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package org.directwebremoting.convert;

import java.lang.reflect.Modifier;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.StringTokenizer;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.directwebremoting.ConversionException;
import org.directwebremoting.extend.ConvertUtil;
import org.directwebremoting.extend.Converter;
import org.directwebremoting.extend.ConverterManager;
import org.directwebremoting.extend.InboundContext;
import org.directwebremoting.extend.InboundVariable;
import org.directwebremoting.extend.ObjectOutboundVariable;
import org.directwebremoting.extend.OutboundContext;
import org.directwebremoting.extend.OutboundVariable;
import org.directwebremoting.extend.Property;
import org.directwebremoting.extend.ProtocolConstants;
import org.directwebremoting.util.JavascriptUtil;
import org.directwebremoting.util.LocalUtil;

/**
 * An implementation of Converter for Maps.
 * @author Joe Walker [joe at getahead dot ltd dot uk]
 */
public class MapConverter implements Converter
{
    /* (non-Javadoc)
     * @see org.directwebremoting.Converter#setConverterManager(org.directwebremoting.ConverterManager)
     */
    public void setConverterManager(ConverterManager converterManager)
    {
        this.converterManager = converterManager;
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.Converter#convertInbound(java.lang.Class, org.directwebremoting.InboundVariable, org.directwebremoting.InboundContext)
     */
    @SuppressWarnings("unchecked")
    public Object convertInbound(Class paramType, InboundVariable data) throws ConversionException
    {
        if (data.isNull())
        {
            return null;
        }

        String value = data.getValue();

        // If the text is null then the whole bean is null
        if (value.trim().equals(ProtocolConstants.INBOUND_NULL))
        {
            return null;
        }

        if (!value.startsWith(ProtocolConstants.INBOUND_MAP_START) || !value.endsWith(ProtocolConstants.INBOUND_MAP_END))
        {
            log.warn("Expected object while converting data for " + paramType.getName() + " in " + data.getContext().getCurrentProperty() + ". Passed: " + value);
            throw new ConversionException(paramType, "Data conversion error. See logs for more details.");
        }

        value = value.substring(1, value.length() - 1);

        try
        {
            // Maybe we ought to check that the paramType isn't expecting a more
            // distinct type of Map and attempt to create that?
            Map map;

            // If paramType is concrete then just use whatever we've got.
            if (!paramType.isInterface() && !Modifier.isAbstract(paramType.getModifiers()))
            {
                // If there is a problem creating the type then we have no way
                // of completing this - they asked for a specific type and we
                // can't create that type. I don't know of a way of finding
                // subclasses that might be instantiable so we accept failure.
                map = (Map) paramType.getDeclaredConstructor().newInstance();
            }
            else
            {
                map = new HashMap();
            }

            // Get the extra type info
            Property parent = data.getContext().getCurrentProperty();

            Property keyProp = parent.createChild(0);
            keyProp = converterManager.checkOverride(keyProp);
            Class keyType = keyProp.getPropertyType();

            Property valProp = parent.createChild(1);
            valProp = converterManager.checkOverride(valProp);
            Class valType = valProp.getPropertyType();

            // We should put the new object into the working map in case it
            // is referenced later nested down in the conversion process.
            data.getContext().addConverted(data, paramType, map);
            InboundContext incx = data.getContext();

            // Loop through the property declarations
            StringTokenizer st = new StringTokenizer(value, ",");
            int size = st.countTokens();
            for (int i = 0; i < size; i++)
            {
                String token = st.nextToken();
                if (token.trim().length() == 0)
                {
                    continue;
                }

                int colonpos = token.indexOf(ProtocolConstants.INBOUND_MAP_ENTRY);
                if (colonpos == -1)
                {
                    throw new ConversionException(paramType, "Missing " + ProtocolConstants.INBOUND_MAP_ENTRY + " in object description: {1}" + token);
                }

                // Convert the value part of the token by splitting it into the
                // type and value (as passed in by Javascript)
                String valStr = token.substring(colonpos + 1).trim();
                String[] splitIv = ConvertUtil.splitInbound(valStr);
                String splitIvValue = splitIv[ConvertUtil.INBOUND_INDEX_VALUE];
                String splitIvType = splitIv[ConvertUtil.INBOUND_INDEX_TYPE];
                InboundVariable valIv = new InboundVariable(incx, null, splitIvType, splitIvValue);
                valIv.dereference();
                Object val = converterManager.convertInbound(valType, valIv, valProp);

                // Keys (unlike values) do not have type info passed with them
                // Could we have recursive key? - I don't think so because keys
                // must be strings in Javascript
                String keyStr = token.substring(0, colonpos).trim();
                //String[] keySplit = LocalUtil.splitInbound(keyStr);
                //InboundVariable keyIv = new InboundVariable(incx, splitIv[LocalUtil.INBOUND_INDEX_TYPE], splitIv[LocalUtil.INBOUND_INDEX_VALUE]);
                InboundVariable keyIv = new InboundVariable(incx, null, ProtocolConstants.TYPE_STRING, keyStr);
                keyIv.dereference();

                Object key = converterManager.convertInbound(keyType, keyIv, keyProp);

                map.put(key, val);
            }

            return map;
        }
        catch (ConversionException ex)
        {
            throw ex;
        }
        catch (Exception ex)
        {
            throw new ConversionException(paramType, ex);
        }
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.Converter#convertOutbound(java.lang.Object, org.directwebremoting.OutboundContext)
     */
    @SuppressWarnings("unchecked")
    public OutboundVariable convertOutbound(Object data, OutboundContext outctx) throws ConversionException
    {
        // First we just collect our converted children
        //noinspection unchecked
        Map ovs = LocalUtil.classNewInstance("OrderedConvertOutbound", "java.util.LinkedHashMap", Map.class);
        if (ovs == null)
        {
            ovs = new HashMap();
        }

        ObjectOutboundVariable ov = new ObjectOutboundVariable(outctx);
        outctx.put(data, ov);

        // Loop through the map outputting any init code and collecting
        // converted outbound variables into the ovs map
        Map map = (Map) data;
        for (Entry entry : map.entrySet())
        {
            Object key = entry.getKey();
            Object value = entry.getValue();

            // If the key is null, retrieve the configured null key value from the configuration of this converter.
            if (null == key && null != nullKey) {
                log.debug("MapConverter: A null key was encountered DWR is using the configured nullKey string: " + nullKey);
                key = nullKey;
            }

            // It would be nice to check for Enums here
            if (!(key instanceof String) && !sentNonStringWarning)
            {
                log.warn("--Javascript does not support non string keys. Converting '" + key.getClass().getName() + "' using toString()");
                sentNonStringWarning = true;
            }

            String outkey = JavascriptUtil.escapeJavaScript(key.toString());

            /*
            OutboundVariable ovkey = converterManager.convertOutbound(key, outctx);
            buffer.append(ovkey.getInitCode());
            outkey = ovkey.getAssignCode();
            */

            OutboundVariable nested = converterManager.convertOutbound(value, outctx);

            ovs.put(outkey, nested);
        }

        ov.setChildren(ovs);

        return ov;
    }

    /**
     * @return the nullKey
     */
    public String getNullKey()
    {
        return nullKey;
    }

    /**
     * @param nullKey the nullKey to set
     */
    public void setNullKey(String nullKey)
    {
        this.nullKey = nullKey;
    }

    /**
     * We don't want to give the non-string warning too many times.
     */
    private static boolean sentNonStringWarning = false;

    /**
     * To forward marshalling requests
     */
    private ConverterManager converterManager = null;

    /**
     * Used by DWR if a null key is encountered.  Configure in the init section when the map converter is declared.
     * 
     *     
     * 
     */
    private String nullKey = null;

    /**
     * The log stream
     */
    private static final Log log = LogFactory.getLog(MapConverter.class);
}