import 'dart:io';

List<void Function()> initializers = [];
List<void Function()> finalizers = [];

/// enablePrefixMatching allows for automatic prefix matching.
/// Automatic prefix matching can be a dangerous thing to automatically enable in CLI tools.
var enablePrefixMatching = false;

/// enableCommandSorting controls sorting of the slice of commands, which is turned on by default.
var enableCommandSorting = true;

/// enableCaseInsensitive allows case-insensitve command names. (case sensitive by default)
var enableCaseInsensitive = false;

/// enableTraverseRunHooks executes persistent pre-run and post-run hooks from all parents.
/// By default this is disabled, which means only the first run hook to be found is executed.
var enableTraverseRunHooks = false;

/// mousetrapHelpText enables an information splash screen on Windows
/// if the CLI is started from explorer.exe.
/// To disable the mousetrap, just set this variable to blank string ("").
// Works only on Microsoft Windows.
String mousetrapHelpText = """This is a command line tool.

You need to open cmd.exe and run it from there.
""";

/// mousetrapDisplayDuration controls how long the mousetrapHelpText message is displayed on Windows
/// if the CLI is started from explorer.exe. Set to 0 to wait for the return key to be pressed.
/// To disable the mousetrap, just set mousetrapHelpText to a blank string ("").
Duration mousetrapDisplayDuration = Duration(seconds: 5);

/// onInitialize sets the passed functions to be run when each command's
/// execute method is called.
void onInitialize(List<void Function()> y) {
  initializers.addAll(y);
}

/// onFinalize sets the passed functions to be run when each command's
/// execute method is terminated.
void onFinalize(List<void Function()> y) {
  finalizers.addAll(y);
}

/// ld compares two strings and returns the levenshtein distance between them.
int ld(String s, String t, bool ignoreCase) {
  if (ignoreCase) {
    s.toLowerCase();
    t.toLowerCase();
  }

  List<List<int>> d = List.generate(
    s.length + 1,
    (_) => List<int>.filled(t.length + 1, 0),
  );

  for (int i = 0; i < d.length; i++) {
    d[i][0] = i;
  }

  for (int j = 0; j < d[0].length; j++) {
    d[0][j] = j;
  }

  for (int j = 1; j <= t.length; j++) {
    for (int i = 1; i <= s.length; i++) {
      if (s[i - 1] == t[j - 1]) {
        d[i][j] = d[i - 1][j - 1];
      } else {
        int min = d[i - 1][j - 1];
        if (d[i][j - 1] < min) {
          min = d[i][j - 1];
        }
        if (d[i - 1][j - 1] < min) {
          min = d[i - 1][j - 1];
        }
        d[i][j] = min + 1;
      }
    }
  }

  return d[s.length][t.length];
}

/// checkError print the msg with the prefix 'Error:' and exits with error code 1. If the msg is null, it does nothing.
void checkError(Object? msg) {
  if (msg != null) {
    stderr.write("Error: $msg");
    exit(1);
  }
}

/// writeStringAndCheck writes a string into a buffer, and checks if the error is not null.
void writeStringAndCheck(StringBuffer b, String s) {
  try {
    b.write(s);
  } catch (e) {
    checkError(e);
  }
}