package org.madore.damlengine;

import java.util.regex.Pattern;
import java.util.regex.Matcher;
import org.w3c.dom.*;

public class TodoWrefAttr extends TodoAttr {

    public static class Factory extends TodoAttr.Factory {
	@Override
	public TodoWrefAttr newItem(Attr attr, Element owner,
				    Context ctx,
				    TodoItem caller) {
	    return new TodoWrefAttr(attr, owner, ctx, caller);
	}
    }

    public TodoWrefAttr(Attr attr, Element owner,
			Context ctx,
			TodoItem caller) {
	super(attr, owner, ctx, caller);
    }

    @Override
    public void handle() {
	String wrefStr = attr.getValue();
	Matcher wrefMatcher = Pattern.compile("^\\#d\\.(\\d{4})-(\\d{2})-(\\d{2})\\.(\\d{4})(|\\..*)$").matcher(wrefStr);
	if ( ! wrefMatcher.matches() )
	    throw new IllegalArgumentException("wref attribute must be of the form #d.YYYY-MM-DD.NNNN[.xxx]");
	String wrefYearStr = wrefMatcher.group(1);
	String wrefMonthStr = wrefMatcher.group(2);
	String wrefDayStr = wrefMatcher.group(3);
	String wrefNumberStr = wrefMatcher.group(4);
	int wrefNumber = Integer.parseInt(wrefNumberStr);
	String wrefSupplementStr = wrefMatcher.group(5);
	String wrefCat;
	if ( this.owner.hasAttributeNS(DamlEngine.DAML_NS, "wrefcat") ) {
	    wrefCat = this.owner.getAttributeNS(DamlEngine.DAML_NS, "wrefcat");
	    this.owner.removeAttributeNS(DamlEngine.DAML_NS, "wrefcat");
	} else {
	    wrefCat = null;
	}
	String targetFile;
	String targetStdDir = (ctx.gc.uriToTop==null)?"":(ctx.gc.uriToTop+"weblog/");
	WeblogSummary wsum = WeblogSummary.getSummary();
	WeblogSummary.EntrySummary esum;
	// Get entry for target link from weblog summary
	if ( wsum != null && wsum.entries != null )
	    esum = wsum.entries.get(wrefNumber);
	else
	    esum = null;
	// Check consistency if summary was available
	if ( esum != null ) {
	    if ( ! ((wrefYearStr+"-"+wrefMonthStr+"-"+wrefDayStr)
		    .equals(esum.date)) )
		throw new IllegalArgumentException("date mismatch for reference to entry "+wrefNumberStr);
	    if ( wrefCat != null && ! wrefCat.equals("@month")
		  && ! wrefCat.equals("@single") ) {
		if ( esum.catSet == null || ! esum.catSet.contains(wrefCat) )
		    throw new IllegalArgumentException("reference to entry "+wrefNumberStr+" in wrong category "+wrefCat);
	    }
	}
	// Choose file portion of link target
	if ( esum != null && esum.doSinglePage != null && ! wrefSupplementStr.equals("") ) {
	    // Linking to a _fragment_ of an entry that has a single page.
	    if ( wrefCat != null && ! wrefCat.equals("@single") )
		System.err.println("warning: ignoring d:wrefcat attribute!");
	    if ( ctx.wsc != null && ctx.wsc.sel != null
		 && ctx.wsc instanceof Context.WeblogSingleSelectionContext
		 && ((Context.WeblogSingleSelectionContext)ctx.wsc).number == wrefNumber )
		targetFile = "";
	    else
		targetFile = targetStdDir + esum.date + "-" + esum.doSinglePage + ".html";
	} else if ( ctx.wsc != null && ctx.wsc.sel != null
	     && ctx.wsc.sel.contains(wrefNumber) ) {
	    // Linking to an entry already present on this page.
	    targetFile = "";
	} else if ( wrefCat != null && ! wrefCat.equals("@month")
		    && ! wrefCat.equals("@single") ) {
	    // Linking to an entry in a designated category.
	    targetFile = targetStdDir + wrefCat + ".html";
	} else {
	    // Linking to an entry in its month, or single page.
	    targetFile = targetStdDir + wrefYearStr + "-" + wrefMonthStr + ".html";
	    if ( esum != null && esum.doSinglePage != null
		 // Note to self: remember we could be called from d:wxref
		 // because of link on "older entries".
		 && ( wrefCat == null || wrefCat.equals("@single") ) ) {
		targetFile = targetStdDir + esum.date + "-" + esum.doSinglePage + ".html";
	    }
	}
	// Construct full link target
	String targetFragment = "d." + wrefYearStr + "-" + wrefMonthStr
	    + "-" + wrefDayStr + "." + wrefNumberStr + wrefSupplementStr;
	String target = targetFile + "#" + targetFragment;
	// Class and title attributes
	if ( ! this.owner.hasAttributeNS(null, "class") )
	    this.owner.setAttributeNS(null, "class", "weblog-internal-link");
	if ( wrefSupplementStr.equals("")
	     && ! this.owner.hasAttributeNS(null, "title")
	     && esum != null && esum.title != null )
	    this.owner.setAttributeNS(null, "title", esum.title);
	// Replace this attribute by computed target
	this.owner.removeAttributeNode(this.attr);
	this.owner.setAttributeNS(null, "href", target);
    }

}