package org.gcube.informationsystem.collector.impl.persistence;

import org.gcube.common.core.utils.logging.GCUBELog;
import org.gcube.informationsystem.collector.impl.persistence.AggregatorPersistentResource;
import org.gcube.informationsystem.collector.impl.xmlstorage.exist.State;

import org.xmldb.api.modules.XMLResource;
import org.xmldb.api.base.XMLDBException;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.StringReader;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.TimeZone;

import java.lang.Exception;

import org.w3c.dom.*;

import org.xml.sax.InputSource;

import javax.xml.parsers.*;
import javax.xml.xpath.*;

/**
 * AggregatorPersistentResource represents a resource in the XML Storage
 * repository
 * 
 * @author Manuele Simi (ISTI-CNR)
 * 
 */

public class AggregatorPersistentResource extends PersistentResource {

    private String resourceID = null;

    private String resource_string = null;

    // the resource type states if the resource contains a profile or generic
    // WS-ResourceProperties
    private RESOURCETYPE type = null;

    // the profile type states which kind of profiles the resource contains
    // (RunningInstance, Service, etc.)
    private String profile_type = null;

    // the various parts of the resource
    private String data, /* service_class, service_id, ri_id, ghn_id, scope, */
    entryKey, groupKey, source, sourceKey = "", completeSourceKey = "";

    private Calendar terminationTime = null, lastUpdateTime = null;

    private static GCUBELog logger = new GCUBELog(
	    AggregatorPersistentResource.class);

    // the source XMLResource (if any)
    private XMLResource originalSource = null;

    // the XML DOM loaded from the resource string
    private Document internalDOM = null;

    // xpath factory to evaluate Xpath expressions
    private XPath path = XPathFactory.newInstance().newXPath();

    /**
     * Builds a new empty DISPersinstentresource
     * 
     */
    public AggregatorPersistentResource() {

	// defatult termination time is now
	Calendar cal = new GregorianCalendar();
	cal.setTimeZone(TimeZone.getTimeZone("GMT"));
	this.setTerminationTime(cal);

	lastUpdateTime = new GregorianCalendar();
	lastUpdateTime.setTimeZone(TimeZone.getTimeZone("GMT"));
    }

    /**
     * Builds a DISPersinstentresource starting from an eXist resource
     * 
     * @param resource
     *            the input eXist resource
     * @throws Exception
     *             if the resource is invalid
     */
    public AggregatorPersistentResource(XMLResource resource) throws Exception {
	try {
	    this.resourceID = resource.getId();
	    this.originalSource = resource;
	    this.resource_string = resource.getContent().toString();
	    this.parseResource();
	} catch (XMLDBException dbe) {
	    throw new Exception("invalid resource");
	}
    }

    /**
     * Sets the content of the resource
     * 
     * @param data
     *            the new content
     * 
     */
    public void setData(String data) {
	this.data = data;
    }

    /**
     * Sets the content of the resource using the content of a file
     * 
     * @param f
     *            the file to use as content source
     * 
     * @throws IOException
     *             if the access to the given file fails
     * 
     */
    public void setData(File f) throws IOException {
	try {
	    FileInputStream fin = new FileInputStream(f);
	    this.data = fin.toString();
	} catch (IOException ioe) {
	    System.out.print(State.logPrefix
		    + "unable to set content from file " + f.getAbsolutePath());
	    throw ioe;
	}
    }

    /**
     * Accesses the resource content
     * 
     * @return the content
     */
    public String getData() {
	return this.data;
    }

    /**
     * 
     * @return the original XMLResource from which the resource has been
     *         generated (if any)
     */
    public XMLResource getOriginalXMLResource() {
	return this.originalSource;
    }

    /**
     * Accesses the resource ID
     * 
     * @return the ID
     */
    public String getID() {

	// create a unique ID unless the resource contains a profile
	if (this.resourceID == null)
	    this.resourceID = this.getGroupKey() + this.getEntryKey();

	return this.resourceID;
    }

    /**
     * Accesses the source GroupKey
     * 
     * @return the ID
     */
    public String getGroupKey() {
	return this.groupKey;
    }

    /**
     * Sets the source GroupKey
     * 
     * @param groupKey
     *            the new group key
     * 
     */
    public void setGroupKey(String groupKey) {
	this.groupKey = groupKey;
    }

    /**
     * Accesses the source EntryKey
     * 
     * @return the ID
     */
    public String getEntryKey() {
	return this.entryKey;
    }

    /**
     * Sets the source EntryKey
     * 
     * @param entryKey
     *            the new entry key
     */
    public void setEntryKey(String entryKey) {
	this.entryKey = entryKey;
    }

    /**
     * Sets the source address of the RI that publishes resource as reported in
     * the servicegroup entry
     * 
     * @param source
     *            the new source address
     */
    public void setSource(String source) {
	this.source = source;
    }

    /**
     * Accesses the source address of the service that published the data
     * 
     * @return the source
     */
    public String getSource() {
	return this.source;
    }

    /**
     * Sets the key of the WS-Resource that published the data
     * 
     * @param key
     *            the new source key
     */
    public void setSourceKey(String key) {
	this.sourceKey = key;
    }

    /**
     * Gets the key of the WS-Resource that published the data
     * 
     * @return the key
     */
    public String getSourceKey() {
	return this.sourceKey;
    }

    /**
     * Sets the complete source key
     * 
     * @param completeKey
     *            the new complete key
     */
    public void setCompleteSourceKey(String completeKey) {
	this.completeSourceKey = completeKey;
    }

    /**
     * Gets the complete source key
     * 
     * @return the complete source key
     */
    public String getCompleteSourceKey() {
	return this.completeSourceKey;
    }

    /**
     * Sets the resource type. The actual implementation supports "Profile" and
     * "Properties" as type
     * 
     * @param type
     *            "Profile" or "Properties"
     */

    public void setType(RESOURCETYPE type) {
	this.type = type;
    }

    /**
     * Accesses the resource type. The actual implementation supports "Profile"
     * and "Properties" as type
     * 
     * @return the type
     */
    public RESOURCETYPE getType() {
	return this.type;
    }

    /**
     * Updates the resource body
     * 
     * @param data
     *            the new body
     * 
     */
    public void updateData(String data) {
	this.data = data;
    }

    /**
     * Builds a XML representation of the resource
     * 
     * @return a String in the form of <Document>... <Data> resource
     *         content </Data> </Document>
     */
    private String toXML() {

	String rep = "<Document>\n";
	rep += "<ID>" + this.getID() + "</ID>\n";
	rep += "<Source>" + this.getSource() + "</Source>\n";
	rep += "<SourceKey>" + this.getSourceKey() + "</SourceKey>\n";
	rep += "<CompleteSourceKey>" + this.getCompleteSourceKey()
		+ "</CompleteSourceKey>\n";
	rep += "<EntryKey>" + this.getEntryKey() + "</EntryKey>\n";
	rep += "<GroupKey>" + this.getGroupKey() + "</GroupKey>\n";
	rep += "<TerminationTime>"
		+ this.getTerminationTime().getTimeInMillis()
		+ "</TerminationTime>\n";
	rep += "<TerminationTimeHuman>"
		+ this.getTerminationTime().getTime().toString()
		+ "</TerminationTimeHuman>\n";
	rep += "<LastUpdateMs>" + this.lastUpdateTime.getTimeInMillis()
		+ "</LastUpdateMs>\n";
	rep += "<LastUpdateHuman>" + this.lastUpdateTime.getTime().toString()
		+ "</LastUpdateHuman>\n";
	rep += this.getData() + "\n";
	rep += "</Document>\n";
	return rep;
    }

    /**
     * 
     * @return a String representation of the resource
     */
    public String toString() {
	if (this.resource_string == null)
	    return this.toXML();
	else
	    return this.resource_string;
    }

    /**
     * Accesses the type of resource to which the profile is related to (if any)
     * 
     * @return null if the resource does not contain a profile
     */
    public String getProfileType() {
	if (this.profile_type != null) {
	    // the profile type has been already extracted
	    return this.profile_type;
	}

	if ((this.type != null) && (type == RESOURCETYPE.Profile)) {
	    try {
		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
		DocumentBuilder builder = factory.newDocumentBuilder();
		StringReader reader = new StringReader(this.toXML());
		InputSource source = new InputSource(reader);
		Document internalDOM = builder.parse(source);
		// gets the type
		XPath path = XPathFactory.newInstance().newXPath();
		this.profile_type = path
			.evaluate(
				"/Document/Data/child::*[local-name()='Profile']/Resource/Type",
				internalDOM);
		// uses the DILIGENT ID as resource ID
		this.resourceID = path
			.evaluate(
				"/Document/Data/child::*[local-name()='Profile']/Resource/ID",
				internalDOM);

	    } catch (Exception e) {
		logger
			.error(State.logPrefix
				+ "Unable to extract the profile type from the resource "
				+ e.getMessage());

	    }
	}
	return this.profile_type;
    }

    /**
     * @return the terminationTime of this resource
     */
    public Calendar getTerminationTime() {
	return terminationTime;
    }

    /**
     * @param terminationTime
     *            the terminationTime to set
     */
    public void setTerminationTime(Calendar terminationTime) {
	this.terminationTime = (Calendar) terminationTime.clone();
	this.terminationTime.setTimeZone(TimeZone.getTimeZone("GMT"));
    }

    /**
     * Compares two resources
     * 
     * @param o
     *            the resource to compare
     * @return true if the resources have the same ID
     */
    public boolean equals(Object o) {
	// check the class this object is instance of
	if (!(o instanceof AggregatorPersistentResource))
	    return false;
	// compare the two objects
	AggregatorPersistentResource key = (AggregatorPersistentResource) o;
	if (key.getID() == this.getID())
	    return true;
	else
	    return false;
    }

    /**
     * @return the lastUpdateTime in milliseconds
     * @throws Exception if an error occurs when accessing the LastUpdateMs field
     */
    public long getLastUpdateTimeinMills() throws Exception {

	if (lastUpdateTime != null)
	    return lastUpdateTime.getTimeInMillis();
	
	if ((lastUpdateTime == null) && (this.internalDOM != null)) {
	    String value = "";
	    try {
		value = path.evaluate("Document/LastUpdateMs", this.internalDOM);
	    } catch (XPathExpressionException xpee) {
		logger.error(State.logPrefix + "" + xpee.getMessage());
		logger.error(State.logPrefix + "" + xpee.getStackTrace());
		throw new Exception("XPath evaluation error");
	    }
	    try {
		return Long.parseLong(value);
	    } catch (NumberFormatException nfe) {
		logger.error("Invalid last update time format found in resource " + this.getID());
		logger.error("Parsed string was " + value);
		throw new Exception("Unable to retrieve last update time for resource "	+ this.getID());
	    }

	} else
	    throw new Exception("unable to retrieve last update time for resource " + this.getID());

    }

    /**
     * Loads the XML DOM from the resource string
     * 
     */
    private void parseResource() throws Exception {
	logger.debug("Parsing resource: " + this.resource_string);
	DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
	DocumentBuilder builder = factory.newDocumentBuilder();
	StringReader reader = new StringReader(this.resource_string);
	InputSource source = new InputSource(reader);
	this.internalDOM = builder.parse(source);

    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.gcube.informationsystem.collector.impl.persistence.PersistentResource
     * #getPublisher()
     */
    @Override
    public String getPublisher() {
	return null;
    }


    /*
     * (non-Javadoc)
     * 
     * @see
     * org.gcube.informationsystem.collector.impl.persistence.PersistentResource
     * #setPublisher(java.lang.String)
     */
    @Override
    public void setPublisher(String publisher) {

    }
}