#include "configfileparser.h"

#include <fcntl.h>
#include <unistd.h>
#include <sstream>
#include "fstream"
#include <regex>

#include "openssl/ssl.h"
#include "openssl/err.h"

#include "exceptions.h"
#include "utils.h"
#include "logger.h"


void ConfigFileParser::testKeyValidity(const std::string &key, const std::set<std::string> &validKeys) const
{
    auto valid_key_it = validKeys.find(key);
    if (valid_key_it == validKeys.end())
    {
        std::ostringstream oss;
        oss << "Config key '" << key << "' is not valid (here).";
        throw ConfigFileException(oss.str());
    }
}

void ConfigFileParser::checkFileExistsAndReadable(const std::string &key, const std::string &pathToCheck) const
{
    if (access(pathToCheck.c_str(), R_OK) != 0)
    {
        std::ostringstream oss;
        oss << "Error for '" << key << "': " << pathToCheck << " is not there or not readable";
        throw ConfigFileException(oss.str());
    }
}

void ConfigFileParser::checkFileOrItsDirWritable(const std::string &filepath) const
{
    if (access(filepath.c_str(), F_OK) == 0)
    {
        if (access(filepath.c_str(), W_OK) != 0)
        {
            std::string msg = formatString("File '%s' is there, but not writable", filepath.c_str());
            throw ConfigFileException(msg);
        }
        return;
    }
    std::string dirname = dirnameOf(filepath);

    if (access(dirname.c_str(), W_OK) != 0)
    {
        std::string msg = formatString("File '%s' is not there and can't be created, because '%s' is also not writable", filepath.c_str(), dirname.c_str());
        throw ConfigFileException(msg);
    }
}

ConfigFileParser::ConfigFileParser(const std::string &path) :
    path(path)
{
    validKeys.insert("auth_plugin");
    validKeys.insert("log_file");
    validKeys.insert("allow_unsafe_clientid_chars");
    validKeys.insert("allow_unsafe_username_chars");
    validKeys.insert("auth_plugin_serialize_init");
    validKeys.insert("auth_plugin_serialize_auth_checks");
    validKeys.insert("client_initial_buffer_size");
    validKeys.insert("max_packet_size");
    validKeys.insert("log_debug");
    validKeys.insert("log_subscriptions");

    validListenKeys.insert("port");
    validListenKeys.insert("protocol");
    validListenKeys.insert("fullchain");
    validListenKeys.insert("privkey");
    validListenKeys.insert("inet_protocol");
    validListenKeys.insert("inet4_bind_address");
    validListenKeys.insert("inet6_bind_address");

    settings.reset(new Settings());
}

void ConfigFileParser::loadFile(bool test)
{
    if (path.empty())
        return;

    checkFileExistsAndReadable("application config file", path);

    std::ifstream infile(path, std::ios::in);

    if (!infile.is_open())
    {
        std::ostringstream oss;
        oss << "Error loading " << path;
        throw ConfigFileException(oss.str());
    }

    std::list<std::string> lines;

    const std::regex key_value_regex("^([a-zA-Z0-9_\\-]+) +([a-zA-Z0-9_\\-/\\.:]+)$");
    const std::regex block_regex_start("^([a-zA-Z0-9_\\-]+) *\\{$");
    const std::regex block_regex_end("^\\}$");

    bool inBlock = false;
    std::ostringstream oss;
    int linenr = 0;

    // First parse the file and keep the valid lines.
    for(std::string line; getline(infile, line ); )
    {
        trim(line);
        linenr++;

        if (startsWith(line, "#"))
            continue;

        if (line.empty())
            continue;

        std::smatch matches;

        const bool blockStartMatch = std::regex_search(line, matches, block_regex_start);
        const bool blockEndMatch = std::regex_search(line, matches, block_regex_end);

        if ((blockStartMatch && inBlock) || (blockEndMatch && !inBlock))
        {
            oss << "Unexpected block start or end at line " << linenr << ": " << line;
            throw ConfigFileException(oss.str());
        }

        if (!std::regex_search(line, matches, key_value_regex) && !blockStartMatch && !blockEndMatch)
        {
            oss << "Line '" << line << "' invalid";
            throw ConfigFileException(oss.str());
        }

        if (blockStartMatch)
            inBlock = true;
        if (blockEndMatch)
            inBlock = false;

        lines.push_back(line);
    }

    if (inBlock)
    {
        throw ConfigFileException("Unclosed config block. Expecting }");
    }

    std::unordered_map<std::string, std::string> authOpts;

    ConfigParseLevel curParseLevel = ConfigParseLevel::Root;
    std::shared_ptr<Listener> curListener;
    std::unique_ptr<Settings> tmpSettings(new Settings);

    // Then once we know the config file is valid, process it.
    for (std::string &line : lines)
    {
        std::smatch matches;

        if (std::regex_match(line, matches, block_regex_start))
        {
            std::string key = matches[1].str();
            if (matches[1].str() == "listen")
            {
                curParseLevel = ConfigParseLevel::Listen;
                curListener.reset(new Listener);
            }
            else
            {
                throw ConfigFileException(formatString("'%s' is not a valid block.", key.c_str()));
            }

            continue;
        }
        else if (std::regex_match(line, matches, block_regex_end))
        {
            if (curParseLevel == ConfigParseLevel::Listen)
            {
                curListener->isValid();
                tmpSettings->listeners.push_back(curListener);
                curListener.reset();
            }

            curParseLevel = ConfigParseLevel::Root;
            continue;
        }

        std::regex_match(line, matches, key_value_regex);

        std::string key = matches[1].str();
        const std::string value = matches[2].str();

        try
        {
            if (curParseLevel == ConfigParseLevel::Listen)
            {
                testKeyValidity(key, validListenKeys);

                if (key == "protocol")
                {
                    if (value != "mqtt" && value != "websockets")
                        throw ConfigFileException(formatString("Protocol '%s' is not a valid listener protocol", value.c_str()));
                    curListener->websocket = value == "websockets";
                }
                else if (key == "port")
                {
                    curListener->port = std::stoi(value);
                }
                else if (key == "fullchain")
                {
                    curListener->sslFullchain = value;
                }
                if (key == "privkey")
                {
                    curListener->sslPrivkey = value;
                }
                if (key == "inet_protocol")
                {
                    if (value == "ip4")
                        curListener->protocol = ListenerProtocol::IPv4;
                    else if (value == "ip6")
                        curListener->protocol = ListenerProtocol::IPv6;
                    else if (value == "ip4_ip6")
                        curListener->protocol = ListenerProtocol::IPv46;
                    else
                        throw ConfigFileException(formatString("Invalid inet protocol: %s", value.c_str()));
                }
                if (key == "inet4_bind_address")
                {
                    curListener->inet4BindAddress = value;
                }
                if (key == "inet6_bind_address")
                {
                    curListener->inet6BindAddress = value;
                }

                continue;
            }


            const std::string auth_opt_ = "auth_opt_";
            if (startsWith(key, auth_opt_))
            {
                key.replace(0, auth_opt_.length(), "");
                authOpts[key] = value;
            }
            else
            {
                testKeyValidity(key, validKeys);

                if (key == "auth_plugin")
                {
                    checkFileExistsAndReadable(key, value);
                    tmpSettings->authPluginPath = value;
                }

                if (key == "log_file")
                {
                    checkFileOrItsDirWritable(value);
                    tmpSettings->logPath = value;
                }

                if (key == "allow_unsafe_clientid_chars")
                {
                    bool tmp = stringTruthiness(value);
                    tmpSettings->allowUnsafeClientidChars = tmp;
                }

                if (key == "allow_unsafe_username_chars")
                {
                    bool tmp = stringTruthiness(value);
                    tmpSettings->allowUnsafeUsernameChars = tmp;
                }

                if (key == "auth_plugin_serialize_init")
                {
                    bool tmp = stringTruthiness(value);
                    tmpSettings->authPluginSerializeInit = tmp;
                }

                if (key == "auth_plugin_serialize_auth_checks")
                {
                    bool tmp = stringTruthiness(value);
                    tmpSettings->authPluginSerializeAuthChecks = tmp;
                }

                if (key == "client_initial_buffer_size")
                {
                    int newVal = std::stoi(value);
                    if (!isPowerOfTwo(newVal))
                        throw ConfigFileException("client_initial_buffer_size value " + value + " is not a power of two.");
                    tmpSettings->clientInitialBufferSize = newVal;
                }

                if (key == "max_packet_size")
                {
                    int newVal = std::stoi(value);
                    if (newVal > ABSOLUTE_MAX_PACKET_SIZE)
                    {
                        std::ostringstream oss;
                        oss << "Value for max_packet_size " << newVal << "is higher than absolute maximum " << ABSOLUTE_MAX_PACKET_SIZE;
                        throw ConfigFileException(oss.str());
                    }
                    tmpSettings->maxPacketSize = newVal;
                }

                if (key == "log_debug")
                {
                    bool tmp = stringTruthiness(value);
                    tmpSettings->logDebug = tmp;
                }

                if (key == "log_subscriptions")
                {
                    bool tmp = stringTruthiness(value);
                    tmpSettings->logSubscriptions = tmp;
                }
            }
        }
        catch (std::invalid_argument &ex) // catch for the stoi()
        {
            throw ConfigFileException(ex.what());
        }
    }

    tmpSettings->authOptCompatWrap = AuthOptCompatWrap(authOpts);

    if (!test)
    {
        this->settings = std::move(tmpSettings);
    }
}

AuthOptCompatWrap &Settings::getAuthOptsCompat()
{
    return authOptCompatWrap;
}