// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/**
 * This contains internal implementation details of the date formatting code
 * which are exposed as public functions because they must be called by other
 * libraries in order to configure the source for the locale data. We don't want
 * them exposed as public API functions in the date formatting library, so they
 * are put in a separate library here. These are for internal use only. User
 * code should import one of the `date_symbol_data...` libraries and call the
 * `initializeDateFormatting` method exposed there.
 */

library date_format_internal;
import 'dart:async';
import 'intl_helpers.dart';
import '../date_symbols.dart';

/**
 * This holds the symbols to be used for date/time formatting, indexed
 * by locale. Note that it will be set differently during initialization,
 * depending on what implementation we are using. By default, it is initialized
 * to an instance of UninitializedLocaleData, so any attempt to use it will
 * result in an informative error message.
 */
var dateTimeSymbols =
    new UninitializedLocaleData('initializeDateFormatting(<locale>)',
        en_USSymbols);

/**
 * This holds the patterns used for date/time formatting, indexed
 * by locale. Note that it will be set differently during initialization,
 * depending on what implementation we are using. By default, it is initialized
 * to an instance of UninitializedLocaleData, so any attempt to use it will
 * result in an informative error message.
 */
var dateTimePatterns =
    new UninitializedLocaleData('initializeDateFormatting(<locale>)',
        en_USPatterns);

/**
 * Initialize the symbols dictionary. This should be passed a function that
 * creates and returns the symbol data. We take a function so that if
 * initializing the data is an expensive operation it need only be done once,
 * no matter how many times this method is called.
 */
void initializeDateSymbols(Function symbols) {
  if (dateTimeSymbols is UninitializedLocaleData) {
    dateTimeSymbols = symbols();
  }
}

/**
 * Initialize the patterns dictionary. This should be passed a function that
 * creates and returns the pattern data. We take a function so that if
 * initializing the data is an expensive operation it need only be done once,
 * no matter how many times this method is called.
 */
void initializeDatePatterns(Function patterns) {
  if (dateTimePatterns is UninitializedLocaleData) {
    dateTimePatterns = patterns();
  }
}

Future initializeIndividualLocaleDateFormatting(Function init) {
  return init(dateTimeSymbols, dateTimePatterns);
}