// 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.cmdline.Label;
import com.google.devtools.build.lib.events.Location;
import com.google.devtools.build.lib.skylarkbuildapi.StarlarkConfigApi.BuildSettingApi;
import com.google.devtools.build.lib.skylarkinterface.Param;
import com.google.devtools.build.lib.skylarkinterface.ParamType;
import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
import com.google.devtools.build.lib.skylarkinterface.SkylarkConstructor;
import com.google.devtools.build.lib.skylarkinterface.SkylarkGlobalLibrary;
import com.google.devtools.build.lib.skylarkinterface.StarlarkContext;
import com.google.devtools.build.lib.syntax.BaseFunction;
import com.google.devtools.build.lib.syntax.Environment;
import com.google.devtools.build.lib.syntax.EvalException;
import com.google.devtools.build.lib.syntax.FuncallExpression;
import com.google.devtools.build.lib.syntax.Runtime.NoneType;
import com.google.devtools.build.lib.syntax.Runtime.UnboundMarker;
import com.google.devtools.build.lib.syntax.SkylarkDict;
import com.google.devtools.build.lib.syntax.SkylarkList;
import com.google.devtools.build.lib.syntax.SkylarkSemantics.FlagIdentifier;

/**
 * Interface for a global Skylark library containing rule-related helper and registration functions.
 */
@SkylarkGlobalLibrary
public interface SkylarkRuleFunctionsApi<FileApiT extends FileApi> {

  static final String PROVIDES_DOC =
      "A list of providers that the implementation function must return."
          + ""
          + "<p>It is an error if the implementation function omits any of the types of providers "
          + "listed here from its return value. However, the implementation function may return "
          + "additional providers not listed here."
          + ""
          + "<p>Each element of the list is an <code>*Info</code> object returned by "
          + "<a href='globals.html#provider'><code>provider()</code></a>, except that a legacy "
          + "provider is represented by its string name instead.";

  @SkylarkCallable(
    name = "provider",
    doc =
        "Creates a declared provider 'constructor'. The return value of this "
            + "function can be used to create \"struct-like\" values. Example:<br>"
            + "<pre class=\"language-python\">data = provider()\n"
            + "d = data(x = 2, y = 3)\n"
            + "print(d.x + d.y) # prints 5</pre>",
    parameters = {
      @Param(
        name = "doc",
        type = String.class,
        legacyNamed = true,
        defaultValue = "''",
        doc =
            "A description of the provider that can be extracted by documentation generating tools."
      ),
      @Param(
        name = "fields",
        doc = "If specified, restricts the set of allowed fields. <br>"
            + "Possible values are:"
            + "<ul>"
            + "  <li> list of fields:<br>"
            + "       <pre class=\"language-python\">provider(fields = ['a', 'b'])</pre><p>"
            + "  <li> dictionary field name -> documentation:<br>"
            + "       <pre class=\"language-python\">provider(\n"
            + "       fields = { 'a' : 'Documentation for a', 'b' : 'Documentation for b' })</pre>"
            + "</ul>"
            + "All fields are optional.",
        allowedTypes = {
            @ParamType(type = SkylarkList.class, generic1 = String.class),
            @ParamType(type = SkylarkDict.class)
        },
        noneable = true,
        named = true,
        positional = false,
        defaultValue = "None"
      )
    },
    useLocation = true
  )
  public ProviderApi provider(String doc, Object fields, Location location) throws EvalException;

  @SkylarkCallable(
      name = "rule",
      doc =
          "Creates a new rule, which can be called from a BUILD file or a macro to create targets."
              + "<p>Rules must be assigned to global variables in a .bzl file; the name of the "
              + "global variable is the rule's name."
              + "<p>Test rules are required to have a name ending in <code>_test</code>, while all "
              + "other rules must not have this suffix. (This restriction applies only to rules, "
              + "not to their targets.)",
      parameters = {
        @Param(
            name = "implementation",
            type = BaseFunction.class,
            legacyNamed = true,
            doc =
                "the function implementing this rule, must have exactly one parameter: "
                    + "<a href=\"ctx.html\">ctx</a>. The function is called during the analysis "
                    + "phase for each instance of the rule. It can access the attributes "
                    + "provided by the user. It must create actions to generate all the declared "
                    + "outputs."),
        @Param(
            name = "test",
            type = Boolean.class,
            legacyNamed = true,
            defaultValue = "False",
            doc =
                "Whether this rule is a test rule, that is, whether it may be the subject of a "
                    + "<code>blaze test</code> command. All test rules are automatically "
                    + "considered <a href='#rule.executable'>executable</a>; it is unnecessary "
                    + "(and discouraged) to explicitly set <code>executable = True</code> for a "
                    + "test rule. See the "
                    + "<a href='../rules.$DOC_EXT#executable-rules-and-test-rules'>Rules page</a> "
                    + "for more information."),
        @Param(
            name = "attrs",
            type = SkylarkDict.class,
            legacyNamed = true,
            noneable = true,
            defaultValue = "None",
            doc =
                "dictionary to declare all the attributes of the rule. It maps from an attribute "
                    + "name to an attribute object (see <a href=\"attr.html\">attr</a> module). "
                    + "Attributes starting with <code>_</code> are private, and can be used to "
                    + "add an implicit dependency on a label. The attribute <code>name</code> is "
                    + "implicitly added and must not be specified. Attributes "
                    + "<code>visibility</code>, <code>deprecation</code>, <code>tags</code>, "
                    + "<code>testonly</code>, and <code>features</code> are implicitly added and "
                    + "cannot be overridden."),
        // TODO(bazel-team): need to give the types of these builtin attributes
        @Param(
            name = "outputs",
            allowedTypes = {
              @ParamType(type = SkylarkDict.class),
              @ParamType(type = NoneType.class),
              @ParamType(type = BaseFunction.class)
            },
            legacyNamed = true,
            callbackEnabled = true,
            noneable = true,
            defaultValue = "None",
            doc =
                "<b>Experimental:</b> This API is in the process of being redesigned."
                    + "<p>A schema for defining predeclared outputs. Unlike "
                    + "<a href='attr.html#output'><code>output</code></a> and "
                    + "<a href='attr.html#output_list'><code>output_list</code></a> attributes, "
                    + "the user does not specify the labels for these files. "
                    + "See the <a href='../rules.$DOC_EXT#files'>Rules page</a> for more on "
                    + "predeclared outputs."
                    + "<p>The value of this argument is either a dictionary or a callback function "
                    + "that produces a dictionary. The callback works similar to computed "
                    + "dependency attributes: The function's parameter names are matched against "
                    + "the rule's attributes, so for example if you pass "
                    + "<code>outputs = _my_func</code> with the definition "
                    + "<code>def _my_func(srcs, deps): ...</code>, the function has access "
                    + "to the attributes <code>srcs</code> and <code>deps</code>. Whether the "
                    + "dictionary is specified directly or via a function, it is interpreted as "
                    + "follows."
                    + "<p>Each entry in the dictionary creates a predeclared output where the key "
                    + "is an identifier and the value is a string template that determines the "
                    + "output's label. In the rule's implementation function, the identifier "
                    + "becomes the field name used to access the output's "
                    + "<a href='File.html'><code>File</code></a> in "
                    + "<a href='ctx.html#outputs'><code>ctx.outputs</code></a>. The output's label "
                    + "has the same package as the rule, and the part after the package is "
                    + "produced by substituting each placeholder of the form "
                    + "<code>\"%{ATTR}\"</code> with a string formed from the value of the "
                    + "attribute <code>ATTR</code>:"
                    + "<ul>"
                    + "<li>String-typed attributes are substituted verbatim."
                    + "<li>Label-typed attributes become the part of the label after the package, "
                    + "minus the file extension. For example, the label "
                    + "<code>\"//pkg:a/b.c\"</code> becomes <code>\"a/b\"</code>."
                    + "<li>Output-typed attributes become the part of the label after the package, "
                    + "including the file extension (for the above example, "
                    + "<code>\"a/b.c\"</code>)."
                    + "<li>All list-typed attributes (for example, <code>attr.label_list</code>) "
                    + "used in placeholders are required to have <i>exactly one element</i>. Their "
                    + "conversion is the same as their non-list version (<code>attr.label</code>)."
                    + "<li>Other attribute types may not appear in placeholders."
                    + "<li>The special non-attribute placeholders <code>%{dirname}</code> and "
                    + "<code>%{basename}</code> expand to those parts of the rule's label, "
                    + "excluding its package. For example, in <code>\"//pkg:a/b.c\"</code>, the "
                    + "dirname is <code>a</code> and the basename is <code>b.c</code>."
                    + "</ul>"
                    + "<p>In practice, the most common substitution placeholder is "
                    + "<code>\"%{name}\"</code>. For example, for a target named \"foo\", the "
                    + "outputs dict <code>{\"bin\": \"%{name}.exe\"}</code> predeclares an output "
                    + "named <code>foo.exe</code> that is accessible in the implementation "
                    + "function as <code>ctx.outputs.bin</code>."),
        @Param(
            name = "executable",
            type = Boolean.class,
            legacyNamed = true,
            defaultValue = "False",
            doc =
                "Whether this rule is considered executable, that is, whether it may be the "
                    + "subject of a <code>blaze run</code> command. See the "
                    + "<a href='../rules.$DOC_EXT#executable-rules-and-test-rules'>Rules page</a> "
                    + "for more information."),
        @Param(
            name = "output_to_genfiles",
            type = Boolean.class,
            legacyNamed = true,
            defaultValue = "False",
            doc =
                "If true, the files will be generated in the genfiles directory instead of the "
                    + "bin directory. Unless you need it for compatibility with existing rules "
                    + "(e.g. when generating header files for C++), do not set this flag."),
        @Param(
            name = "fragments",
            type = SkylarkList.class,
            legacyNamed = true,
            generic1 = String.class,
            defaultValue = "[]",
            doc =
                "List of names of configuration fragments that the rule requires "
                    + "in target configuration."),
        @Param(
            name = "host_fragments",
            type = SkylarkList.class,
            legacyNamed = true,
            generic1 = String.class,
            defaultValue = "[]",
            doc =
                "List of names of configuration fragments that the rule requires "
                    + "in host configuration."),
        @Param(
            name = "_skylark_testable",
            type = Boolean.class,
            legacyNamed = true,
            defaultValue = "False",
            doc =
                "<i>(Experimental)</i><br/><br/>"
                    + "If true, this rule will expose its actions for inspection by rules that "
                    + "depend on it via an <a href=\"globals.html#Actions\">Actions</a> "
                    + "provider. The provider is also available to the rule itself by calling "
                    + "<a href=\"ctx.html#created_actions\">ctx.created_actions()</a>."
                    + "<br/><br/>"
                    + "This should only be used for testing the analysis-time behavior of "
                    + "Starlark rules. This flag may be removed in the future."),
        @Param(
            name = "toolchains",
            type = SkylarkList.class,
            legacyNamed = true,
            generic1 = String.class,
            defaultValue = "[]",
            doc =
                "<i>(Experimental)</i><br/><br/>"
                    + "If set, the set of toolchains this rule requires. Toolchains will be "
                    + "found by checking the current platform, and provided to the rule "
                    + "implementation via <code>ctx.toolchain</code>."),
        @Param(
            name = "doc",
            type = String.class,
            legacyNamed = true,
            defaultValue = "''",
            doc =
                "A description of the rule that can be extracted by documentation generating "
                    + "tools."),
        @Param(
            name = "provides",
            type = SkylarkList.class,
            named = true,
            positional = false,
            defaultValue = "[]",
            doc = PROVIDES_DOC),
        @Param(
            name = "execution_platform_constraints_allowed",
            type = Boolean.class,
            named = true,
            positional = false,
            defaultValue = "False",
            doc =
                "If true, a special attribute named <code>exec_compatible_with</code> of "
                    + "label-list type is added, which must not already exist in "
                    + "<code>attrs</code>. Targets may use this attribute to specify additional "
                    + "constraints on the execution platform beyond those given in the "
                    + "<code>exec_compatible_with</code> argument to <code>rule()</code>."),
        @Param(
            name = "exec_compatible_with",
            type = SkylarkList.class,
            generic1 = String.class,
            named = true,
            positional = false,
            defaultValue = "[]",
            doc =
                "A list of constraints on the execution platform that apply to all targets of "
                    + "this rule type."),
        @Param(
            name = "analysis_test",
            allowedTypes = {
              @ParamType(type = Boolean.class),
              @ParamType(type = UnboundMarker.class)
            },
            named = true,
            positional = false,
            // TODO(cparsons): Make the default false when this is no longer experimental.
            defaultValue = "unbound",
            // TODO(cparsons): Link to in-build testing documentation when it is available.
            doc =
                "<b>Experimental: This parameter is experimental and subject to change at any "
                    + "time.</b><p> If true, then this rule is treated as an analysis test."),
        @Param(
            name = "build_setting",
            type = BuildSettingApi.class,
            noneable = true,
            defaultValue = "None",
            named = true,
            positional = false,
            enableOnlyWithFlag = FlagIdentifier.EXPERIMENTAL_BUILD_SETTING_API,
            valueWhenDisabled = "None",
            // TODO(juliexxia): Link to in-build testing documentation when it is available.
            doc =
                "If set, describes what kind of build setting this rule is. "
                    + "See the <a href='config.html'><code>config</code></a> module. If this is "
                    + "set, a mandatory attribute named \"build_setting_default\" is automatically"
                    + "added to this rule, with a type corresponding to the value passed in here."),
        @Param(
            name = "cfg",
            type = Object.class,
            noneable = true,
            defaultValue = "None",
            named = true,
            positional = false,
            enableOnlyWithFlag = FlagIdentifier.EXPERIMENTAL_STARLARK_CONFIG_TRANSITION,
            valueWhenDisabled = "None",
            doc =
                "If set, points to the configuration transition the rule will "
                    + "apply to its own configuration before analysis.")
      },
      useAst = true,
      useEnvironment = true,
      useContext = true)
  public BaseFunction rule(
      BaseFunction implementation,
      Boolean test,
      Object attrs,
      Object implicitOutputs,
      Boolean executable,
      Boolean outputToGenfiles,
      SkylarkList<?> fragments,
      SkylarkList<?> hostFragments,
      Boolean skylarkTestable,
      SkylarkList<?> toolchains,
      String doc,
      SkylarkList<?> providesArg,
      Boolean executionPlatformConstraintsAllowed,
      SkylarkList<?> execCompatibleWith,
      Object analysisTest,
      Object buildSetting,
      Object cfg,
      FuncallExpression ast,
      Environment funcallEnv,
      StarlarkContext context)
      throws EvalException;

  @SkylarkCallable(
      name = "aspect",
      doc =
          "Creates a new aspect. The result of this function must be stored in a global value. "
              + "Please see the <a href=\"../aspects.md\">introduction to Aspects</a> for more "
              + "details.",
      parameters = {
          @Param(
              name = "implementation",
              type = BaseFunction.class,
              legacyNamed = true,
              doc =
                  "the function implementing this aspect. Must have two parameters: "
                      + "<a href=\"Target.html\">Target</a> (the target to which the aspect is "
                      + "applied) and <a href=\"ctx.html\">ctx</a>. Attributes of the target are "
                      + "available via ctx.rule field. The function is called during the analysis "
                      + "phase for each application of an aspect to a target."
          ),
          @Param(
              name = "attr_aspects",
              type = SkylarkList.class,
              legacyNamed = true,
              generic1 = String.class,
              defaultValue = "[]",
              doc = "List of attribute names.  The aspect propagates along dependencies specified "
                  + "by attributes of a target with this name. The list can also contain a single "
                  + "string '*': in that case aspect propagates along all dependencies of a target."
          ),
          @Param(
              name = "attrs",
              type = SkylarkDict.class,
              legacyNamed = true,
              noneable = true,
              defaultValue = "None",
              doc = "dictionary to declare all the attributes of the aspect.  "
                  + "It maps from an attribute name to an attribute object "
                  + "(see <a href=\"attr.html\">attr</a> module). "
                  + "Aspect attributes are available to implementation function as fields of ctx "
                  + "parameter. Implicit attributes starting with <code>_</code> must have default "
                  + "values, and have type <code>label</code> or <code>label_list</code>. "
                  + "Explicit attributes must have type <code>string</code>, and must use the "
                  + "<code>values</code> restriction. If explicit attributes are present, the "
                  + "aspect can only be used with rules that have attributes of the same name and "
                  + "type, with valid values."
          ),
          @Param(
              name = "required_aspect_providers",
              type = SkylarkList.class,
              legacyNamed = true,
              defaultValue = "[]",
              doc = "Allow the aspect to inspect other aspects. If the aspect propagates along "
                  + "a dependency, and the underlying rule sends a different aspect along that "
                  + "dependency, and that aspect provides one of the providers listed here, this "
                  + "aspect will see the providers provided by that aspect. "
                  + "<p>The value should be either a list of providers, or a "
                  + "list of lists of providers. This aspect will 'see'  the underlying aspects "
                  + "that provide  ALL providers from at least ONE of these lists. A single list "
                  + "of providers will be automatically converted to a list containing one list of "
                  + "providers."
          ),
          @Param(
              name = "provides",
              type = SkylarkList.class,
              legacyNamed = true,
              defaultValue = "[]",
              doc = PROVIDES_DOC
          ),
          @Param(
              name = "fragments",
              type = SkylarkList.class,
              legacyNamed = true,
              generic1 = String.class,
              defaultValue = "[]",
              doc =
                  "List of names of configuration fragments that the aspect requires "
                      + "in target configuration."
          ),
          @Param(
              name = "host_fragments",
              type = SkylarkList.class,
              legacyNamed = true,
              generic1 = String.class,
              defaultValue = "[]",
              doc =
                  "List of names of configuration fragments that the aspect requires "
                      + "in host configuration."
          ),
          @Param(
              name = "toolchains",
              type = SkylarkList.class,
              legacyNamed = true,
              generic1 = String.class,
              defaultValue = "[]",
              doc =
                  "<i>(Experimental)</i><br/><br/>"
                      + "If set, the set of toolchains this rule requires. Toolchains will be "
                      + "found by checking the current platform, and provided to the rule "
                      + "implementation via <code>ctx.toolchain</code>."
          ),
          @Param(
              name = "doc",
              type = String.class,
              legacyNamed = true,
              defaultValue = "''",
              doc = "A description of the aspect that can be extracted by documentation generating "
                  + "tools."
          )
      },
      useEnvironment = true,
      useAst = true
  )
  public SkylarkAspectApi aspect(
      BaseFunction implementation,
      SkylarkList<?> attributeAspects,
      Object attrs,
      SkylarkList<?> requiredAspectProvidersArg,
      SkylarkList<?> providesArg,
      SkylarkList<?> fragments,
      SkylarkList<?> hostFragments,
      SkylarkList<?> toolchains,
      String doc,
      FuncallExpression ast,
      Environment funcallEnv)
      throws EvalException;

  @SkylarkCallable(
      name = "Label",
      doc =
          "Creates a Label referring to a BUILD target. Use "
              + "this function only when you want to give a default value for the label "
              + "attributes. The argument must refer to an absolute label. "
              + "Example: <br><pre class=language-python>Label(\"//tools:default\")</pre>",
      parameters = {
        @Param(
            name = "label_string",
            type = String.class,
            legacyNamed = true,
            doc = "the label string."),
        @Param(
            name = "relative_to_caller_repository",
            type = Boolean.class,
            defaultValue = "False",
            named = true,
            positional = false,
            doc =
                "Deprecated. Do not use. "
                    + "When relative_to_caller_repository is True and the calling thread is a "
                    + "rule's implementation function, then a repo-relative label //foo:bar is "
                    + "resolved relative to the rule's repository.  For calls to Label from any "
                    + "other thread, or calls in which the relative_to_caller_repository flag is "
                    + "False, a repo-relative label is resolved relative to the file in which the "
                    + "Label() call appears.")
      },
      useLocation = true,
      useEnvironment = true,
      useContext = true)
  @SkylarkConstructor(objectType = Label.class)
  public Label label(
      String labelString,
      Boolean relativeToCallerRepository,
      Location loc,
      Environment env,
      StarlarkContext context)
      throws EvalException;

  @SkylarkCallable(
      name = "FileType",
      doc =
          "Deprecated. Creates a file filter from a list of strings. For example, to match "
              + "files ending with .cc or .cpp, use: "
              + "<pre class=language-python>FileType([\".cc\", \".cpp\"])</pre>",
      parameters = {
          @Param(
              name = "types",
              type = SkylarkList.class,
              legacyNamed = true,
              generic1 = String.class,
              defaultValue = "[]",
              doc = "a list of the accepted file extensions."
          )
      },
      useLocation = true,
      useEnvironment = true
  )
  @SkylarkConstructor(objectType = FileTypeApi.class)
  public FileTypeApi<FileApiT> fileType(SkylarkList<?> types, Location loc, Environment env)
     throws EvalException;
}