#ifndef REVERSI_ARGUMENTPARSER_H
#define REVERSI_ARGUMENTPARSER_H

#include <stdexcept>
#include <string>
#include <utility>
#include <vector>
#include <iostream>
#include <unordered_map>
#include <cassert>

namespace cb::argparser {

enum class Mode {
    POSITIONAL,
    REQUIRED,
    OPTIONAL,
};

enum class Type {
    STRING,
    BOOL,
    INTEGER,
};

struct ParseArgument {
    std::string shortName;
    std::string name;
    std::string description;
    std::string defaultValue;
    Type type;
    Mode mode;

    bool isPresent{false};
};


class Argument {
private:
    std::string content;
    Type type{Type::STRING};
public:

    Argument() = default;

    explicit Argument(std::string content, Type type = Type::STRING) : content{std::move(content)}, type{type} {
        if (type == Type::BOOL && this->content == "false") {
            this->content = "";
        }
    }

    [[nodiscard]] const std::string &asStr() const {
        return content;
    }

    [[nodiscard]] bool asBool() const {
        return !content.empty();
    }

    int asInt() {
        assert(type == Type::INTEGER);
        return std::stoi(content);
    }

    explicit operator bool() const {
        return asBool();
    }
};


using ArgumentMapType = std::unordered_map<std::string, Argument>;

class ArgumentMap : public ArgumentMapType {
public:

    Argument &operator[](std::string &&argumentName) {
        assert(count(argumentName) > 0 && "Argument  not found!");
        return this->at(argumentName);
    }
};


class ArgumentParser {
private:
    std::vector<ParseArgument> arguments;
    std::vector<ParseArgument> positionalArguments;

public:
    void addArgument(const std::string &shortName, const std::string &name, Type type, std::string description,
                     bool defaultValue, Mode mode = Mode::OPTIONAL) {
        assert(type == Type::BOOL);
        std::string value = defaultValue ? "1" : "";
        addArgument(shortName, name, type, std::move(description), value, mode);
    }

    void addArgument(const std::string &shortName, const std::string &name, Type type, std::string description,
                     const char *defaultValue, Mode mode = Mode::OPTIONAL) {
        addArgument(shortName, name, type, std::move(description), std::string{defaultValue}, mode);
    }

    void addArgument(const std::string &shortName, const std::string &name, Type type, std::string description,
                     int defaultValue, Mode mode = Mode::OPTIONAL) {
        assert(type == Type::INTEGER);
        addArgument(shortName, name, type, std::move(description), std::to_string(defaultValue), mode);
    }

    void addArgument(const std::string &shortName, const std::string &name, Type type, std::string description,
                     std::string defaultValue = "", Mode mode = Mode::OPTIONAL) {
        if (argumentExists(shortName, name)) {
            const auto errorMessage = "ParseArgument already exists --" + name + " -" + shortName;
            throw std::runtime_error(errorMessage);
        }

        ParseArgument argument{};
        argument.shortName = shortName;
        argument.name = name;
        argument.type = type;
        argument.mode = mode;
        argument.description = std::move(description);
        argument.defaultValue = std::move(defaultValue);

        if (mode == Mode::POSITIONAL) {
            positionalArguments.push_back(argument);
        } else {
            arguments.push_back(argument);
        }
    }

    ArgumentMap parse(int argc, char *argv[]) {
        if (argc <= positionalArguments.size()) {
            const auto errorMessage =
                    "Not enough arguments provided";
            // TODO print help message
            throw std::runtime_error(errorMessage);
        }

        for (auto &&arg: arguments) {
            arg.isPresent = false;
        }

        ArgumentMap parsedArgs = parseArguments(argc, argv);

        verifyRequiredArgumentsPresent();

        return parsedArgs;
    }

private:

    static void insertArgument(ArgumentMap &parsedArgs, ParseArgument &positionalArg, const Argument &argument) {
        parsedArgs.insert_or_assign(positionalArg.name, argument);
        if (!positionalArg.shortName.empty()) {
            parsedArgs.insert_or_assign(positionalArg.shortName, argument);
        }
    }

    ArgumentMap parseArguments(int argc, char *const *argv) {
        ArgumentMap parsedArgs{};

        // TODO gen help message
        parsedArgs.insert_or_assign("-h", Argument{"Help"});
        parsedArgs.insert_or_assign("--help", Argument{"Help"});

        for (int i = 0; i < argc; i++) {
            bool handled = false;

            for (auto &&positionalArg: positionalArguments) {
                insertArgument(parsedArgs, positionalArg, Argument{argv[i], positionalArg.type});
                handled = true;
            }

            if (handled) {
                continue;
            }

            for (auto &&arg: arguments) {
                if (!matchesArgument(argv[i], arg)) {
                    continue;
                }

                if (requiresAdditionalArgument(arg, argc, argv, i)) {
                    auto content = std::string{argv[i + 1]};
                    consumeArgument(parsedArgs, arg, std::move(content));
                    i++;
                } else {
                    consumeArgument(parsedArgs, arg);
                }
            }
        }


        for (auto &&arg: arguments) {
            if (parsedArgs.find(arg.name) != parsedArgs.end()) {
                continue; // already in parsed args
            }

            insertArgument(parsedArgs, arg, Argument{arg.defaultValue, arg.type});
        }

        return parsedArgs;
    }

    static bool requiresAdditionalArgument(const ParseArgument &parseArgument, int argc, char *const *argv, int i) {
        if (parseArgument.type != Type::BOOL) {
            return true;
        }

        if (i + 1 >= argc) {
            return false;
        }

        if (argv[i + 1][0] == '-') {
            return false;
        }

        return true;
    }

    static void consumeArgument(ArgumentMap &parsedArgs, ParseArgument &arg, std::string content = "1") {
        insertArgument(parsedArgs, arg, Argument{std::move(content), arg.type});
        arg.isPresent = true;
    }

    void verifyRequiredArgumentsPresent() const {
        for (auto &&argument: arguments) {
            if (argument.mode != Mode::REQUIRED) {
                continue;
            }
            if (!argument.isPresent) {
                const auto errorMessage =
                        "Required argument not present: --" + argument.name + " -" + argument.shortName;
                throw std::runtime_error(errorMessage);
            }
        }
    }

    static bool matchesArgument(const std::string &text, const ParseArgument &arg) {
        return text == arg.shortName || text == arg.name;
    }

    bool argumentExists(const std::string &shortName, const std::string &name) {
        return std::any_of(arguments.begin(), arguments.end(), [&](ParseArgument &arg) {
            return arg.shortName == shortName || arg.name == name;
        });
    }
};

}

#endif //REVERSI_ARGUMENTPARSER_H