/*
 * Copyright 2019 Scott Logic Ltd
 *
 * 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 com.scottlogic.datahelix.generator.core.generation;

import com.google.inject.Inject;
import com.scottlogic.datahelix.generator.common.RandomNumberGenerator;
import com.scottlogic.datahelix.generator.common.profile.Field;
import com.scottlogic.datahelix.generator.core.config.detail.DataGenerationType;
import com.scottlogic.datahelix.generator.core.fieldspecs.FieldSpec;
import com.scottlogic.datahelix.generator.core.generation.databags.DataBagValue;
import com.scottlogic.datahelix.generator.core.generation.fieldvaluesources.FieldValueSource;
import com.scottlogic.datahelix.generator.core.utils.JavaUtilRandomNumberGenerator;

import java.util.stream.Stream;

public class FieldSpecValueGenerator {
    private final DataGenerationType dataType;
    private final RandomNumberGenerator randomNumberGenerator;

    @Inject
    public FieldSpecValueGenerator(DataGenerationType dataGenerationType,
                                   JavaUtilRandomNumberGenerator randomNumberGenerator) {
        this.dataType = dataGenerationType;
        this.randomNumberGenerator = randomNumberGenerator;
    }

    public FieldSpecValueGenerator(DataGenerationType dataGenerationType,
                                   RandomNumberGenerator randomNumberGenerator) {
        this.dataType = dataGenerationType;
        this.randomNumberGenerator = randomNumberGenerator;
    }

    public boolean isRandom() {
        return dataType == DataGenerationType.RANDOM;
    }

    public Stream<DataBagValue> generate(Field field, FieldSpec spec) {
        FieldValueSource fieldValueSource = spec.getFieldValueSource();

        return getDataValues(fieldValueSource, field.isUnique())
            .map(DataBagValue::new);
    }

    private Stream<Object> getDataValues(FieldValueSource source, boolean unique) {
        if (unique) {
            return source.generateAllValues();
        } 

        switch (dataType) {
            case FULL_SEQUENTIAL:
                return source.generateAllValues();
            case RANDOM:
                return source.generateRandomValues(randomNumberGenerator);
            default:
                throw new UnsupportedOperationException("No data generation type set.");
        }
    }
}

