/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.myfaces.tobago.renderkit.css;

import org.apache.myfaces.tobago.component.Attributes;
import org.apache.myfaces.tobago.context.Markup;
import org.apache.myfaces.tobago.layout.AlignItems;
import org.apache.myfaces.tobago.layout.JustifyContent;
import org.apache.myfaces.tobago.layout.Margin;
import org.apache.myfaces.tobago.layout.MarginTokens;
import org.apache.myfaces.tobago.layout.Measure;
import org.apache.myfaces.tobago.layout.MeasureList;
import org.apache.myfaces.tobago.layout.TextAlign;
import org.apache.myfaces.tobago.util.ComponentUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.faces.application.FacesMessage;
import javax.faces.component.UIComponent;
import java.lang.invoke.MethodHandles;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * CSS classes for the Bootstrap Library.
 *
 * @since 3.0.0
 */
public enum BootstrapClass implements CssItem {

  ACTIVE("active"),
  ALERT("alert"),
  ALERT_DANGER("alert-danger"),
  ALERT_WARNING("alert-warning"),
  ALERT_INFO("alert-info"),
  ALERT_DISMISSIBLE("alert-dismissible"),
  ALIGN_ITEMS_BASELINE("align-items-baseline"),
  ALIGN_ITEMS_CENTER("align-items-center"),
  ALIGN_ITEMS_END("align-items-end"),
  ALIGN_ITEMS_START("align-items-start"),
  ALIGN_ITEMS_STRETCH("align-items-stretch"),
  BG_DARK("bg-dark"),
  /**
   * @deprecated since 4.0.0, please use {@link #BG_DARK}
   */
  @Deprecated
  BG_INVERSE("bg-dark"),
  BADGE("badge"),
  BADGE_DANGER("badge-danger"),
  BADGE_DARK("badge-dark"),
  /**
   * @deprecated since 4.0.0
   */
  @Deprecated
  BADGE_DEFAULT("badge-default"),
  BADGE_INFO("badge-info"),
  BADGE_LIGHT("badge-light"),
  BADGE_PILL("badge-pill"),
  BADGE_PRIMARY("badge-primary"),
  BADGE_SECONDARY("badge-secondary"),
  BADGE_SUCCESS("badge-success"),
  BADGE_WARNING("badge-warning"),
  BORDER_DANGER("border-danger"),
  BORDER_INFO("border-info"),
  BORDER_WARNING("border-warning"),
  BTN("btn"),
  BTN_DANGER("btn-danger"),
  BTN_DARK("btn-dark"),
  BTN_GROUP("btn-group"),
  BTN_GROUP_VERTICAL("btn-group-vertical"),
  BTN_INFO("btn-info"),
  BTN_LIGHT("btn-light"),
  BTN_LINK("btn-link"),
  BTN_PRIMARY("btn-primary"),
  BTN_OUTLINE_INFO("btn-outline-info"),
  BTN_SECONDARY("btn-secondary"),
  BTN_SUCCESS("btn-success"),
  BTN_TOOLBAR("btn-toolbar"),
  BTN_WARNING("btn-warning"),
  CARD("card"),
  /**
   * @deprecated since 4.0.0, please use {@link #CARD_BODY}
   */
  @Deprecated
  CARD_BLOCK("card-body"),
  CARD_BODY("card-body"),
  CARD_HEADER("card-header"),
  CARD_HEADER_TABS("card-header-tabs"),
  CARD_TITLE("card-title"),
  CLOSE("close"),
  COLLAPSE("collapse"),
  COL_FORM_LABEL("col-form-label"),
  COL_LG("col-lg"),
  COL_LG_1("col-lg-1"),
  COL_LG_2("col-lg-2"),
  COL_LG_3("col-lg-3"),
  COL_LG_4("col-lg-4"),
  COL_LG_5("col-lg-5"),
  COL_LG_6("col-lg-6"),
  COL_LG_7("col-lg-7"),
  COL_LG_8("col-lg-8"),
  COL_LG_9("col-lg-9"),
  COL_LG_10("col-lg-10"),
  COL_LG_11("col-lg-11"),
  COL_LG_12("col-lg-12"),
  COL_LG_AUTO("col-lg-auto"),
  COL_MD("col-md"),
  COL_MD_1("col-md-1"),
  COL_MD_2("col-md-2"),
  COL_MD_3("col-md-3"),
  COL_MD_4("col-md-4"),
  COL_MD_5("col-md-5"),
  COL_MD_6("col-md-6"),
  COL_MD_7("col-md-7"),
  COL_MD_8("col-md-8"),
  COL_MD_9("col-md-9"),
  COL_MD_10("col-md-10"),
  COL_MD_11("col-md-11"),
  COL_MD_12("col-md-12"),
  COL_MD_AUTO("col-md-auto"),
  COL_SM("col-sm"),
  COL_SM_1("col-sm-1"),
  COL_SM_2("col-sm-2"),
  COL_SM_3("col-sm-3"),
  COL_SM_4("col-sm-4"),
  COL_SM_5("col-sm-5"),
  COL_SM_6("col-sm-6"),
  COL_SM_7("col-sm-7"),
  COL_SM_8("col-sm-8"),
  COL_SM_9("col-sm-9"),
  COL_SM_10("col-sm-10"),
  COL_SM_11("col-sm-11"),
  COL_SM_12("col-sm-12"),
  COL_SM_AUTO("col-sm-auto"),
  COL_XL("col-xl"),
  COL_XL_1("col-xl-1"),
  COL_XL_2("col-xl-2"),
  COL_XL_3("col-xl-3"),
  COL_XL_4("col-xl-4"),
  COL_XL_5("col-xl-5"),
  COL_XL_6("col-xl-6"),
  COL_XL_7("col-xl-7"),
  COL_XL_8("col-xl-8"),
  COL_XL_9("col-xl-9"),
  COL_XL_10("col-xl-10"),
  COL_XL_11("col-xl-11"),
  COL_XL_12("col-xl-12"),
  COL_XL_AUTO("col-xl-auto"),
  COL("col"),
  COL_1("col-1"),
  COL_2("col-2"),
  COL_3("col-3"),
  COL_4("col-4"),
  COL_5("col-5"),
  COL_6("col-6"),
  COL_7("col-7"),
  COL_8("col-8"),
  COL_9("col-9"),
  COL_10("col-10"),
  COL_11("col-11"),
  COL_12("col-12"),
  COL_AUTO("col-auto"),
  /**
   * @deprecated since 4.0.0, please use {@link #COL_1}
   */
  @Deprecated
  COL_XS_1("col-1"),
  /**
   * @deprecated since 4.0.0, please use {@link #COL_2}
   */
  @Deprecated
  COL_XS_2("col-2"),
  /**
   * @deprecated since 4.0.0, please use {@link #COL_3}
   */
  @Deprecated
  COL_XS_3("col-3"),
  /**
   * @deprecated since 4.0.0, please use {@link #COL_4}
   */
  @Deprecated
  COL_XS_4("col-4"),
  /**
   * @deprecated since 4.0.0, please use {@link #COL_5}
   */
  @Deprecated
  COL_XS_5("col-5"),
  /**
   * @deprecated since 4.0.0, please use {@link #COL_6}
   */
  @Deprecated
  COL_XS_6("col-6"),
  /**
   * @deprecated since 4.0.0, please use {@link #COL_7}
   */
  @Deprecated
  COL_XS_7("col-7"),
  /**
   * @deprecated since 4.0.0, please use {@link #COL_8}
   */
  @Deprecated
  COL_XS_8("col-8"),
  /**
   * @deprecated since 4.0.0, please use {@link #COL_9}
   */
  @Deprecated
  COL_XS_9("col-9"),
  /**
   * @deprecated since 4.0.0, please use {@link #COL_10}
   */
  @Deprecated
  COL_XS_10("col-10"),
  /**
   * @deprecated since 4.0.0, please use {@link #COL_11}
   */
  @Deprecated
  COL_XS_11("col-11"),
  /**
   * @deprecated since 4.0.0, please use {@link #COL_12}
   */
  @Deprecated
  COL_XS_12("col-12"),
  CONTAINER("container"),
  CONTAINER_FLUID("container-fluid"),
  CUSTOM_FILE("custom-file"),
  CUSTOM_FILE_INPUT("custom-file-input"),
  CUSTOM_FILE_LABEL("custom-file-label"),
  CUSTOM_SELECT("custom-select"),
  D_FLEX("d-flex"),
  D_INLINE("d-inline"),
  D_NONE("d-none"),
  D_SM_NONE("d-sm-none"),
  DISABLED("disabled"),
  DROPDOWN("dropdown"),
  DROPDOWN_DIVIDER("dropdown-divider"),
  DROPDOWN_ITEM("dropdown-item"),
  DROPDOWN_MENU("dropdown-menu"),
  DROPDOWN_MENU_RIGHT("dropdown-menu-right"),
  DROPDOWN_TOGGLE("dropdown-toggle"),
  FADE("fade"),
  FIGURE("figure"),
  FIGURE_CAPTION("figure-caption"),
  FIGURE_IMG("figure-img"),
  FIXED_BOTTOM("fixed-bottom"),
  /**
   * @deprecated since 5.0.0, please use {@link #STICKY_TOP}
   */
  @Deprecated
  FIXED_TOP("fixed-top"),
  FLEX_COLUMN("flex-column"),
  FLEX_COLUMN_REVERSE("flex-column-reverse"),
  FLEX_ROW("flex-row"),
  FLEX_ROW_REVERSE("flex-row-reverse"),
  FONT_ITALIC("font-italic"),
  FONT_WEIGHT_BOLD("font-weight-bold"),
  FONT_WEIGHT_LIGHT("font-weight-light"),
  FORM_CHECK("form-check"),
  FORM_CHECK_INLINE("form-check-inline"),
  FORM_CHECK_INPUT("form-check-input"),
  FORM_CHECK_LABEL("form-check-label"),
  FORM_CONTROL("form-control"),
  FORM_CONTROL_PLAINTEXT("form-control-plaintext"),
  /**
   * @deprecated since 4.0.0, please use {@link #FORM_CONTROL_PLAINTEXT}
   */
  @Deprecated
  FORM_CONTROL_STATIC("form-control-plaintext"),
  FORM_GROUP("form-group"),
  FORM_INLINE("form-inline"),
  //TODO: adjust to the new bootstrap concept
  /**
   * @deprecated since 4.0.0
   */
  @Deprecated
  HAS_DANGER("has-danger"),
  /**
   * @deprecated since 4.0.0
   */
  @Deprecated
  HAS_SUCCESS("has-success"),
  /**
   * @deprecated since 4.0.0
   */
  @Deprecated
  HAS_WARNING("has-warning"),
  /**
   * @deprecated since 4.0.0, please use {@link #D_SM_NONE}
   */
  @Deprecated
  HIDDEN_SM_UP("d-sm-none"),
  INPUT_GROUP("input-group"),
  INPUT_GROUP_APPEND("input-group-append"),
  /**
   * @deprecated since 4.1.0
   */
  @Deprecated
  INPUT_GROUP_ADDON("input-group-addon"),
  /**
   * @deprecated since 4.1.0
   */
  @Deprecated
  INPUT_GROUP_BTN("input-group-btn"),
  INPUT_GROUP_PREPEND("input-group-prepend"),
  INPUT_GROUP_TEXT("input-group-text"),
  INVISIBLE("invisible"),
  JUSTIFY_CONTENT_AROUND("justify-content-around"),
  JUSTIFY_CONTENT_BETWEEN("justify-content-between"),
  JUSTIFY_CONTENT_CENTER("justify-content-center"),
  JUSTIFY_CONTENT_END("justify-content-end"),
  JUSTIFY_CONTENT_START("justify-content-start"),
  ML_AUTO("ml-auto"),
  ML_LG_AUTO("ml-lg-auto"),
  ML_MD_AUTO("ml-md-auto"),
  ML_SM_AUTO("ml-sm-auto"),
  ML_XL_AUTO("ml-xl-auto"),
  MODAL("modal"),
  MODAL_CONTENT("modal-content"),
  MODAL_DIALOG("modal-dialog"),
  MODAL_LG("modal-lg"),
  MODAL_SM("modal-sm"),
  MR_AUTO("mr-auto"),
  MR_LG_AUTO("mr-lg-auto"),
  MR_MD_AUTO("mr-md-auto"),
  MR_SM_AUTO("mr-sm-auto"),
  MR_XL_AUTO("mr-xl-auto"),
  MY_LG_0("my-lg-0"),
  MY_LG_1("my-lg-1"),
  MY_LG_2("my-lg-2"),
  MY_LG_3("my-lg-3"),
  MY_LG_4("my-lg-4"),
  MY_LG_5("my-lg-5"),
  MX_AUTO("mx-auto"),
  MX_LG_AUTO("mx-lg-auto"),
  MX_MD_AUTO("mx-md-auto"),
  MX_SM_AUTO("mx-sm-auto"),
  MX_XL_AUTO("mx-xl-auto"),
  NAV("nav"),
  NAV_ITEM("nav-item"),
  NAV_LINK("nav-link"),
  NAV_TABS("nav-tabs"),
  NAVBAR("navbar"),
  NAVBAR_COLLAPSE("navbar-collapse"),
  NAVBAR_BRAND("navbar-brand"),
  NAVBAR_DARK("navbar-dark"),
  NAVBAR_EXPAND("navbar-expand"),
  NAVBAR_EXPAND_LG("navbar-expand-lg"),
  NAVBAR_EXPAND_MD("navbar-expand-md"),
  NAVBAR_EXPAND_SM("navbar-expand-sm"),
  NAVBAR_EXPAND_XL("navbar-expand-xl"),
  /**
   * @deprecated since 4.0.0, please use {@link #FIXED_BOTTOM}
   */
  @Deprecated
  NAVBAR_FIXED_BOTTOM("fixed-bottom"),
  /**
   * @deprecated since 4.0.0, please use {@link #STICKY_TOP}
   */
  @Deprecated
  NAVBAR_FIXED_TOP("fixed-top"),
  /**
   * @deprecated since 4.0.0, please use {@link #NAVBAR_DARK}
   */
  @Deprecated
  NAVBAR_INVERSE("navbar-inverse"),
  NAVBAR_LIGHT("navbar-light"),
  NAVBAR_NAV("navbar-nav"),
  /**
   * @deprecated since 4.0.0, please use {@link #NAVBAR_EXPAND_SM}
   */
  @Deprecated
  NAVBAR_TOGGLEABLE("navbar-expand-sm"),
  /**
   * @deprecated since 4.0.0, please use {@link #NAVBAR_EXPAND_SM}
   */
  @Deprecated
  NAVBAR_TOGGLEABLE_XS("navbar-expand-sm"),
  NAVBAR_TOGGLER("navbar-toggler"),
  NAVBAR_TOGGLER_ICON("navbar-toggler-icon"),
  /**
   * @deprecated since 4.0.0, please use markup in tc:bar
   */
  @Deprecated
  NAVBAR_TOGGLER_LEFT("navbar-toggler-left"),
  /**
   * @deprecated since 4.0.0, please use markup in tc:bar
   */
  @Deprecated
  NAVBAR_TOGGLER_RIGHT("navbar-toggler-right"),
  OFFSET_1("offset-1"),
  OFFSET_2("offset-2"),
  OFFSET_3("offset-3"),
  OFFSET_4("offset-4"),
  OFFSET_5("offset-5"),
  OFFSET_6("offset-6"),
  OFFSET_7("offset-7"),
  OFFSET_8("offset-8"),
  OFFSET_9("offset-9"),
  OFFSET_10("offset-10"),
  OFFSET_11("offset-11"),
  OFFSET_LG_0("offset-lg-0"),
  OFFSET_LG_1("offset-lg-1"),
  OFFSET_LG_2("offset-lg-2"),
  OFFSET_LG_3("offset-lg-3"),
  OFFSET_LG_4("offset-lg-4"),
  OFFSET_LG_5("offset-lg-5"),
  OFFSET_LG_6("offset-lg-6"),
  OFFSET_LG_7("offset-lg-7"),
  OFFSET_LG_8("offset-lg-8"),
  OFFSET_LG_9("offset-lg-9"),
  OFFSET_LG_10("offset-lg-10"),
  OFFSET_LG_11("offset-lg-11"),
  OFFSET_MD_0("offset-md-0"),
  OFFSET_MD_1("offset-md-1"),
  OFFSET_MD_2("offset-md-2"),
  OFFSET_MD_3("offset-md-3"),
  OFFSET_MD_4("offset-md-4"),
  OFFSET_MD_5("offset-md-5"),
  OFFSET_MD_6("offset-md-6"),
  OFFSET_MD_7("offset-md-7"),
  OFFSET_MD_8("offset-md-8"),
  OFFSET_MD_9("offset-md-9"),
  OFFSET_MD_10("offset-md-10"),
  OFFSET_MD_11("offset-md-11"),
  OFFSET_SM_0("offset-sm-0"),
  OFFSET_SM_1("offset-sm-1"),
  OFFSET_SM_2("offset-sm-2"),
  OFFSET_SM_3("offset-sm-3"),
  OFFSET_SM_4("offset-sm-4"),
  OFFSET_SM_5("offset-sm-5"),
  OFFSET_SM_6("offset-sm-6"),
  OFFSET_SM_7("offset-sm-7"),
  OFFSET_SM_8("offset-sm-8"),
  OFFSET_SM_9("offset-sm-9"),
  OFFSET_SM_10("offset-sm-10"),
  OFFSET_SM_11("offset-sm-11"),
  OFFSET_XL_0("offset-xl-0"),
  OFFSET_XL_1("offset-xl-1"),
  OFFSET_XL_2("offset-xl-2"),
  OFFSET_XL_3("offset-xl-3"),
  OFFSET_XL_4("offset-xl-4"),
  OFFSET_XL_5("offset-xl-5"),
  OFFSET_XL_6("offset-xl-6"),
  OFFSET_XL_7("offset-xl-7"),
  OFFSET_XL_8("offset-xl-8"),
  OFFSET_XL_9("offset-xl-9"),
  OFFSET_XL_10("offset-xl-10"),
  OFFSET_XL_11("offset-xl-11"),
  /**
   * @deprecated since 4.0.0, please use {@link #SHOW}
   */
  @Deprecated
  OPEN("show"),
  PAGE_ITEM("page-item"),
  PAGE_LINK("page-link"),
  PAGINATION("pagination"),
  PROGRESS("progress"),
  PROGRESS_BAR("progress-bar"),
  ROW("row"),
  SHOW("show"),
  SR_ONLY("sr-only"),
  STICKY_TOP("sticky-top"),
  TEXT_DANGER("text-danger"),
  TEXT_DARK("text-dark"),
  TEXT_INFO("text-info"),
  TEXT_LIGHT("text-light"),
  TEXT_PRIMARY("text-primary"),
  TEXT_SECONDARY("text-secondary"),
  TEXT_SUCCESS("text-success"),
  TEXT_WARNING("text-warning"),
  TEXT_CENTER("text-center"),
  TEXT_JUSTIFY("text-justify"),
  TEXT_LEFT("text-left"),
  TEXT_RIGHT("text-right"),
  TAB_CONTENT("tab-content"),
  TAB_PANE("tab-pane"),
  TABLE("table"),
  TABLE_BORDERED("table-bordered"),
  TABLE_DARK("table-dark"),
  TABLE_HOVER("table-hover"),
  TABLE_INFO("table-info"),
  /**
   * @deprecated since 4.0.0, please use {@link #TABLE_DARK}
   */
  @Deprecated
  TABLE_INVERSE("table-dark"),
  TABLE_SM("table-sm"),
  TABLE_STRIPED("table-striped");

  private static final Logger LOG = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());

  private static final int SEVERITY_ERROR = FacesMessage.SEVERITY_ERROR.getOrdinal();
  private static final int SEVERITY_WARN = FacesMessage.SEVERITY_WARN.getOrdinal();
  private static final int SEVERITY_INFO = FacesMessage.SEVERITY_INFO.getOrdinal();

  private final String name;

  BootstrapClass(final String name) {
    this.name = name;
  }

  @Override
  public String getName() {
    return name;
  }

  public static CssItem alert(final FacesMessage.Severity severity) {

    // switch over severity.getOrdinal() doesn't work, because different implementations use different ordinals,
    // see MYFACES-3768
    // may be optimized with a cache...

    if (severity == null) {
      return null;
    } else if (severity.getOrdinal() >= SEVERITY_ERROR) {
      return ALERT_DANGER;
    } else if (severity.getOrdinal() >= SEVERITY_WARN) {
      return ALERT_WARNING;
    } else if (severity.getOrdinal() >= SEVERITY_INFO) {
      return ALERT_INFO;
    } else {
      return null;
    }
  }

  public static CssItem borderColor(final FacesMessage.Severity severity) {
    if (severity == null) {
      return null;
    }
    return getSeverityCssItem(severity, BORDER_INFO, BORDER_WARNING, BORDER_DANGER);
  }

  public static CssItem buttonColor(final FacesMessage.Severity severity) {
    if (severity == null) {
      return null;
    }
    return getSeverityCssItem(severity, BTN_INFO, BTN_WARNING, BTN_DANGER);
  }

  private static CssItem getSeverityCssItem(FacesMessage.Severity severity,
      BootstrapClass info, BootstrapClass warning, BootstrapClass error) {
    if (severity.equals(FacesMessage.SEVERITY_INFO)) {
      return info;
    } else if (severity.equals(FacesMessage.SEVERITY_WARN)) {
      return warning;
    } else {
      return error;
    }
  }

  /**
   * @deprecated since 4.0.0, please use ComponentUtils.getMaximumSeverity()
   * with {@link #borderColor(FacesMessage.Severity)} or {@link #buttonColor(FacesMessage.Severity)}
   */
  @Deprecated
  public static CssItem maximumSeverity(final UIComponent input) {
    final FacesMessage.Severity maximumSeverity = ComponentUtils.getMaximumSeverity(input);
    if (maximumSeverity == null) {
      return null;
    } else if (maximumSeverity.getOrdinal() >= SEVERITY_ERROR) {
      return HAS_DANGER;
    } else if (maximumSeverity.getOrdinal() >= SEVERITY_WARN) {
      return HAS_WARNING;
    } else if (maximumSeverity.getOrdinal() >= SEVERITY_INFO) {
      return TobagoClass.HAS__INFO;
    } else {
      return null;
    }
  }

  /**
   * @since 4.0.0
   */
  public static CssItem textAlign(final TextAlign textAlign) {
    switch (textAlign) {
      case left:
        return BootstrapClass.TEXT_LEFT;
      case right:
        return BootstrapClass.TEXT_RIGHT;
      case justify:
        return BootstrapClass.TEXT_JUSTIFY;
      case center:
        return BootstrapClass.TEXT_CENTER;
      default:
        LOG.warn("Not a bootstrap class defined for {}", textAlign);
        return BootstrapClass.TEXT_LEFT;
    }
  }

  public static CssItem textColor(final Markup markup) {
    if (markup == null || markup.contains(Markup.NONE)) {
      return null;
    } else if (markup.contains(Markup.PRIMARY)) {
      return BootstrapClass.TEXT_PRIMARY;
    } else if (markup.contains(Markup.SECONDARY)) {
      return BootstrapClass.TEXT_SECONDARY;
    } else if (markup.contains(Markup.SUCCESS)) {
      return BootstrapClass.TEXT_SUCCESS;
    } else if (markup.contains(Markup.DANGER)) {
      return BootstrapClass.TEXT_DANGER;
    } else if (markup.contains(Markup.WARNING)) {
      return BootstrapClass.TEXT_WARNING;
    } else if (markup.contains(Markup.INFO)) {
      return BootstrapClass.TEXT_INFO;
    } else if (markup.contains(Markup.LIGHT)) {
      return BootstrapClass.TEXT_LIGHT;
    } else if (markup.contains(Markup.DARK)) {
      return BootstrapClass.TEXT_DARK;
    } else {
      return null;
    }
  }

  public static CssItem fontStyle(final Markup markup) {
    if (markup == null || markup.contains(Markup.NONE)) {
      return null;
    } else if (markup.contains(Markup.BOLD)) {
      return BootstrapClass.FONT_WEIGHT_BOLD;
    } else if (markup.contains(Markup.THIN)) {
      return BootstrapClass.FONT_WEIGHT_LIGHT;
    } else if (markup.contains(Markup.ITALIC)) {
      return BootstrapClass.FONT_ITALIC;
    } else {
      return null;
    }
  }

  public static class Generator {

    private static final BootstrapClass[] OFFSET_EXTRA_SMALL = new BootstrapClass[]{
        null, OFFSET_1, OFFSET_2, OFFSET_3, OFFSET_4, OFFSET_5,
        OFFSET_6, OFFSET_7, OFFSET_8, OFFSET_9, OFFSET_10, OFFSET_11
    };
    private static final BootstrapClass[] OFFSET_SMALL = new BootstrapClass[]{
        OFFSET_SM_0, OFFSET_SM_1, OFFSET_SM_2, OFFSET_SM_3, OFFSET_SM_4, OFFSET_SM_5,
        OFFSET_SM_6, OFFSET_SM_7, OFFSET_SM_8, OFFSET_SM_9, OFFSET_SM_10, OFFSET_SM_11
    };
    private static final BootstrapClass[] OFFSET_MEDIUM = new BootstrapClass[]{
        OFFSET_MD_0, OFFSET_MD_1, OFFSET_MD_2, OFFSET_MD_3, OFFSET_MD_4, OFFSET_MD_5,
        OFFSET_MD_6, OFFSET_MD_7, OFFSET_MD_8, OFFSET_MD_9, OFFSET_MD_10, OFFSET_MD_11
    };
    private static final BootstrapClass[] OFFSET_LARGE = new BootstrapClass[]{
        OFFSET_LG_0, OFFSET_LG_1, OFFSET_LG_2, OFFSET_LG_3, OFFSET_LG_4, OFFSET_LG_5,
        OFFSET_LG_6, OFFSET_LG_7, OFFSET_LG_8, OFFSET_LG_9, OFFSET_LG_10, OFFSET_LG_11
    };
    private static final BootstrapClass[] OFFSET_EXTRA_LARGE = new BootstrapClass[]{
        OFFSET_XL_0, OFFSET_XL_1, OFFSET_XL_2, OFFSET_XL_3, OFFSET_XL_4, OFFSET_XL_5,
        OFFSET_XL_6, OFFSET_XL_7, OFFSET_XL_8, OFFSET_XL_9, OFFSET_XL_10, OFFSET_XL_11
    };

    private final MeasureList extraSmall;
    private final MeasureList small;
    private final MeasureList medium;
    private final MeasureList large;
    private final MeasureList extraLarge;
    private final MarginTokens marginExtraSmall;
    private final MarginTokens marginSmall;
    private final MarginTokens marginMedium;
    private final MarginTokens marginLarge;
    private final MarginTokens marginExtraLarge;

    private int index = 0;

    public Generator(
        final MeasureList extraSmall, final MeasureList small, final MeasureList medium,
        final MeasureList large, final MeasureList extraLarge,
        final MarginTokens marginExtraSmall, final MarginTokens marginSmall, final MarginTokens marginMedium,
        final MarginTokens marginLarge, final MarginTokens marginExtraLarge) {
      if (extraSmall == null && small == null && medium == null && large == null && extraLarge == null) {
        this.extraSmall = MeasureList.parse("*"); // TBD: is this needed? if yes, use Measure.FRACTION1
      } else {
        this.extraSmall = extraSmall;
      }
      this.small = small;
      this.medium = medium;
      this.large = large;
      this.extraLarge = extraLarge;
      this.marginExtraSmall = marginExtraSmall;
      this.marginSmall = marginSmall;
      this.marginMedium = marginMedium;
      this.marginLarge = marginLarge;
      this.marginExtraLarge = marginExtraLarge;
    }

    public void reset() {
      index = 0;
    }

    public void next() {
      index++;
    }

    public BootstrapClass[] generate(final UIComponent child) {
      final ArrayList<BootstrapClass> result = new ArrayList<>(10);
      final Map<String, Object> attributes = child.getAttributes();
      generate(result, extraSmall, attributes, Attributes.overwriteExtraSmall);
      generate(result, small, attributes, Attributes.overwriteSmall);
      generate(result, medium, attributes, Attributes.overwriteMedium);
      generate(result, large, attributes, Attributes.overwriteLarge);
      generate(result, extraLarge, attributes, Attributes.overwriteExtraLarge);

      generate(result, marginExtraSmall, attributes, Attributes.overwriteMarginExtraSmall);
      generate(result, marginSmall, attributes, Attributes.overwriteMarginSmall);
      generate(result, marginMedium, attributes, Attributes.overwriteMarginMedium);
      generate(result, marginLarge, attributes, Attributes.overwriteMarginLarge);
      generate(result, marginExtraLarge, attributes, Attributes.overwriteMarginExtraLarge);

      generateOffset(result, attributes.get(Attributes.offsetExtraSmall.name()), OFFSET_EXTRA_SMALL);
      generateOffset(result, attributes.get(Attributes.offsetSmall.name()), OFFSET_SMALL);
      generateOffset(result, attributes.get(Attributes.offsetMedium.name()), OFFSET_MEDIUM);
      generateOffset(result, attributes.get(Attributes.offsetLarge.name()), OFFSET_LARGE);
      generateOffset(result, attributes.get(Attributes.offsetExtraLarge.name()), OFFSET_EXTRA_LARGE);
      return result.toArray(new BootstrapClass[0]);
    }

    private void generate(
        final List<BootstrapClass> result, final MeasureList tokens,
        final Map<String, Object> attributes, final Attributes attribute) {
      final Object overwrite = attributes.get(attribute.name());

      if (overwrite != null) {
        final Measure measure = Measure.valueOf(overwrite.toString(), Measure.Unit.SEG);
        final BootstrapClass bootstrapClass = valueOf(getSegmentMeasure(measure), attribute);
        result.add(bootstrapClass);
      } else if (tokens != null && tokens.getSize() > 0) {
        final Measure measure = tokens.get(index % tokens.getSize());
        final BootstrapClass bootstrapClass = valueOf(getSegmentMeasure(measure), attribute);
        result.add(bootstrapClass);
      }
    }

    private Measure getSegmentMeasure(final Measure measure) {
      if (measure != null && Measure.Unit.SEG.equals(measure.getUnit())) {
        final int number = (int) measure.getValue();
        if (number < 1) {
          LOG.warn("Segment values must been between 1 and 12. Use '1' instead of '{}'.", number);
          return new Measure(1, Measure.Unit.SEG);
        } else if (number > 12) {
          LOG.warn("Segment values must been between 1 and 12. Use '12' instead of '{}'.", number);
          return new Measure(12, Measure.Unit.SEG);
        }
      }
      return measure;
    }

    private void generate(final List<BootstrapClass> result, final MarginTokens margins,
        final Map<String, Object> attributes, final Attributes attribute) {
      final Object overwrite = attributes.get(attribute.name());

      if (overwrite != null) {
        final Margin margin = MarginTokens.parseToken((String) overwrite);
        final BootstrapClass bootstrapClass = valueOf(margin, attribute);
        result.add(bootstrapClass);
      } else if (margins != null && margins.getSize() > 0) {
        final Margin margin = margins.get(index % margins.getSize());
        final BootstrapClass bootstrapClass = valueOf(margin, attribute);
        result.add(bootstrapClass);
      }
    }

    private void generateOffset(final List<BootstrapClass> result, final Object offset, final BootstrapClass[] values) {
      if (offset != null) {
        int offsetIndex = Integer.valueOf((String) offset);
        if (offsetIndex >= 0) {
          offsetIndex = offsetIndex > 11 ? 11 : offsetIndex;
          result.add(values[offsetIndex]);
        }
      }
    }
  }

  public static BootstrapClass valueOf(final Measure measure, final Attributes attributes) {
    final String size = getSizeSuffix(attributes);

    if (measure != null) {
      if (measure.getUnit() == Measure.Unit.FR) {
        return valueOf("COL" + size);
      } else if (measure.getUnit() == Measure.Unit.AUTO) {
        return valueOf("COL" + size + "_AUTO");
      } else if (measure.getUnit() == Measure.Unit.SEG) {
        final float value = measure.getValue();
        return valueOf(
            "COL" + size + "_" + (value == (long) value ? Long.toString((long) value) : Float.toString(value)));
      }
    }
    return null;
  }

  public static BootstrapClass valueOf(final Margin margin, final Attributes attribute) {
    final String size = getSizeSuffix(attribute);

    switch (margin) {
      case left:
        return valueOf("ML" + size + "_AUTO");
      case right:
        return valueOf("MR" + size + "_AUTO");
      case both:
        return valueOf("MX" + size + "_AUTO");
      default:
        return null;
    }
  }

  private static String getSizeSuffix(final Attributes attribute) {
    switch (attribute) {
      case extraLarge:
      case marginExtraLarge:
      case overwriteExtraLarge:
      case overwriteMarginExtraLarge:
        return "_XL";
      case large:
      case marginLarge:
      case overwriteLarge:
      case overwriteMarginLarge:
        return "_LG";
      case medium:
      case marginMedium:
      case overwriteMedium:
      case overwriteMarginMedium:
        return "_MD";
      case small:
      case marginSmall:
      case overwriteSmall:
      case overwriteMarginSmall:
        return "_SM";
      case extraSmall:
      case marginExtraSmall:
      case overwriteExtraSmall:
      case overwriteMarginExtraSmall:
      default:
        return "";
    }
  }

  public static CssItem valueOf(final AlignItems alignItems) {
    if (alignItems == null) {
      return null;
    } else {
      switch (alignItems) {
        case baseline:
          return ALIGN_ITEMS_BASELINE;
        case center:
          return ALIGN_ITEMS_CENTER;
        case flexEnd:
          return ALIGN_ITEMS_END;
        case flexStart:
          return ALIGN_ITEMS_START;
        case stretch:
          return ALIGN_ITEMS_STRETCH;
        default:
          LOG.warn("Undefined alignItems: '{}'.", alignItems);
          return null;
      }
    }
  }

  public static CssItem valueOf(final JustifyContent justifyContent) {
    if (justifyContent == null) {
      return null;
    } else {
      switch (justifyContent) {
        case center:
          return JUSTIFY_CONTENT_CENTER;
        case flexEnd:
          return JUSTIFY_CONTENT_END;
        case flexStart:
          return JUSTIFY_CONTENT_START;
        case spaceBetween:
          return JUSTIFY_CONTENT_BETWEEN;
        case spaceAround:
          return JUSTIFY_CONTENT_AROUND;
        default:
          LOG.warn("Undefined justifyContent: '{}'.", justifyContent);
          return null;
      }
    }
  }

}