// Copyright (C) 2013 The Android Open Source Project
//
// 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.googlesource.gerrit.plugins.hooks.jira;

import com.atlassian.jira.rest.client.api.domain.Comment;
import com.atlassian.jira.rest.client.api.domain.ServerInfo;
import com.google.gerrit.extensions.annotations.PluginName;
import com.google.gerrit.server.config.GerritServerConfig;
import com.google.inject.Inject;
import com.googlesource.gerrit.plugins.hooks.its.ItsFacade;
import org.eclipse.jgit.lib.Config;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.net.URL;
import java.util.concurrent.Callable;

public class JiraItsFacade implements ItsFacade {

  private static final String GERRIT_CONFIG_USERNAME = "username";
  private static final String GERRIT_CONFIG_PASSWORD = "password";
  private static final String GERRIT_CONFIG_URL = "url";

  private static final int MAX_ATTEMPTS = 3;

  private Logger log = LoggerFactory.getLogger(JiraItsFacade.class);

  private final String pluginName;
  private Config gerritConfig;

  private JiraClient client;

  @Inject
  public JiraItsFacade(@PluginName String pluginName,
                       @GerritServerConfig Config cfg) {
    this.pluginName = pluginName;
    try {
      this.gerritConfig = cfg;
      ServerInfo info = client().sysInfo();
      log.info("Connected to JIRA at {}, reported version is {}", info.getBaseUri(), info.getVersion());
    } catch (Exception ex) {
      log.warn("Jira is currently not available", ex);
    }
  }

  @Override
  public String healthCheck(final Check check) throws IOException {

    return execute(new Callable<String>(){
      @Override
      public String call() throws Exception {
        if (check.equals(Check.ACCESS))
          return healthCheckAccess();
        else
          return healthCheckSysinfo();
      }});
  }

  @Override
  public void addComment(final String issueKey, final String comment) throws IOException {

    execute(new Callable<String>(){
      @Override
      public String call() throws Exception {
        log.debug("Adding comment {} to issue {}", comment, issueKey);
        client().addComment(issueKey, Comment.valueOf(comment));
        log.debug("Added comment {} to issue {}", comment, issueKey);
        return issueKey;
      }});
  }

  @Override
  public void addRelatedLink(final String issueKey, final URL relatedUrl, String description)
      throws IOException {
    addComment(issueKey, "Related URL: " + createLinkForWebui(relatedUrl.toExternalForm(), description));
  }

  @Override
  public void performAction(final String issueKey, final String actionName)
      throws IOException {

    execute(new Callable<String>() {
      @Override
      public String call() throws Exception {
        log.debug("Performing action {} on issue {}", actionName, issueKey);
        doPerformAction(issueKey, actionName);
        return issueKey;
      }});
  }

  private void doPerformAction(final String issueKey, final String actionName)
      throws IOException {
    log.debug("Trying to perform action: " + actionName + " on issue " + issueKey);
    boolean ret = client().doTransition(issueKey, actionName);
    if (ret) {
      log.debug("Action " + actionName + " successful on Issue " + issueKey);
    } else {
      log.debug("Action {} on Issue {} not possible", actionName, issueKey);
    }
  }

  @Override
  public boolean exists(final String issueKey) throws IOException {
    return execute(new Callable<Boolean>() {
      @Override
      public Boolean call() throws Exception {
        return client().issueExists(issueKey);
      }});
  }

  private JiraClient client() throws IOException {
    if (client == null) {
      try {
        log.debug("Connecting to jira at {}", getUrl());
        client = new JiraClient(getUrl(), getUsername(), getPassword());
        log.debug("Authenticating as User {}", getUsername());
      } catch (Exception e) {
        log.info("Unable to connect to " + getUrl() + " as "
          + getUsername());
        throw new IOException(e);
      }
    }
    return client;
  }

  private <P> P execute(Callable<P> function) throws IOException {
    int attempt = 0;
    while(true) {
      try {
        return function.call();
      } catch (Exception ex) {
        if (isRecoverable(ex) && ++attempt < MAX_ATTEMPTS) {
          log.debug("Call failed - retrying, attempt {} of {}", attempt, MAX_ATTEMPTS);
          continue;
        }
        if (ex instanceof IOException)
          throw ((IOException)ex);
        else
          throw new IOException(ex);
      }
    }
  }
  private boolean isRecoverable(Exception ex) {
    String className = ex.getClass().getName();
    return className.startsWith("java.net");
  }

  private String getPassword() {
    return gerritConfig.getString(pluginName, null,
      GERRIT_CONFIG_PASSWORD);
  }

  private String getUsername() {
    return gerritConfig.getString(pluginName, null,
      GERRIT_CONFIG_USERNAME);
  }

  private String getUrl() {
    return gerritConfig.getString(pluginName, null, GERRIT_CONFIG_URL);
  }

  @Override
  public String createLinkForWebui(String url, String text) {
    return "[" + text + "|" + url + "]";
  }

  private String healthCheckAccess() throws IOException {
    client().sysInfo();
    final String result = "{\"status\"=\"ok\",\"username\"=\"" + getUsername() + "\"}";
    log.debug("Healtheck on access result: {}", result);
    return result;
  }

  private String healthCheckSysinfo() throws IOException {
    ServerInfo info = client().sysInfo();
    final String result = "{\"status\"=\"ok\",\"system\"=\"Jira\",\"version\"=\""+info.getVersion()+"\",\"url\"=\""+getUrl()+"\",\"build\"=\""+info.getBuildNumber()+"\"}";
    log.debug("Healtheck on sysinfo result: {}", result);
    return result;
  }
}