/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

#include <config.h>

#include <iostream>
#include <iomanip>
#include <sstream>
#include <termios.h>

#include <openssl/rand.h>
#include <openssl/evp.h>

#include <Poco/Exception.h>
#include <Poco/Util/Application.h>
#include <Poco/Util/HelpFormatter.h>
#include <Poco/Util/Option.h>
#include <Poco/Util/OptionSet.h>
#include <Poco/Util/XMLConfiguration.h>

#include <Util.hpp>
#include <Crypto.hpp>

using Poco::Util::Application;
using Poco::Util::HelpFormatter;
using Poco::Util::Option;
using Poco::Util::OptionSet;
using Poco::Util::XMLConfiguration;

#define MIN_PWD_SALT_LENGTH 20
#define MIN_PWD_ITERATIONS 1000
#define MIN_PWD_HASH_LENGTH 20

class LoolConfig final: public XMLConfiguration
{
public:
    LoolConfig()
        {}
};

struct AdminConfig
{
    unsigned pwdSaltLength = 128;
    unsigned pwdIterations = 10000;
    unsigned pwdHashLength = 128;
};

// Config tool to change loolwsd configuration (loolwsd.xml)
class Config: public Application
{
    // Display help information on the console
    void displayHelp();

    LoolConfig _loolConfig;

    AdminConfig _adminConfig;

public:
    static std::string ConfigFile;
    static std::string SupportKeyString;
    static bool SupportKeyStringProvided;

protected:
    void defineOptions(OptionSet&) override;
    void handleOption(const std::string&, const std::string&) override;
    int main(const std::vector<std::string>&) override;
};

std::string Config::ConfigFile =
#if ENABLE_DEBUG
    DEBUG_ABSSRCDIR
#else
    LOOLWSD_CONFIGDIR
#endif
    "/loolwsd.xml";

std::string Config::SupportKeyString;
bool Config::SupportKeyStringProvided = false;

void Config::displayHelp()
{
    HelpFormatter helpFormatter(options());
    helpFormatter.setCommand(commandName());
    helpFormatter.setUsage("COMMAND [OPTIONS]");
    helpFormatter.setHeader("loolconfig - Configuration tool for LibreOffice Online.\n"
                            "\n"
                            "Some options make sense only with a specific command.\n\n"
                            "Options:");

    helpFormatter.format(std::cout);

    // Command list
    std::cout << std::endl
              << "Commands: " << std::endl
              << "    set-admin-password" << std::endl
#if ENABLE_SUPPORT_KEY
              << "    set-support-key" << std::endl
#endif
              << "    set <key> <value>" << std::endl
              << "    update-system-template" << std::endl << std::endl;
}

void Config::defineOptions(OptionSet& optionSet)
{
    Application::defineOptions(optionSet);

    optionSet.addOption(Option("help", "h", "Show this usage information.")
                        .required(false)
                        .repeatable(false));
    optionSet.addOption(Option("config-file", "", "Specify configuration file path manually.")
                        .required(false)
                        .repeatable(false)
                        .argument("path"));

    optionSet.addOption(Option("pwd-salt-length", "", "Length of the salt to use to hash password [set-admin-password].")
                        .required(false)
                        .repeatable(false).
                        argument("number"));
    optionSet.addOption(Option("pwd-iterations", "", "Number of iterations to do in PKDBF2 password hashing [set-admin-password].")
                        .required(false)
                        .repeatable(false)
                        .argument("number"));
    optionSet.addOption(Option("pwd-hash-length", "", "Length of password hash to generate [set-admin-password].")
                        .required(false)
                        .repeatable(false)
                        .argument("number"));

#if ENABLE_SUPPORT_KEY
    optionSet.addOption(Option("support-key", "", "Specify the support key [set-support-key].")
                        .required(false)
                        .repeatable(false)
                        .argument("key"));
#endif
}

void Config::handleOption(const std::string& optionName, const std::string& optionValue)
{
    Application::handleOption(optionName, optionValue);
    if (optionName == "help")
    {
        displayHelp();
        std::exit(Application::EXIT_OK);
    }
    else if (optionName == "config-file")
    {
        ConfigFile = optionValue;
    }
    else if (optionName == "pwd-salt-length")
    {
        unsigned len = std::stoi(optionValue);
        if (len < MIN_PWD_SALT_LENGTH)
        {
            len = MIN_PWD_SALT_LENGTH;
            std::cout << "Password salt length adjusted to minimum " << len << std::endl;
        }
        _adminConfig.pwdSaltLength = len;
    }
    else if (optionName == "pwd-iterations")
    {
        unsigned len = std::stoi(optionValue);
        if (len < MIN_PWD_ITERATIONS)
        {
            len = MIN_PWD_ITERATIONS;
            std::cout << "Password iteration adjusted to minimum " << len << std::endl;
        }
        _adminConfig.pwdIterations = len;
    }
    else if (optionName == "pwd-hash-length")
    {
        unsigned len = std::stoi(optionValue);
        if (len < MIN_PWD_HASH_LENGTH)
        {
            len = MIN_PWD_HASH_LENGTH;
            std::cout << "Password hash length adjusted to minimum " << len << std::endl;
        }
        _adminConfig.pwdHashLength = len;
    }
    else if (optionName == "support-key")
    {
        SupportKeyString = optionValue;
        SupportKeyStringProvided = true;
    }
}

int Config::main(const std::vector<std::string>& args)
{
    if (args.empty())
    {
        std::cerr << "Nothing to do." << std::endl;
        displayHelp();
        return Application::EXIT_NOINPUT;
    }

    bool changed = false;
    _loolConfig.load(ConfigFile);

    if (args[0] == "set-admin-password")
    {
#if HAVE_PKCS5_PBKDF2_HMAC
        unsigned char pwdhash[_adminConfig.pwdHashLength];
        unsigned char salt[_adminConfig.pwdSaltLength];
        RAND_bytes(salt, _adminConfig.pwdSaltLength);
        std::stringstream stream;

        // Ask for user password
        termios oldTermios;
        tcgetattr(STDIN_FILENO, &oldTermios);
        termios newTermios = oldTermios;
        // Disable user input mirroring on console for password input
        newTermios.c_lflag &= ~ECHO;
        tcsetattr(STDIN_FILENO, TCSANOW, &newTermios);
        std::string adminPwd;
        std::cout << "Enter admin password: ";
        std::getline(std::cin, adminPwd);
        std::string reAdminPwd;
        std::cout << std::endl << "Confirm admin password: ";
        std::getline(std::cin, reAdminPwd);
        std::cout << std::endl;
        // Set the termios to old state
        tcsetattr(STDIN_FILENO, TCSANOW, &oldTermios);
        if (adminPwd != reAdminPwd)
        {
            std::cout << "Password mismatch." << std::endl;
            return Application::EXIT_DATAERR;
        }

        // Do the magic !
        PKCS5_PBKDF2_HMAC(adminPwd.c_str(), -1,
                          salt, _adminConfig.pwdSaltLength,
                          _adminConfig.pwdIterations,
                          EVP_sha512(),
                          _adminConfig.pwdHashLength, pwdhash);

        // Make salt randomness readable
        for (unsigned j = 0; j < _adminConfig.pwdSaltLength; ++j)
            stream << std::hex << std::setw(2) << std::setfill('0') << static_cast<int>(salt[j]);
        const std::string saltHash = stream.str();

        // Clear our used hex stream to make space for password hash
        stream.str("");
        stream.clear();

        // Make the hashed password readable
        for (unsigned j = 0; j < _adminConfig.pwdHashLength; ++j)
            stream << std::hex << std::setw(2) << std::setfill('0') << static_cast<int>(pwdhash[j]);
        const std::string passwordHash = stream.str();

        std::stringstream pwdConfigValue("pbkdf2.sha512.", std::ios_base::in | std::ios_base::out | std::ios_base::ate);
        pwdConfigValue << std::to_string(_adminConfig.pwdIterations) << ".";
        pwdConfigValue << saltHash << "." << passwordHash;
        _loolConfig.setString("admin_console.secure_password[@desc]",
                              "Salt and password hash combination generated using PBKDF2 with SHA512 digest.");
        _loolConfig.setString("admin_console.secure_password", pwdConfigValue.str());

        changed = true;
#else
        std::cerr << "This application was compiled with old OpenSSL. Operation not supported. You can use plain text password in /etc/loolwsd/loolwsd.xml." << std::endl;
        return Application::EXIT_UNAVAILABLE;
#endif
    }
#if ENABLE_SUPPORT_KEY
    else if (args[0] == "set-support-key")
    {
        std::string supportKeyString;
        if (SupportKeyStringProvided)
            supportKeyString = SupportKeyString;
        else
        {
            std::cout << "Enter support key: ";
            std::getline(std::cin, supportKeyString);
        }

        if (!supportKeyString.empty())
        {
            SupportKey key(supportKeyString);
            if (!key.verify())
                std::cerr << "Invalid key\n";
            else {
                int validDays =  key.validDaysRemaining();
                if (validDays <= 0)
                    std::cerr << "Valid but expired key\n";
                else
                {
                    std::cerr << "Valid for " << validDays << " days - setting to config\n";
                    _loolConfig.setString("support_key", supportKeyString);
                }
            }
        }
        else
        {
            std::cerr << "Removing empty support key\n";
            _loolConfig.remove("support_key");
        }
        changed = true;
    }
#endif
    else if (args[0] == "set")
    {
        if (args.size() == 3)
        {
            // args[1] = key
            // args[2] = value
            if (_loolConfig.has(args[1]))
            {
                const std::string val = _loolConfig.getString(args[1]);
                std::cout << "Previous value found in config file: \""  << val << "\"" << std::endl;
                std::cout << "Changing value to: \"" << args[2] << "\"" << std::endl;
                _loolConfig.setString(args[1], args[2]);
                changed = true;
            }
            else
                std::cerr << "No property, \"" << args[1] << "\"," << " found in config file." << std::endl;
        }
        else
            std::cerr << "set expects a key and value as arguments" << std::endl
                      << "Eg: " << std::endl
                      << "    set logging.level trace" << std::endl;

    }
    else if (args[0] == "update-system-template")
    {
        const char command[] = "su lool --shell=/bin/sh -c 'loolwsd-systemplate-setup /opt/lool/systemplate " LO_PATH " >/dev/null 2>&1'";
        std::cout << "Running the following command:" << std::endl
                  << command << std::endl;
        system(command);
    }
    else
    {
        std::cerr << "No such command, \"" << args[0]  << "\"" << std::endl;
        displayHelp();
    }

    if (changed)
    {
        std::cout << "Saving configuration to : " << ConfigFile << " ..." << std::endl;
        _loolConfig.save(ConfigFile);
        std::cout << "Saved" << std::endl;
    }

    // This tool only handles options, nothing to do here
    return Application::EXIT_OK;
}

POCO_APP_MAIN(Config);

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */