package com.ca.chorus.teiid.customfunctions;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;

import org.teiid.metadata.FunctionMethod;
import org.teiid.metadata.FunctionParameter;
import org.teiid.metadata.MetadataFactory;
import org.teiid.translator.ExecutionFactory;
import org.teiid.translator.Translator;
import org.teiid.translator.TranslatorException;

@Translator(name = "teiid-translator-customfunctions")
public class TeiidUDFExecutionFactory
    extends ExecutionFactory<Object, Object>
{

    public TeiidUDFExecutionFactory()
    {
        super();
        super.setSourceRequired(false);
        super.setSourceRequiredForMetadata(false);
    }

    @Override
    public void start() throws TranslatorException
    {
        super.start();

    }

    @Override
    public void getMetadata(final MetadataFactory metadataFactory,
                            final Object conn) throws TranslatorException
    {

        definePrimaryKeyFunctionMetadata(metadataFactory);

    }

    private void definePrimaryKeyFunctionMetadata(final MetadataFactory metadataFactory) throws TranslatorException
    {

        final FunctionMethod getPKColumnsFor = metadataFactory.addFunction("primary_key");
        final List<FunctionParameter> inParamList = new ArrayList<FunctionParameter>();
        final FunctionParameter inParam = new FunctionParameter("objecttypeName",
                                                                "String");
        inParam.setVarArg(true);
        inParamList.add(inParam);
        final FunctionParameter outParam = new FunctionParameter("pkstr",
                                                                 "string");
        getPKColumnsFor.setDeterministicBoolean(true);
        getPKColumnsFor.setPushDown("ALLOWED");
        getPKColumnsFor.setInvocationClass("com.ca.chorus.teiid.customfunctions.TeiidUDFExecutionFactory");
        getPKColumnsFor.setInvocationMethod("primary_key");
        getPKColumnsFor.setCategory("string");
        getPKColumnsFor.setInputParameters(inParamList);
        getPKColumnsFor.setOutputParameter(outParam);

    }

    public static String primary_key(final Object... params) throws TranslatorException
    {
        if (params == null || params.length == 0)
        {
            throw new TranslatorException(new IllegalArgumentException("Null or empty parameters provided."));
        }
        if (params.length < 3 || params.length % 2 == 0)
        {
            throw new TranslatorException(new IllegalArgumentException("Object type or column name/ value pair missing. Expected  atleast one column name and value pair along with the object type."));
        }

        if (params.length < 1
            || params.length == 2
            || (params.length + 1) % 2 != 0)
        {
            return null;
        }

        final List<String> xmlTokensList = new ArrayList<String>();
        final String objectName = params[0].toString();

        final Map<String, String> columnMap = new TreeMap<String, String>();

        for (int i = 1; i < params.length; i = i + 2)
        {
            columnMap.put(params[i] == null ? null : params[i].toString(),
                          params[i + 1] == null
                                               ? null
                                               : params[i + 1].toString());
        }

        xmlTokensList.add(objectName);
        for (final Map.Entry<String, String> entry : columnMap.entrySet())
        {
            xmlTokensList.add(entry.getKey());
            xmlTokensList.add(entry.getValue());

        }
        return buildPrimaryKeyXML(xmlTokensList);
    }

    private static String buildPrimaryKeyXML(final List<String> xmlTokens)
    {
        final StringBuilder xmlString = new StringBuilder();
        int count = 0;

        for (final String token : xmlTokens)
        {
            if (xmlString.length() == 0)
            {
                xmlString.append("<" + token);
                if (xmlTokens.size() == 1)
                {
                    xmlString.append("></" + token + ">");
                    continue;
                }
                count++;
                continue;
            }
            if (count % 2 == 0)
            {
                xmlString.append(token);
            } else
            {
                xmlString.append(count == 1 ? " " + token + "=\'" : "\' "
                                                                    + token
                                                                    + "=\'");
            }

            if (count + 1 == xmlTokens.size())
            {
                xmlString.append("\'></" + xmlTokens.get(0) + ">");
            }
            count++;
        }
        return xmlString.toString();
    }

}