/*
 *  ******************************************************************************
 *  *
 *  *
 *  * 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.
 *  *
 *  *  See the NOTICE file distributed with this work for additional
 *  *  information regarding copyright ownership.
 *  * 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.api.transform.transform.column;

import lombok.Data;
import org.datavec.api.transform.ColumnType;
import org.datavec.api.transform.Transform;
import org.datavec.api.transform.metadata.ColumnMetaData;
import org.datavec.api.transform.schema.Schema;
import org.datavec.api.writable.Writable;
import com.fasterxml.jackson.annotation.JsonProperty;

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

@Data
public class AddConstantColumnTransform implements Transform {

    private final String newColumnName;
    private final ColumnType newColumnType;
    private final Writable fixedValue;

    private Schema inputSchema;


    public AddConstantColumnTransform(@JsonProperty("newColumnName") String newColumnName,
                    @JsonProperty("newColumnType") ColumnType newColumnType,
                    @JsonProperty("fixedValue") Writable fixedValue) {
        this.newColumnName = newColumnName;
        this.newColumnType = newColumnType;
        this.fixedValue = fixedValue;
    }


    @Override
    public Schema transform(Schema inputSchema) {
        List<ColumnMetaData> outMeta = new ArrayList<>(inputSchema.getColumnMetaData());

        ColumnMetaData newColMeta = newColumnType.newColumnMetaData(newColumnName);
        outMeta.add(newColMeta);
        return inputSchema.newSchema(outMeta);
    }

    @Override
    public void setInputSchema(Schema inputSchema) {
        this.inputSchema = inputSchema;
    }

    @Override
    public Schema getInputSchema() {
        return inputSchema;
    }

    @Override
    public String outputColumnName() {
        return newColumnName;
    }

    @Override
    public String[] outputColumnNames() {
        return new String[] {outputColumnName()};
    }

    @Override
    public String[] columnNames() {
        return new String[0];
    }

    @Override
    public String columnName() {
        return newColumnName;
    }

    @Override
    public List<Writable> map(List<Writable> writables) {
        List<Writable> out = new ArrayList<>(writables.size() + 1);
        out.addAll(writables);
        out.add(fixedValue);
        return out;
    }

    @Override
    public List<List<Writable>> mapSequence(List<List<Writable>> sequence) {
        List<List<Writable>> outSeq = new ArrayList<>(sequence.size());
        for (List<Writable> l : sequence) {
            outSeq.add(map(l));
        }
        return outSeq;
    }

    @Override
    public Object map(Object input) {
        throw new UnsupportedOperationException();
    }

    @Override
    public Object mapSequence(Object sequence) {
        throw new UnsupportedOperationException();
    }
}
