#include <iostream>
#include <vector>
#include <string>
#include <random>
#include <algorithm>
#include <limits>
#include <fmt/core.h>
#include <fmt/color.h>

enum class Color { Red, Green, Blue, Yellow };

std::string colorToString(Color c) {
    switch (c) {
    case Color::Red: return "Red";
    case Color::Green: return "Green";
    case Color::Blue: return "Blue";
    case Color::Yellow: return "Yellow";
    default: return "Unknown";
    }
}

struct Card {
    Color color;
    int number;

    void print() const {
        fmt::color fmt_color;
        switch (color) {
        case Color::Red: fmt_color = fmt::color::red; break;
        case Color::Green: fmt_color = fmt::color::green; break;
        case Color::Blue: fmt_color = fmt::color::blue; break;
        case Color::Yellow: fmt_color = fmt::color::yellow; break;
        }
        fmt::print(fmt::fg(fmt_color), "[{} {}] ", colorToString(color), number);
    }

    bool matches(const Card& other) const {
        return color == other.color || number == other.number;
    }
};

std::vector<Card> createDeck() {
    std::vector<Card> deck;
    for (int c = 0; c < 4; ++c) {
        for (int n = 0; n <= 9; ++n) {
            // Two of each card (except 0 which appears once)
            deck.push_back({ static_cast<Color>(c), n });
            if (n != 0) deck.push_back({ static_cast<Color>(c), n });
        }
    }
    std::random_device rd;
    std::mt19937 g(rd()); // Mersenne Twister random number generator

    for (int i = 0; i < 10; ++i) {
        std::shuffle(deck.begin(), deck.end(), g);
    }
    return deck;
}

Card drawCard(std::vector<Card>& deck) {
    if (deck.empty()) throw std::runtime_error("Deck is empty!");
    Card c = deck.back();
    deck.pop_back();
    return c;
}

void printHand(const std::vector<Card>& hand) {
    for (size_t i = 0; i < hand.size(); ++i) {
        fmt::print("[{}] ", i);
        hand[i].print();
        fmt::print("\n");
    }
}

bool hasPlayableCard(const std::vector<Card>& hand, const Card& topCard) {
    for (const auto& card : hand) {
        if (card.matches(topCard)) return true;
    }
    return false;
}

void clearScreen() {
#ifdef _WIN32
    std::system("cls");
#else
    std::system("clear");
#endif
}

std::string rightAlign(std::string text, size_t width = 50) {
    if (text.length() >= width) return text;
    return std::string(width - text.length(), ' ') + text;
}

int main() {
    auto deck = createDeck();
    std::vector<Card> playerHand, aiHand;

    for (int i = 0; i < 7; ++i) {
        playerHand.push_back(drawCard(deck));
        aiHand.push_back(drawCard(deck));
    }

    Card topCard = drawCard(deck);
    bool playerTurn = true;

    while (true) {
        clearScreen();

        // Prepare UNO! labels if needed
        std::string playerUno = (playerHand.size() == 1) ? rightAlign(fmt::format(fmt::emphasis::bold, "YOU: UNO!")) : "";
        std::string aiUno = (aiHand.size() == 1) ? rightAlign(fmt::format(fmt::emphasis::bold, "AI: UNO!")) : "";

        // Print top card and UNO! indicator
        fmt::print("Top card: ");
        topCard.print();
        if (!playerUno.empty()) fmt::print("{}", playerUno);
        if (!aiUno.empty())     fmt::print("{}", aiUno);
        fmt::print("\n");

        fmt::print("AI has {} card(s).\n\n", aiHand.size());

        if (playerHand.empty()) {
            fmt::print(fmt::fg(fmt::color::green), "You win!\n");
            break;
        }

        if (aiHand.empty()) {
            fmt::print(fmt::fg(fmt::color::red), "AI wins!\n");
            break;
        }

        if (deck.empty()) {
            fmt::print(fmt::fg(fmt::color::gray), "Deck is empty! Reshuffling...\n");
            deck = createDeck(); // not perfect, doesn’t exclude cards in play
        }

        if (playerTurn) {
            fmt::print(fmt::fg(fmt::color::cyan), "Your turn:\n");
            printHand(playerHand);

            if (!hasPlayableCard(playerHand, topCard)) {
                fmt::print("No playable card. Press 'd' to draw: ");
                char input;
                std::cin >> input;
                if (input == 'd' || input == 'D') {
                    Card drawn = drawCard(deck);
                    playerHand.push_back(drawn);
                    fmt::print("You drew: ");
                    drawn.print();
                    fmt::print("\nPress Enter to continue...");
                    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
                    std::cin.get();
                    std::cin.putback('\n');
                    playerTurn = false;
                    continue;
                }
            }
            else {
                while (true) {
                    fmt::print("Choose card index to play or 'd' to draw: ");
                    std::string input;
                    std::cin >> input;

                    if (input == "d" || input == "D") {
                        Card drawn = drawCard(deck);
                        playerHand.push_back(drawn);
                        fmt::print("You drew: ");
                        drawn.print();
                        fmt::print("\nPress Enter to continue...");
                        std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
                        std::cin.get();
                        std::cin.putback('\n');
                        playerTurn = false;
                        break;
                    }

                    try {
                        int choice = std::stoi(input);
                        if (choice >= 0 && choice < static_cast<int>(playerHand.size())) {
                            if (playerHand[choice].matches(topCard)) {
                                topCard = playerHand[choice];
                                playerHand.erase(playerHand.begin() + choice);
                                playerTurn = false;
                                break;
                            }
                            else {
                                fmt::print("Invalid move. You must match color or number.\n");
                            }
                        }
                        else {
                            fmt::print("Invalid index.\n");
                        }
                    }
                    catch (...) {
                        fmt::print("Invalid input.\n");
                    }
                }
            }
        }
        else {
            fmt::print(fmt::fg(fmt::color::yellow), "AI's turn...\n");
            bool played = false;
            for (size_t i = 0; i < aiHand.size(); ++i) {
                if (aiHand[i].matches(topCard)) {
                    topCard = aiHand[i];
                    aiHand.erase(aiHand.begin() + i);
                    fmt::print("AI played: ");
                    topCard.print();
                    fmt::print("\n");
                    played = true;
                    break;
                }
            }

            if (!played) {
                aiHand.push_back(drawCard(deck));
                fmt::print("AI drew a card.\n");
            }

            fmt::print("Press Enter to continue...");
            std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
            std::cin.get();

            playerTurn = true;
        }
    }

    return 0;
}