/**
 * The MIT License (MIT)
 *
 * Copyright (c) 2014-2017 Yegor Bugayenko
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package org.takes.rq.form;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.util.Iterator;
import lombok.EqualsAndHashCode;
import org.takes.HttpException;
import org.takes.rq.RqForm;

/**
 * Smart decorator, with extra features.
 *
 * <p>The class is immutable and thread-safe.
 *
 * @author Yegor Bugayenko (yegor256@gmail.com)
 * @version $Id: 2f118eaaa0845cfec57300b257f217e5259742c5 $
 * @since 0.33
 */
@EqualsAndHashCode
public final class RqFormSmart implements RqForm {

    /**
     * Original.
     */
    private final RqForm origin;

    /**
     * Ctor.
     * @param req Original request
     */
    public RqFormSmart(final RqForm req) {
        this.origin = req;
    }

    @Override
    public Iterable<String> param(final CharSequence name)
        throws IOException {
        return this.origin.param(name);
    }

    @Override
    public Iterable<String> names() throws IOException {
        return this.origin.names();
    }

    @Override
    public Iterable<String> head() throws IOException {
        return this.origin.head();
    }

    @Override
    public InputStream body() throws IOException {
        return this.origin.body();
    }

    /**
     * Get single param or throw HTTP exception.
     * @param name Name of query param
     * @return Value of it
     * @throws IOException If fails
     */
    public String single(final CharSequence name) throws IOException {
        final Iterator<String> params = this.param(name).iterator();
        if (!params.hasNext()) {
            throw new HttpException(
                HttpURLConnection.HTTP_BAD_REQUEST,
                String.format(
                    "form param \"%s\" is mandatory", name
                )
            );
        }
        return params.next();
    }

    /**
     * Get single param or default.
     * @param name Name of query param
     * @param def Default, if not found
     * @return Value of it
     * @throws IOException if something fails reading parameters
     */
    public String single(final CharSequence name, final String def)
        throws IOException {
        final String value;
        final Iterator<String> params = this.param(name).iterator();
        if (params.hasNext()) {
            value = params.next();
        } else {
            value = def;
        }
        return value;
    }
}