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package org.robobinding.attribute;

import static org.robobinding.attribute.StaticResourceAttribute.isStaticResourceAttribute;
import static org.robobinding.attribute.ValueModelAttribute.isValueModelAttribute;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * 
 * @since 1.0
 * @version $Revision: 1.0 $
 * @author Robert Taylor
 * @author Cheng Wei
 */
public class PropertyAttributeParser {
    public AbstractPropertyAttribute parse(String name, String value) {
	if (isValueModelAttribute(value)) {
	    return new ValueModelAttribute(name, value);
	} else if (isStaticResourceAttribute(value)) {
	    return new StaticResourceAttribute(name, value);
	}

	throw new MalformedAttributeException(name, describeSyntaxError(value));
    }

    public ValueModelAttribute parseAsValueModelAttribute(String name, String value) {
	if (isValueModelAttribute(value)) {
	    return new ValueModelAttribute(name, value);
	}

	throw new MalformedAttributeException(name, describeSyntaxError(value));
    }

    StaticResourceAttribute parseAsStaticResourceAttribute(String name, String value) {
	if (isStaticResourceAttribute(value)) {
	    return new StaticResourceAttribute(name, value);
	}

	throw new MalformedAttributeException(name, describeSyntaxError(value));
    }

    private String describeSyntaxError(String value) {
	String errorMessage = "Invalid binding syntax: '" + value + "'.";

	Matcher propertyBindingAttempted = Pattern.compile("\\{.+|.+\\}").matcher(value);
	Matcher resourceBindingAttempted = Pattern.compile(".*@.*").matcher(value);

	if (!propertyBindingAttempted.matches())
	    errorMessage += "\n\nDid you mean '{" + value + "}' or '${" + value + "}'? (one/two-way binding)\n";
	else if (resourceBindingAttempted.matches())
	    errorMessage += "\n\nDid you mean to omit the curly braces? (Curly braces are for binding to a property on the presentation model, "
		    		+ "not static resources)";

	return errorMessage;
    }
}