/*******************************************************************************
 * Copyright (c) 2015-2018 Skymind, Inc.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Apache License, Version 2.0 which is available at
 * https://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.
 *
 * SPDX-License-Identifier: Apache-2.0
 ******************************************************************************/

package org.datavec.local.transforms.analysis.aggregate;

import lombok.AllArgsConstructor;
import org.datavec.api.transform.ColumnType;
import org.datavec.api.transform.analysis.AnalysisCounter;
import org.datavec.api.transform.analysis.counter.*;
import org.datavec.api.transform.schema.Schema;
import org.datavec.api.writable.Writable;
import org.nd4j.linalg.function.BiFunction;

import java.util.ArrayList;
import java.util.List;

/**
 * Add function used for undertaking analysis of a data set via Spark
 *
 * @author Alex Black
 */
@AllArgsConstructor
public class AnalysisAddFunction implements BiFunction<List<AnalysisCounter>, List<Writable>, List<AnalysisCounter>> {
    private Schema schema;

    @Override
    public List<AnalysisCounter> apply(List<AnalysisCounter> analysisCounters, List<Writable> writables){
        if (analysisCounters == null) {
            analysisCounters = new ArrayList<>();
            List<ColumnType> columnTypes = schema.getColumnTypes();
            for (ColumnType ct : columnTypes) {
                switch (ct) {
                    case String:
                        analysisCounters.add(new StringAnalysisCounter());
                        break;
                    case Integer:
                        analysisCounters.add(new IntegerAnalysisCounter());
                        break;
                    case Long:
                        analysisCounters.add(new LongAnalysisCounter());
                        break;
                    case Double:
                        analysisCounters.add(new DoubleAnalysisCounter());
                        break;
                    case Categorical:
                        analysisCounters.add(new CategoricalAnalysisCounter());
                        break;
                    case Time:
                        analysisCounters.add(new LongAnalysisCounter());
                        break;
                    case Bytes:
                        analysisCounters.add(new BytesAnalysisCounter());
                        break;
                    case NDArray:
                        analysisCounters.add(new NDArrayAnalysisCounter());
                        break;
                    default:
                        throw new IllegalArgumentException("Unknown column type: " + ct);
                }
            }
        }

        int size = analysisCounters.size();
        if (size != writables.size())
            throw new IllegalStateException("Writables list and number of counters does not match (" + writables.size()
                            + " vs " + size + ")");
        for (int i = 0; i < size; i++) {
            analysisCounters.get(i).add(writables.get(i));
        }

        return analysisCounters;
    }
}
