/**
 * Copyright (C) 2001-2017 by RapidMiner and the contributors
 * 
 * Complete list of developers available at our web site:
 * 
 * http://rapidminer.com
 * 
 * This program is free software: you can redistribute it and/or modify it under the terms of the
 * GNU Affero General Public License as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License along with this program.
 * If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.operator.io;

import com.rapidminer.operator.Annotations;
import com.rapidminer.operator.IOObject;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.ProcessSetupError.Severity;
import com.rapidminer.operator.SimpleProcessSetupError;
import com.rapidminer.operator.UserError;
import com.rapidminer.operator.ports.metadata.AttributeMetaData;
import com.rapidminer.operator.ports.metadata.ExampleSetMetaData;
import com.rapidminer.operator.ports.metadata.MetaData;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeRepositoryLocation;
import com.rapidminer.parameter.UndefinedParameterError;
import com.rapidminer.repository.Entry;
import com.rapidminer.repository.IOObjectEntry;
import com.rapidminer.repository.RepositoryException;
import com.rapidminer.repository.RepositoryLocation;

import java.util.List;
import java.util.logging.Level;


/**
 * 
 * @author Sebastian Land
 */
public class RepositorySource extends AbstractReader<IOObject> {

	public static final String PARAMETER_REPOSITORY_ENTRY = "repository_entry";

	public RepositorySource(OperatorDescription description) {
		super(description, IOObject.class);
	}

	@Override
	public MetaData getGeneratedMetaData() throws OperatorException {
		IOObjectEntry entry;
		try {
			entry = getRepositoryEntry();
		} catch (RepositoryException e) {
			addError(new SimpleProcessSetupError(Severity.WARNING, getPortOwner(), "repository_access_error",
					getParameterAsRepositoryLocation(PARAMETER_REPOSITORY_ENTRY), e.getMessage()));
			return super.getGeneratedMetaData();
		} catch (UndefinedParameterError e) {
			return super.getGeneratedMetaData();
		}
		if (entry != null) {
			try {
				MetaData metaData = entry.retrieveMetaData().clone();
				// We reduce the number of nominal values to a limit here to keep meta data
				// transformations fast.
				if (metaData instanceof ExampleSetMetaData) {
					for (AttributeMetaData amd : ((ExampleSetMetaData) metaData).getAllAttributes()) {
						if (amd.isNominal()) {
							amd.shrinkValueSet();
						}
					}
				}
				return metaData;
			} catch (RepositoryException e) {
				getLogger().log(Level.INFO, "Error retrieving meta data from " + entry.getLocation() + ": " + e, e);
				return super.getGeneratedMetaData();
			}
		} else {
			addError(new SimpleProcessSetupError(Severity.WARNING, getPortOwner(), "repository_location_does_not_exist",
					getParameterAsRepositoryLocation(PARAMETER_REPOSITORY_ENTRY)));
			return super.getGeneratedMetaData();
		}
	}

	private IOObjectEntry getRepositoryEntry() throws RepositoryException, UserError {
		RepositoryLocation location = getParameterAsRepositoryLocation(PARAMETER_REPOSITORY_ENTRY);
		Entry entry = location.locateEntry();
		if (entry == null) {
			throw new RepositoryException("Entry '" + location + "' does not exist.");
		} else if (entry instanceof IOObjectEntry) {
			return (IOObjectEntry) entry;
		} else {
			throw new RepositoryException("Entry '" + location + "' is not a data entry, but " + entry.getType());
		}
	}

	@Override
	public IOObject read() throws OperatorException {
		try {
			final IOObject data = getRepositoryEntry().retrieveData(null);
			data.getAnnotations().setAnnotation(Annotations.KEY_SOURCE, getRepositoryEntry().getLocation().toString());
			return data;
		} catch (RepositoryException e) {
			throw new UserError(this, e, 312, getParameterAsString(PARAMETER_REPOSITORY_ENTRY), e.getMessage());
		}
	}

	@Override
	public List<ParameterType> getParameterTypes() {
		List<ParameterType> types = super.getParameterTypes();
		ParameterTypeRepositoryLocation type = new ParameterTypeRepositoryLocation(PARAMETER_REPOSITORY_ENTRY,
				"Repository entry.", false);
		type.setExpert(false);
		types.add(type);
		return types;
	}
}