/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package net.sourceforge.phpdt.internal.core.jdom;

import java.util.Stack;

import net.sourceforge.phpdt.core.compiler.IProblem;
import net.sourceforge.phpdt.core.jdom.IDOMCompilationUnit;
import net.sourceforge.phpdt.core.jdom.IDOMFactory;
import net.sourceforge.phpdt.core.jdom.IDOMNode;
import net.sourceforge.phpdt.internal.compiler.IDocumentElementRequestor;
import net.sourceforge.phpdt.internal.compiler.env.ICompilationUnit;
import net.sourceforge.phpdt.internal.core.util.ReferenceInfoAdapter;

/**
 * An abstract DOM builder that contains shared functionality of DOMBuilder and
 * SimpleDOMBuilder.
 */
public class AbstractDOMBuilder extends ReferenceInfoAdapter implements
		ILineStartFinder {
	/**
	 * Set to true when an error is encounterd while fuzzy parsing
	 */
	protected boolean fAbort;

	/**
	 * True when a compilation unit is being constructed. False when any other
	 * type of document fragment is being constructed.
	 */
	protected boolean fBuildingCU = false;

	/**
	 * True when a compilation unit or type is being constructed. False when any
	 * other type of document fragment is being constructed.
	 */
	protected boolean fBuildingType = false;

	/**
	 * The String on which the JDOM is being created.
	 */
	protected char[] fDocument = null;

	/**
	 * The source positions of all of the line separators in the document.
	 */
	protected int[] fLineStartPositions = new int[] { 0 };

	/**
	 * A stack of enclosing scopes used when constructing a compilation unit or
	 * type. The top of the stack is the document fragment that children are
	 * added to.
	 */
	protected Stack fStack = null;

	/**
	 * The number of fields constructed in the current document. This is used
	 * when building a single field document fragment, since the DOMBuilder only
	 * accepts documents with one field declaration.
	 */
	protected int fFieldCount;

	/**
	 * The current node being constructed.
	 */
	protected DOMNode fNode;

	/**
	 * AbstractDOMBuilder constructor.
	 */
	public AbstractDOMBuilder() {
		super();
	}

	/**
	 * Accepts the line separator table and converts it into a line start table.
	 * 
	 * <p>
	 * A line separator might corresponds to several characters in the source.
	 * 
	 * @see IDocumentElementRequestor#acceptLineSeparatorPositions(int[])
	 */
	public void acceptLineSeparatorPositions(int[] positions) {
		if (positions != null) {
			int length = positions.length;
			if (length > 0) {
				fLineStartPositions = new int[length + 1];
				fLineStartPositions[0] = 0;
				int documentLength = fDocument.length;
				for (int i = 0; i < length; i++) {
					int iPlusOne = i + 1;
					int positionPlusOne = positions[i] + 1;
					if (positionPlusOne < documentLength) {
						if (iPlusOne < length) {
							// more separators
							fLineStartPositions[iPlusOne] = positionPlusOne;
						} else {
							// no more separators
							if (fDocument[positionPlusOne] == '\n') {
								fLineStartPositions[iPlusOne] = positionPlusOne + 1;
							} else {
								fLineStartPositions[iPlusOne] = positionPlusOne;
							}
						}
					} else {
						fLineStartPositions[iPlusOne] = positionPlusOne;
					}
				}
			}
		}
	}

	/**
	 * Does nothing.
	 */
	public void acceptProblem(IProblem problem) {
	} // TODO: (olivier) unused?

	/**
	 * Adds the given node to the current enclosing scope, building the JDOM
	 * tree. Nodes are only added to an enclosing scope when a compilation unit
	 * or type is being built (since those are the only nodes that have
	 * children).
	 * 
	 * <p>
	 * NOTE: nodes are added to the JDOM via the method #basicAddChild such that
	 * the nodes in the newly created JDOM are not fragmented.
	 */
	protected void addChild(IDOMNode child) {
		if (fStack.size() > 0) {
			DOMNode parent = (DOMNode) fStack.peek();
			if (fBuildingCU || fBuildingType) {
				parent.basicAddChild(child);
			}
		}
	}

	/**
	 * @see IDOMFactory#createCompilationUnit(String, String)
	 */
	public IDOMCompilationUnit createCompilationUnit(char[] contents,
			char[] name) {
		return createCompilationUnit(new CompilationUnit(contents, name));
	}

	/**
	 * @see IDOMFactory#createCompilationUnit(String, String)
	 */
	public IDOMCompilationUnit createCompilationUnit(
			ICompilationUnit compilationUnit) {
		if (fAbort) {
			return null;
		}
		fNode.normalize(this);
		return (IDOMCompilationUnit) fNode;
	}

	/**
	 * @see IDocumentElementRequestor#enterClass(int, int[], int, int, int,
	 *      char[], int, int, char[], int, int, char[][], int[], int[], int)
	 */
	public void enterCompilationUnit() {
		if (fBuildingCU) {
			IDOMCompilationUnit cu = new DOMCompilationUnit(fDocument,
					new int[] { 0, fDocument.length - 1 });
			fStack.push(cu);
		}
	}

	/**
	 * Finishes the configuration of the compilation unit DOM object which was
	 * created by a previous enterCompilationUnit call.
	 * 
	 * @see IDocumentElementRequestor#exitCompilationUnit(int)
	 */
	public void exitCompilationUnit(int declarationEnd) {
		DOMCompilationUnit cu = (DOMCompilationUnit) fStack.pop();
		cu.setSourceRangeEnd(declarationEnd);
		fNode = cu;
	}

	/**
	 * Finishes the configuration of the class and interface DOM objects.
	 * 
	 * @param bodyEnd -
	 *            a source position corresponding to the closing bracket of the
	 *            class
	 * @param declarationEnd -
	 *            a source position corresponding to the end of the class
	 *            declaration. This can include whitespace and comments
	 *            following the closing bracket.
	 */
	protected void exitType(int bodyEnd, int declarationEnd) {
		DOMType type = (DOMType) fStack.pop();
		type.setSourceRangeEnd(declarationEnd);
		type.setCloseBodyRangeStart(bodyEnd);
		type.setCloseBodyRangeEnd(bodyEnd);
		fNode = type;
	}

	/**
	 * @see ILineStartFinder#getLineStart(int)
	 */
	public int getLineStart(int position) {
		int lineSeparatorCount = fLineStartPositions.length;
		// reverse traversal intentional.
		for (int i = lineSeparatorCount - 1; i >= 0; i--) {
			if (fLineStartPositions[i] <= position)
				return fLineStartPositions[i];
		}
		return 0;
	}

	/**
	 * Initializes the builder to create a document fragment.
	 * 
	 * @param sourceCode -
	 *            the document containing the source code to be analyzed
	 * @param buildingCompilationUnit -
	 *            true if a the document is being analyzed to create a
	 *            compilation unit, otherwise false
	 * @param buildingType -
	 *            true if the document is being analyzed to create a type or
	 *            compilation unit
	 */
	protected void initializeBuild(char[] sourceCode,
			boolean buildingCompilationUnit, boolean buildingType) {
		fBuildingCU = buildingCompilationUnit;
		fBuildingType = buildingType;
		fStack = new Stack();
		fDocument = sourceCode;
		fFieldCount = 0;
		fAbort = false;
	}
}