Practice real estate system in C++

housing.cpp

/**
 * Copyright (C) 2025 Launium, all rights reserved.
 * This is a practice project and comes with ABSOLUTELY
 * NO WARRANTY, full of unsafe function calls, unverified code
 * and your computer may end up nuked.
 * DO NOT COPY ANY PART OF THE CODE or you may face
 * attacks such as buffer overflow, code injection, etc.
 * Anyway, use at your own risk. :)
 * @date May 9th, 2025
 */
#include <algorithm>
#include <iostream>
#include <string>
#include <fstream>
#include <sstream>
#include <vector>
#include <iomanip>
#include <cstdint>
#include <cstdlib>

#ifdef _WIN32
#define clear_screen() system("cls")
#else // assume ANSI compatible terminal
#define clear_screen() std::cout << "\e[1;1H\e[2J"
#endif

using namespace std;

constexpr int width_id = 6;
constexpr int width_area = 10;
constexpr int width_unit_price = 15;
constexpr int width_total_price = 15;
constexpr int width_address = 40;
constexpr int width_owner = 15;
constexpr int width_contact = 20;
constexpr int width_date = 12;

string truncate(const string &s, size_t max_length)
{
    return s.length() >= max_length - 5 ? s.substr(0, max_length - 5) + "..." : s;
}

struct Resource
{
    struct StringTable
    {
        string language_name;
        string you_have_chosen;
        string as_display_language;
        string save_is_not_found_and_creating;
        string available_commands;
        string prompt_continue_from_save;
        string prompt_continue_with_enter;
        string prompt_enter_id;
        string prompt_enter_to_return_to_main;
        string prompt_zero_to_generate_an_id;
        string unknown_command;
        string no_id_found;
        string saved_successfully;
        string property_record_removed;
        string new_property_record_added;
        string unsaved_exit_warning;
        string exit_thanks;

        string unknown_contact_method;
        string contact_method_phone;
        string contact_method_email;

        string main_menu_view_database;
        string main_menu_get_by_id;
        string main_menu_add_new;
        string main_menu_save_to_file;
        string main_menu_exit;

        string database_area;
        string database_unit_price;
        string database_total_price;
        string database_address;
        string database_owner;
        string database_contact;
        string database_purchase_date;

        string info_menu_commands_for;
        string info_menu_delete;
        string info_menu_back;
    } string;
} R;

// uint8 causes problems for cin input since
// cin would concider it as character type
// and store ASCII value of the input into it
// Another C shit :)
#define command_t uint_fast16_t
#define LANG_EN 1
#define LANG_CN 2

void load_translation(command_t lang)
{
    switch (lang)
    {
    case LANG_EN:
        R.string.language_name = "English - en_US";
        R.string.you_have_chosen = "You have chosen ";
        R.string.as_display_language = " as the display language.";
        R.string.save_is_not_found_and_creating = "No save is found. Creating new database...";
        R.string.available_commands = "Available Commands";
        R.string.prompt_continue_from_save = "Do you want to continue from a previous save? [Y/n]: ";
        R.string.prompt_continue_with_enter = "Press enter to continue...";
        R.string.prompt_enter_id = "Enter the ID: ";
        R.string.prompt_enter_to_return_to_main = "Press enter to return to main menu...";
        R.string.prompt_zero_to_generate_an_id = "0 to generate an ID";
        R.string.no_id_found = "No house found with ID: ";
        R.string.saved_successfully = "Database saved.";
        R.string.property_record_removed = "Removed property record.";
        R.string.new_property_record_added = "Added new property record to the database.";
        R.string.unsaved_exit_warning = "You have unsaved changes. Exit anyway? [y/N]: ";
        R.string.exit_thanks = "Thanks for using the Real Estate System. Goodbye!";

        R.string.unknown_contact_method = "Unknown contact method";
        R.string.contact_method_phone = "Phone";
        R.string.contact_method_email = "Email";

        R.string.main_menu_view_database = "View database";
        R.string.main_menu_get_by_id = "Get real estate information by ID";
        R.string.main_menu_add_new = "Add new real estate information";
        R.string.main_menu_save_to_file = "Save the database to file";
        R.string.main_menu_exit = "Exit program";

        R.string.info_menu_commands_for = "Available commands for this property record:";
        R.string.info_menu_delete = "Delete";
        R.string.info_menu_back = "Back to main menu";

        R.string.database_area = "Area/m²";
        R.string.database_unit_price = "Unit Price/m²";
        R.string.database_total_price = "Total Price";
        R.string.database_address = "Address";
        R.string.database_owner = "Owner";
        R.string.database_contact = "Contact";
        R.string.database_purchase_date = "Purchase Date";

        R.string.unknown_command = "Unknown command: ";
        break;

    case LANG_CN:
        R.string.language_name = "简体中文（中国） - zh_CN";
        R.string.you_have_chosen = "您已选择 ";
        R.string.as_display_language = " 作为显示语言。";
        R.string.save_is_not_found_and_creating = "未找到存档。正在创建新的数据库...";
        R.string.available_commands = "可用的命令";
        R.string.prompt_continue_from_save = "您想从先前的存档中继续吗？[Y/n]: ";
        R.string.prompt_continue_with_enter = "请按回车键以继续...";
        R.string.prompt_enter_id = "输入 ID: ";
        R.string.prompt_enter_to_return_to_main = "请按回车键以回到主菜单...";
        R.string.prompt_zero_to_generate_an_id = "0 以生成一个 ID";
        R.string.no_id_found = "没找到对应 ID 的房地产：";
        R.string.saved_successfully = "数据库已保存。";
        R.string.property_record_removed = "已删除财产记录。";
        R.string.new_property_record_added = "已将新财产记录添加到数据库。";
        R.string.unsaved_exit_warning = "您有未保存的变更。仍然退出？[y/N]: ";
        R.string.exit_thanks = "感谢使用房地产系统。再见！";

        R.string.unknown_contact_method = "未知联系方式";
        R.string.contact_method_phone = "电话";
        R.string.contact_method_email = "电子邮件";

        R.string.main_menu_view_database = "查看数据库";
        R.string.main_menu_get_by_id = "获取指定 ID 房地产信息";
        R.string.main_menu_add_new = "添加新的房地产信息";
        R.string.main_menu_save_to_file = "保存数据库到文件";
        R.string.main_menu_exit = "退出程序";

        R.string.info_menu_commands_for = "针对此财产记录的可用命令：";
        R.string.info_menu_delete = "删除";
        R.string.info_menu_back = "返回主菜单";

        R.string.database_area = "面积/m²";
        R.string.database_unit_price = "单价/m²";
        R.string.database_total_price = "总价";
        R.string.database_address = "地址";
        R.string.database_owner = "业主";
        R.string.database_contact = "联系方式";
        R.string.database_purchase_date = "购买日期";

        R.string.unknown_command = "未知的命令：";
        break;

    default:
        cout << "Unknown language code: " << lang << endl;
        exit(1);
    }
}

void pause()
{
    cout << R.string.prompt_continue_with_enter;
    cin.ignore();
    cin.get();
    cout << endl;
}

void print_banner()
{
    cout << "______           _   _____    _        _         _____           _" << endl
         << "| ___ \\         | | |  ___|  | |      | |       /  ___|         | |" << endl
         << "| |_/ /___  __ _| | | |__ ___| |_ __ _| |_ ___  \\ `--. _   _ ___| |_ ___ _ __ ___" << endl
         << "|    // _ \\/ _` | | |  __/ __| __/ _` | __/ _ \\  `--. \\ | | / __| __/ _ \\ '_ ` _ \\" << endl
         << "| |\\ \\  __/ (_| | | | |__\\__ \\ || (_| | ||  __/ /\\__/ / |_| \\__ \\ ||  __/ | | | | |" << endl
         << "\\_| \\_\\___|\\__,_|_| \\____/___/\\__\\__,_|\\__\\___| \\____/ \\__, |___/\\__\\___|_| |_| |_|" << endl
         << "    Copyright (C) 2025 Launium, all rights reserved.    __/ |" << endl
         << "                                                       |___/" << endl;
}

#define MAIN_MENU_VIEW_DATABASE 1
#define MAIN_MENU_GET_BY_ID 2
#define MAIN_MENU_ADD_NEW 3
#define MAIN_MENU_SAVE_TO_FILE 4
#define MAIN_MENU_EXIT 5

void print_main_menu()
{
    cout << "======= " << R.string.available_commands << " =======" << endl
         << "1 - " << R.string.main_menu_view_database << endl
         << "2 - " << R.string.main_menu_get_by_id << endl
         << "3 - " << R.string.main_menu_add_new << endl
         << "4 - " << R.string.main_menu_save_to_file << endl
         << "5 - " << R.string.main_menu_exit << endl;
}

#define INFO_MENU_DELETE 1
#define INFO_MENU_BACK 2

void print_information_menu()
{
    cout << "======= " << R.string.available_commands << " =======" << endl
         << "1 - " << R.string.info_menu_delete << endl
         << "2 - " << R.string.info_menu_back << endl;
}

class Contact
{
public:
    Contact()
    {
    }
    virtual string method_descriptor()
    {
        return "unknown";
    }
    virtual string method_name()
    {
        return R.string.unknown_contact_method;
    }
    virtual string to_string()
    {
        return "";
    };
};

class PhoneContact : public Contact
{
private:
    uint64_t phone_number;

public:
    PhoneContact(uint64_t phone_number)
    {
        this->phone_number = phone_number;
    }
    PhoneContact(const char *raw)
    {
        this->phone_number = strtoull(raw, nullptr, 10);
    }
    string method_descriptor()
    {
        return "phone";
    }
    string method_name()
    {
        return R.string.contact_method_phone;
    }
    string to_string()
    {
        return std::to_string(phone_number);
    }
};

class EmailContact : public Contact
{
private:
    string email;

public:
    EmailContact(string email)
    {
        this->email = email;
    }
    string method_descriptor()
    {
        return "email";
    }
    string method_name()
    {
        return R.string.contact_method_email;
    }
    string to_string()
    {
        return email;
    }
};

class House
{
public:
    uint64_t id;
    uint32_t area;                   // in square centimeters
    uint32_t price_per_square_meter; // in coins per square meter

    string address;
    string owner;
    Contact *contact;
    uint32_t purchase_time; // YYYYMMDD, e.g. 20250102

    House()
    {
    }
    ~House()
    {
        if (contact)
        {
            delete contact;
        }
    }
    bool operator<(const House &another)
    {
        return id > another.id;
    }
    bool operator>(const House &another)
    {
        return id < another.id;
    }

    double get_area_in_square_meters()
    {
        return 1.0e-6 * area;
    }
};

class Database
{
private:
    vector<House *> houses;
    bool updated;

public:
    Database()
    {
        updated = false;
    }
    Database(fstream &f)
    {
        updated = false;
        string line;
        while (getline(f, line))
        {
            if (line.empty())
                continue;

            stringstream ss(line);
            string temp;

            House *house = new House();

            getline(ss, temp, ',');
            house->id = strtoull(temp.c_str(), nullptr, 10);

            getline(ss, temp, ',');
            house->area = stoul(temp);

            getline(ss, temp, ',');
            house->price_per_square_meter = stoul(temp);

            getline(ss, house->address, ',');
            getline(ss, house->owner, ',');

            string contact_method;
            getline(ss, contact_method, ',');

            string contact_detail;
            getline(ss, contact_detail, ',');

            if (contact_method == "phone")
            {
                house->contact = new PhoneContact(contact_detail.c_str());
            }
            else if (contact_method == "email")
            {
                house->contact = new EmailContact(contact_detail);
            }
            else
            {
                house->contact = new Contact();
            }

            getline(ss, temp, ',');
            house->purchase_time = stoul(temp);

            houses.push_back(house);
        }
        sort_database_by_id();
    }
    ~Database()
    {
        for (House *h : houses)
            delete h;
        houses.clear();
    }
    inline void sort_database_by_id()
    {
        sort(houses.begin(), houses.end());
    }
    void event_loop()
    {
        for (;;)
        {
            print_main_menu();
            cout << endl
                 << "> ";
            command_t command;
            cin >> command;
            switch (command)
            {
            case MAIN_MENU_VIEW_DATABASE:
            {
                clear_screen();
                cout << left
                     << setw(width_id) << "ID"
                     << setw(width_area) << R.string.database_area
                     << setw(width_unit_price) << R.string.database_unit_price
                     << setw(width_total_price) << R.string.database_total_price
                     << setw(width_address) << R.string.database_address
                     << setw(width_owner) << R.string.database_owner
                     << setw(width_contact) << R.string.database_contact
                     << setw(width_date) << R.string.database_purchase_date
                     << endl;

                for (House *h : houses)
                {
                    double area = h->get_area_in_square_meters();
                    cout << left
                         << setw(width_id) << h->id
                         << setw(width_area) << area
                         << setw(width_unit_price) << h->price_per_square_meter
                         << setw(width_total_price) << area * h->price_per_square_meter
                         << setw(width_address) << truncate(h->address, width_address)
                         << setw(width_owner) << truncate(h->owner, width_owner)
                         << setw(width_contact) << h->contact->to_string()
                         << setw(width_date) << h->purchase_time
                         << endl;
                }
                cout << endl;
                pause();
                break;
            }

            case MAIN_MENU_GET_BY_ID:
            {
                uint64_t query_id;
                cout << R.string.prompt_enter_id;
                cin >> query_id;
                vector<House *>::iterator it = find_if(houses.begin(), houses.end(), [&](House *h)
                                                       { return h->id == query_id; });
                if (it != houses.end())
                {
                    House *h = *it;
                    double area = h->get_area_in_square_meters();
                    cout << "ID: " << h->id << endl
                         << R.string.database_area << ": " << area << endl
                         << R.string.database_unit_price << ": " << h->price_per_square_meter << endl
                         << R.string.database_total_price << ": " << area * h->price_per_square_meter << endl
                         << R.string.database_address << ": " << h->address << endl
                         << R.string.database_owner << ": " << h->owner << endl
                         << R.string.database_contact << ": [" << h->contact->method_name() << "] " << h->contact->to_string() << endl
                         << R.string.database_purchase_date << "(YYYY MM DD): " << h->purchase_time << endl;

                    cout << endl
                         << R.string.info_menu_commands_for << endl;
                    bool loop = true;
                    while (loop)
                    {
                        print_information_menu();
                        cout << endl
                             << "> ";
                        cin >> command;
                        switch (command)
                        {
                        case INFO_MENU_DELETE:
                        {
                            houses.erase(it);
                            delete h;
                            cout << R.string.property_record_removed << endl;
                            updated = true;
                            loop = false;
                            break;
                        }

                        case INFO_MENU_BACK:
                        {
                            loop = false;
                            break;
                        }

                        default:
                        {
                            cout << R.string.unknown_command << command << endl;
                            break;
                        }
                        }
                    }
                }
                else
                {
                    cout << R.string.no_id_found << query_id << endl;
                }
                cout << endl;
                pause();
                break;
            }

            case MAIN_MENU_ADD_NEW:
            {
                clear_screen();
                House *new_house = new House();

                cout << "ID (" << R.string.prompt_zero_to_generate_an_id << "): ";
                cin >> new_house->id;
                if (new_house->id <= 0)
                { // default ID by rules
                    if (houses.empty())
                    {
                        new_house->id = 0;
                    }
                    else
                    {
                        new_house->id = houses.back()->id + 1;
                    }
                }

                double area_m2;
                cout << R.string.database_area << " (m²): ";
                cin >> area_m2;
                new_house->area = area_m2 * 1e6; // converts to square centimeter

                cout << R.string.database_unit_price << ": ";
                cin >> new_house->price_per_square_meter;

                cout << R.string.database_address << ": ";
                cin.ignore();
                getline(cin, new_house->address);

                cout << R.string.database_owner << ": ";
                getline(cin, new_house->owner);

                cout << R.string.database_contact << " (1 = Phone, 2 = Email): ";
                int contact_type;
                cin >> contact_type;
                cin.ignore();
                if (contact_type == 1)
                {
                    string phone;
                    cout << R.string.contact_method_phone << ": ";
                    getline(cin, phone);
                    new_house->contact = new PhoneContact(phone.c_str());
                }
                else if (contact_type == 2)
                {
                    string email;
                    cout << R.string.contact_method_email << ": ";
                    getline(cin, email);
                    new_house->contact = new EmailContact(email);
                }
                else
                {
                    new_house->contact = new Contact(); // fallback
                }

                cout << R.string.database_purchase_date << " (YYYYMMDD): ";
                cin >> new_house->purchase_time;

                houses.push_back(new_house);
                sort_database_by_id();
                updated = true;

                cout << endl
                     << R.string.new_property_record_added << endl;
                pause();
                break;
            }

            case MAIN_MENU_SAVE_TO_FILE:
            {
                ofstream out("real_estate_database.csv");
                for (House *h : houses)
                {
                    out << h->id << "," << h->area << "," << h->price_per_square_meter << ","
                        << h->address << "," << h->owner << ","
                        << h->contact->method_descriptor() << "," << h->contact->to_string() << ","
                        << h->purchase_time << endl;
                }
                out.close();
            }
                updated = false;
                cout << R.string.saved_successfully << endl;
                pause();
                break;

            case MAIN_MENU_EXIT:
            {
                if (updated)
                {
                    cout << R.string.unsaved_exit_warning;
                    char exit_choice;
                    cin >> exit_choice;
                    if (exit_choice != 'y' && exit_choice != 'Y')
                    {
                        break; // back to main menu
                    }
                }
                cout << endl
                     << R.string.exit_thanks << endl;
                pause();
                return;
            }

            default:
                cout << R.string.unknown_command << command << endl;
                pause();
                break;
            }
            clear_screen();
            print_banner();
        }
    }
};

int main()
{
    clear_screen();
#ifdef _WIN32
    system("chcp 65001>nul"); // Set the console to expect codepage 65001 = UTF-8.
#endif
    print_banner();
    cout << "Welcome to Real Estate System." << endl;
    cout << endl
         << "Choose a display language:" << endl
         << endl;
    cout << "1 - English (United States) - en_US" << endl;
    cout << "2 - 简体中文（中国） - zh_CN" << endl;
    cout << endl
         << "Default 1. Enter your choice: ";
    {
        command_t lang;
        cin >> lang;
        load_translation(lang);
    }

    clear_screen();
    print_banner();
    cout << R.string.you_have_chosen << R.string.language_name << R.string.as_display_language << endl
         << endl;

    // load save
    Database *database;
    fstream file_save;
    file_save.open("real_estate_database.csv", ios_base::in);
    if (file_save)
    {
        cout << R.string.prompt_continue_from_save;
        char continue_from_save;
        cin >> continue_from_save;
        if (continue_from_save != 'n' && continue_from_save != 'N')
        {
            database = new Database(file_save);
        }
        else
        {
            database = new Database();
        }
        file_save.close();
    }
    else
    {
        cout << R.string.save_is_not_found_and_creating << endl;
    }

    database->event_loop();
    return 0;
}