/*
 * Copyright 2009 Google Inc.
 *
 * 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.template.soy.bidifunctions;

import com.google.common.collect.ImmutableSet;
import com.google.template.soy.data.Dir;
import com.google.template.soy.data.SanitizedContent;
import com.google.template.soy.data.SanitizedContent.ContentKind;
import com.google.template.soy.data.SoyValue;
import com.google.template.soy.data.UnsafeSanitizedContentOrdainer;
import com.google.template.soy.internal.i18n.BidiFormatter;
import com.google.template.soy.internal.i18n.BidiGlobalDir;
import com.google.template.soy.internal.i18n.BidiUtils;
import com.google.template.soy.internal.i18n.SoyBidiUtils;
import com.google.template.soy.jssrc.restricted.JsExpr;
import com.google.template.soy.jssrc.restricted.SoyJsSrcFunction;
import com.google.template.soy.pysrc.restricted.PyExpr;
import com.google.template.soy.pysrc.restricted.SoyPySrcFunction;
import com.google.template.soy.shared.restricted.SoyJavaFunction;

import java.util.List;
import java.util.Set;

import javax.inject.Inject;
import javax.inject.Provider;
import javax.inject.Singleton;

/**
 * Soy function that maybe inserts an HTML attribute for bidi directionality ('dir=ltr' or
 * 'dir=rtl'). The function requires the text string that will make up the body of the associated
 * HTML tag pair. If the text string is detected to require different directionality than the
 * current global directionality, then the appropriate HTML attribute is inserted. Otherwise,
 * nothing is inserted.
 *
 */
@Singleton
class BidiDirAttrFunction implements SoyJavaFunction, SoyJsSrcFunction, SoyPySrcFunction {


  /** Provider for the current bidi global directionality. */
  private final Provider<BidiGlobalDir> bidiGlobalDirProvider;


  /**
   * @param bidiGlobalDirProvider Provider for the current bidi global directionality.
   */
  @Inject
  BidiDirAttrFunction(Provider<BidiGlobalDir> bidiGlobalDirProvider) {
    this.bidiGlobalDirProvider = bidiGlobalDirProvider;
  }


  @Override public String getName() {
    return "bidiDirAttr";
  }

  @Override public Set<Integer> getValidArgsSizes() {
    return ImmutableSet.of(1, 2);
  }

  @Override public SoyValue computeForJava(List<SoyValue> args) {
    SoyValue value = args.get(0);
    Dir valueDir = null;
    boolean isHtmlForValueDirEstimation = false;
    if (value instanceof SanitizedContent) {
      SanitizedContent sanitizedContent = (SanitizedContent) value;
      valueDir = sanitizedContent.getContentDirection();
      if (valueDir == null) {
        isHtmlForValueDirEstimation = sanitizedContent.getContentKind() == ContentKind.HTML;
      }
    }
    if (valueDir == null) {
      isHtmlForValueDirEstimation = isHtmlForValueDirEstimation ||
          (args.size() == 2 && args.get(1).booleanValue());
      valueDir = BidiUtils.estimateDirection(value.coerceToString(), isHtmlForValueDirEstimation);
    }

    BidiFormatter bidiFormatter = SoyBidiUtils.getBidiFormatter(
        bidiGlobalDirProvider.get().getStaticValue());
    String dirAttr = bidiFormatter.knownDirAttr(valueDir);
    return UnsafeSanitizedContentOrdainer.ordainAsSafe(dirAttr, ContentKind.ATTRIBUTES);
  }

  @Override public JsExpr computeForJsSrc(List<JsExpr> args) {
    JsExpr value = args.get(0);
    JsExpr isHtml = (args.size() == 2) ? args.get(1) : null;

    String callText =
        "soy.$$bidiDirAttr(" + bidiGlobalDirProvider.get().getCodeSnippet() + ", " +
        value.getText() + (isHtml != null ? ", " + isHtml.getText() : "") + ")";

    return new JsExpr(callText, Integer.MAX_VALUE);
  }

  @Override public PyExpr computeForPySrc(List<PyExpr> args) {
    PyExpr value = args.get(0);
    PyExpr isHtml = (args.size() == 2) ? args.get(1) : null;

    String callText =
        "bidi.dir_attr(" + bidiGlobalDirProvider.get().getCodeSnippet() + ", " +
        value.getText() + (isHtml != null ? ", " + isHtml.getText() : "") + ")";

    return new PyExpr(callText, Integer.MAX_VALUE);
  }
}