/*
 * Copyright 2016 The Netty Project
 *
 * The Netty Project 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 io.netty.example.redis;

import io.netty.buffer.ByteBufUtil;
import io.netty.channel.ChannelDuplexHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPromise;
import io.netty.handler.codec.CodecException;
import io.netty.handler.codec.redis.ArrayRedisMessage;
import io.netty.handler.codec.redis.ErrorRedisMessage;
import io.netty.handler.codec.redis.FullBulkStringRedisMessage;
import io.netty.handler.codec.redis.IntegerRedisMessage;
import io.netty.handler.codec.redis.RedisMessage;
import io.netty.handler.codec.redis.SimpleStringRedisMessage;
import io.netty.util.CharsetUtil;
import io.netty.util.ReferenceCountUtil;

import java.util.ArrayList;
import java.util.List;

An example Redis client handler. This handler read input from STDIN and write output to STDOUT.
/**
 * An example Redis client handler. This handler read input from STDIN and write output to STDOUT.
 */
public class RedisClientHandler extends ChannelDuplexHandler {

    @Override
    public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) {
        String[] commands = ((String) msg).split("\\s+");
        List<RedisMessage> children = new ArrayList<RedisMessage>(commands.length);
        for (String cmdString : commands) {
            children.add(new FullBulkStringRedisMessage(ByteBufUtil.writeUtf8(ctx.alloc(), cmdString)));
        }
        RedisMessage request = new ArrayRedisMessage(children);
        ctx.write(request, promise);
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) {
        RedisMessage redisMessage = (RedisMessage) msg;
        printAggregatedRedisResponse(redisMessage);
        ReferenceCountUtil.release(redisMessage);
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        System.err.print("exceptionCaught: ");
        cause.printStackTrace(System.err);
        ctx.close();
    }

    private static void printAggregatedRedisResponse(RedisMessage msg) {
        if (msg instanceof SimpleStringRedisMessage) {
            System.out.println(((SimpleStringRedisMessage) msg).content());
        } else if (msg instanceof ErrorRedisMessage) {
            System.out.println(((ErrorRedisMessage) msg).content());
        } else if (msg instanceof IntegerRedisMessage) {
            System.out.println(((IntegerRedisMessage) msg).value());
        } else if (msg instanceof FullBulkStringRedisMessage) {
            System.out.println(getString((FullBulkStringRedisMessage) msg));
        } else if (msg instanceof ArrayRedisMessage) {
            for (RedisMessage child : ((ArrayRedisMessage) msg).children()) {
                printAggregatedRedisResponse(child);
            }
        } else {
            throw new CodecException("unknown message type: " + msg);
        }
    }

    private static String getString(FullBulkStringRedisMessage msg) {
        if (msg.isNull()) {
            return "(null)";
        }
        return msg.content().toString(CharsetUtil.UTF_8);
    }
}