/*******************************************************************************
 * Copyright (c) 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jst.jsp.core.internal.java;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import com.ibm.icu.util.StringTokenizer;

import org.eclipse.core.filebuffers.ITextFileBuffer;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.content.IContentType;
import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.Position;
import org.eclipse.jface.text.TextUtilities;
import org.eclipse.jst.jsp.core.internal.Logger;
import org.eclipse.jst.jsp.core.internal.regions.DOMJSPRegionContexts;
import org.eclipse.text.edits.DeleteEdit;
import org.eclipse.text.edits.InsertEdit;
import org.eclipse.text.edits.MalformedTreeException;
import org.eclipse.text.edits.MultiTextEdit;
import org.eclipse.text.edits.ReplaceEdit;
import org.eclipse.text.edits.TextEdit;
import org.eclipse.text.edits.UndoEdit;
import org.eclipse.wst.sse.core.StructuredModelManager;
import org.eclipse.wst.sse.core.internal.FileBufferModelManager;
import org.eclipse.wst.sse.core.internal.provisional.IStructuredModel;
import org.eclipse.wst.sse.core.internal.provisional.text.IStructuredDocument;
import org.eclipse.wst.sse.core.internal.provisional.text.IStructuredDocumentRegion;
import org.eclipse.wst.xml.core.internal.regions.DOMRegionContext;


/**
 * Adds the notion of IDocuments (jsp Document and java Document)
 * Used for TextEdit translation
 * @author pavery
 */
public class JSPTranslationExtension extends JSPTranslation {
	
	// for debugging
	private static final boolean DEBUG;
	static {
		String value= Platform.getDebugOption("org.eclipse.jst.jsp.core/debug/jsptranslation"); //$NON-NLS-1$
		DEBUG= value != null && value.equalsIgnoreCase("true"); //$NON-NLS-1$
	}
	
	private static final String CT_ID_JSP_FRAGMENT = "org.eclipse.jst.jsp.core.jspfragmentsource"; //$NON-NLS-1$
	
	// just a convenience data structure
	// to keep track of java position deltas
	private class PositionDelta {
		
		public boolean isDeleted = false;
		public int preOffset = 0;
		public int preLength = 0;
		public int postOffset = 0;
		public int postLength = 0;
		
		public PositionDelta(int preOffset, int preLength) {
			this.preOffset = preOffset;
			this.preLength = preLength;
		}
		public void setPostEditData(int postOffset, int postLength, boolean isDeleted) {
			this.postOffset = postOffset;
			this.postLength = postLength;
			this.isDeleted = isDeleted;
		}
	}
	
	private IDocument fJspDocument = null;
	private IDocument fJavaDocument = null;
	
	public JSPTranslationExtension(IDocument jspDocument, IDocument javaDocument, IJavaProject javaProj, JSPTranslator translator) {
		super(javaProj, translator);
		fJspDocument = jspDocument;
		fJavaDocument = javaDocument;
		
		// make sure positions are added to Java and JSP documents
		// this is necessary for text edits
		addPositionsToDocuments();
	}
	
	public IDocument getJspDocument() {
		return fJspDocument;
	}
	
	public IDocument getJavaDocument() {
		return fJavaDocument;
	}
	
	public String getJavaText() {
		return getJavaDocument() != null ? getJavaDocument().get() : ""; //$NON-NLS-1$
	}
	
	/**
	 * Returns a corresponding TextEdit for the JSP file given a TextEdit for a Java file.
	 * 
	 * @param javaEdit
	 * @return the corresponding JSP edits (not applied to the document yet)
	 */
	public TextEdit getJspEdit(TextEdit javaEdit) {

		if(javaEdit == null)
			return null;
		
		List jspEdits = new ArrayList();

		int offset = javaEdit.getOffset();
		int length = javaEdit.getLength();
		
		if(javaEdit instanceof MultiTextEdit && javaEdit.getChildren().length > 0) {
	
			IRegion r = TextEdit.getCoverage(getAllEdits(javaEdit));
			offset = r.getOffset();
			length = r.getLength();
		}
		
		// get java ranges that will be affected by the edit
		Position[] javaPositions = getJavaRanges(offset, length);
		
		// record position data before the change
		Position[] jspPositions = new Position[javaPositions.length];
		PositionDelta[] deltas = new PositionDelta[javaPositions.length];
		for(int i=0; i<javaPositions.length; i++) {
			deltas[i] = new PositionDelta(javaPositions[i].offset, javaPositions[i].length);
			// isIndirect means the position doesn't actually exist as exact text 
			// mapping from java <-> jsp (eg. an import statement)
			if(!isIndirect(javaPositions[i].offset))
				jspPositions[i] = (Position)getJava2JspMap().get(javaPositions[i]);
		}

		if(DEBUG) {
			System.out.println("================================================"); //$NON-NLS-1$
			System.out.println("deltas:"); //$NON-NLS-1$
			String javaText = getJavaText();
			for(int i=0; i<deltas.length; i++) 
				System.out.println("pos[" + deltas[i].preOffset + ":" + deltas[i].preLength + "]" + javaText.substring(deltas[i].preOffset, deltas[i].preOffset + deltas[i].preLength) ); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
			System.out.println("==============================================="); //$NON-NLS-1$
		}
		UndoEdit undo = null;
		// apply the edit to the java document
		try {
			undo = javaEdit.apply(getJavaDocument());
		} catch (MalformedTreeException e) {
			Logger.logException(e);
		} catch (BadLocationException e) {
			Logger.logException(e);
		}
		// now at this point Java positions are unreliable since they were updated after applying java edit.
		
		String newJavaText = getJavaDocument().get();
		if(DEBUG) 
			System.out.println("java post format text:\n" + newJavaText); //$NON-NLS-1$
		
		// record post edit data
		for(int i=0; i<javaPositions.length; i++)
			deltas[i].setPostEditData(javaPositions[i].offset, javaPositions[i].length, javaPositions[i].isDeleted);
		
		// create appropriate text edits for deltas
		Position jspPos = null;
		String replaceText = ""; //$NON-NLS-1$
		for(int i=0; i<deltas.length; i++) {
			jspPos = jspPositions[i];
			// can be null if it's an indirect mapping position
			// or if something was added into java that was not originally in JSP (like a new import...)

			if(jspPos != null) {
				if(deltas[i].isDeleted) {
					jspEdits.add(new DeleteEdit(jspPos.offset, jspPos.length));
				}
				else {
					replaceText = newJavaText.substring(deltas[i].postOffset, deltas[i].postOffset + deltas[i].postLength);
					
					// get rid of pre and post white space or fine tuned adjustment later.
					// fix text here...
					replaceText = fixJspReplaceText(replaceText, jspPos.offset);
					
					jspEdits.add(new ReplaceEdit(jspPos.offset, jspPos.length, replaceText));
				}
				if(DEBUG) 
					debugReplace(deltas, jspPos, replaceText, i);
			}
			else {
				// the new Java text has no corresponding JSP position
				// possible new import?
				if(isImport(javaPositions[i].getOffset()) && replaceText.lastIndexOf("import ") != -1) { //$NON-NLS-1$
					replaceText = newJavaText.substring(deltas[i].postOffset, deltas[i].postOffset + deltas[i].postLength);
					String importText = replaceText.substring(replaceText.lastIndexOf("import "), replaceText.indexOf(";")); //$NON-NLS-1$ //$NON-NLS-2$
					// evenutally need to check if it's XML-JSP
					importText = "<%@page import=\"" + importText + "\" %>\n"; //$NON-NLS-1$ //$NON-NLS-2$
					jspEdits.add(new InsertEdit(0, importText));
				}
			}
		}
		TextEdit allJspEdits =  createMultiTextEdit((TextEdit[])jspEdits.toArray(new TextEdit[jspEdits.size()]));
		
		// https://bugs.eclipse.org/bugs/show_bug.cgi?id=105632
		// undo the java edit 
		// (so the underlying Java document still represents what's in the editor)
		if(undo != null) {
			try {
				undo.apply(getJavaDocument());
			}
			catch (MalformedTreeException e) {
				Logger.logException(e);
			}
			catch (BadLocationException e) {
				Logger.logException(e);
			}
		}
		
		return allJspEdits;
	}
	
	private String fixJspReplaceText(String replaceText, int jspOffset) {
		
		// result is the text inbetween the delimiters
		// eg.
		// 
		// <%  result 
		// %>
		String result = replaceText.trim();
		String preDelimiterWhitespace = ""; //$NON-NLS-1$
		
		IDocument jspDoc = getJspDocument();
		if(jspDoc instanceof IStructuredDocument) {
			IStructuredDocument sDoc = (IStructuredDocument)jspDoc;
			IStructuredDocumentRegion[] regions = sDoc.getStructuredDocumentRegions(0, jspOffset);
			IStructuredDocumentRegion lastRegion = regions[regions.length-1];
			
			// only specifically modify scriptlets
			if(lastRegion != null && lastRegion.getType() == DOMJSPRegionContexts.JSP_SCRIPTLET_OPEN) {
				for (int i = regions.length-1; i >= 0; i--) {
					IStructuredDocumentRegion region = regions[i];
					
					// is there a better way to check whitespace?
					if(region.getType() == DOMRegionContext.XML_CONTENT && region.getFullText().trim().equals("")) { //$NON-NLS-1$
						
						preDelimiterWhitespace = region.getFullText();
						preDelimiterWhitespace = preDelimiterWhitespace.replaceAll("\r", ""); //$NON-NLS-1$ //$NON-NLS-2$
						preDelimiterWhitespace = preDelimiterWhitespace.replaceAll("\n", ""); //$NON-NLS-1$ //$NON-NLS-2$
						
						// need to determine indent for that first line...
						 String initialIndent = getInitialIndent(result);
						 
						 // fix the first line of java code
						result = TextUtilities.getDefaultLineDelimiter(sDoc) 
									+ initialIndent 
									+ result;
						
						result = adjustIndent(result, preDelimiterWhitespace, TextUtilities.getDefaultLineDelimiter(sDoc));
						
						// add whitespace before last delimiter to match
					    // it w/ the opening delimiter
						result = result + TextUtilities.getDefaultLineDelimiter(sDoc) + preDelimiterWhitespace;
						break;
					}
				}
			}
		}
		return result;
	}
	
	private String adjustIndent(String textBefore, String indent, String delim) {
		
		// first replace multiple indent with single indent
		// the triple indent occurs because the scriptlet code
		// actually occurs under:
		// 
		//    class
		//       method
		//          code
		// 
		// in the translated java document
		
		textBefore = textBefore.replaceAll("\t\t\t", "\t"); //$NON-NLS-1$ //$NON-NLS-2$
		
		// get indent after 2nd line break
		StringBuffer textAfter = new StringBuffer();
		// will this work on mac?
		textBefore = textBefore.replaceAll("\r", ""); //$NON-NLS-1$ //$NON-NLS-2$
		StringTokenizer st = new StringTokenizer(textBefore, "\n", true); //$NON-NLS-1$
		while(st.hasMoreTokens()) {
			String tok = st.nextToken();
			if(tok.equals("\n")) { //$NON-NLS-1$
				textAfter.append(delim);
			}
			else {
				// prepend each line w/ specified indent
				textAfter.append(indent);
				textAfter.append(tok);
			}
		}
		return textAfter.toString();
		
	}
	
	private String getInitialIndent(String result) {
		
		// get indent after 2nd line break
		String indent = ""; //$NON-NLS-1$
		StringTokenizer st = new StringTokenizer(result, "\r\n", false); //$NON-NLS-1$
		if(st.countTokens() > 1) {
			String tok = st.nextToken();
			tok = st.nextToken();
			int index =0;
			if(tok != null) {
				while(tok.charAt(index) == ' ' || tok.charAt(index) == '\t') {
					indent += tok.charAt(index);
					index++;
				}
			}
		}
		return indent;
	}


	/**
	 * Combines an array of edits into one MultiTextEdit (with the appropriate coverage region)
	 * @param edits
	 * @return
	 */
	private TextEdit createMultiTextEdit(TextEdit[] edits) {
		
		if(edits.length == 0)
			return new MultiTextEdit();
			
		IRegion region = TextEdit.getCoverage(edits);
		MultiTextEdit multiEdit = new MultiTextEdit(region.getOffset(), region.getLength());
		for (int i = 0; i < edits.length; i++) {
			addToMultiEdit(edits[i], multiEdit);
		}
		return multiEdit;
	}
	
	
	private void addToMultiEdit(TextEdit edit, MultiTextEdit multiEdit) {
		
		// check for overlap here
		// discard overlapping edits..
		// possible exponential performance hit... need a better way...
		TextEdit[] children = multiEdit.getChildren();
		for (int i = 0; i < children.length; i++) {
			if(children[i].covers(edit))
				// don't add
				return;
		}
		multiEdit.addChild(edit);
	}
	
	
	/**
	 * @param translation
	 */
	private void addPositionsToDocuments() {
		
		// can be null if it's a NullJSPTranslation
		if(getJavaDocument() != null && getJspDocument() != null) {

			HashMap java2jsp = getJava2JspMap();
			Iterator it = java2jsp.keySet().iterator();
			Position javaPos = null;
			while(it.hasNext()) {
				javaPos =(Position)it.next();
				try {
					
					fJavaDocument.addPosition(javaPos);
					
				} catch (BadLocationException e) {
					if(DEBUG) {
						System.out.println("tyring to add Java Position:[" + javaPos.offset + ":" + javaPos.length + "] to " + getJavaPath()); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$					
						//System.out.println("substring :[" + fJavaDocument.get().substring(javaPos.offset) + "]"); //$NON-NLS-1$ //$NON-NLS-2$
						Logger.logException(e);
					}
				}
				
				try {
					
					fJspDocument.addPosition((Position)java2jsp.get(javaPos));
					
				} catch (BadLocationException e) {
					if(DEBUG) {
						System.out.println("tyring to add JSP Position:[" + ((Position)java2jsp.get(javaPos)).offset + ":" +((Position)java2jsp.get(javaPos)).length + "] to " + getJavaPath()); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
						Logger.logException(e);
					}
				}
			}
		}
	}
	
	/**
	 * Recursively gets all child edits
	 * @param javaEdit
	 * @return all child edits
	 */
	private TextEdit[] getAllEdits(TextEdit javaEdit) {
		
		List result = new ArrayList();
		if(javaEdit instanceof MultiTextEdit) {
			TextEdit[] children = javaEdit.getChildren();
			for (int i = 0; i < children.length; i++) 
				result.addAll(Arrays.asList(getAllEdits(children[i])));
		}
		else 
			result.add(javaEdit);
		return (TextEdit[])result.toArray(new TextEdit[result.size()]);
	}

	public void reconcileCompilationUnit() {
		
		// https://bugs.eclipse.org/bugs/show_bug.cgi?id=105109
		// don't want errors for JSP fragments
		// since it's likely we don't know their context
		if(!isJspFragment())
			super.reconcileCompilationUnit();
	}
	
	private boolean isJspFragment() {
		
		boolean isFrag = false;
		
		// pa_TODO
		// need a way to get underlying IResource or IFile
		// from IDocument
		
		// then check content type to see if it's JSP fragment
		ITextFileBuffer buf = FileBufferModelManager.getInstance().getBuffer(getJspDocument());
		if(buf != null) {
			isFrag = isJspFragment(buf);
		}
		else {
			isFrag = isJspFragment(getJspDocument());
		}
		return isFrag;
	}

	private boolean isJspFragment(IDocument sDoc) {
		boolean isFrag = false;
		// buffer is null (no live models around)
		IStructuredModel sModel = StructuredModelManager.getModelManager().getExistingModelForRead(sDoc);
		try {
			if(sModel != null) {
				IPath p = new Path(sModel.getBaseLocation());
				IFile f = ResourcesPlugin.getWorkspace().getRoot().getFile(p);
				if(f != null && f.exists()) {
					IContentType jspFragType = Platform.getContentTypeManager().getContentType(CT_ID_JSP_FRAGMENT);
					if(jspFragType != null)
						isFrag = jspFragType.isAssociatedWith(f.getName());
				}
			}
		}
		finally {
			if(sModel != null)
				sModel.releaseFromRead();
		}
		return isFrag;
	}

	private boolean isJspFragment(ITextFileBuffer buf) {
		boolean isFrag = false;
		IPath loc = buf.getLocation();
		if(loc != null) {
			IFile f = ResourcesPlugin.getWorkspace().getRoot().getFile(loc);
			if(f != null && f.exists()) {
				IContentType jspFragType = Platform.getContentTypeManager().getContentType(CT_ID_JSP_FRAGMENT);
				if(jspFragType != null)
					isFrag = jspFragType.isAssociatedWith(f.getName());
			}
		}
		return isFrag;
	}
	
	/**
	 * @param deltas
	 * @param jspPos
	 * @param replaceText
	 * @param jspText
	 * @param i
	 */
	private void debugReplace(PositionDelta[] deltas, Position jspPos, String replaceText, int i) {
		String jspChunk;
		jspChunk = getJspDocument().get().substring(jspPos.offset, jspPos.offset + jspPos.length);
		if(!deltas[i].isDeleted) {
			System.out.println("replacing:"); //$NON-NLS-1$
			System.out.println("jsp:[" + jspChunk + "]"); //$NON-NLS-1$ //$NON-NLS-2$
			System.out.println("w/ :[" + replaceText + "]"); //$NON-NLS-1$ //$NON-NLS-2$
			System.out.println("--------------------------------"); //$NON-NLS-1$
		}
	}
}