// Copyright 2015 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 "webservd/config.h"

#include <base/files/file_util.h>
#include <base/json/json_reader.h>
#include <base/logging.h>
#include <base/values.h>
#include <brillo/errors/error_codes.h>

#include "webservd/error_codes.h"

namespace webservd {

#ifdef __ANDROID__
const char kDefaultLogDirectory[] = "/data/misc/webservd/logs";
#else
const char kDefaultLogDirectory[] = "/var/log/webservd";
#endif

namespace {

const char kLogDirectoryKey[] = "log_directory";
const char kProtocolHandlersKey[] = "protocol_handlers";
const char kNameKey[] = "name";
const char kPortKey[] = "port";
const char kUseTLSKey[] = "use_tls";
const char kInterfaceKey[] = "interface";

// Default configuration for the web server.
const char kDefaultConfig[] = R"({
  "protocol_handlers": [
    {
      "name": "http",
      "port": 80,
      "use_tls": false
    },
    {
      "name": "https",
      "port": 443,
      "use_tls": true
    }
  ]
})";

bool LoadHandlerConfig(const base::DictionaryValue* handler_value,
                       Config::ProtocolHandler* handler_config,
                       brillo::ErrorPtr* error) {
  int port = 0;
  if (!handler_value->GetInteger(kPortKey, &port)) {
    brillo::Error::AddTo(error,
                         FROM_HERE,
                         webservd::errors::kDomain,
                         webservd::errors::kInvalidConfig,
                         "Port is missing");
    return false;
  }
  if (port < 1 || port > 0xFFFF) {
    brillo::Error::AddToPrintf(error,
                               FROM_HERE,
                               webservd::errors::kDomain,
                               webservd::errors::kInvalidConfig,
                               "Invalid port value: %d", port);
    return false;
  }
  handler_config->port = port;

  // Allow "use_tls" to be omitted, so not returning an error here.
  bool use_tls = false;
  if (handler_value->GetBoolean(kUseTLSKey, &use_tls))
    handler_config->use_tls = use_tls;

  // "interface" is also optional.
  std::string interface_name;
  if (handler_value->GetString(kInterfaceKey, &interface_name))
    handler_config->interface_name = interface_name;

  return true;
}

}  // anonymous namespace

Config::ProtocolHandler::~ProtocolHandler() {
  if (socket_fd != -1)
    close(socket_fd);
}

void LoadDefaultConfig(Config* config) {
  LOG(INFO) << "Loading default server configuration...";
  CHECK(LoadConfigFromString(kDefaultConfig, config, nullptr));
}

bool LoadConfigFromFile(const base::FilePath& json_file_path, Config* config) {
  std::string config_json;
  LOG(INFO) << "Loading server configuration from " << json_file_path.value();
  return base::ReadFileToString(json_file_path, &config_json) &&
         LoadConfigFromString(config_json, config, nullptr);
}

bool LoadConfigFromString(const std::string& config_json,
                          Config* config,
                          brillo::ErrorPtr* error) {
  std::string error_msg;
  auto value = base::JSONReader::ReadAndReturnError(
      config_json, base::JSON_ALLOW_TRAILING_COMMAS, nullptr, &error_msg);

  if (!value) {
    brillo::Error::AddToPrintf(error, FROM_HERE,
                               brillo::errors::json::kDomain,
                               brillo::errors::json::kParseError,
                               "Error parsing server configuration: %s",
                               error_msg.c_str());
    return false;
  }

  auto dict_value = base::DictionaryValue::From(std::move(value));
  if (!dict_value) {
    brillo::Error::AddTo(error,
                         FROM_HERE,
                         brillo::errors::json::kDomain,
                         brillo::errors::json::kObjectExpected,
                         "JSON object is expected.");
    return false;
  }

  // "log_directory" is optional, so ignoring the return value here.
  dict_value->GetString(kLogDirectoryKey, &config->log_directory);

  const base::ListValue* protocol_handlers = nullptr;  // Owned by |dict_value|
  if (dict_value->GetList(kProtocolHandlersKey, &protocol_handlers)) {
    for (base::Value* handler_value : *protocol_handlers) {
      const base::DictionaryValue* handler_dict = nullptr;  // Owned by
                                                            // |dict_value|
      if (!handler_value->GetAsDictionary(&handler_dict)) {
        brillo::Error::AddTo(
            error,
            FROM_HERE,
            brillo::errors::json::kDomain,
            brillo::errors::json::kObjectExpected,
            "Protocol handler definition must be a JSON object");
        return false;
      }

      std::string name;
      if (!handler_dict->GetString(kNameKey, &name)) {
        brillo::Error::AddTo(
            error,
            FROM_HERE,
            errors::kDomain,
            errors::kInvalidConfig,
            "Protocol handler definition must include its name");
        return false;
      }

      Config::ProtocolHandler handler_config;
      handler_config.name = name;
      if (!LoadHandlerConfig(handler_dict, &handler_config, error)) {
        brillo::Error::AddToPrintf(
            error,
            FROM_HERE,
            errors::kDomain,
            errors::kInvalidConfig,
            "Unable to parse config for protocol handler '%s'",
            name.c_str());
        return false;
      }
      config->protocol_handlers.push_back(std::move(handler_config));
    }
  }
  return true;
}

}  // namespace webservd