// Copyright 2018 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.lib.skylarkbuildapi;

import com.google.devtools.build.lib.collect.nestedset.Depset;
import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
import com.google.devtools.build.lib.skylarkinterface.StarlarkBuiltin;
import com.google.devtools.build.lib.skylarkinterface.StarlarkDocumentationCategory;
import com.google.devtools.build.lib.syntax.Dict;
import com.google.devtools.build.lib.syntax.EvalException;
import com.google.devtools.build.lib.syntax.Sequence;
import com.google.devtools.build.lib.syntax.StarlarkSemantics.FlagIdentifier;
import com.google.devtools.build.lib.syntax.StarlarkValue;
import java.io.IOException;
import javax.annotation.Nullable;

/** Interface for actions in Starlark. */
@StarlarkBuiltin(
    name = "Action",
    category = StarlarkDocumentationCategory.BUILTIN,
    doc =
        "An action created during rule analysis."
            + "<p>This object is visible for the purpose of testing, and may be obtained from an "
            + "<a href=\"globals.html#Actions\">Actions</a> provider. It is normally not necessary "
            + "to access <code>Action</code> objects or their fields within a rule's "
            + "implementation function. You may instead want to see the "
            + "<a href='../rules.$DOC_EXT#actions'>Rules page</a> for a general discussion of how "
            + "to use actions when defining custom rules, or the <a href='actions.html'>API "
            + "reference</a> for creating actions."
            + "<p>Some fields of this object are only applicable for certain kinds of actions. "
            + "Fields that are inapplicable are set to <code>None</code>.")
public interface ActionApi extends StarlarkValue {

  @SkylarkCallable(name = "mnemonic", structField = true, doc = "The mnemonic for this action.")
  String getMnemonic();

  @SkylarkCallable(
      name = "inputs",
      doc = "A set of the input files of this action.",
      structField = true)
  Depset getSkylarkInputs();

  @SkylarkCallable(
      name = "outputs",
      doc = "A set of the output files of this action.",
      structField = true)
  Depset getSkylarkOutputs();

  @SkylarkCallable(
      name = "argv",
      doc =
          "For actions created by <a href=\"actions.html#run\">ctx.actions.run()</a> "
              + "or <a href=\"actions.html#run_shell\">ctx.actions.run_shell()</a>  an immutable "
              + "list of the arguments for the command line to be executed. Note that "
              + "for shell actions the first two arguments will be the shell path "
              + "and <code>\"-c\"</code>.",
      structField = true,
      allowReturnNones = true)
  Sequence<String> getSkylarkArgv() throws EvalException;

  @SkylarkCallable(
      name = "args",
      doc =
          "A list of frozen <a href=\"Args.html\">Args</a> objects containing information about"
              + " the action arguments. These objects contain accurate argument information,"
              + " including arguments involving expanded action output directories. However, <a"
              + " href=\"Args.html\">Args</a> objects are not readable in the analysis phase. For"
              + " a less accurate account of arguments which is available in the analysis phase,"
              + " see <a href=\"#argv\">argv</a>."
              + " <p>Note that some types of actions do not yet support exposure of this field."
              + " For such action types, this is <code>None</code>.",
      structField = true,
      allowReturnNones = true,
      enableOnlyWithFlag = FlagIdentifier.EXPERIMENTAL_ACTION_ARGS)
  Sequence<CommandLineArgsApi> getStarlarkArgs() throws EvalException;

  /**
   * If the action writes a file whose content is known at analysis time, returns that content;
   * returns null otherwise.
   *
   * <p>The content might be unknown if, for instance, the action expands an {@code Args} object
   * that includes a directory ({@link TreeArtifact}) with {@code expand_directories=False}.
   *
   * @throws EvalException if there is a Starlark evaluation error, e.g. in an {@code Args} object's
   *     call to a {@code map_each} callback.
   * @throws IOException if there is a non-Starlark error in expanding an {@code Args} object.
   */
  @SkylarkCallable(
      name = "content",
      doc =
          "For actions created by <a href=\"actions.html#write\">ctx.actions.write()</a> or "
              + "<a href=\"actions.html#expand_template\">ctx.actions.expand_template()</a>,"
              + " the contents of the file to be written, if those contents can be computed during "
              + " the analysis phase. The value is <code>None</code> if the contents cannot be "
              + "determined until the execution phase, such as when a directory in an {@code Args} "
              + "object needs to be expanded.",
      structField = true,
      allowReturnNones = true)
  @Nullable
  String getSkylarkContent() throws IOException, EvalException;

  @SkylarkCallable(
      name = "substitutions",
      doc =
          "For actions created by "
              + "<a href=\"actions.html#expand_template\">ctx.actions.expand_template()</a>,"
              + " an immutable dict holding the substitution mapping.",
      structField = true,
      allowReturnNones = true)
  Dict<String, String> getSkylarkSubstitutions();

  @SkylarkCallable(
      name = "env",
      structField = true,
      doc =
          "The 'fixed' environment variables for this action. This includes only environment"
              + " settings which are explicitly set by the action definition, and thus omits"
              + " settings which are only pre-set in the execution environment.")
  Dict<String, String> getEnv();

  @SkylarkCallable(
      name = "execution_info",
      structField = true,
      doc =
          "The execution requirements for this action, set for this action specifically. This is a"
              + " dictionary that maps strings specifying execution info to arbitrary strings."
              + " This is in order to match the structure of execution info in other parts of the"
              + " code base; all relevant info is in the keyset. Returns None if this action does"
              + " not expose execution requirements.",
      allowReturnNones = true,
      enableOnlyWithFlag = FlagIdentifier.EXPERIMENTAL_GOOGLE_LEGACY_API)
  @Nullable
  public Dict<String, String> getExecutionInfoDict();
}