// 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.common.base.Joiner;
import com.google.common.collect.ImmutableList;
import com.google.devtools.build.lib.skylarkinterface.Param;
import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
import com.google.devtools.build.lib.skylarkinterface.SkylarkInterfaceUtils;
import com.google.devtools.build.lib.syntax.EvalUtils;
import com.google.devtools.build.lib.syntax.StarlarkSemantics.FlagIdentifier;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;

/**
 * A class representing a Java method callable from Skylark with annotation.
 */
public final class SkylarkJavaMethodDoc extends SkylarkMethodDoc {
  private final String moduleName;
  private final String name;
  private final Method method;
  private final SkylarkCallable callable;
  private final ImmutableList<SkylarkParamDoc> params;

  private boolean isOverloaded;

  public SkylarkJavaMethodDoc(String moduleName, Method method, SkylarkCallable callable) {
    this.moduleName = moduleName;
    this.name = callable.name();
    this.method = method;
    this.callable = callable;
    this.params =
        SkylarkDocUtils.determineParams(
            this,
            withoutSelfParam(callable, method),
            callable.extraPositionals(),
            callable.extraKeywords());
  }

  public Method getMethod() {
    return method;
  }

  @Override
  public boolean documented() {
    return callable.documented();
  }

  @Override
  public String getName() {
    // Normally we refer to methods by their name, e.g. "foo" for method foo(arg1, arg2).
    // However, if a method is overloaded, the name is no longer unique, which forces us to append
    // the names of the method parameters in order to get a unique value.
    // In this case, the return value for the previous example would be "foo(arg1, arg2)".

    // We decided against ALWAYS returning the full name since we didn't want to pollute the
    // TOC of documentation pages too much. This comes at the cost of inconsistency and more
    // complex code.
    return isOverloaded ? getFullName() : name;
  }

  /**
   * Returns the full name of the method, consisting of
   * <method name>(<name of first param>, <name of second param>, ...).
   */
  private String getFullName() {
    List<String> paramNames = new ArrayList<>();
    for (Param param : callable.parameters()) {
      paramNames.add(param.name());
    }
    return String.format("%s(%s)", name, Joiner.on(", ").join(paramNames));
  }

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

  @Override
  public String getDocumentation() {
    String prefixWarning = "";
    if (callable.enableOnlyWithFlag() != FlagIdentifier.NONE) {
      prefixWarning = "<b>Experimental</b>. This API is experimental and may change at any time. "
          + "Please do not depend on it. It may be enabled on an experimental basis by setting "
          + "<code>--" + callable.enableOnlyWithFlag().getFlagName() + "</code> <br>";
    } else if (callable.disableWithFlag() != FlagIdentifier.NONE) {
      prefixWarning = "<b>Deprecated</b>. This API is deprecated and will be removed soon. "
          + "Please do not depend on it. It is <i>disabled</i> with "
          + "<code>--" + callable.disableWithFlag().getFlagName() + "</code>. Use this flag "
          + "to verify your code is compatible with its imminent removal. <br>";
    }
    return prefixWarning + SkylarkDocUtils.substituteVariables(callable.doc());
  }

  @Override
  public String getSignature() {
    return getSignature(moduleName, name, method);
  }

  @Override
  public String getReturnTypeExtraMessage() {
    if (callable.allowReturnNones()) {
      return " May return <code>None</code>.\n";
    }
    return "";
  }

  @Override
  public String getReturnType() {
    return EvalUtils.getDataTypeNameFromClass(method.getReturnType());
  }

  @Override
  public List<SkylarkParamDoc> getParams() {
    return params;
  }

  public void setOverloaded(boolean isOverloaded) {
    this.isOverloaded = isOverloaded;
  }

  @Override
  public Boolean isCallable() {
    return !SkylarkInterfaceUtils.getSkylarkCallable(this.method).structField();
  }
}