/*******************************************************************************
 * Copyright (c) 2000, 2016 IBM Corporation and others.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 * 
 * SPDX-License-Identifier: EPL-2.0
 *
 *          (report 36180: Callers/Callees view)
 *******************************************************************************/
package org.eclipse.dltk.internal.corext.callhierarchy;

import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.dltk.core.IBuffer;
import org.eclipse.dltk.core.IModelElement;
import org.eclipse.dltk.core.IOpenable;
import org.eclipse.dltk.core.ISourceModule;
import org.eclipse.dltk.core.ModelException;
import org.eclipse.dltk.ui.DLTKUIPlugin;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.Document;

public class CallLocation implements IAdaptable {
	public static final int UNKNOWN_LINE_NUMBER = -1;
	private IModelElement fMember;
	private IModelElement fCalledMember;
	private int fStart;
	private int fEnd;

	private String fCallText;
	private int fLineNumber;

	public CallLocation(IModelElement member, IModelElement calledMember,
			int start, int end, int lineNumber) {
		this.fMember = member;
		this.fCalledMember = calledMember;
		this.fStart = start;
		this.fEnd = end;
		this.fLineNumber = lineNumber;
	}

	/**
	 * @return IMethod
	 */
	public IModelElement getCalledMember() {
		return fCalledMember;
	}

	/**
     *
     */
	public int getEnd() {
		return fEnd;
	}

	public IModelElement getMember() {
		return fMember;
	}

	/**
     *
     */
	public int getStart() {
		return fStart;
	}

	public int getLineNumber() {
		initCallTextAndLineNumber();
		return fLineNumber;
	}

	public String getCallText() {
		initCallTextAndLineNumber();
		return fCallText;
	}

	private void initCallTextAndLineNumber() {
		if (fCallText != null)
			return;

		String buffer = getBufferForMember();
		if (buffer == null || buffer.length() < fEnd) { // binary, without
			// source attachment
			// || buffer
			// contents out of
			// sync (bug 121900)
			fCallText = ""; //$NON-NLS-1$
			fLineNumber = UNKNOWN_LINE_NUMBER;
			return;
		}

		fCallText = buffer.substring(fStart, fEnd);

		if (fLineNumber == UNKNOWN_LINE_NUMBER) {
			Document document = new Document(buffer);
			try {
				fLineNumber = document.getLineOfOffset(fStart) + 1;
			} catch (BadLocationException e) {
				DLTKUIPlugin.log(e);
			}
		}
	}

	/**
	 * Returns the IBuffer for the IMember represented by this CallLocation.
	 * 
	 * @return IBuffer for the IMember or null if the member doesn't have a
	 *         buffer (for example if it is a binary file without source
	 *         attachment).
	 */
	private String getBufferForMember() {
		IBuffer buffer = null;
		try {
			IOpenable openable = fMember.getOpenable();
			if (openable != null && fMember.exists()) {
				buffer = openable.getBuffer();
				if (buffer != null) {
					return buffer.getContents();
				}
				if (openable instanceof ISourceModule) {
					return ((ISourceModule) openable).getSource();
				}
			}
		} catch (ModelException e) {
			DLTKUIPlugin.log(e);
		}
		return null;
	}

	@Override
	public String toString() {
		return getCallText();
	}

	@SuppressWarnings("unchecked")
	@Override
	public <T> T getAdapter(Class<T> adapter) {
		if (IModelElement.class.isAssignableFrom(adapter)) {
			return (T) getMember();
		}

		return null;
	}
}