// Copyright (C) 2008 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.google.gerrit.client;

import com.google.gerrit.client.change.Resources;
import com.google.gerrit.client.info.AccountInfo;
import com.google.gerrit.client.info.GeneralPreferences;
import com.google.gwt.i18n.client.NumberFormat;
import java.util.Date;

/** Misc. formatting functions. */
public class FormatUtil {
  private static DateFormatter dateFormatter;

  public static void setPreferences(GeneralPreferences prefs) {
    dateFormatter = new DateFormatter(prefs);
  }

  /** Format a date using a really short format. */
  public static String shortFormat(Date dt) {
    ensureInited();
    return dateFormatter.shortFormat(dt);
  }

  /** Format a date using a really short format. */
  public static String shortFormatDayTime(Date dt) {
    ensureInited();
    return dateFormatter.shortFormatDayTime(dt);
  }

  /** Format a date using the locale's medium length format. */
  public static String mediumFormat(Date dt) {
    ensureInited();
    return dateFormatter.mediumFormat(dt);
  }

  private static void ensureInited() {
    if (dateFormatter == null) {
      setPreferences(Gerrit.getUserPreferences());
    }
  }

  /** Format a date using git log's relative date format. */
  public static String relativeFormat(Date dt) {
    return RelativeDateFormatter.format(dt);
  }

  /**
   * Formats an account as a name and an email address.
   *
   * <p>Example output:
   *
   * <ul>
   *   <li>{@code A U. Thor &lt;author@example.com&gt;}: full populated
   *   <li>{@code A U. Thor (12)}: missing email address
   *   <li>{@code Anonymous Coward &lt;author@example.com&gt;}: missing name
   *   <li>{@code Anonymous Coward (12)}: missing name and email address
   * </ul>
   */
  public static String nameEmail(AccountInfo info) {
    return createAccountFormatter().nameEmail(info);
  }

  /**
   * Formats an account name.
   *
   * <p>If the account has a full name, it returns only the full name. Otherwise it returns a longer
   * form that includes the email address.
   */
  public static String name(AccountInfo info) {
    return createAccountFormatter().name(info);
  }

  private static AccountFormatter createAccountFormatter() {
    return new AccountFormatter(Gerrit.info().user().anonymousCowardName());
  }

  /** The returned format string doesn't contain any +/- sign. */
  public static String formatAbsBytes(long bytes) {
    return formatBytes(bytes, true);
  }

  public static String formatBytes(long bytes) {
    return formatBytes(bytes, false);
  }

  private static String formatBytes(long bytes, boolean abs) {
    bytes = abs ? Math.abs(bytes) : bytes;

    if (bytes == 0) {
      return abs ? "0 B" : "+/- 0 B";
    }

    if (Math.abs(bytes) < 1024) {
      return (bytes > 0 && !abs ? "+" : "") + bytes + " B";
    }

    int exp = (int) (Math.log(Math.abs(bytes)) / Math.log(1024));
    return (bytes > 0 && !abs ? "+" : "")
        + NumberFormat.getFormat("#.0").format(bytes / Math.pow(1024, exp))
        + " "
        + "KMGTPE".charAt(exp - 1)
        + "iB";
  }

  public static String formatPercentage(long size, long delta) {
    if (size == 0) {
      return Resources.C.notAvailable();
    }
    return (delta > 0 ? "+" : "-") + formatAbsPercentage(size, delta);
  }

  public static String formatAbsPercentage(long size, long delta) {
    if (size == 0) {
      return Resources.C.notAvailable();
    }
    long percentage = Math.abs(Math.round(delta * 100.0 / size));
    return percentage + "%";
  }
}