/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.camel.model.language;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlTransient;
import javax.xml.xpath.XPathFactory;

import org.apache.camel.CamelContext;
import org.apache.camel.Expression;
import org.apache.camel.Predicate;
import org.apache.camel.builder.xml.XPathBuilder;
import org.apache.camel.util.ObjectHelper;

/**
 * For XPath expressions and predicates
 */
@XmlRootElement(name = "xpath")
@XmlAccessorType(XmlAccessType.FIELD)
public class XPathExpression extends NamespaceAwareExpression {
    @XmlAttribute(name = "resultType")
    private String resultTypeName;
    @XmlAttribute(name = "saxon")
    private Boolean saxon;
    @XmlAttribute(name = "factoryRef")
    private String factoryRef;
    @XmlAttribute(name = "objectModel")
    private String objectModel;
    @XmlAttribute(name = "traceNamespaces")
    private Boolean traceNamespaces;

    @XmlTransient
    private Class<?> resultType;
    @XmlTransient
    private XPathFactory xpathFactory;

    public XPathExpression() {
    }

    public XPathExpression(String expression) {
        super(expression);
    }

    public XPathExpression(Expression expression) {
        setExpressionValue(expression);
    }

    public String getLanguage() {
        return "xpath";
    }

    public Class<?> getResultType() {
        return resultType;
    }

    public void setResultType(Class<?> resultType) {
        this.resultType = resultType;
    }

    public String getResultTypeName() {
        return resultTypeName;
    }

    public void setResultTypeName(String resultTypeName) {
        this.resultTypeName = resultTypeName;
    }

    public void setSaxon(Boolean saxon) {
        this.saxon = saxon;
    }

    public Boolean getSaxon() {
        return saxon;
    }

    public boolean isSaxon() {
        return saxon != null && saxon;
    }

    public void setFactoryRef(String factoryRef) {
        this.factoryRef = factoryRef;
    }

    public String getFactoryRef() {
        return factoryRef;
    }

    public void setObjectModel(String objectModel) {
        this.objectModel = objectModel;
    }

    public String getObjectModel() {
        return objectModel;
    }

    public void setTraceNamespaces(Boolean traceNamespaces) {
        this.traceNamespaces = traceNamespaces;
    }

    public Boolean getTraceNamespaces() {
        return traceNamespaces;
    }

    public boolean isTraceNamespaces() {
        return traceNamespaces != null && traceNamespaces;
    }

    @Override
    public Expression createExpression(CamelContext camelContext) {
        if (resultType == null && resultTypeName != null) {
            try {
                resultType = camelContext.getClassResolver().resolveMandatoryClass(resultTypeName);
            } catch (ClassNotFoundException e) {
                throw ObjectHelper.wrapRuntimeCamelException(e);
            }
        }
        resolveXPathFactory(camelContext);
        return super.createExpression(camelContext);
    }

    @Override
    public Predicate createPredicate(CamelContext camelContext) {
        resolveXPathFactory(camelContext);
        return super.createPredicate(camelContext);
    }

    @Override
    protected void configureExpression(CamelContext camelContext, Expression expression) {
        if (resultType != null) {
            setProperty(expression, "resultType", resultType);
        }
        if (isSaxon()) {
            ObjectHelper.cast(XPathBuilder.class, expression).enableSaxon();
        }
        if (xpathFactory != null) {
            setProperty(expression, "xPathFactory", xpathFactory);
        }
        if (objectModel != null) {
            setProperty(expression, "objectModelUri", objectModel);
        }
        if (isTraceNamespaces()) {
            ObjectHelper.cast(XPathBuilder.class, expression).setTraceNamespaces(true);
        }
        // moved the super configuration to the bottom so that the namespace init picks up the newly set XPath Factory
        super.configureExpression(camelContext, expression);

    }

    @Override
    protected void configurePredicate(CamelContext camelContext, Predicate predicate) {
        if (resultType != null) {
            setProperty(predicate, "resultType", resultType);
        }
        if (isSaxon()) {
            ObjectHelper.cast(XPathBuilder.class, predicate).enableSaxon();
        }
        if (xpathFactory != null) {
            setProperty(predicate, "xPathFactory", xpathFactory);
        }
        if (objectModel != null) {
            setProperty(predicate, "objectModelUri", objectModel);
        }
        if (isTraceNamespaces()) {
            ObjectHelper.cast(XPathBuilder.class, predicate).setTraceNamespaces(true);
        }
        // moved the super configuration to the bottom so that the namespace init picks up the newly set XPath Factory
        super.configurePredicate(camelContext, predicate);
    }

    private void resolveXPathFactory(CamelContext camelContext) {
        // Factory and Object Model can be set simultaneously. The underlying XPathBuilder allows for setting Saxon too, as it is simply a shortcut for
        // setting the appropriate Object Model, it is not wise to allow this in XML because the order of invocation of the setters by JAXB may cause undeterministic behaviour 
        if ((ObjectHelper.isNotEmpty(factoryRef) || ObjectHelper.isNotEmpty(objectModel)) && (saxon != null)) {
            throw new IllegalArgumentException("The saxon attribute cannot be set on the xpath element if any of the following is also set: factory, objectModel" + this);
        }

        // Validate the factory class
        if (ObjectHelper.isNotEmpty(factoryRef)) {
            xpathFactory = camelContext.getRegistry().lookup(factoryRef, XPathFactory.class);
            if (xpathFactory == null) {
                throw new IllegalArgumentException("The provided XPath Factory is invalid; either it cannot be resolved or it is not an XPathFactory instance");
            }
        }
    }
}
