/**
 * Licensed to Apereo under one or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information regarding copyright ownership. Apereo
 * 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 the
 * following location:
 *
 * <p>http://www.apache.org/licenses/LICENSE-2.0
 *
 * <p>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.apereo.portal.portlet.delegation.jsp;

import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import javax.portlet.PortletMode;
import javax.portlet.PortletSession;
import javax.portlet.RenderRequest;
import javax.portlet.RenderResponse;
import javax.portlet.WindowState;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.Tag;
import javax.servlet.jsp.tagext.TagData;
import javax.servlet.jsp.tagext.TagExtraInfo;
import javax.servlet.jsp.tagext.TagSupport;
import javax.servlet.jsp.tagext.ValidationMessage;
import org.apereo.portal.api.portlet.DelegateState;
import org.apereo.portal.api.portlet.DelegationRequest;
import org.apereo.portal.api.portlet.PortletDelegationDispatcher;
import org.apereo.portal.api.portlet.PortletDelegationLocator;
import org.apereo.portal.portlet.PortletUtils;
import org.apereo.portal.portlet.om.IPortletWindowId;

/**
 */
public class RenderPortletTag extends TagSupport {
    private static final long serialVersionUID = 1L;

    public static final String DEFAULT_SESSION_KEY_PREFIX = "DELEGATE_WINDOW_ID__";

    public static class TEI extends TagExtraInfo {
        @Override
        public ValidationMessage[] validate(TagData data) {
            final List<ValidationMessage> messages = new ArrayList<ValidationMessage>();

            Object o = data.getAttribute("fname");
            if (o == null) {
                messages.add(new ValidationMessage(data.getId(), "fname cannot be null."));
            }

            if (messages.size() == 0) {
                return null;
            }

            return messages.toArray(new ValidationMessage[messages.size()]);
        }
    }

    private String sessionKeyPrefix = DEFAULT_SESSION_KEY_PREFIX;
    private String fname = null;
    private String windowState = null;
    private String portletMode = null;

    private transient WindowState parentUrlState = null;
    private transient PortletMode parentUrlMode = null;
    private Map<String, List<String>> parentUrlParameters = null;

    public String getSessionKeyPrefix() {
        return this.sessionKeyPrefix;
    }

    public void setSessionKeyPrefix(String windowSessionKey) {
        this.sessionKeyPrefix = windowSessionKey;
    }

    public String getFname() {
        return this.fname;
    }

    public void setFname(String fname) {
        this.fname = fname;
    }

    public String getWindowState() {
        return this.windowState;
    }

    public void setWindowState(String windowState) {
        this.windowState = windowState;
    }

    public String getPortletMode() {
        return this.portletMode;
    }

    public void setPortletMode(String portletMode) {
        this.portletMode = portletMode;
    }

    @Override
    public int doStartTag() throws JspException {
        return EVAL_BODY_INCLUDE;
    }

    @Override
    public int doEndTag() throws JspException {
        //From portlet:defineObjects
        final RenderRequest renderRequest =
                (RenderRequest) this.pageContext.getAttribute("renderRequest");
        final RenderResponse renderResponse =
                (RenderResponse) this.pageContext.getAttribute("renderResponse");

        final PortletDelegationLocator portletDelegationLocator =
                (PortletDelegationLocator)
                        renderRequest.getAttribute(
                                PortletDelegationLocator.PORTLET_DELECATION_LOCATOR_ATTR);

        final String sessionKey = this.sessionKeyPrefix + this.fname;

        final PortletSession portletSession = renderRequest.getPortletSession();
        IPortletWindowId portletWindowId =
                (IPortletWindowId) portletSession.getAttribute(sessionKey);

        final PortletDelegationDispatcher portletDelegationDispatcher;
        final DelegateState delegateState;
        //No id in session, create a new dispatcher
        if (portletWindowId == null) {
            portletDelegationDispatcher =
                    portletDelegationLocator.createRequestDispatcher(renderRequest, this.fname);
            portletWindowId = portletDelegationDispatcher.getPortletWindowId();
            portletSession.setAttribute(sessionKey, portletWindowId);

            final PortletMode portletMode = PortletUtils.getPortletMode(this.portletMode);
            final WindowState windowState = PortletUtils.getWindowState(this.windowState);

            delegateState = new DelegateState(portletMode, windowState);
        }
        //id in session, get the old dispatcher
        else {
            portletDelegationDispatcher =
                    portletDelegationLocator.getRequestDispatcher(renderRequest, portletWindowId);
            delegateState = null;
        }

        final DelegationRequest delegationRequest = new DelegationRequest();
        delegationRequest.setDelegateState(delegateState);

        //Setup base for portlet URLs
        delegationRequest.setParentPortletMode(this.parentUrlMode);
        delegationRequest.setParentWindowState(this.parentUrlState);
        delegationRequest.setParentParameters(this.parentUrlParameters);

        final JspWriter out = this.pageContext.getOut();
        try {
            portletDelegationDispatcher.doRender(
                    renderRequest,
                    renderResponse,
                    delegationRequest,
                    new JspWriterPortletOutputHandler(out, renderResponse));
        } catch (IOException e) {
            throw new JspException(
                    "Failed to execute delegate render on portlet '" + this.fname + "'", e);
        }

        return Tag.EVAL_PAGE;
    }

    protected void setParentUrlState(WindowState parentUrlState) {
        this.parentUrlState = parentUrlState;
    }

    protected void setParentUrlMode(PortletMode parentUrlMode) {
        this.parentUrlMode = parentUrlMode;
    }

    protected void setParentUrlParameters(Map<String, List<String>> parentUrlParameters) {
        this.parentUrlParameters = parentUrlParameters;
    }

    private void writeObject(ObjectOutputStream oos) throws IOException {
        oos.defaultWriteObject();
        oos.writeObject(this.parentUrlState.toString());
        oos.writeObject(this.parentUrlMode.toString());
    }

    private void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException {
        //Read & validate non-transient fields
        ois.defaultReadObject();

        //Read & validate transient fields
        final String portletModeStr = (String) ois.readObject();
        if (portletModeStr == null) {
            throw new InvalidObjectException("portletMode can not be null");
        }
        this.parentUrlMode = PortletUtils.getPortletMode(portletModeStr);

        final String windowStateStr = (String) ois.readObject();
        if (windowStateStr == null) {
            throw new InvalidObjectException("windowState can not be null");
        }
        this.parentUrlState = PortletUtils.getWindowState(windowStateStr);
    }
}