/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch 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.elasticsearch.cli;

import joptsimple.OptionSet;
import joptsimple.OptionSpec;
import joptsimple.util.KeyValuePair;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.env.Environment;
import org.elasticsearch.node.InternalSettingsPreparer;

import java.util.HashMap;
import java.util.Locale;
import java.util.Map;

/** A cli command which requires an {@link org.elasticsearch.env.Environment} to use current paths and settings. */
public abstract class EnvironmentAwareCommand extends Command {

    private final OptionSpec<KeyValuePair> settingOption;

    public EnvironmentAwareCommand(String description) {
        super(description);
        this.settingOption = parser.accepts("E", "Configure a setting").withRequiredArg().ofType(KeyValuePair.class);
    }

    @Override
    protected void execute(Terminal terminal, OptionSet options) throws Exception {
        final Map<String, String> settings = new HashMap<>();
        for (final KeyValuePair kvp : settingOption.values(options)) {
            if (kvp.value.isEmpty()) {
                throw new UserException(ExitCodes.USAGE, "setting [" + kvp.key + "] must not be empty");
            }
            if (settings.containsKey(kvp.key)) {
                final String message = String.format(
                        Locale.ROOT,
                        "setting [%s] already set, saw [%s] and [%s]",
                        kvp.key,
                        settings.get(kvp.key),
                        kvp.value);
                throw new UserException(ExitCodes.USAGE, message);
            }
            settings.put(kvp.key, kvp.value);
        }

        putSystemPropertyIfSettingIsMissing(settings, "path.conf", "es.path.conf");
        putSystemPropertyIfSettingIsMissing(settings, "path.data", "es.path.data");
        putSystemPropertyIfSettingIsMissing(settings, "path.home", "es.path.home");
        putSystemPropertyIfSettingIsMissing(settings, "path.logs", "es.path.logs");

        execute(terminal, options, createEnv(terminal, settings));
    }

    /** Create an {@link Environment} for the command to use. Overrideable for tests. */
    protected Environment createEnv(Terminal terminal, Map<String, String> settings) {
        return InternalSettingsPreparer.prepareEnvironment(Settings.EMPTY, terminal, settings);
    }

    /** Ensure the given setting exists, reading it from system properties if not already set. */
    protected static void putSystemPropertyIfSettingIsMissing(final Map<String, String> settings, final String setting, final String key) {
        final String value = System.getProperty(key);
        if (value != null) {
            if (settings.containsKey(setting)) {
                final String message =
                        String.format(
                                Locale.ROOT,
                                "duplicate setting [%s] found via command-line [%s] and system property [%s]",
                                setting,
                                settings.get(setting),
                                value);
                throw new IllegalArgumentException(message);
            } else {
                settings.put(setting, value);
            }
        }
    }

    /** Execute the command with the initialized {@link Environment}. */
    protected abstract void execute(Terminal terminal, OptionSet options, Environment env) throws Exception;

}