package org.apache.http42.util;

/*
 * #%L
 * ====================================================================
 *
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 * #L%
 */


import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.nio.charset.UnsupportedCharsetException;

import org.apache.http.HeaderElement;
import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.ParseException;
import org.apache.http.util.ByteArrayBuffer;
import org.apache.http.util.CharArrayBuffer;
import org.apache.http42.entity.ContentType;
import org.apache.http42.protocol.HTTP;

/**
 * Static helpers for dealing with {@link HttpEntity}s.
 *
 * @since 4.0
 */
public final class EntityUtils {

    private EntityUtils() {
    }

    /**
     * Ensures that the entity content is fully consumed and the content stream, if exists,
     * is closed. The process is done, <i>quietly</i> , without throwing any IOException.
     *
     * @param entity
     *
     *
     * @since 4.2
     */
    public static void consumeQuietly(final HttpEntity entity) {
        try {
          consume(entity);
        } catch (IOException ioex) {
        }
    }

    /**
     * Ensures that the entity content is fully consumed and the content stream, if exists,
     * is closed.
     *
     * @param entity
     * @throws IOException if an error occurs reading the input stream
     *
     * @since 4.1
     */
    public static void consume(final HttpEntity entity) throws IOException {
        if (entity == null) {
            return;
        }
        if (entity.isStreaming()) {
            InputStream instream = entity.getContent();
            if (instream != null) {
                instream.close();
            }
        }
    }

    /**
     * Read the contents of an entity and return it as a byte array.
     *
     * @param entity
     * @return byte array containing the entity content. May be null if
     *   {@link HttpEntity#getContent()} is null.
     * @throws IOException if an error occurs reading the input stream
     * @throws IllegalArgumentException if entity is null or if content length > Integer.MAX_VALUE
     */
    public static byte[] toByteArray(final HttpEntity entity) throws IOException {
        if (entity == null) {
            throw new IllegalArgumentException("HTTP entity may not be null");
        }
        InputStream instream = entity.getContent();
        if (instream == null) {
            return null;
        }
        try {
            if (entity.getContentLength() > Integer.MAX_VALUE) {
                throw new IllegalArgumentException("HTTP entity too large to be buffered in memory");
            }
            int i = (int)entity.getContentLength();
            if (i < 0) {
                i = 4096;
            }
            ByteArrayBuffer buffer = new ByteArrayBuffer(i);
            byte[] tmp = new byte[4096];
            int l;
            while((l = instream.read(tmp)) != -1) {
                buffer.append(tmp, 0, l);
            }
            return buffer.toByteArray();
        } finally {
            instream.close();
        }
    }

    /**
     * Obtains character set of the entity, if known.
     *
     * @param entity must not be null
     * @return the character set, or null if not found
     * @throws ParseException if header elements cannot be deserialized
     * @throws IllegalArgumentException if entity is null
     *
     * @deprecated (4.1.3) use {@link ContentType#getOrDefault(HttpEntity)}
     */
    @Deprecated
    public static String getContentCharSet(final HttpEntity entity) throws ParseException {
        if (entity == null) {
            throw new IllegalArgumentException("HTTP entity may not be null");
        }
        String charset = null;
        if (entity.getContentType() != null) {
            HeaderElement values[] = entity.getContentType().getElements();
            if (values.length > 0) {
                NameValuePair param = values[0].getParameterByName("charset");
                if (param != null) {
                    charset = param.getValue();
                }
            }
        }
        return charset;
    }

    /**
     * Obtains mime type of the entity, if known.
     *
     * @param entity must not be null
     * @return the character set, or null if not found
     * @throws ParseException if header elements cannot be deserialized
     * @throws IllegalArgumentException if entity is null
     *
     * @since 4.1
     *
     * @deprecated (4.1.3) use {@link ContentType#getOrDefault(HttpEntity)}
     */
    @Deprecated
    public static String getContentMimeType(final HttpEntity entity) throws ParseException {
        if (entity == null) {
            throw new IllegalArgumentException("HTTP entity may not be null");
        }
        String mimeType = null;
        if (entity.getContentType() != null) {
            HeaderElement values[] = entity.getContentType().getElements();
            if (values.length > 0) {
                mimeType = values[0].getName();
            }
        }
        return mimeType;
    }

    /**
     * Get the entity content as a String, using the provided default character set
     * if none is found in the entity.
     * If defaultCharset is null, the default "ISO-8859-1" is used.
     *
     * @param entity must not be null
     * @param defaultCharset character set to be applied if none found in the entity
     * @return the entity content as a String. May be null if
     *   {@link HttpEntity#getContent()} is null.
     * @throws ParseException if header elements cannot be deserialized
     * @throws IllegalArgumentException if entity is null or if content length > Integer.MAX_VALUE
     * @throws IOException if an error occurs reading the input stream
     */
    public static String toString(
            final HttpEntity entity, final Charset defaultCharset) throws IOException, ParseException {
        if (entity == null) {
            throw new IllegalArgumentException("HTTP entity may not be null");
        }
        InputStream instream = entity.getContent();
        if (instream == null) {
            return null;
        }
        try {
            if (entity.getContentLength() > Integer.MAX_VALUE) {
                throw new IllegalArgumentException("HTTP entity too large to be buffered in memory");
            }
            int i = (int)entity.getContentLength();
            if (i < 0) {
                i = 4096;
            }
            Charset charset = null;
            try {
                ContentType contentType = ContentType.getOrDefault(entity);
                charset = contentType.getCharset();
            } catch (UnsupportedCharsetException ex) {
                throw new UnsupportedEncodingException(ex.getMessage());
            }
            if (charset == null) {
                charset = defaultCharset;
            }
            if (charset == null) {
                charset = HTTP.DEF_CONTENT_CHARSET;
            }
            Reader reader = new InputStreamReader(instream, charset);
            CharArrayBuffer buffer = new CharArrayBuffer(i);
            char[] tmp = new char[1024];
            int l;
            while((l = reader.read(tmp)) != -1) {
                buffer.append(tmp, 0, l);
            }
            return buffer.toString();
        } finally {
            instream.close();
        }
    }

    /**
     * Get the entity content as a String, using the provided default character set
     * if none is found in the entity.
     * If defaultCharset is null, the default "ISO-8859-1" is used.
     *
     * @param entity must not be null
     * @param defaultCharset character set to be applied if none found in the entity
     * @return the entity content as a String. May be null if
     *   {@link HttpEntity#getContent()} is null.
     * @throws ParseException if header elements cannot be deserialized
     * @throws IllegalArgumentException if entity is null or if content length > Integer.MAX_VALUE
     * @throws IOException if an error occurs reading the input stream
     */
    public static String toString(
            final HttpEntity entity, final String defaultCharset) throws IOException, ParseException {
        return toString(entity, Charset.forName(defaultCharset));
    }

    /**
     * Read the contents of an entity and return it as a String.
     * The content is converted using the character set from the entity (if any),
     * failing that, "ISO-8859-1" is used.
     *
     * @param entity
     * @return String containing the content.
     * @throws ParseException if header elements cannot be deserialized
     * @throws IllegalArgumentException if entity is null or if content length > Integer.MAX_VALUE
     * @throws IOException if an error occurs reading the input stream
     */
    public static String toString(final HttpEntity entity)
        throws IOException, ParseException {
        return toString(entity, (Charset)null);
    }

}