// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "tools/gn/err.h"
#include "tools/gn/filesystem_utils.h"
#include "tools/gn/functions.h"
#include "tools/gn/label.h"
#include "tools/gn/parse_tree.h"
#include "tools/gn/value.h"

namespace functions {

namespace {

bool ToolchainIsDefault(const Scope* scope, const Label& toolchain_label) {
  return scope->settings()->default_toolchain_label() == toolchain_label;
}

}  // namespace

const char kGetLabelInfo[] = "get_label_info";
const char kGetLabelInfo_HelpShort[] =
    "get_label_info: Get an attribute from a target's label.";
const char kGetLabelInfo_Help[] =
    "get_label_info: Get an attribute from a target's label.\n"
    "\n"
    "  get_label_info(target_label, what)\n"
    "\n"
    "  Given the label of a target, returns some attribute of that target.\n"
    "  The target need not have been previously defined in the same file,\n"
    "  since none of the attributes depend on the actual target definition,\n"
    "  only the label itself.\n"
    "\n"
    "  See also \"gn help get_target_outputs\".\n"
    "\n"
    "Possible values for the \"what\" parameter\n"
    "\n"
    "  \"name\"\n"
    "      The short name of the target. This will match the value of the\n"
    "      \"target_name\" variable inside that target's declaration. For the\n"
    "      label \"//foo/bar:baz\" this will return \"baz\".\n"
    "\n"
    "  \"dir\"\n"
    "      The directory containing the target's definition, with no slash at\n"
    "      the end. For the label \"//foo/bar:baz\" this will return\n"
    "      \"//foo/bar\".\n"
    "\n"
    "  \"target_gen_dir\"\n"
    "      The generated file directory for the target. This will match the\n"
    "      value of the \"target_gen_dir\" variable when inside that target's\n"
    "      declaration.\n"
    "\n"
    "  \"root_gen_dir\"\n"
    "      The root of the generated file tree for the target. This will\n"
    "      match the value of the \"root_gen_dir\" variable when inside that\n"
    "      target's declaration.\n"
    "\n"
    "  \"target_out_dir\n"
    "      The output directory for the target. This will match the\n"
    "      value of the \"target_out_dir\" variable when inside that target's\n"
    "      declaration.\n"
    "\n"
    "  \"root_out_dir\"\n"
    "      The root of the output file tree for the target. This will\n"
    "      match the value of the \"root_out_dir\" variable when inside that\n"
    "      target's declaration.\n"
    "\n"
    "  \"label_no_toolchain\"\n"
    "      The fully qualified version of this label, not including the\n"
    "      toolchain. For the input \":bar\" it might return\n"
    "      \"//foo:bar\".\n"
    "\n"
    "  \"label_with_toolchain\"\n"
    "      The fully qualified version of this label, including the\n"
    "      toolchain. For the input \":bar\" it might return\n"
    "      \"//foo:bar(//toolchain:x64)\".\n"
    "\n"
    "  \"toolchain\"\n"
    "      The label of the toolchain. This will match the value of the\n"
    "      \"current_toolchain\" variable when inside that target's\n"
    "      declaration.\n"
    "\n"
    "Examples\n"
    "\n"
    "  get_label_info(\":foo\", \"name\")\n"
    "  # Returns string \"foo\".\n"
    "\n"
    "  get_label_info(\"//foo/bar:baz\", \"gen_dir\")\n"
    "  # Returns string \"//out/Debug/gen/foo/bar\".\n";

Value RunGetLabelInfo(Scope* scope,
                      const FunctionCallNode* function,
                      const std::vector<Value>& args,
                      Err* err) {
  if (args.size() != 2) {
    *err = Err(function, "Expected two arguments.");
    return Value();
  }

  // Resolve the requested label.
  Label label = Label::Resolve(scope->GetSourceDir(),
                               ToolchainLabelForScope(scope), args[0], err);
  if (label.is_null())
    return Value();

  // Extract the "what" parameter.
  if (!args[1].VerifyTypeIs(Value::STRING, err))
    return Value();
  const std::string& what = args[1].string_value();

  Value result(function, Value::STRING);
  if (what == "name") {
    result.string_value() = label.name();

  } else if (what == "dir") {
    result.string_value() = DirectoryWithNoLastSlash(label.dir());

  } else if (what == "target_gen_dir") {
    result.string_value() = DirectoryWithNoLastSlash(
        GetGenDirForSourceDir(scope->settings(), label.dir()));

  } else if (what == "root_gen_dir") {
    Label toolchain_label = label.GetToolchainLabel();
    result.string_value() = DirectoryWithNoLastSlash(
        GetToolchainGenDir(scope->settings()->build_settings(),
                           toolchain_label,
                           ToolchainIsDefault(scope, toolchain_label)));

  } else if (what == "target_out_dir") {
    Label toolchain_label = label.GetToolchainLabel();
    result.string_value() = DirectoryWithNoLastSlash(
        GetOutputDirForSourceDir(scope->settings()->build_settings(),
                                 label.dir(), toolchain_label,
                                 ToolchainIsDefault(scope, toolchain_label)));

  } else if (what == "root_out_dir") {
    Label toolchain_label = label.GetToolchainLabel();
    result.string_value() = DirectoryWithNoLastSlash(
        GetToolchainOutputDir(scope->settings()->build_settings(),
                              toolchain_label,
                              ToolchainIsDefault(scope, toolchain_label)));

  } else if (what == "toolchain") {
    result.string_value() = label.GetToolchainLabel().GetUserVisibleName(false);

  } else if (what == "label_no_toolchain") {
    result.string_value() =
        label.GetWithNoToolchain().GetUserVisibleName(false);

  } else if (what == "label_with_toolchain") {
    result.string_value() = label.GetUserVisibleName(true);

  } else {
    *err = Err(args[1], "Unknown value for \"what\" parameter.");
    return Value();
  }

  return result;
}

}  // namespace functions