package strutsrewriting;

import org.eclipse.core.filebuffers.FileBuffers;
import org.eclipse.core.filebuffers.ITextFileBuffer;
import org.eclipse.core.filebuffers.ITextFileBufferManager;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.jdt.core.dom.CompilationUnit;
import org.eclipse.jdt.core.dom.rewrite.ASTRewrite;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.text.edits.MalformedTreeException;
import org.eclipse.text.edits.TextEdit;

public class RefactoringUtilities {

    /**
     * Writes changes to Java source. This method does not distinguish how the
     * AST was changed.
     * 
     * @param unit
     *            the AST node of the compilation unit that has been changed
     * @param textEditProvider
     *            provides the change information
     * @throws CoreException
     *             thrown if file paths cannot be connected or disconnected
     */
    public static void save(CompilationUnit unit, TextEditProvider textEditProvider) throws CoreException {
	ITextFileBufferManager bufferManager = FileBuffers.getTextFileBufferManager();
	IPath path = unit.getJavaElement().getPath();

	try {
	    // connect the path
	    bufferManager.connect(path, null);

	    ITextFileBuffer textFileBuffer = bufferManager.getTextFileBuffer(path);
	    // retrieve the buffer
	    IDocument document = textFileBuffer.getDocument();

	    // ask the textEditProvider for the change information
	    TextEdit edit = textEditProvider.getTextEdit(document);

	    // apply the changes to the document
	    edit.apply(document);

	    // write the changes from the buffer to the file
	    textFileBuffer.commit(null /* ProgressMonitor */, false /* Overwrite */);

	} catch (MalformedTreeException e) {
	    e.printStackTrace();
	} catch (BadLocationException e) {
	    e.printStackTrace();
	} finally {
	    // disconnect the path
	    bufferManager.disconnect(path, null);
	}
    }

    /**
     * Convenience method that saves changes that have been made directly to an
     * AST.
     * 
     * @param unit
     *            the unit that contains changes.
     * @throws CoreException
     *             forwards the exception from
     *             {@link #save(CompilationUnit, net.sourceforge.earticleast.app.ManipulatorHelper.TextEditProvider)}
     */
    public static void saveDirectlyModifiedUnit(final CompilationUnit unit) {
	try {
	    save(unit, new TextEditProvider() {
		public TextEdit getTextEdit(IDocument document) {
		    return unit.rewrite(document, null);
		}
	    });
	} catch (CoreException e) {
	    e.printStackTrace();
	    System.exit(0);
	}
    }

    /**
     * Convenience method that saves changes to an AST that have been recorded
     * in by an instance of {@link ASTRewrite}.
     * 
     * @param unit
     *            the unit (in its origininal state)
     * @param rewrite
     *            contains the rewrite instructions
     * @throws CoreException
     *             forwards the exception from
     *             {@link #save(CompilationUnit, net.sourceforge.earticleast.app.ManipulatorHelper.TextEditProvider)}
     */
    public static void saveASTRewriteContents(CompilationUnit unit, final ASTRewrite rewrite) throws CoreException {
	save(unit, new TextEditProvider() {
	    public TextEdit getTextEdit(IDocument document) {
		return rewrite.rewriteAST(document, null);
	    }
	});

    }

}