/*
 *  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.
 *
 */
package org.apache.asyncweb.common.codec;

import java.nio.charset.CharsetDecoder;

import org.apache.asyncweb.common.HttpVersion;
import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.filter.codec.ProtocolDecoderOutput;
import org.apache.mina.filter.codec.statemachine.ConsumeToCrLfDecodingState;
import org.apache.mina.filter.codec.statemachine.ConsumeToLinearWhitespaceDecodingState;
import org.apache.mina.filter.codec.statemachine.DecodingState;
import org.apache.mina.filter.codec.statemachine.DecodingStateMachine;
import org.apache.mina.filter.codec.statemachine.LinearWhitespaceSkippingState;

/**
 * Decodes a HTTP response line.
 *
 * @author The Apache MINA Project (dev@mina.apache.org)
 */
abstract class HttpResponseLineDecodingState extends DecodingStateMachine {

    private final CharsetDecoder asciiDecoder = 
        HttpCodecUtils.US_ASCII_CHARSET.newDecoder();
    private final CharsetDecoder defaultDecoder = 
        HttpCodecUtils.DEFAULT_CHARSET.newDecoder();

    @Override
    protected DecodingState init() throws Exception {
        return READ_PROTOCOL_VERSION;
    }

    @Override
    protected void destroy() throws Exception {
    }

    private final DecodingState READ_PROTOCOL_VERSION = new HttpVersionDecodingState() {
        @Override
        protected DecodingState finishDecode(HttpVersion version,
                ProtocolDecoderOutput out) throws Exception {
            out.write(version);
            return AFTER_READ_PROTOCOL_VERSION;
        }
    };
    
    private final DecodingState AFTER_READ_PROTOCOL_VERSION = new LinearWhitespaceSkippingState() {
        @Override
        protected DecodingState finishDecode(int skippedBytes) throws Exception {
            return READ_STATUS_CODE;
        }
    };
    
    private final DecodingState READ_STATUS_CODE = new ConsumeToLinearWhitespaceDecodingState() {
        @Override
        protected DecodingState finishDecode(IoBuffer product,
                ProtocolDecoderOutput out) throws Exception {
            String statusCode = product.getString(asciiDecoder);
            try {
                out.write(Integer.parseInt(statusCode));
            } catch (NumberFormatException e) {
                HttpCodecUtils.throwDecoderException("Bad status code");
            }
            return READ_REASON_PHRASE;
        }
    };

    private final DecodingState READ_REASON_PHRASE = new ConsumeToCrLfDecodingState() {
        @Override
        protected DecodingState finishDecode(IoBuffer product,
                ProtocolDecoderOutput out) throws Exception {
            out.write(product.getString(defaultDecoder).trim());
            return null;
        }
    };
}