//main.cpp
#include <fstream>
#include <vector>
#include <string>
#include <ctime>

#define USERS 1000000
#define PRODUCTS 500000
#define FRIENDS_BY_USER 20
#define PRODUCTS_BY_USER 5

const std::vector<std::string> P_NAME = {
"peakers",
"fridge",
"shampoo",
"sun glasses",
"house",
"cat",
"cookie jar",
"puddle",
"sofa",
"lotion",
"playing card",
"stockings",
"packing peanuts",
"CD",
"flowers",
"wallet",
"soda can",
"key chain",
"pillow",
"buckel",
};

const std::vector<std::string> NAMES = {
"Metheny",
"Christofferse",
"Hester",
"Sugrue",
"Seawood",
"Raper",
"Brakebill",
"Hotaling",
"Arcand",
"Teaster",
"Lovings",
"Paugh",
"Smelley",
"Pegg",
"Bratton",
"Tilly",
"Axelrod",
"Madry",
"Wiegand",
"Strawser"
};

template<typename T>
T randomElement(const std::vector<T> &from)
{
    return from[std::rand() % from.size()];
}

std::string randomProduct()
{
    return randomElement(P_NAME);
}

std::string randomName()
{
    return randomElement(NAMES);
}

std::string uuid()
{
    static const std::string CHARS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
    std::string uuid = std::string(36,' ');
    int rnd = 0;

    uuid[8] = '-';
    uuid[13] = '-';
    uuid[18] = '-';
    uuid[23] = '-';

    uuid[14] = '4';

    for(std::size_t i=0;i<36;i++){
        if (i != 8 && i != 13 && i != 18 && i != 14 && i != 23) {
            if (rnd <= 0x02) {
                rnd = (0x2000000 + (std::rand() * 0x1000000)) | 0;
            }
            rnd >>= 4;
            uuid[i] = CHARS[(i == 19) ? ((rnd & 0xf) & 0x3) | 0x8 : rnd & 0xf];
        }
    }
    return uuid;
}

int main()
{
    std::srand(std::time(0));
    std::ofstream friendFiles("users.csv");
    std::vector<std::string> userList;
    std::vector<std::string> productList;
    userList.reserve(USERS);
    productList.reserve(PRODUCTS);
    for(int i = 0; i < USERS; ++i){
        std::string id = uuid();
        std::string name = randomName();
        userList.push_back(id);
        friendFiles << id << "," << name << "\n";
    }
    friendFiles.close();

    std::ofstream productFiles("products.csv");
    for(int i = 0; i < PRODUCTS; ++i){
        std::string id = uuid();
        std::string name = randomProduct();
        productList.push_back(id);
        productFiles << id << "," << name << "\n";
    }
    productFiles.close();


    std::ofstream friendsFile("friends.csv");
    for(const std::string &id : userList){
        for(int i = 0; i < 1 + std::rand() % FRIENDS_BY_USER; ++i){
            std::string friendWith = randomElement(userList);
            if(id == friendWith) continue;
            friendsFile << id << "," << friendWith << "\n";
        }
    }
    friendsFile.close();

    std::ofstream productBuy("buy.csv");
    for(const std::string &id : userList){
        for(int i = 0; i < 1 + std::rand() % PRODUCTS_BY_USER; ++i){
            std::string buying = randomElement(productList);
            productBuy << id << "," << buying << "\n";
        }
    }
    productBuy.close();
}