/*
 * Copyright 2000-2018 JetBrains s.r.o.
 *
 * 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 jetbrains.buildServer.agent.ruby.rvm;

import com.intellij.openapi.util.SystemInfo;
import java.io.File;
import java.io.IOException;
import java.util.*;
import jetbrains.buildServer.RunBuildException;
import jetbrains.buildServer.agent.AgentBuildFeature;
import jetbrains.buildServer.agent.AgentRunningBuild;
import jetbrains.buildServer.agent.BuildRunnerContext;
import jetbrains.buildServer.agent.feature.RubyEnvConfiguratorService;
import jetbrains.buildServer.agent.runner.BuildCommandLineProcessor;
import jetbrains.buildServer.agent.runner.ProgramCommandLine;
import jetbrains.buildServer.feature.RubyEnvConfiguratorConfiguration;
import jetbrains.buildServer.feature.RubyEnvConfiguratorConstants;
import jetbrains.buildServer.log.Loggers;
import jetbrains.buildServer.messages.serviceMessages.MapSerializerUtil;
import jetbrains.buildServer.util.FileUtil;
import jetbrains.buildServer.util.StringUtil;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

/**
 * @author Vladislav.Rassokhin
 */
public class RVMCommandLineProcessor implements BuildCommandLineProcessor {

  private static final String CUSTOM_EXECUTABLE = "/bin/sh";
  private static final String SCRIPT_PERMISSIONS = "u+x";

  @NotNull
  public ProgramCommandLine process(@NotNull final BuildRunnerContext context, @NotNull final ProgramCommandLine origCommandLine)
    throws RunBuildException {
    if (!SystemInfo.isUnix) {
      return origCommandLine;
    }
    final AgentRunningBuild build = context.getBuild();

    // check if feature is enabled
    final Collection<AgentBuildFeature> features =
      build.getBuildFeaturesOfType(RubyEnvConfiguratorConstants.RUBY_ENV_CONFIGURATOR_FEATURE_TYPE);

    if (features.isEmpty()) {
      return origCommandLine;
    }

    final Map<String, String> featureParameters = features.iterator().next().getParameters();

    final RubyEnvConfiguratorConfiguration configuration = new RubyEnvConfiguratorConfiguration(featureParameters);

    // Remove some env variables
    final Map<String, String> environment = new HashMap<String, String>(origCommandLine.getEnvironment());
    String envsToUnsetStr = context.getRunnerParameters().get(RubyEnvConfiguratorService.ENVS_TO_UNSET_PARAM);
    if (envsToUnsetStr != null) {
      List<String> envs = StringUtil.split(envsToUnsetStr, ",");
      for (String key : envs) {
        environment.remove(key);
      }
    }

    switch (configuration.getType()) {
      case INTERPRETER_PATH: {
        return new ProgramCommandLine() {
          @NotNull
          public String getExecutablePath() throws RunBuildException {
            return origCommandLine.getExecutablePath();
          }

          @NotNull
          public String getWorkingDirectory() throws RunBuildException {
            return origCommandLine.getWorkingDirectory();
          }

          @NotNull
          public List<String> getArguments() throws RunBuildException {
            return origCommandLine.getArguments();
          }

          @NotNull
          public Map<String, String> getEnvironment() {
            return environment;
          }
        };
      }
      case RBENV:
      case RBENV_FILE:
      case RVM:
      case RVM_RUBY_VERSION:
      case RVMRC: {
        // Lets patch it!
        final File script = createScriptFile(origCommandLine, build.getAgentTempDirectory());

        return new ProgramCommandLine() {
          @NotNull
          public String getExecutablePath() {
            return CUSTOM_EXECUTABLE;
          }

          @NotNull
          public String getWorkingDirectory() throws RunBuildException {
            return origCommandLine.getWorkingDirectory();
          }

          @NotNull
          public List<String> getArguments() {
            return Collections.singletonList(script.getAbsolutePath());
          }

          @NotNull
          public Map<String, String> getEnvironment() {
            return environment;
          }
        };
      }
      default:
        throw new RunBuildException("Unsupported REC configuration type " + configuration.getType());
    }
  }

  private static File createScriptFile(@NotNull final ProgramCommandLine origCommandLine, @NotNull final File directory)
    throws RunBuildException {
    final File script;
    try {
      script = File.createTempFile("build", ".sh", directory);
      StringBuilder content = new StringBuilder();
      content.append("cd ").append(origCommandLine.getWorkingDirectory()).append("\n");
      content.append(createOriginalCommandLine(origCommandLine));
      FileUtil.writeFileAndReportErrors(script, content.toString());

      setPermissions(script, SCRIPT_PERMISSIONS); // script needs to be made executable for all (chmod a+x)
    } catch (IOException e) {
      throw new RunBuildException("Failed to create temp file, error: " + e.toString());
    }
    return script;
  }

  private static void setPermissions(@NotNull final File script, @NotNull final String perms) throws IOException {
    Process process = Runtime.getRuntime().exec(new String[]{"chmod", perms, script.getAbsolutePath()});
    try {
      process.waitFor();
    } catch (InterruptedException e) {
      Loggers.AGENT.warn("Failed to execute chmod " + perms + " " + script.getAbsolutePath() + ", error: " + e.toString());
    }
  }

  private static String createOriginalCommandLine(@NotNull final ProgramCommandLine commandLine) throws RunBuildException {
    StringBuilder sb = new StringBuilder();
    sb.append(commandLine.getExecutablePath());
    List<String> arguments = commandLine.getArguments();
    if (!arguments.isEmpty()) {
      sb.append(' ');
      doFormatShellArguments(sb, arguments);
    }
    return sb.toString();
  }

  static void doFormatShellArguments(final StringBuilder sb, final List<String> arguments) {
    for (int i = 0; i < arguments.size(); i++) {
      String arg = arguments.get(i);
      if (i != 0) sb.append(' ');
      final boolean hasSpecialCharacters = arg.isEmpty() || StringUtil.containsAnyChar(arg, " !\"$&'()*,:;<=>?@[\\]^`{|}");
      if (hasSpecialCharacters) {
        sb.append("\"");
      }
      sb.append(escapeShellArgument(arg));
      if (hasSpecialCharacters) {
        sb.append("\"");
      }
    }
  }

  @NotNull
  static String escapeShellArgument(final String arg) {
    return StringUtil.escapeStr(arg, new StringUtil.EscapeInfoProvider2() {
      @Nullable
      @Override
      public String escape(final char c) {
        switch (c) {
          case '\"':
            return "\"";
          case '$':
            return "$";
          case '`':
            return "`";
          case '\\':
            return "\\";
          case '\n':
            return "\n";
          default:
            return null;
        }
      }

      @Nullable
      @Override
      public MapSerializerUtil.UnescapeResult unescape(@NotNull final String str, final int startPos) {
        return null;
      }

      @Override
      public char escapeCharacter() {
        return '\\';
      }
    });
  }
}