package org.apache.myfaces.test.mock;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

import javax.faces.FacesException;
import javax.faces.application.StateManager.SerializedView;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;
import javax.faces.render.RenderKitFactory;
import javax.faces.render.ResponseStateManager;

/**
 * Mock class that encode view state in hex format
 * 
 * @author lu4242
 *
 */
public class MockResponseStateManager extends ResponseStateManager
{
    // ------------------------------------------------------------ Constructors

    // ------------------------------------------------------ Instance Variables
    
    private static final int TREE_PARAM = 0;
    private static final int STATE_PARAM = 1;
    private static final int VIEWID_PARAM = 2;
    private static final String ZIP_CHARSET = "ISO-8859-1";

    
    // ----------------------------------------------------- Mock Object Methods

    // -------------------------------------------------- ResponseStateManager Methods
    
    public Object getState(FacesContext facesContext, String viewId)
    {
        Object[] savedState = getSavedState(facesContext);
        if (savedState == null)
        {
            return null;
        }

        return new Object[] { savedState[TREE_PARAM], savedState[STATE_PARAM] };
    }

    public Object getTreeStructureToRestore(FacesContext facesContext, String viewId)
    {
        // Although this method won't be called anymore,
        // it has been kept for backward compatibility.
        Object[] savedState = getSavedState(facesContext);
        if (savedState == null)
        {
            return null;
        }

        return savedState[TREE_PARAM];
    }

    public Object getComponentStateToRestore(FacesContext facesContext)
    {
        // Although this method won't be called anymore,
        // it has been kept for backward compatibility.
        Object[] savedState = getSavedState(facesContext);
        if (savedState == null)
        {
            return null;
        }

        return savedState[STATE_PARAM];
    }

    public boolean isPostback(FacesContext context)
    {
        return context.getExternalContext().getRequestParameterMap().containsKey(ResponseStateManager.VIEW_STATE_PARAM);
    }

    public void writeState(FacesContext facescontext, SerializedView serializedview)
            throws IOException
    {
        ResponseWriter responseWriter = facescontext.getResponseWriter();

        Object[] savedState = new Object[3];

        if (facescontext.getApplication().getStateManager().isSavingStateInClient(facescontext))
        {
            Object treeStruct = serializedview.getStructure();
            Object compStates = serializedview.getState();

            if (treeStruct != null)
            {
                savedState[TREE_PARAM] = treeStruct;
            }

            if (compStates != null)
            {
                savedState[STATE_PARAM] = compStates;
            }
        }
        else
        {
            // write viewSequence
            Object treeStruct = serializedview.getStructure();
            if (treeStruct != null)
            {
                if (treeStruct instanceof String)
                {
                    savedState[TREE_PARAM] = treeStruct;
                }
            }
        }

        savedState[VIEWID_PARAM] = facescontext.getViewRoot().getViewId();

        // write the view state field
        writeViewStateField(facescontext, responseWriter, savedState);

        // renderKitId field
        writeRenderKitIdField(facescontext, responseWriter);
    }

    private void writeViewStateField(FacesContext facesContext, ResponseWriter responseWriter, Object savedState)
    throws IOException
    {
        
        String serializedState = construct(facesContext, savedState);
        responseWriter.startElement("input", null);
        responseWriter.writeAttribute("type", "hidden", null);
        responseWriter.writeAttribute("name", VIEW_STATE_PARAM, null);
        responseWriter.writeAttribute("value", serializedState, null);
        responseWriter.endElement("input");
    }
    

    private void writeRenderKitIdField(FacesContext facesContext, ResponseWriter responseWriter) throws IOException
    {
    
        String defaultRenderKitId = facesContext.getApplication().getDefaultRenderKitId();
        if (defaultRenderKitId != null && !RenderKitFactory.HTML_BASIC_RENDER_KIT.equals(defaultRenderKitId))
        {
            responseWriter.startElement("input", null);
            responseWriter.writeAttribute("type", "hidden", null);
            responseWriter.writeAttribute("name", ResponseStateManager.RENDER_KIT_ID_PARAM, null);
            responseWriter.writeAttribute("value", defaultRenderKitId, null);
            responseWriter.endElement("input");
        }
    }
    
    private String construct(FacesContext facesContext, Object savedState) throws IOException
    {
        byte[] bytes = null;
        ByteArrayOutputStream baos = null;
        ObjectOutputStream oos = null;
        try
        {
            baos = new ByteArrayOutputStream();
            oos = new ObjectOutputStream(baos);
            oos.writeObject(savedState);
            bytes = baos.toByteArray();
        }
        finally
        {
            if (oos != null)
            {
                try
                {
                    oos.close();
                }
                catch(IOException e)
                {
                }
                finally
                {
                    oos = null;
                }
            }
            if (baos != null)
            {
                try
                {
                    baos.close();
                }
                catch(IOException e)
                {
                }
                finally
                {
                    baos = null;
                }
            }
        }
        return new String(new _Hex().encode(bytes), ZIP_CHARSET);
    }
    
    private Object reconstruct(FacesContext facesContext, String encodedState) throws IOException
    {
        byte[] bytes = encodedState.getBytes(ZIP_CHARSET);
        
        ByteArrayInputStream input = null;
        ObjectInputStream s = null;
        Object object = null;
        
        try
        {
            input = new ByteArrayInputStream(bytes);
            s = new ObjectInputStream(input); 
            object = s.readObject();
        }
        catch (ClassNotFoundException e)
        {
            throw new IOException(e.getMessage());
        }
        finally
        {
            if (s != null)
            {
                try
                {
                    s.close();
                }
                catch(IOException e)
                {
                }
                finally
                {
                    s = null;
                }
            }
            if (input != null)
            {
                try
                {
                    input.close();
                }
                catch(IOException e)
                {
                }
                finally
                {
                    input = null;
                }
            }
        }
        return object;
    }

    private Object[] getSavedState(FacesContext facesContext) {
        Object encodedState = 
            facesContext.getExternalContext().
                getRequestParameterMap().get(VIEW_STATE_PARAM);
        if(encodedState==null || (((String) encodedState).length() == 0)) { 
            return null;
        }

        Object[] savedState = null;
        
        try
        {
            savedState = (Object[])reconstruct(facesContext, (String)encodedState);
        }
        catch(IOException e)
        {
            facesContext.getExternalContext().log("Cannot reconstruct view state", e);
        }

        if (savedState == null)
        {
            return null;
        }
        
        String restoredViewId = (String)savedState[VIEWID_PARAM];

        if (restoredViewId == null)
        {
            return null;
        }
        return savedState;
    }
    
    public String getViewState(FacesContext facesContext, Object state)
    {
        if (state == null)
        {
            return null;
        }
        
        Object treeStruct = null;
        Object compStates = null;
        
        if (state instanceof SerializedView)
        {
            SerializedView view = (SerializedView)state; 
            treeStruct = view.getStructure();
            compStates = view.getState();
        }
        else if (state instanceof Object[])
        {
            Object[] structureAndState = (Object[])state;

            if (structureAndState.length == 2)
            {
                treeStruct = structureAndState[0];
                compStates = structureAndState[1];
            }
            else
            {
                throw new FacesException("The state should be an array of Object[] of lenght 2");
            }
        }
        else
        {
            throw new FacesException("The state should be an array of Object[] of lenght 2, or a SerializedView instance");
        }
        
        Object[] savedState = new Object[3];

        if (facesContext.getApplication().getStateManager().isSavingStateInClient(facesContext))
        {
            if (treeStruct != null)
            {
                savedState[TREE_PARAM] = treeStruct;
            }

            if (compStates != null)
            {
                savedState[STATE_PARAM] = compStates;
            }
        }
        else
        {
            // write viewSequence
            if (treeStruct != null)
            {
                if (treeStruct instanceof String)
                {
                    savedState[TREE_PARAM] = treeStruct;
                }
            }
        }
        savedState[VIEWID_PARAM] = facesContext.getViewRoot().getViewId();

        try
        {
            return construct(facesContext, savedState);
        }
        catch(IOException e)
        {
            throw new RuntimeException(e);
        }
    }    
}