package xyz.zhouxy.jdbc;

import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Optional;
import java.util.OptionalDouble;
import java.util.OptionalInt;
import java.util.OptionalLong;
import java.util.function.Function;
import java.util.stream.Collectors;

import com.google.common.base.Preconditions;

import xyz.zhouxy.plusone.commons.collection.CollectionTools;
import xyz.zhouxy.plusone.commons.util.ArrayTools;
import xyz.zhouxy.plusone.commons.util.OptionalTools;

public class ParamBuilder {
    public static final Object[] EMPTY_OBJECT_ARRAY = {};

    public static Object[] buildParams(final Object... params) {
        if (ArrayTools.isNullOrEmpty(params)) {
            return EMPTY_OBJECT_ARRAY;
        }
        return Arrays.stream(params)
                .map(param -> {
                    if (param instanceof Optional) {
                        return OptionalTools.orElseNull((Optional<?>) param);
                    }
                    if (param instanceof OptionalInt) {
                        return OptionalTools.toInteger(((OptionalInt) param));
                    }
                    if (param instanceof OptionalLong) {
                        return OptionalTools.toLong(((OptionalLong) param));
                    }
                    if (param instanceof OptionalDouble) {
                        return OptionalTools.toDouble(((OptionalDouble) param));
                    }
                    return param;
                })
                .toArray();
    }

    public static <T> List<Object[]> buildBatchParams(final Collection<T> c, final Function<T, Object[]> func) {
        Preconditions.checkNotNull(c, "The collection can not be null.");
        Preconditions.checkNotNull(func, "The func can not be null.");
        if (CollectionTools.isEmpty(c)) {
            return Collections.emptyList();
        }
        return c.stream().map(func).collect(Collectors.toList());
    }

    private ParamBuilder() {
        throw new IllegalStateException("Utility class");
    }
}