// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_REGIONAL_CAPABILITIES_REGIONAL_CAPABILITIES_UTILS_H_
#define COMPONENTS_REGIONAL_CAPABILITIES_REGIONAL_CAPABILITIES_UTILS_H_

#include <optional>
#include <variant>
#include <vector>

#include "base/auto_reset.h"
#include "base/containers/flat_map.h"
#include "base/feature_list.h"
#include "base/memory/raw_ptr.h"

class PrefService;

namespace country_codes {
class CountryId;
}

namespace TemplateURLPrepopulateData {
struct PrepopulatedEngine;
}

namespace regional_capabilities {

enum class SearchEngineListType;
enum class Program;

// Override of the regional program set from the
// `switches::kSearchEngineChoiceCountry` command line flag.
enum class RegionalProgramOverride {
  // Display the program for Japan
  kTaiyaki,
};

// Override of the search engines list set from the
// `switches::kSearchEngineChoiceCountry` command line flag.
enum class SearchEngineCountryListOverride {
  // Display all the search engines used in the EEA region.
  kEeaAll,
  // Display the search engines that we default to when the country is unknown.
  kEeaDefault,
  // Display search engines explicitly set in the currently running automated
  // test's setup. Requires hardcoding some test overrides.
  kTestOverride,
};

// The state of the search engine choice country command line override.
// See `switches::kSearchEngineChoiceCountry`.
using SearchEngineCountryOverride =
    std::variant<country_codes::CountryId,
                 RegionalProgramOverride,
                 SearchEngineCountryListOverride>;

// Gets the search engine country command line override.
// Returns an int if the country id is passed to the command line or a
// `SearchEngineCountryListOverride` if the special values of
// `kDefaultListCountryOverride` or `kEeaListCountryOverride` are passed.
std::optional<SearchEngineCountryOverride> GetSearchEngineCountryOverride();

// Returns whether the search engine list is overridden in the command line to
// a special value that forces the program and the engines list, instead of
// simply to a given country.
bool HasSearchEngineCountryListOverride();

// Returns the prepopulated engines for the given country.
std::vector<raw_ptr<const TemplateURLPrepopulateData::PrepopulatedEngine>>
GetPrepopulatedEngines(country_codes::CountryId country_id,
                       PrefService& prefs,
                       SearchEngineListType search_engine_list_type);

const base::span<
    const raw_ptr<const TemplateURLPrepopulateData::PrepopulatedEngine>>
GetAllPrepopulatedEngines();

// Maps from the `id` of a new entry to the deprecated `PrepopulatedEngine` that
// points to it.
using MigratingEngines = base::flat_map<
    int,
    raw_ptr<const TemplateURLPrepopulateData::PrepopulatedEngine>>;
const MigratingEngines& GetMigratingPrepopulatedEngines();

// Returns all the prepopulated engines that are used in the EEA region.
std::vector<raw_ptr<const TemplateURLPrepopulateData::PrepopulatedEngine>>
GetAllEeaRegionPrepopulatedEngines();

// Returns the set of search engines that is used when the country is unknown.
std::vector<raw_ptr<const TemplateURLPrepopulateData::PrepopulatedEngine>>
GetDefaultPrepopulatedEngines();

// -- Test-only utils ---------------------------------------------------------

struct PrepopulatedEnginesOverride {
  PrepopulatedEnginesOverride();
  ~PrepopulatedEnginesOverride();

  // If you need to copy or move this struct,
  // you should declare those out-of-line as well
  PrepopulatedEnginesOverride(const PrepopulatedEnginesOverride&);
  PrepopulatedEnginesOverride& operator=(const PrepopulatedEnginesOverride&);
  // Move operations
  PrepopulatedEnginesOverride(PrepopulatedEnginesOverride&&);
  PrepopulatedEnginesOverride& operator=(PrepopulatedEnginesOverride&&);

  std::vector<raw_ptr<const TemplateURLPrepopulateData::PrepopulatedEngine>>
      regional_engines;
  std::vector<raw_ptr<const TemplateURLPrepopulateData::PrepopulatedEngine>>
      all_engines;
  MigratingEngines migrating_engines;
};

using ScopedPrepopulatedEnginesOverride =
    base::AutoReset<std::optional<PrepopulatedEnginesOverride>>;

const PrepopulatedEnginesOverride& GetPrepopulatedEnginesOverrideForTesting();

ScopedPrepopulatedEnginesOverride SetPrepopulatedEnginesOverrideForTesting(
    std::vector<raw_ptr<const TemplateURLPrepopulateData::PrepopulatedEngine>>
        regional_engines,
    std::vector<raw_ptr<const TemplateURLPrepopulateData::PrepopulatedEngine>>
        other_known_engines);

void ClearPrepopulatedEnginesOverrideForTesting();

}  // namespace regional_capabilities

#endif  // COMPONENTS_REGIONAL_CAPABILITIES_REGIONAL_CAPABILITIES_UTILS_H_