenceElement()
	{
		return getNamespaceReference();
	}
}