/*
 * Copyright 2017 Couchbase, Inc.
 *
 *    Licensed 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 com.couchbase.mock.control;

import com.couchbase.mock.CouchbaseMock;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import org.jetbrains.annotations.NotNull;

import java.util.Set;

/**
 * The MockCommand class is the base class for all commands
 * that the client may send to the mock to instruct it to
 * do certain actions.
 *
 * All commands is sent as JSON objects with a certain form:
 * <p> { "command" : "name of the command", "payload" : {  } } </p>
 * The response for the command will be delivered at its most basic
 * level will be a JSON object consisting of the following fields:
 * <p> { "status" : "ok", "payload" : { } } </p>
 *
 * For "non-successful" commands the object may be:
 * <p> { "status" : "fail", "error" : "error description" } </p>
 *
 * To implement a new command you should subclass the MockCommand
 * class and add implement the execute method. You must add the
 * name of the command to the Command enum, and register the
 * class in MockCommandDispatcher.
 *
 * @author mnunberg
 */
public abstract class MockCommand {
    public enum Command {
        FAILOVER,
        RESPAWN,
        HICCUP,
        TRUNCATE,
        MOCKINFO,

        PERSIST,
        CACHE,
        UNPERSIST,
        UNCACHE,
        ENDURE,
        PURGE,

        KEYINFO,
        TIME_TRAVEL,
        HELP,
        OPFAIL,
        SET_CCCP,
        GET_MCPORTS,
        REGEN_VBCOORDS,
        RESET_QUERYSTATE,
        START_CMDLOG,
        STOP_CMDLOG,
        GET_CMDLOG,
        START_RETRY_VERIFY,
        CHECK_RETRY_VERIFY,
        SET_ENHANCED_ERRORS,
        SET_QUERY_ERROR_STATE,
        SET_COMPRESSION,
        SET_SASL_MECHANISMS
    }

    /**
     * Get the response to send to the client.
     * @return a CommandStatus object indicating the status
     */
    @NotNull
    protected CommandStatus getResponse() {
        return new CommandStatus();
    }

    /**
     * Execute the command
     *
     * @param mock    the couchbase mock object to operate on
     * @param command the actual command being executed (in case a handler
     *                implements multiple commands
     * @param payload the payload containing arguments to the command
     * @return command status
     */
    public abstract
    @NotNull
    CommandStatus execute(@NotNull CouchbaseMock mock, @NotNull Command command, @NotNull JsonObject payload);

    public static void loadServers(@NotNull JsonObject payload, Set<Integer> enabledServers) {
        if (payload.has("servers")) {
            JsonArray arr = payload.get("servers").getAsJsonArray();
            for (int ii = 0; ii < arr.size(); ii++) {
                JsonElement e = arr.get(ii);
                enabledServers.add(e.getAsInt());
            }
        }
    }

    public static void loadBuckets(@NotNull CouchbaseMock mock, @NotNull JsonObject payload, Set<String> enabledBuckets) {
        if (payload.has("bucket")) {
            enabledBuckets.add(payload.get("bucket").getAsString());
        } else {
            enabledBuckets.addAll(mock.getBuckets().keySet());
        }
    }
}