// Copyright 2014 The Bazel Authors. All rights reserved.
//
// 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.devtools.build.docgen.skylark;

import com.google.devtools.build.lib.syntax.EvalUtils;
import com.google.devtools.build.lib.syntax.FuncallExpression;
import com.google.devtools.build.lib.syntax.Runtime.NoneType;
import com.google.devtools.build.lib.syntax.SkylarkList;
import com.google.devtools.build.lib.syntax.SkylarkList.MutableList;
import com.google.devtools.build.lib.syntax.SkylarkList.Tuple;
import com.google.devtools.build.lib.syntax.SkylarkModule;
import com.google.devtools.build.lib.syntax.SkylarkSignature;
import com.google.devtools.build.lib.syntax.SkylarkSignature.Param;

import java.util.Arrays;
import java.util.Map;

/**
 * Abstract class for containing documentation for a Skylark syntactic entity.
 */
abstract class SkylarkDoc {
  protected static final String TOP_LEVEL_ID = "globals";

  /**
   * Returns a string containing the name of the entity being documented.
   */
  public abstract String getName();

  /**
   * Returns a string containing the HTML documentation of the entity being
   * documented.
   */
  public abstract String getDocumentation();

  protected String getTypeAnchor(Class<?> returnType, Class<?> generic1) {
    return getTypeAnchor(returnType) + " of " + getTypeAnchor(generic1) + "s";
  }

  protected String getTypeAnchor(Class<?> type) {
    if (type.equals(Boolean.class) || type.equals(boolean.class)) {
      return "<a class=\"anchor\" href=\"" + TOP_LEVEL_ID + ".html#bool\">bool</a>";
    } else if (type.equals(String.class)) {
      return "<a class=\"anchor\" href=\"string.html\">string</a>";
    } else if (Map.class.isAssignableFrom(type)) {
      return "<a class=\"anchor\" href=\"dict.html\">dict</a>";
    } else if (type.equals(Tuple.class)) {
      return "<a class=\"anchor\" href=\"list.html\">tuple</a>";
    } else if (type.equals(MutableList.class)) {
      return "<a class=\"anchor\" href=\"list.html\">list</a>";
    } else if (type.equals(SkylarkList.class)) {
      return "<a class=\"anchor\" href=\"list.html\">sequence</a>";
    } else if (type.equals(Void.TYPE) || type.equals(NoneType.class)) {
      return "<a class=\"anchor\" href=\"" + TOP_LEVEL_ID + ".html#None\">None</a>";
    } else if (type.isAnnotationPresent(SkylarkModule.class)) {
      // TODO(bazel-team): this can produce dead links for types don't show up in the doc.
      // The correct fix is to generate those types (e.g. SkylarkFileType) too.
      String module = type.getAnnotation(SkylarkModule.class).name();
      return "<a class=\"anchor\" href=\"" + module + ".html\">" + module + "</a>";
    } else {
      return EvalUtils.getDataTypeNameFromClass(type);
    }
  }

  // Elide self parameter from mandatoryPositionals in class methods.
  protected static Param[] adjustedMandatoryPositionals(SkylarkSignature annotation) {
    Param[] mandatoryPos = annotation.mandatoryPositionals();
    if (mandatoryPos.length > 0
        && annotation.objectType() != Object.class
        && !FuncallExpression.isNamespace(annotation.objectType())) {
      // Skip the self parameter, which is the first mandatory positional parameter.
      return Arrays.copyOfRange(mandatoryPos, 1, mandatoryPos.length);
    } else {
      return mandatoryPos;
    }
  }
}