/*****************************************************************************
 * 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.wst.css.ui.contentassist;


import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.eclipse.wst.css.core.document.ICSSCharsetRule;
import org.eclipse.wst.css.core.document.ICSSDocument;
import org.eclipse.wst.css.core.document.ICSSImportRule;
import org.eclipse.wst.css.core.document.ICSSModel;
import org.eclipse.wst.css.core.document.ICSSNode;
import org.eclipse.wst.css.core.metamodel.CSSMMNode;
import org.eclipse.wst.css.core.metamodel.util.CSSMetaModelUtil;
import org.eclipse.wst.css.core.parser.CSSRegionContexts;
import org.eclipse.wst.css.core.preferences.CSSPreferenceHelper;
import org.eclipse.wst.css.core.util.SelectionCollector;
import org.eclipse.wst.css.ui.image.CSSImageType;
import org.eclipse.wst.sse.core.text.ITextRegion;

class CSSProposalGeneratorForAtmarkRule extends CSSProposalGenerator {

	private boolean fUseUpperCase = false;
	private static final String CHARSET = "@charset";//$NON-NLS-1$
	private static final String FONT_FACE = "@font-face";//$NON-NLS-1$
	private static final String IMPORT = "@import";//$NON-NLS-1$
	private static final String MEDIA = "@media";//$NON-NLS-1$
	private static final String PAGE = "@page";//$NON-NLS-1$

	/**
	 * CSSAtmarkRuleProposalGenerator constructor comment.
	 * 
	 * @param context
	 *            com.ibm.sed.contentassist.old.css.CSSContentAssistContext
	 */
	CSSProposalGeneratorForAtmarkRule(CSSContentAssistContext context) {
		super(context);
		fUseUpperCase = CSSPreferenceHelper.getInstance().isIdentUpperCase();
	}

	/**
	 *  
	 */
	private CSSCACandidate getCandidateCharsetRule() {
		// check content model
		CSSMetaModelUtil util = new CSSMetaModelUtil(fContext.getMetaModel());
		if (!util.collectNodesByType(CSSMMNode.TYPE_CHARSET_RULE).hasNext()) {
			return null;
		}

		// check if embedded or not
		if (fContext.getModel().getStyleSheetType() == ICSSModel.EMBEDDED) {
			return null;
		}

		// check if caret precede all other rules.
		int offset = fContext.getCursorPos();
		if (0 < offset) {
			SelectionCollector trav = new SelectionCollector();
			trav.setRegion(0, offset - 1);
			trav.apply(fContext.getModel().getDocument());
			Iterator i = trav.getSelectedNodes().iterator();
			while (i.hasNext()) {
				Object obj = i.next();
				if (obj instanceof ICSSNode && !(obj instanceof ICSSDocument)) {
					return null;
				}
			}
		}

		int cursorPos = 0;
		String ident = (fUseUpperCase) ? CHARSET.toUpperCase() : CHARSET.toLowerCase();
		StringBuffer buf = new StringBuffer();
		buf.append(ident);
		buf.append(" ");//$NON-NLS-1$
		cursorPos = buf.length();
		StringAndOffset sao;
		sao = generateQuotes();
		buf.append(sao.fString);
		cursorPos += sao.fOffset;
		sao = generateSemicolon();
		buf.append(sao.fString);

		String text = buf.toString();

		if (isMatch(text)) {
			CSSCACandidate item = new CSSCACandidate();
			item.setReplacementString(text);
			item.setCursorPosition(cursorPos);
			item.setDisplayString(ident);
			item.setImageType(CSSImageType.RULE_CHARSET);
			return item;
		} else {
			return null;
		}
	}

	/**
	 *  
	 */
	private CSSCACandidate getCandidateFontFaceRule() {
		CSSMetaModelUtil util = new CSSMetaModelUtil(fContext.getMetaModel());
		if (!util.collectNodesByType(CSSMMNode.TYPE_FONT_FACE_RULE).hasNext()) {
			return null;
		}

		int cursorPos = 0;
		String ident = (fUseUpperCase) ? FONT_FACE.toUpperCase() : FONT_FACE.toLowerCase();
		StringBuffer buf = new StringBuffer();
		buf.append(ident);
		buf.append(" ");//$NON-NLS-1$
		cursorPos = buf.length();
		StringAndOffset sao;
		sao = generateBraces();
		buf.append(sao.fString);
		cursorPos += sao.fOffset;

		String text = buf.toString();

		if (isMatch(text)) {
			CSSCACandidate item = new CSSCACandidate();
			item.setReplacementString(buf.toString());
			item.setCursorPosition(cursorPos);
			item.setDisplayString(ident);
			item.setImageType(CSSImageType.RULE_FONTFACE);
			return item;
		} else {
			return null;
		}
	}

	/**
	 *  
	 */
	private CSSCACandidate getCandidateImportRule() {
		// check content model
		CSSMetaModelUtil util = new CSSMetaModelUtil(fContext.getMetaModel());
		if (!util.collectNodesByType(CSSMMNode.TYPE_IMPORT_RULE).hasNext()) {
			return null;
		}

		// charset and import can precede import rule.
		int offset = fContext.getCursorPos();
		if (0 < offset) {
			SelectionCollector trav = new SelectionCollector();
			trav.setRegion(0, offset - 1);
			trav.apply(fContext.getModel().getDocument());
			Iterator i = trav.getSelectedNodes().iterator();
			while (i.hasNext()) {
				Object obj = i.next();
				if (obj instanceof ICSSNode && !(obj instanceof ICSSDocument || obj instanceof ICSSCharsetRule || obj instanceof ICSSImportRule)) {
					return null;
				}
			}
		}

		int cursorPos = 0;
		String ident = (fUseUpperCase) ? IMPORT.toUpperCase() : IMPORT.toLowerCase();
		StringBuffer buf = new StringBuffer();
		buf.append(ident);
		buf.append(" ");//$NON-NLS-1$
		cursorPos = buf.length();
		StringAndOffset sao;
		sao = generateURI();
		buf.append(sao.fString);
		cursorPos += sao.fOffset;
		sao = generateSemicolon();
		buf.append(sao.fString);

		String text = buf.toString();

		if (isMatch(text)) {
			CSSCACandidate item = new CSSCACandidate();
			item.setReplacementString(buf.toString());
			item.setCursorPosition(cursorPos);
			item.setDisplayString(ident);
			item.setImageType(CSSImageType.RULE_IMPORT);
			return item;
		} else {
			return null;
		}
	}

	/**
	 *  
	 */
	private CSSCACandidate getCandidateMediaRule() {
		CSSMetaModelUtil util = new CSSMetaModelUtil(fContext.getMetaModel());
		if (!util.collectNodesByType(CSSMMNode.TYPE_MEDIA_RULE).hasNext()) {
			return null;
		}

		int cursorPos = 0;
		String ident = (fUseUpperCase) ? MEDIA.toUpperCase() : MEDIA.toLowerCase();
		StringBuffer buf = new StringBuffer();
		buf.append(ident);
		buf.append("  ");//$NON-NLS-1$
		cursorPos = buf.length() - 1;
		StringAndOffset sao;
		sao = generateBraces();
		buf.append(sao.fString);

		String text = buf.toString();

		if (isMatch(text)) {
			CSSCACandidate item = new CSSCACandidate();
			item.setReplacementString(buf.toString());
			item.setCursorPosition(cursorPos);
			item.setDisplayString(ident);
			item.setImageType(CSSImageType.RULE_MEDIA);
			return item;
		} else {
			return null;
		}
	}

	/**
	 *  
	 */
	private CSSCACandidate getCandidatePageRule() {
		CSSMetaModelUtil util = new CSSMetaModelUtil(fContext.getMetaModel());
		if (!util.collectNodesByType(CSSMMNode.TYPE_PAGE_RULE).hasNext()) {
			return null;
		}

		int cursorPos = 0;
		String ident = (fUseUpperCase) ? PAGE.toUpperCase() : PAGE.toLowerCase();
		StringBuffer buf = new StringBuffer();
		buf.append(ident);
		buf.append(" ");//$NON-NLS-1$
		cursorPos = buf.length();
		StringAndOffset sao;
		sao = generateBraces();
		buf.append(sao.fString);
		cursorPos += sao.fOffset;

		String text = buf.toString();

		if (isMatch(text)) {
			CSSCACandidate item = new CSSCACandidate();
			item.setReplacementString(buf.toString());
			item.setCursorPosition(cursorPos);
			item.setDisplayString(ident);
			item.setImageType(CSSImageType.RULE_PAGE);
			return item;
		} else {
			return null;
		}
	}

	/**
	 * getCandidates method comment.
	 */
	protected Iterator getCandidates() {
		List candidates = new ArrayList();

		ITextRegion region = fContext.getTargetRegionPrevious();
		//	ITextRegion region = fContext.getSignificantTargetRegion();
		if (region != null) {
			String type = region.getType();
			if (type != CSSRegionContexts.CSS_RBRACE && type != CSSRegionContexts.CSS_DELIMITER) {
				return candidates.iterator();
			}
		}

		CSSCACandidate item;
		if ((item = getCandidateImportRule()) != null) {
			candidates.add(item);
		}
		if ((item = getCandidateCharsetRule()) != null) {
			candidates.add(item);
		}
		if ((item = getCandidateMediaRule()) != null) {
			candidates.add(item);
		}
		if ((item = getCandidatePageRule()) != null) {
			candidates.add(item);
		}
		if ((item = getCandidateFontFaceRule()) != null) {
			candidates.add(item);
		}
		return candidates.iterator();
	}
}