// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "components/attribution_reporting/registrar_info.h"

#include <optional>

#include "base/containers/enum_set.h"
#include "base/functional/function_ref.h"
#include "base/metrics/histogram_functions.h"
#include "components/attribution_reporting/registrar.h"
#include "services/network/public/cpp/attribution_utils.h"
#include "services/network/public/mojom/attribution.mojom-shared.h"

namespace attribution_reporting {

namespace {

using SetRegistrarOrIssueFunc = base::FunctionRef<
    void(bool, network::mojom::AttributionSupport, RegistrarInfo&)>;

void SetRegistrarOrIssue(
    bool is_source,
    network::mojom::AttributionSupport support,
    Registrar registrar,
    IssueType issue,
    base::FunctionRef<bool(network::mojom::AttributionSupport)> check_func,
    RegistrarInfo& info) {
  if (check_func(support)) {
    info.registrar = registrar;
  } else {
    info.issues.Put(issue);
  }
}

void SetWebRegistrarOrIssue(bool is_source,
                            network::mojom::AttributionSupport support,
                            RegistrarInfo& info) {
  SetRegistrarOrIssue(is_source, support, Registrar::kWeb,
                      IssueType::kWebIgnored,
                      &network::HasAttributionWebSupport, info);
}

void SetOsRegistrarOrIssue(bool is_source,
                           network::mojom::AttributionSupport support,
                           RegistrarInfo& info) {
  SetRegistrarOrIssue(is_source, support, Registrar::kOs, IssueType::kOsIgnored,
                      &network::HasAttributionOsSupport, info);
}

void HandlePreferredPlatform(bool is_source,
                             network::mojom::AttributionSupport support,
                             IssueType issue,
                             bool has_preferred_header,
                             SetRegistrarOrIssueFunc preferred_func,
                             bool has_secondary_header,
                             SetRegistrarOrIssueFunc secondary_func,
                             RegistrarInfo& info) {
  if (!has_preferred_header) {
    info.issues.Put(issue);
    return;
  }

  preferred_func(is_source, support, info);

  if (!info.registrar.has_value() && has_secondary_header) {
    secondary_func(is_source, support, info);
  }
}

}  // namespace

RegistrarInfo::RegistrarInfo() = default;

RegistrarInfo::~RegistrarInfo() = default;

RegistrarInfo::RegistrarInfo(const RegistrarInfo&) = default;

RegistrarInfo& RegistrarInfo::operator=(const RegistrarInfo&) = default;

RegistrarInfo::RegistrarInfo(RegistrarInfo&&) = default;

RegistrarInfo& RegistrarInfo::operator=(RegistrarInfo&&) = default;

// static
RegistrarInfo RegistrarInfo::Get(bool has_web_header,
                                 bool has_os_header,
                                 bool is_source,
                                 std::optional<Registrar> preferred_platform,
                                 network::mojom::AttributionSupport support) {
  if (!has_web_header && !has_os_header) {
    return RegistrarInfo();
  }

  RegistrarInfo info;

  if (preferred_platform.has_value()) {
    switch (preferred_platform.value()) {
      case attribution_reporting::Registrar::kWeb:
        HandlePreferredPlatform(is_source, support, IssueType::kNoWebHeader,
                                has_web_header, &SetWebRegistrarOrIssue,
                                has_os_header, &SetOsRegistrarOrIssue, info);
        break;
      case attribution_reporting::Registrar::kOs:
        HandlePreferredPlatform(is_source, support, IssueType::kNoOsHeader,
                                has_os_header, &SetOsRegistrarOrIssue,
                                has_web_header, &SetWebRegistrarOrIssue, info);
        break;
    }
  } else {
    if (has_web_header && has_os_header) {
      info.issues.Put(IssueType::kWebAndOsHeaders);
    } else if (has_web_header) {
      SetWebRegistrarOrIssue(is_source, support, info);
    } else if (has_os_header) {
      SetOsRegistrarOrIssue(is_source, support, info);
    }
  }

  const char* metric = is_source
                           ? "Conversions.SourceRegistrationRegistrarIssue"
                           : "Conversions.TriggerRegistrationRegistrarIssue";

  for (IssueType issue : info.issues) {
    base::UmaHistogramEnumeration(metric, issue);
  }

  return info;
}

}  // namespace attribution_reporting