//
// Copyright (C) 2014 The Android Open Source Project
//
// 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.
//

#include "shill/cellular/cellular_bearer.h"

#include <ModemManager/ModemManager.h>

#include <base/bind.h>

#include "shill/control_interface.h"
#include "shill/dbus_properties_proxy_interface.h"
#include "shill/logging.h"

using std::string;
using std::vector;

namespace shill {

namespace Logging {
static auto kModuleLogScope = ScopeLogger::kCellular;
static string ObjectID(const CellularBearer* c) { return "(cellular_bearer)"; }
}

namespace {

const char kPropertyAddress[] = "address";
const char kPropertyDNS1[] = "dns1";
const char kPropertyDNS2[] = "dns2";
const char kPropertyDNS3[] = "dns3";
const char kPropertyGateway[] = "gateway";
const char kPropertyMethod[] = "method";
const char kPropertyPrefix[] = "prefix";

IPConfig::Method ConvertMMBearerIPConfigMethod(uint32_t method) {
  switch (method) {
    case MM_BEARER_IP_METHOD_PPP:
      return IPConfig::kMethodPPP;
    case MM_BEARER_IP_METHOD_STATIC:
      return IPConfig::kMethodStatic;
    case MM_BEARER_IP_METHOD_DHCP:
      return IPConfig::kMethodDHCP;
    default:
      return IPConfig::kMethodUnknown;
  }
}

}  // namespace

CellularBearer::CellularBearer(ControlInterface* control_interface,
                               const string& dbus_path,
                               const string& dbus_service)
    : control_interface_(control_interface),
      dbus_path_(dbus_path),
      dbus_service_(dbus_service),
      connected_(false),
      ipv4_config_method_(IPConfig::kMethodUnknown),
      ipv6_config_method_(IPConfig::kMethodUnknown) {
  CHECK(control_interface_);
}

CellularBearer::~CellularBearer() {}

bool CellularBearer::Init() {
  SLOG(this, 3) << __func__ << ": path='" << dbus_path_
                << "', service='" << dbus_service_ << "'";

  dbus_properties_proxy_.reset(
      control_interface_->CreateDBusPropertiesProxy(dbus_path_, dbus_service_));
  // It is possible that ProxyFactory::CreateDBusPropertiesProxy() returns
  // nullptr as the bearer DBus object may no longer exist.
  if (!dbus_properties_proxy_) {
    LOG(WARNING) << "Failed to create DBus properties proxy for bearer '"
                 << dbus_path_ << "'. Bearer is likely gone.";
    return false;
  }

  dbus_properties_proxy_->set_properties_changed_callback(base::Bind(
      &CellularBearer::OnPropertiesChanged, base::Unretained(this)));
  UpdateProperties();
  return true;
}

void CellularBearer::GetIPConfigMethodAndProperties(
    const KeyValueStore& properties,
    IPAddress::Family address_family,
    IPConfig::Method* ipconfig_method,
    std::unique_ptr<IPConfig::Properties>* ipconfig_properties) const {
  DCHECK(ipconfig_method);
  DCHECK(ipconfig_properties);

  uint32_t method = MM_BEARER_IP_METHOD_UNKNOWN;
  if (properties.ContainsUint(kPropertyMethod)) {
    method = properties.GetUint(kPropertyMethod);
  } else {
    SLOG(this, 2) << "Bearer '" << dbus_path_
                  << "' does not specify an IP configuration method.";
  }

  *ipconfig_method = ConvertMMBearerIPConfigMethod(method);
  ipconfig_properties->reset();

  if (*ipconfig_method != IPConfig::kMethodStatic)
    return;

  if (!properties.ContainsString(kPropertyAddress) ||
      !properties.ContainsString(kPropertyGateway)) {
    SLOG(this, 2) << "Bearer '" << dbus_path_
                  << "' static IP configuration does not specify valid "
                         "address/gateway information.";
    *ipconfig_method = IPConfig::kMethodUnknown;
    return;
  }

  ipconfig_properties->reset(new IPConfig::Properties);
  (*ipconfig_properties)->address_family = address_family;
  (*ipconfig_properties)->address = properties.GetString(kPropertyAddress);
  (*ipconfig_properties)->gateway = properties.GetString(kPropertyGateway);

  uint32_t prefix;
  if (!properties.ContainsUint(kPropertyPrefix)) {
    prefix = IPAddress::GetMaxPrefixLength(address_family);
  } else {
    prefix = properties.GetUint(kPropertyPrefix);
  }
  (*ipconfig_properties)->subnet_prefix = prefix;

  if (properties.ContainsString(kPropertyDNS1)) {
    (*ipconfig_properties)->dns_servers.push_back(
        properties.GetString(kPropertyDNS1));
  }
  if (properties.ContainsString(kPropertyDNS2)) {
    (*ipconfig_properties)->dns_servers.push_back(
        properties.GetString(kPropertyDNS2));
  }
  if (properties.ContainsString(kPropertyDNS3)) {
    (*ipconfig_properties)->dns_servers.push_back(
        properties.GetString(kPropertyDNS3));
  }
}

void CellularBearer::ResetProperties() {
  connected_ = false;
  data_interface_.clear();
  ipv4_config_method_ = IPConfig::kMethodUnknown;
  ipv4_config_properties_.reset();
  ipv6_config_method_ = IPConfig::kMethodUnknown;
  ipv6_config_properties_.reset();
}

void CellularBearer::UpdateProperties() {
  ResetProperties();

  if (!dbus_properties_proxy_)
    return;

  KeyValueStore properties =
      dbus_properties_proxy_->GetAll(MM_DBUS_INTERFACE_BEARER);
  if (properties.IsEmpty()) {
    LOG(WARNING) << "Could not get properties of bearer '" << dbus_path_
                 << "'. Bearer is likely gone and thus ignored.";
    return;
  }

  OnPropertiesChanged(MM_DBUS_INTERFACE_BEARER,
                      properties,
                      vector<string>());
}

void CellularBearer::OnPropertiesChanged(
    const string& interface,
    const KeyValueStore& changed_properties,
    const vector<string>& /*invalidated_properties*/) {
  SLOG(this, 3) << __func__ << ": path=" << dbus_path_
                << ", interface=" << interface;

  if (interface != MM_DBUS_INTERFACE_BEARER)
    return;

  if (changed_properties.ContainsBool(MM_BEARER_PROPERTY_CONNECTED)) {
    connected_ = changed_properties.GetBool(MM_BEARER_PROPERTY_CONNECTED);
  }

  string data_interface;
  if (changed_properties.ContainsString(MM_BEARER_PROPERTY_INTERFACE)) {
    data_interface_ =
        changed_properties.GetString(MM_BEARER_PROPERTY_INTERFACE);
  }

  if (changed_properties.ContainsKeyValueStore(MM_BEARER_PROPERTY_IP4CONFIG)) {
    KeyValueStore ipconfig =
        changed_properties.GetKeyValueStore(MM_BEARER_PROPERTY_IP4CONFIG);
    GetIPConfigMethodAndProperties(ipconfig,
                                   IPAddress::kFamilyIPv4,
                                   &ipv4_config_method_,
                                   &ipv4_config_properties_);
  }
  if (changed_properties.ContainsKeyValueStore(MM_BEARER_PROPERTY_IP6CONFIG)) {
    KeyValueStore ipconfig =
        changed_properties.GetKeyValueStore(MM_BEARER_PROPERTY_IP6CONFIG);
    GetIPConfigMethodAndProperties(ipconfig,
                                   IPAddress::kFamilyIPv6,
                                   &ipv6_config_method_,
                                   &ipv6_config_properties_);
  }
}

}  // namespace shill