/*
Copyright (c) 2020 Intel Corporation

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 "event_log.hpp"

#include "logging.hpp"
#include "registries.hpp"
#include "str_utility.hpp"

#include <nlohmann/json.hpp>

#include <cerrno>
#include <cstddef>
#include <ctime>
#include <iomanip>
#include <span>
#include <sstream>
#include <string>
#include <string_view>
#include <utility>
#include <vector>

namespace redfish
{

namespace event_log
{

bool getUniqueEntryID(const std::string& logEntry, std::string& entryID)
{
    static time_t prevTs = 0;
    static int index = 0;

    // Get the entry timestamp
    std::time_t curTs = 0;
    std::tm timeStruct = {};
    std::istringstream entryStream(logEntry);
    if (entryStream >> std::get_time(&timeStruct, "%Y-%m-%dT%H:%M:%S"))
    {
        curTs = std::mktime(&timeStruct);
        if (curTs == -1)
        {
            return false;
        }
    }
    // If the timestamp isn't unique, increment the index
    index = (curTs == prevTs) ? index + 1 : 0;

    // Save the timestamp
    prevTs = curTs;

    entryID = std::to_string(curTs);
    if (index > 0)
    {
        entryID += "_" + std::to_string(index);
    }
    return true;
}

int getEventLogParams(const std::string& logEntry, std::string& timestamp,
                      std::string& messageID,
                      std::vector<std::string>& messageArgs)
{
    // The redfish log format is "<Timestamp> <MessageId>,<MessageArgs>"
    // First get the Timestamp
    size_t space = logEntry.find_first_of(' ');
    if (space == std::string::npos)
    {
        BMCWEB_LOG_ERROR("EventLog Params: could not find first space: {}",
                         logEntry);
        return -EINVAL;
    }
    timestamp = logEntry.substr(0, space);
    // Then get the log contents
    size_t entryStart = logEntry.find_first_not_of(' ', space);
    if (entryStart == std::string::npos)
    {
        BMCWEB_LOG_ERROR("EventLog Params: could not find log contents: {}",
                         logEntry);
        return -EINVAL;
    }
    std::string_view entry(logEntry);
    entry.remove_prefix(entryStart);
    // Use split to separate the entry into its fields
    std::vector<std::string> logEntryFields;
    bmcweb::split(logEntryFields, entry, ',');
    // We need at least a MessageId to be valid
    if (logEntryFields.empty())
    {
        BMCWEB_LOG_ERROR("EventLog Params: could not find entry fields: {}",
                         logEntry);
        return -EINVAL;
    }
    messageID = logEntryFields[0];

    // Get the MessageArgs from the log if there are any
    if (logEntryFields.size() > 1)
    {
        const std::string& messageArgsStart = logEntryFields[1];
        // If the first string is empty, assume there are no MessageArgs
        if (!messageArgsStart.empty())
        {
            messageArgs.assign(logEntryFields.begin() + 1,
                               logEntryFields.end());
        }
    }

    return 0;
}

int formatEventLogEntry(
    const std::string& logEntryID, const std::string& messageID,
    const std::span<std::string_view> messageArgs, std::string timestamp,
    const std::string& customText, nlohmann::json::object_t& logEntryJson)
{
    // Get the Message from the MessageRegistry
    const registries::Message* message = registries::getMessage(messageID);

    if (message == nullptr)
    {
        return -1;
    }

    std::string msg =
        redfish::registries::fillMessageArgs(messageArgs, message->message);
    if (msg.empty())
    {
        return -1;
    }

    // Get the Created time from the timestamp. The log timestamp is in
    // RFC3339 format which matches the Redfish format except for the
    // fractional seconds between the '.' and the '+', so just remove them.
    std::size_t dot = timestamp.find_first_of('.');
    std::size_t plus = timestamp.find_first_of('+', dot);
    if (dot != std::string::npos && plus != std::string::npos)
    {
        timestamp.erase(dot, plus - dot);
    }

    // Fill in the log entry with the gathered data
    logEntryJson["EventId"] = logEntryID;

    logEntryJson["Severity"] = message->messageSeverity;
    logEntryJson["Message"] = std::move(msg);
    logEntryJson["MessageId"] = messageID;
    logEntryJson["MessageArgs"] = messageArgs;
    logEntryJson["EventTimestamp"] = std::move(timestamp);
    logEntryJson["Context"] = customText;
    return 0;
}

} // namespace event_log

} // namespace redfish