/*
    * SPDX-FileCopyrightText: none
    * SPDX-License-Identifier: CC0-1.0
    */
   
   package gov.nist.secauto.metaschema.cli.processor;
   
   import static org.fusesource.jansi.Ansi.ansi;
   
  import gov.nist.secauto.metaschema.cli.processor.command.CommandExecutionException;
  import gov.nist.secauto.metaschema.cli.processor.command.CommandService;
  import gov.nist.secauto.metaschema.cli.processor.command.ExtraArgument;
  import gov.nist.secauto.metaschema.cli.processor.command.ICommand;
  import gov.nist.secauto.metaschema.cli.processor.command.ICommandExecutor;
  import gov.nist.secauto.metaschema.core.util.AutoCloser;
  import gov.nist.secauto.metaschema.core.util.CollectionUtil;
  import gov.nist.secauto.metaschema.core.util.IVersionInfo;
  import gov.nist.secauto.metaschema.core.util.ObjectUtils;
  
  import org.apache.commons.cli.CommandLine;
  import org.apache.commons.cli.CommandLineParser;
  import org.apache.commons.cli.DefaultParser;
  import org.apache.commons.cli.HelpFormatter;
  import org.apache.commons.cli.Option;
  import org.apache.commons.cli.Options;
  import org.apache.commons.cli.ParseException;
  import org.apache.logging.log4j.Level;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  import org.apache.logging.log4j.core.LoggerContext;
  import org.apache.logging.log4j.core.config.Configuration;
  import org.apache.logging.log4j.core.config.LoggerConfig;
  import org.fusesource.jansi.AnsiConsole;
  import org.fusesource.jansi.AnsiPrintStream;
  
  import java.io.PrintStream;
  import java.io.PrintWriter;
  import java.nio.charset.StandardCharsets;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.atomic.AtomicBoolean;
  import java.util.function.Function;
  import java.util.stream.Collectors;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  import edu.umd.cs.findbugs.annotations.Nullable;
  import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  
  /**
   * Processes command line arguments and dispatches called commands.
   * <p>
   * This implementation make significant use of the command pattern to support a
   * delegation chain of commands based on implementations of {@link ICommand}.
   */
  @SuppressWarnings("PMD.CouplingBetweenObjects")
  public class CLIProcessor {
    private static final Logger LOGGER = LogManager.getLogger(CLIProcessor.class);
  
    /**
     * This option indicates if the help should be shown.
     */
    @NonNull
    public static final Option HELP_OPTION = ObjectUtils.notNull(Option.builder("h")
        .longOpt("help")
        .desc("display this help message")
        .build());
    /**
     * This option indicates if colorized output should be disabled.
     */
    @NonNull
    public static final Option NO_COLOR_OPTION = ObjectUtils.notNull(Option.builder()
        .longOpt("no-color")
        .desc("do not colorize output")
        .build());
    /**
     * This option indicates if non-errors should be suppressed.
     */
    @NonNull
    public static final Option QUIET_OPTION = ObjectUtils.notNull(Option.builder("q")
        .longOpt("quiet")
        .desc("minimize output to include only errors")
        .build());
    /**
     * This option indicates if a strack trace should be shown for an error
     * {@link ExitStatus}.
     */
    @NonNull
    public static final Option SHOW_STACK_TRACE_OPTION = ObjectUtils.notNull(Option.builder()
        .longOpt("show-stack-trace")
        .desc("display the stack trace associated with an error")
        .build());
    /**
     * This option indicates if the version information should be shown.
     */
    @NonNull
    public static final Option VERSION_OPTION = ObjectUtils.notNull(Option.builder()
       .longOpt("version")
       .desc("display the application version")
       .build());
 
   @NonNull
   private static final List<Option> OPTIONS = ObjectUtils.notNull(List.of(
       HELP_OPTION,
       NO_COLOR_OPTION,
       QUIET_OPTION,
       SHOW_STACK_TRACE_OPTION,
       VERSION_OPTION));
 
   /**
    * Used to identify the version info for the command.
    */
   public static final String COMMAND_VERSION = "http://csrc.nist.gov/ns/metaschema-java/cli/command-version";
 
   @NonNull
   private final List<ICommand> commands = new LinkedList<>();
   @NonNull
   private final String exec;
   @NonNull
   private final Map<String, IVersionInfo> versionInfos;
 
   /**
    * The main entry point for command execution.
    *
    * @param args
    *          the command line arguments to process
    */
   public static void main(String... args) {
     System.setProperty("java.util.logging.manager", "org.apache.logging.log4j.jul.LogManager");
     CLIProcessor processor = new CLIProcessor("metaschema-cli");
 
     CommandService.getInstance().getCommands().stream().forEach(command -> {
       assert command != null;
       processor.addCommandHandler(command);
     });
     System.exit(processor.process(args).getExitCode().getStatusCode());
   }
 
   /**
    * The main entry point for CLI processing.
    * <p>
    * This uses the build-in version information.
    *
    * @param args
    *          the command line arguments
    */
   public CLIProcessor(@NonNull String args) {
     this(args, CollectionUtil.singletonMap(COMMAND_VERSION, new ProcessorVersion()));
   }
 
   /**
    * The main entry point for CLI processing.
    * <p>
    * This uses the provided version information.
    *
    * @param exec
    *          the command name
    * @param versionInfos
    *          the version info to display when the version option is provided
    */
   public CLIProcessor(@NonNull String exec, @NonNull Map<String, IVersionInfo> versionInfos) {
     this.exec = exec;
     this.versionInfos = versionInfos;
     AnsiConsole.systemInstall();
   }
 
   /**
    * Gets the command used to execute for use in help text.
    *
    * @return the command name
    */
   @NonNull
   public String getExec() {
     return exec;
   }
 
   /**
    * Retrieve the version information for this application.
    *
    * @return the versionInfo
    */
   @NonNull
   public Map<String, IVersionInfo> getVersionInfos() {
     return versionInfos;
   }
 
   /**
    * Register a new command handler.
    *
    * @param handler
    *          the command handler to register
    */
   public void addCommandHandler(@NonNull ICommand handler) {
     commands.add(handler);
   }
 
   /**
    * Process a set of CLIProcessor arguments.
    * <p>
    * process().getExitCode().getStatusCode()
    *
    * @param args
    *          the arguments to process
    * @return the exit status
    */
   @NonNull
   public ExitStatus process(String... args) {
     return parseCommand(args);
   }
 
   @NonNull
   private ExitStatus parseCommand(String... args) {
     List<String> commandArgs = Arrays.asList(args);
     assert commandArgs != null;
     CallingContext callingContext = new CallingContext(commandArgs);
 
     if (LOGGER.isDebugEnabled()) {
       String commandChain = callingContext.getCalledCommands().stream()
           .map(ICommand::getName)
           .collect(Collectors.joining(" -> "));
       LOGGER.debug("Processing command chain: {}", commandChain);
     }
 
     ExitStatus status;
     // the first two arguments should be the <command> and <operation>, where <type>
     // is the object type
     // the <operation> is performed against.
     if (commandArgs.isEmpty()) {
       status = ExitCode.INVALID_COMMAND.exit();
       callingContext.showHelp();
     } else {
       status = callingContext.processCommand();
     }
     return status;
   }
 
   /**
    * Get the root-level commands.
    *
    * @return the list of commands
    */
   @NonNull
   protected final List<ICommand> getTopLevelCommands() {
     return CollectionUtil.unmodifiableList(commands);
   }
 
   /**
    * Get the root-level commands, mapped from name to command.
    *
    * @return the map of command names to command
    */
   @NonNull
   protected final Map<String, ICommand> getTopLevelCommandsByName() {
     return ObjectUtils.notNull(getTopLevelCommands()
         .stream()
         .collect(Collectors.toUnmodifiableMap(ICommand::getName, Function.identity())));
   }
 
   private static void handleNoColor() {
     System.setProperty(AnsiConsole.JANSI_MODE, AnsiConsole.JANSI_MODE_STRIP);
     AnsiConsole.systemUninstall();
   }
 
   /**
    * Configure the logger to only report errors.
    */
   public static void handleQuiet() {
     LoggerContext ctx = (LoggerContext) LogManager.getContext(false); // NOPMD not closable here
     Configuration config = ctx.getConfiguration();
     LoggerConfig loggerConfig = config.getLoggerConfig(LogManager.ROOT_LOGGER_NAME);
     Level oldLevel = loggerConfig.getLevel();
     if (oldLevel.isLessSpecificThan(Level.ERROR)) {
       loggerConfig.setLevel(Level.ERROR);
       ctx.updateLoggers();
     }
   }
 
   /**
    * Output version information.
    */
   protected void showVersion() {
     @SuppressWarnings("resource")
     PrintStream out = AnsiConsole.out(); // NOPMD - not owner
     getVersionInfos().values().stream().forEach(info -> {
       out.println(ansi()
           .bold().a(info.getName()).boldOff()
           .a(" ")
           .bold().a(info.getVersion()).boldOff()
           .a(" built at ")
           .bold().a(info.getBuildTimestamp()).boldOff()
           .a(" from branch ")
           .bold().a(info.getGitBranch()).boldOff()
           .a(" (")
           .bold().a(info.getGitCommit()).boldOff()
           .a(") at ")
           .bold().a(info.getGitOriginUrl()).boldOff()
           .reset());
     });
     out.flush();
   }
 
   /**
    * Records information about the command line options and called command
    * hierarchy.
    */
   @SuppressWarnings("PMD.GodClass")
   public final class CallingContext {
     @NonNull
     private final List<Option> options;
     @NonNull
     private final List<ICommand> calledCommands;
     @Nullable
     private final ICommand targetCommand;
     @NonNull
     private final List<String> extraArgs;
 
     @SuppressFBWarnings(value = "CT_CONSTRUCTOR_THROW", justification = "Use of final fields")
     private CallingContext(@NonNull List<String> args) {
       @SuppressWarnings("PMD.LooseCoupling") // needed to support getLast
       LinkedList<ICommand> calledCommands = new LinkedList<>();
       List<Option> options = new LinkedList<>(OPTIONS);
       List<String> extraArgs = new LinkedList<>();
 
       AtomicBoolean endArgs = new AtomicBoolean();
       args.forEach(arg -> {
         if (endArgs.get() || arg.startsWith("-")) {
           extraArgs.add(arg);
         } else if ("--".equals(arg)) {
           endArgs.set(true);
         } else {
           ICommand command = calledCommands.isEmpty()
               ? getTopLevelCommandsByName().get(arg)
               : calledCommands.getLast().getSubCommandByName(arg);
 
           if (command == null) {
             extraArgs.add(arg);
             endArgs.set(true);
           } else {
             calledCommands.add(command);
             options.addAll(command.gatherOptions());
           }
         }
       });
 
       this.calledCommands = CollectionUtil.unmodifiableList(calledCommands);
       this.targetCommand = calledCommands.peekLast();
       this.options = CollectionUtil.unmodifiableList(options);
       this.extraArgs = CollectionUtil.unmodifiableList(extraArgs);
     }
 
     /**
      * Get the command line processor instance that generated this calling context.
      *
      * @return the instance
      */
     @NonNull
     public CLIProcessor getCLIProcessor() {
       return CLIProcessor.this;
     }
 
     /**
      * Get the command that was triggered by the CLI arguments.
      *
      * @return the command or {@code null} if no command was triggered
      */
     @Nullable
     public ICommand getTargetCommand() {
       return targetCommand;
     }
 
     /**
      * Get the options that are in scope for the current command context.
      *
      * @return the list of options
      */
     @NonNull
     private List<Option> getOptionsList() {
       return options;
     }
 
     @NonNull
     private List<ICommand> getCalledCommands() {
       return calledCommands;
     }
 
     /**
      * Get any left over arguments that were not consumed by CLI options.
      *
      * @return the list of remaining arguments, which may be empty
      */
     @NonNull
     private List<String> getExtraArgs() {
       return extraArgs;
     }
 
     /**
      * Get the collections of in scope options as an options group.
      *
      * @return the options group
      */
     private Options toOptions() {
       Options retval = new Options();
       for (Option option : getOptionsList()) {
         retval.addOption(option);
       }
       return retval;
     }
 
     /**
      * Process the command identified by the CLI arguments.
      *
      * @return the result of processing the command
      */
     @SuppressWarnings({
         "PMD.OnlyOneReturn",
         "PMD.NPathComplexity",
         "PMD.CyclomaticComplexity"
     })
     @NonNull
     public ExitStatus processCommand() {
       // TODO: Consider refactoring as follows to reduce complexity:
       // - Extract the parsing logic for each phase into separate methods (e.g.,
       // parsePhaseOneOptions, parsePhaseTwoOptions).
       // - Encapsulate error handling into dedicated methods.
       // - Separate command execution logic into its own method if possible.
       CommandLineParser parser = new DefaultParser();
 
       // this uses a three phase approach where:
       // phase 1: checks if help or version are used
       // phase 2: parse and validate arguments
       // phase 3: executes the command
 
       // phase 1
       CommandLine cmdLine;
       try {
         Options phase1Options = new Options();
         phase1Options.addOption(HELP_OPTION);
         phase1Options.addOption(VERSION_OPTION);
 
         cmdLine = ObjectUtils.notNull(parser.parse(phase1Options, getExtraArgs().toArray(new String[0]), true));
       } catch (ParseException ex) {
         String msg = ex.getMessage();
         assert msg != null;
         return handleInvalidCommand(msg);
       }
 
       if (cmdLine.hasOption(VERSION_OPTION)) {
         showVersion();
         return ExitCode.OK.exit();
       }
       if (cmdLine.hasOption(HELP_OPTION)) {
         showHelp();
         return ExitCode.OK.exit();
       }
 
       // phase 2
       try {
         cmdLine = ObjectUtils.notNull(parser.parse(toOptions(), getExtraArgs().toArray(new String[0])));
       } catch (ParseException ex) {
         String msg = ex.getMessage();
         assert msg != null;
         return handleInvalidCommand(msg);
       }
 
       ICommand targetCommand = getTargetCommand();
       if (targetCommand != null) {
         try {
           targetCommand.validateExtraArguments(this, cmdLine);
         } catch (InvalidArgumentException ex) {
           return handleError(
               ExitCode.INVALID_ARGUMENTS.exitMessage(ex.getLocalizedMessage()),
               cmdLine,
               true);
         }
       }
 
       for (ICommand cmd : getCalledCommands()) {
         try {
           cmd.validateOptions(this, cmdLine);
         } catch (InvalidArgumentException ex) {
           String msg = ex.getMessage();
           assert msg != null;
           return handleInvalidCommand(msg);
         }
       }
 
       // phase 3
       if (cmdLine.hasOption(NO_COLOR_OPTION)) {
         handleNoColor();
       }
 
       if (cmdLine.hasOption(QUIET_OPTION)) {
         handleQuiet();
       }
       return invokeCommand(cmdLine);
     }
 
     /**
      * Directly execute the logic associated with the command.
      *
      * @param cmdLine
      *          the command line information
      * @return the result of executing the command
      */
     @SuppressWarnings({
         "PMD.OnlyOneReturn", // readability
         "PMD.AvoidCatchingGenericException" // needed here
     })
     @NonNull
     private ExitStatus invokeCommand(@NonNull CommandLine cmdLine) {
       ExitStatus retval;
       try {
         ICommand targetCommand = getTargetCommand();
         if (targetCommand == null) {
           retval = ExitCode.INVALID_COMMAND.exit();
         } else {
           ICommandExecutor executor = targetCommand.newExecutor(this, cmdLine);
           try {
             executor.execute();
             retval = ExitCode.OK.exit();
           } catch (CommandExecutionException ex) {
             retval = ex.toExitStatus();
           } catch (RuntimeException ex) {
             retval = ExitCode.RUNTIME_ERROR
                 .exitMessage("Unexpected error occured: " + ex.getLocalizedMessage())
                 .withThrowable(ex);
           }
         }
       } catch (RuntimeException ex) {
         retval = ExitCode.RUNTIME_ERROR
             .exitMessage(String.format("An uncaught runtime error occurred. %s", ex.getLocalizedMessage()))
             .withThrowable(ex);
       }
 
       if (!ExitCode.OK.equals(retval.getExitCode())) {
         retval.generateMessage(cmdLine.hasOption(SHOW_STACK_TRACE_OPTION));
 
         if (ExitCode.INVALID_COMMAND.equals(retval.getExitCode())) {
           showHelp();
         }
       }
       return retval;
     }
 
     /**
      * Handle an error that occurred while executing the command.
      *
      * @param exitStatus
      *          the execution result
      * @param cmdLine
      *          the command line information
      * @param showHelp
      *          if {@code true} show the help information
      * @return the resulting exit status
      */
     @NonNull
     public ExitStatus handleError(
         @NonNull ExitStatus exitStatus,
         @NonNull CommandLine cmdLine,
         boolean showHelp) {
       exitStatus.generateMessage(cmdLine.hasOption(SHOW_STACK_TRACE_OPTION));
       if (showHelp) {
         showHelp();
       }
       return exitStatus;
     }
 
     /**
      * Generate the help message and exit status for an invalid command using the
      * provided message.
      *
      * @param message
      *          the error message
      * @return the resulting exit status
      */
     @NonNull
     public ExitStatus handleInvalidCommand(
         @NonNull String message) {
       showHelp();
 
       ExitStatus retval = ExitCode.INVALID_COMMAND.exitMessage(message);
       retval.generateMessage(false);
       return retval;
     }
 
     /**
      * Callback for providing a help header.
      *
      * @return the header or {@code null}
      */
     @Nullable
     private String buildHelpHeader() {
       // TODO: build a suitable header
       return null;
     }
 
     /**
      * Callback for providing a help footer.
      *
      * @param exec
      *          the executable name
      *
      * @return the footer or {@code null}
      */
     @NonNull
     private String buildHelpFooter() {
 
       ICommand targetCommand = getTargetCommand();
       Collection<ICommand> subCommands;
       if (targetCommand == null) {
         subCommands = getTopLevelCommands();
       } else {
         subCommands = targetCommand.getSubCommands();
       }
 
       String retval;
       if (subCommands.isEmpty()) {
         retval = "";
       } else {
         StringBuilder builder = new StringBuilder(128);
         builder
             .append(System.lineSeparator())
             .append("The following are available commands:")
             .append(System.lineSeparator());
 
         int length = subCommands.stream()
             .mapToInt(command -> command.getName().length())
             .max().orElse(0);
 
         for (ICommand command : subCommands) {
           builder.append(
               ansi()
                   .render(String.format("   @|bold %-" + length + "s|@ %s%n",
                       command.getName(),
                       command.getDescription())));
         }
         builder
             .append(System.lineSeparator())
             .append('\'')
             .append(getExec())
             .append(" <command> --help' will show help on that specific command.")
             .append(System.lineSeparator());
         retval = builder.toString();
         assert retval != null;
       }
       return retval;
     }
 
     /**
      * Get the CLI syntax.
      *
      * @return the CLI syntax to display in help output
      */
     private String buildHelpCliSyntax() {
 
       StringBuilder builder = new StringBuilder(64);
       builder.append(getExec());
 
       List<ICommand> calledCommands = getCalledCommands();
       if (!calledCommands.isEmpty()) {
         builder.append(calledCommands.stream()
             .map(ICommand::getName)
             .collect(Collectors.joining(" ", " ", "")));
       }
 
       // output calling commands
       ICommand targetCommand = getTargetCommand();
       if (targetCommand == null) {
         builder.append(" <command>");
       } else {
         builder.append(getSubCommands(targetCommand));
       }
 
       // output required options
       getOptionsList().stream()
           .filter(Option::isRequired)
           .forEach(option -> {
             builder
                 .append(' ')
                 .append(OptionUtils.toArgument(ObjectUtils.notNull(option)));
             if (option.hasArg()) {
               builder
                   .append('=')
                   .append(option.getArgName());
             }
           });
 
       // output non-required option placeholder
       builder.append(" [<options>]");
 
       // output extra arguments
       if (targetCommand != null) {
         // handle extra arguments
         builder.append(getExtraArguments(targetCommand));
       }
 
       String retval = builder.toString();
       assert retval != null;
       return retval;
     }
 
     @NonNull
     private CharSequence getSubCommands(ICommand targetCommand) {
       Collection<ICommand> subCommands = targetCommand.getSubCommands();
 
       StringBuilder builder = new StringBuilder();
       if (!subCommands.isEmpty()) {
         builder.append(' ');
         if (!targetCommand.isSubCommandRequired()) {
           builder.append('[');
         }
 
         builder.append("<command>");
 
         if (!targetCommand.isSubCommandRequired()) {
           builder.append(']');
         }
       }
       return builder;
     }
 
     @NonNull
     private CharSequence getExtraArguments(@NonNull ICommand targetCommand) {
       StringBuilder builder = new StringBuilder();
       for (ExtraArgument argument : targetCommand.getExtraArguments()) {
         builder.append(' ');
         if (!argument.isRequired()) {
           builder.append('[');
         }
 
         builder.append('<')
             .append(argument.getName())
             .append('>');
 
         if (argument.getNumber() > 1) {
           builder.append("...");
         }
 
         if (!argument.isRequired()) {
           builder.append(']');
         }
       }
       return builder;
     }
 
     /**
      * Output the help text to the console.
      */
     public void showHelp() {
 
       HelpFormatter formatter = new HelpFormatter();
       formatter.setLongOptSeparator("=");
 
       @SuppressWarnings("resource")
       AnsiPrintStream out = AnsiConsole.out();
 
       try (PrintWriter writer = new PrintWriter( // NOPMD not owned
           AutoCloser.preventClose(out),
           true,
           StandardCharsets.UTF_8)) {
         formatter.printHelp(
             writer,
             Math.max(out.getTerminalWidth(), 50),
             buildHelpCliSyntax(),
             buildHelpHeader(),
             toOptions(),
             HelpFormatter.DEFAULT_LEFT_PAD,
             HelpFormatter.DEFAULT_DESC_PAD,
             buildHelpFooter(),
             false);
         writer.flush();
       }
     }
   }
 }