#include <cstdio>
#include <readline/readline.h>
#include <readline/history.h>
#include <iostream>
#include <memory>
#include <cmath>
#include "game_state.h"

namespace Hanabi {

    std::ostream& operator<<(std::ostream& os, const std::optional<probability_t>& prob) {
        if (prob.has_value()) {
            os << prob.value() << " ~ " << std::setprecision(5) << boost::rational_cast<double>(prob.value()) * 100 << "%";
        } else {
            os << "unknown";
        }
        return os;
    }

    std::string read_line_memory_safe(const char *prompt) {
        char *line = readline(prompt);
        std::string ret;
        if (line == nullptr) {
            ret = "";
        } else {
            ret = std::string(line);
        }
        free(line);
        return ret;
    }

    constexpr static std::array<std::string, 12> cli_commands = {
            "play",
            "clue",
            "discard",
            "id",
            "state",
            "revert",
            "actions",
            "evaluate",
            "help",
            "quit",
            "initials",
            "opt",
    };

    char * cli_commands_generator(const char *text, int state) {
        std::string text_str (text);
        for(auto& command : cli_commands) {
            if (command.starts_with(text_str) && state-- <= 0) {
                return strdup(command.c_str());
            }
        }
        return nullptr;
    }

    char **
    cli_command_completion(const char *text, int start, int end)
    {
        rl_attempted_completion_over = 1;
        return rl_completion_matches(text, cli_commands_generator);
    }


    Card parse_card(std::string card_str) {
        if (card_str == "trash" or card_str == "kt") {
            return Cards::trash;
        }
        if(card_str.size() != 2) {
            return Cards::unknown;
        }
        auto it = std::find(suit_initials.begin(), suit_initials.end(), card_str[0]);
        if (it == suit_initials.end()) {
            return Cards::unknown;
        }
        const suit_t suit = std::distance(suit_initials.begin(), it);
        try {
            const rank_t rank = 5 - std::stoi(card_str.substr(1, 1));
            return Card {suit, rank};
        } catch(std::invalid_argument&) {
            return Cards::unknown;
        }
    }

    bool ask_for_card_and_rotate_draw(const std::shared_ptr<HanabiStateIF>& game, hand_index_t index, bool play) {
        const auto next_states = game->possible_next_states(index, play);
        if (next_states.size() <= 1) {
            return true;
        }
        std::cout << "Choose drawn card: " << std::endl;
        unsigned num_trash = 0;
        std::optional<probability_t> trash_discard_prob = 0;
        for(const auto &[card_multiplicity, probability]: next_states) {
            if (game->is_trash(card_multiplicity.card)) {
                num_trash += card_multiplicity.multiplicity;
                trash_discard_prob = probability;
            } else {
                std::cout << card_multiplicity.card << " (" << card_multiplicity.multiplicity;
                std::cout << " copie(s) in draw) " << probability << std::endl;
            }
        }

        if (num_trash > 0) {
            std::cout << Cards::trash << " (" << num_trash << " copie(s) in draw) " << trash_discard_prob << std::endl;
        }

        std::stringstream prompt;
        prompt << "draw? [";
        if (num_trash > 0) {
            prompt << Cards::trash;
        } else {
            prompt << next_states.front().first.card;
        }
        prompt << "] ";
        const std::string card_str = read_line_memory_safe(prompt.str().c_str());
        const Card drawn_card = [&card_str, &num_trash, &next_states](){
            if (card_str.empty()) {
                if (num_trash > 0) {
                    return Cards::trash;
                }
                return next_states.front().first.card;
            }
            return parse_card(card_str);
        }();

        if (drawn_card == Cards::unknown) {
            std::cout << "Could not parse card " << card_str << std::endl;
            return false;
        }

        auto selected_draw_it = std::find_if(next_states.begin(), next_states.end(), [&drawn_card, &game](const std::pair<CardMultiplicity, std::optional<probability_t>>& pair) {
            return (game->is_trash(pair.first.card) and drawn_card == Cards::trash) or pair.first.card == drawn_card;
        });
        if (selected_draw_it == next_states.end()){
            std::cout << "That card is not in the draw pile, aborting." << std::endl;
            return false;
        };
        game->rotate_next_draw(selected_draw_it->first.card);
        return true;
    }

    void cli(const std::shared_ptr<HanabiStateIF>& game) {
        rl_attempted_completion_function = cli_command_completion;
        using_history();
        unsigned depth = 0;
        while (true) {
            const std::string prompt = read_line_memory_safe("> ");
            add_history(prompt.c_str());

            if (prompt.starts_with("help")) {
                std::cout << "state:       print information on current game state." << std::endl;
                std::cout << "clue:        give a clue." << std::endl;
                std::cout << "play <card>: play specified card." << std::endl;
                std::cout << "discard:     discard trash from hand." << std::endl;
                std::cout << "opt:         take optimal action. In case of ties, prefers plays and discards in that order." << std::endl;
                std::cout << "revert:      revert last turn of game." << std::endl;
                std::cout << "actions:     display list of reasonable actions to take and their winning chances." << std::endl;
                std::cout << "evaluate:    evaluate current game state recursively. Potentially runtime-expensive." << std::endl;
                std::cout << "id:          display id of state. Has no inherent meaning, useful for debugging." << std::endl;
                std::cout << "quit:        Quit this interactive shell." << std::endl;
                continue;
            }

            if (prompt.starts_with("quit")) {
                std::cout << "Quitting." << std::endl;
                clear_history();
                break;
            }

            if (prompt.starts_with("initials")) {
                if (prompt.length() < 12) {
                    std::cout << "At least 3 initials need to be specified" << std::endl;
                    continue;
                }
                const std::string new_initials = prompt.substr(9);
                for(size_t i = 0; i < std::min(size_t(6), new_initials.length()); i++) {
                    suit_initials[i] = new_initials[i];
                }
                std::cout << "Updated initials to ";
                for(const char c: suit_initials) {
                    std::cout << c;
                }
                std::cout << std::endl;
                continue;
            }

            if (prompt.starts_with("state")) {
                std::cout << *game << std::endl;
                const std::optional<probability_t> prob = game->lookup();
                std::cout << "Winning chance: " << prob << std::endl;
                continue;
            }

            if (prompt.starts_with("evaluate")) {
                std::cout << "Evaluating current game state, this might take a while." << std::endl;
                game->evaluate_state();
                std::cout << "Evaluated state." << std::endl;
                continue;
            }

            if (prompt.starts_with("revert")) {
                if (depth == 0) {
                    std::cout << "Cannot revert more than base state." << std::endl;
                    continue;
                }
                std::cout << "Reverting one turn" << std::endl;
                game->revert();
                depth--;
                continue;
            }

            if (prompt.starts_with("id")) {
                std::cout << game->unique_id() << std::endl;
                continue;
            }

            if (prompt.starts_with("play")) {
                const Card card = parse_card(prompt.substr(5,2));
                if (prompt.length() < 7) {
                    std::cout << "No card specified." << std::endl;
                    continue;
                }
                if (card == Cards::unknown) {
                    std::cout << "Could not parse card " << prompt.substr(5,2) << std::endl;
                    continue;
                }
                const hand_index_t index = game->find_card_in_hand(card);
                if (index == hand_index_t(-1)) {
                    std::cout << "This card is not in the current players hand, aborting." << std::endl;
                    continue;
                }
                if (!ask_for_card_and_rotate_draw(game, index, true)) {
                    continue;
                }
                game->play(index);
                depth++;
                continue;
            }

            if (prompt.starts_with("discard")) {
                const auto hand = game->cur_hand();
                hand_index_t trash_index = invalid_hand_idx;
                for(hand_index_t index = 0; index < hand.size(); index++) {
                    if (game->is_trash(hand[index])) {
                        trash_index = index;
                        break;
                    }
                }
                if (trash_index == invalid_hand_idx) {
                    std::cout << "No trash in hand found, discarding not supported." << std::endl;
                    continue;
                }
                if (game->num_clues() == max_num_clues) {
                    std::cout << "You cannot discard at " << max_num_clues << " clues." << std::endl;
                    continue;
                }
                if (!ask_for_card_and_rotate_draw(game, trash_index, false)) {
                    continue;
                }
                game->discard(trash_index);
                depth++;
                continue;
            }

            if (prompt.starts_with("clue")) {
                if (game->num_clues() == 0) {
                    std::cout << "You cannot give a clue at 0 clues." << std::endl;
                    continue;
                }
                game->give_clue();
                depth++;
                continue;
            }

            if (prompt.starts_with("actions")) {
                for (const auto &[action, probability] : game->get_reasonable_actions()) {
                    std::cout << action << ": " << probability << std::endl;
                }
                continue;
            }

            if (prompt.starts_with("opt")) {
                const auto reasonable_actions = game->get_reasonable_actions();
                if(reasonable_actions.empty()) {
                    std::cout << "Game is over, no actions to take." << std::endl;
                    continue;
                }
                Action best_action;
                std::optional<probability_t> best_probability;
                for (const auto &[action, probability] : game->get_reasonable_actions()) {
                    if (!best_probability.has_value() or (probability.has_value() and probability.value() > best_probability.value())) {
                        best_action = action;
                        best_probability = probability;
                    }
                }
                switch(best_action.type) {
                    case ActionType::play:
                        std::cout << "Playing " << best_action.card << std::endl;
                        game->play(game->find_card_in_hand(best_action.card));
                        break;
                    case ActionType::discard:
                        std::cout << "Discarding" << std::endl;
                        game->discard(game->find_card_in_hand(best_action.card));
                        break;
                    case ActionType::clue:
                        std::cout << "Giving a clue" << std::endl;
                        game->give_clue();
                        break;
                    default:
                        break;
                }
            }

            std::cout << "Unrecognized command. Type 'help' for a list of available commands." << std::endl;
        }
    }
}