/*
 * Copyright (c) 2011-2019 Contributors to the Eclipse Foundation
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 * which is available at https://www.apache.org/licenses/LICENSE-2.0.
 *
 * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 */

package io.vertx.core.eventbus.impl;

import io.vertx.core.buffer.Buffer;
import io.vertx.core.eventbus.MessageCodec;
import io.vertx.core.eventbus.ReplyException;
import io.vertx.core.eventbus.impl.codecs.*;
import io.vertx.core.json.JsonArray;
import io.vertx.core.json.JsonObject;

import java.util.Objects;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/**
 * @author <a href="http://tfox.org">Tim Fox</a>
 */
public class CodecManager {

  // The standard message codecs
  public static final MessageCodec<String, String> PING_MESSAGE_CODEC = new PingMessageCodec();
  public static final MessageCodec<String, String> NULL_MESSAGE_CODEC = new NullMessageCodec();
  public static final MessageCodec<String, String> STRING_MESSAGE_CODEC = new StringMessageCodec();
  public static final MessageCodec<Buffer, Buffer> BUFFER_MESSAGE_CODEC = new BufferMessageCodec();
  public static final MessageCodec<JsonObject, JsonObject> JSON_OBJECT_MESSAGE_CODEC = new JsonObjectMessageCodec();
  public static final MessageCodec<JsonArray, JsonArray> JSON_ARRAY_MESSAGE_CODEC = new JsonArrayMessageCodec();
  public static final MessageCodec<byte[], byte[]> BYTE_ARRAY_MESSAGE_CODEC = new ByteArrayMessageCodec();
  public static final MessageCodec<Integer, Integer> INT_MESSAGE_CODEC = new IntMessageCodec();
  public static final MessageCodec<Long, Long> LONG_MESSAGE_CODEC = new LongMessageCodec();
  public static final MessageCodec<Float, Float> FLOAT_MESSAGE_CODEC = new FloatMessageCodec();
  public static final MessageCodec<Double, Double> DOUBLE_MESSAGE_CODEC = new DoubleMessageCodec();
  public static final MessageCodec<Boolean, Boolean> BOOLEAN_MESSAGE_CODEC = new BooleanMessageCodec();
  public static final MessageCodec<Short, Short> SHORT_MESSAGE_CODEC = new ShortMessageCodec();
  public static final MessageCodec<Character, Character> CHAR_MESSAGE_CODEC = new CharMessageCodec();
  public static final MessageCodec<Byte, Byte> BYTE_MESSAGE_CODEC = new ByteMessageCodec();
  public static final MessageCodec<ReplyException, ReplyException> REPLY_EXCEPTION_MESSAGE_CODEC = new ReplyExceptionMessageCodec();

  private final MessageCodec[] systemCodecs;
  private final ConcurrentMap<String, MessageCodec> userCodecMap = new ConcurrentHashMap<>();
  private final ConcurrentMap<Class, MessageCodec> defaultCodecMap = new ConcurrentHashMap<>();

  public CodecManager() {
    this.systemCodecs = codecs(NULL_MESSAGE_CODEC, PING_MESSAGE_CODEC, STRING_MESSAGE_CODEC, BUFFER_MESSAGE_CODEC, JSON_OBJECT_MESSAGE_CODEC, JSON_ARRAY_MESSAGE_CODEC,
      BYTE_ARRAY_MESSAGE_CODEC, INT_MESSAGE_CODEC, LONG_MESSAGE_CODEC, FLOAT_MESSAGE_CODEC, DOUBLE_MESSAGE_CODEC,
      BOOLEAN_MESSAGE_CODEC, SHORT_MESSAGE_CODEC, CHAR_MESSAGE_CODEC, BYTE_MESSAGE_CODEC, REPLY_EXCEPTION_MESSAGE_CODEC);
  }

  public MessageCodec lookupCodec(Object body, String codecName) {
    MessageCodec codec;
    if (codecName != null) {
      codec = userCodecMap.get(codecName);
      if (codec == null) {
        throw new IllegalArgumentException("No message codec for name: " + codecName);
      }
    } else if (body == null) {
      codec = NULL_MESSAGE_CODEC;
    } else if (body instanceof String) {
      codec = STRING_MESSAGE_CODEC;
    } else if (body instanceof Buffer) {
      codec = BUFFER_MESSAGE_CODEC;
    } else if (body instanceof JsonObject) {
      codec = JSON_OBJECT_MESSAGE_CODEC;
    } else if (body instanceof JsonArray) {
      codec = JSON_ARRAY_MESSAGE_CODEC;
    } else if (body instanceof byte[]) {
      codec = BYTE_ARRAY_MESSAGE_CODEC;
    } else if (body instanceof Integer) {
      codec = INT_MESSAGE_CODEC;
    } else if (body instanceof Long) {
      codec = LONG_MESSAGE_CODEC;
    } else if (body instanceof Float) {
      codec = FLOAT_MESSAGE_CODEC;
    } else if (body instanceof Double) {
      codec = DOUBLE_MESSAGE_CODEC;
    } else if (body instanceof Boolean) {
      codec = BOOLEAN_MESSAGE_CODEC;
    } else if (body instanceof Short) {
      codec = SHORT_MESSAGE_CODEC;
    } else if (body instanceof Character) {
      codec = CHAR_MESSAGE_CODEC;
    } else if (body instanceof Byte) {
      codec = BYTE_MESSAGE_CODEC;
    } else if (body instanceof ReplyException) {
      codec = defaultCodecMap.get(body.getClass());
      if (codec == null) {
        codec = REPLY_EXCEPTION_MESSAGE_CODEC;
      }
    } else {
      codec = defaultCodecMap.get(body.getClass());
      if (codec == null) {
        throw new IllegalArgumentException("No message codec for type: " + body.getClass());
      }
    }
    return codec;
  }

  public MessageCodec getCodec(String codecName) {
    return userCodecMap.get(codecName);
  }

  public void registerCodec(MessageCodec codec) {
    Objects.requireNonNull(codec, "codec");
    Objects.requireNonNull(codec.name(), "code.name()");
    checkSystemCodec(codec);
    if (userCodecMap.containsKey(codec.name())) {
      throw new IllegalStateException("Already a codec registered with name " + codec.name());
    }
    userCodecMap.put(codec.name(), codec);
  }

  public void unregisterCodec(String name) {
    Objects.requireNonNull(name);
    userCodecMap.remove(name);
  }

  public <T> void registerDefaultCodec(Class<T> clazz, MessageCodec<T, ?> codec) {
    Objects.requireNonNull(clazz);
    Objects.requireNonNull(codec, "codec");
    Objects.requireNonNull(codec.name(), "code.name()");
    checkSystemCodec(codec);
    if (defaultCodecMap.containsKey(clazz)) {
      throw new IllegalStateException("Already a default codec registered for class " + clazz);
    }
    if (userCodecMap.containsKey(codec.name())) {
      throw new IllegalStateException("Already a codec registered with name " + codec.name());
    }
    defaultCodecMap.put(clazz, codec);
    userCodecMap.put(codec.name(), codec);
  }

  public void unregisterDefaultCodec(Class clazz) {
    Objects.requireNonNull(clazz);
    MessageCodec codec = defaultCodecMap.remove(clazz);
    if (codec != null) {
      userCodecMap.remove(codec.name());
    }
  }

  public MessageCodec[] systemCodecs() {
    return systemCodecs;
  }

  private void checkSystemCodec(MessageCodec codec) {
    if (codec.systemCodecID() != -1) {
      throw new IllegalArgumentException("Can't register a system codec");
    }
  }

  private MessageCodec[] codecs(MessageCodec... codecs) {
    MessageCodec[] arr = new MessageCodec[codecs.length];
    for (MessageCodec codec: codecs) {
      arr[codec.systemCodecID()] = codec;
    }
    return arr;
  }


}
