/**
 * Copyright 2010 JBoss Inc
 *
 * Licensed 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
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * 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.drools.guvnor.server.contenthandler;

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

import org.drools.compiler.DrlParser;
import org.drools.compiler.DroolsParserException;
import org.drools.guvnor.client.factmodel.FactMetaModel;
import org.drools.guvnor.client.factmodel.FactModels;
import org.drools.guvnor.client.factmodel.FieldMetaModel;
import org.drools.guvnor.client.rpc.RuleAsset;
import org.drools.guvnor.client.rpc.RuleContentText;
import org.drools.lang.descr.PackageDescr;
import org.drools.lang.descr.TypeDeclarationDescr;
import org.drools.lang.descr.TypeFieldDescr;
import org.drools.repository.AssetItem;
import org.drools.repository.PackageItem;

import com.google.gwt.user.client.rpc.SerializationException;


public class FactModelContentHandler extends ContentHandler {

	@Override
	public void retrieveAssetContent(RuleAsset asset, PackageItem pkg,
			AssetItem item) throws SerializationException {
		try {
			List<FactMetaModel> models = toModel(item.getContent());
			FactModels ms = new FactModels();
			ms.models = models;
			asset.content = ms;
		} catch (DroolsParserException e) {
			System.err.println("Unable to parse the DRL for the model - falling back to text (" + e.getMessage() + ")");
			RuleContentText text = new RuleContentText();
			text.content = item.getContent();
			asset.content = text;
		}

	}

	@Override
	public void storeAssetContent(RuleAsset asset, AssetItem repoAsset)
			throws SerializationException {
		if (asset.content instanceof FactModels) {
			FactModels fm = (FactModels) asset.content;
			repoAsset.updateContent(toDRL(fm.models));
		} else {
			RuleContentText text = (RuleContentText) asset.content;
			repoAsset.updateContent(text.content);
		}

	}


	String toDRL(FactMetaModel mm) {
		StringBuilder sb = new StringBuilder();
		sb.append("declare " + mm.name);
		for (int i = 0; i < mm.fields.size(); i++) {
			FieldMetaModel f = (FieldMetaModel) mm.fields.get(i);
			sb.append("\n\t");
			sb.append(f.name + ": " + f.type);
		}
		sb.append("\nend");
		return sb.toString();
	}

	List<FactMetaModel> toModel(String drl) throws DroolsParserException {
        if (drl != null && drl.startsWith("#advanced")) {
            throw new DroolsParserException("Using advanced editor");
        }
    	DrlParser parser = new DrlParser();
    	PackageDescr pkg = parser.parse(drl);
    	if (parser.hasErrors()) {
    		throw new DroolsParserException("The model drl " + drl + " is not valid");
    	}

    	if (pkg == null) return new ArrayList<FactMetaModel>();
    	List<TypeDeclarationDescr> types = pkg.getTypeDeclarations();
    	List<FactMetaModel> list = new ArrayList<FactMetaModel>(types.size());
    	for (TypeDeclarationDescr td : types) {
    		FactMetaModel mm = new FactMetaModel();
			mm.name = td.getTypeName();
			if (td.getMetaAttributes().size() > 0) {
				//can't do this yet
				throw new DroolsParserException("will have to use text for this");
			}


			Map<String, TypeFieldDescr> fields = td.getFields();
			for (Iterator<Map.Entry<String, TypeFieldDescr>> iterator = fields.entrySet().iterator(); iterator.hasNext();) {
				Map.Entry<String, TypeFieldDescr> en = iterator.next();
				String fieldName = en.getKey();
				TypeFieldDescr descr = en.getValue();
				if (descr.getMetaAttributes().size() > 0) {
					//can't do this yet
					throw new DroolsParserException("using text");
				}
				FieldMetaModel fm = new FieldMetaModel(fieldName, descr.getPattern().getObjectType());

				mm.fields.add(fm);
			}
			list.add(mm);
		}
    	return list;
	}

	String toDRL(List<FactMetaModel> models) {
		StringBuilder sb = new StringBuilder();
		for (FactMetaModel factMetaModel : models) {
			String drl = toDRL(factMetaModel);
			sb.append(drl + "\n\n");
		}
		return sb.toString().trim();
	}


}