/*-
 * -\-\-
 * Helios Tools
 * --
 * Copyright (C) 2016 Spotify AB
 * --
 * 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.spotify.helios.cli.command;

import static com.google.common.base.Strings.repeat;
import static java.lang.String.format;

import com.google.common.base.Throwables;
import com.spotify.helios.cli.Target;
import com.spotify.helios.cli.Utils;
import com.spotify.helios.client.HeliosClient;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintStream;
import java.net.URI;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeoutException;
import net.sourceforge.argparse4j.inf.Namespace;
import net.sourceforge.argparse4j.inf.Subparser;

public abstract class ControlCommand implements CliCommand {

  // If true and multiple domains are passed in, will abort the command on the first non-zero
  // exit code returned for a domain. If false, the command will keep running.
  private final boolean shortCircuit;

  ControlCommand(final Subparser parser) {
    this(parser, false);
  }

  ControlCommand(final Subparser parser, final boolean shortCircuit) {
    parser.setDefault("command", this).defaultHelp(true);
    this.shortCircuit = shortCircuit;
  }

  @Override
  public int run(final Namespace options, final List<Target> targets, final PrintStream out,
                 final PrintStream err, final String username, final boolean json,
                 final BufferedReader stdin)
      throws Exception {
    boolean allSuccessful = true;

    boolean isFirst = true;

    // TODO (dxia) The json = true branches below are a hack to get valid JSON for multiple domains.
    // Refactor concrete command implementations later to return an Object that can then be put into
    // a {"$DOMAIN": $VALUE} dict before json serializing and returning it.

    // Execute the control command over each target cluster
    final Iterator<Target> targetIterator = targets.iterator();
    while (targetIterator.hasNext()) {
      final Target target = targetIterator.next();

      if (targets.size() > 1) {
        if (!json) {
          final List<URI> endpoints = target.getEndpointSupplier().get();
          final String header = format("%s (%s)", target.getName(), endpoints);
          out.println(header);
          out.println(repeat("-", header.length()));
          out.flush();
        } else {
          if (isFirst) {
            out.println("{");
            isFirst = false;
          }
          out.println("\"" + target.getName() + "\": ");
        }
      }

      final boolean successful = run(options, target, out, err, username, json, stdin);
      if (shortCircuit && !successful) {
        return 1;
      }
      allSuccessful &= successful;

      if (targets.size() > 1) {
        if (!json) {
          out.println();
        } else {
          if (targetIterator.hasNext()) {
            out.println(",\n");
          } else {
            out.println("}");
          }
        }
      }
    }

    return allSuccessful ? 0 : 1;
  }

  /**
   * Execute against a cluster at a specific endpoint.
   */
  private boolean run(final Namespace options, final Target target, final PrintStream out,
                      final PrintStream err, final String username, final boolean json,
                      final BufferedReader stdin)
      throws Exception {

    final HeliosClient client = Utils.getClient(target, err, username, options);
    if (client == null) {
      return false;
    }

    try {
      final int result = run(options, client, out, json, stdin);
      return result == 0;
    } catch (ExecutionException e) {
      final Throwable cause = e.getCause();
      // if target is a domain, print message like
      // "Request timed out to master in ash.spotify.net (http://ash2-helios-a4.ash2.spotify.net)",
      // otherwise "Request timed out to master http://ash2-helios-a4.ash2.spotify.net:5800"
      if (cause instanceof TimeoutException) {
        err.println("Request timed out to master in " + target);
      } else {
        throw new RuntimeException(cause);
      }
      return false;
    } finally {
      client.close();
    }
  }

  abstract int run(final Namespace options, final HeliosClient client, PrintStream out,
                   final boolean json, BufferedReader stdin)
      throws ExecutionException, InterruptedException, IOException;
}