#ifndef ARGPARSER_BUILTIN_PARSER_H
#define ARGPARSER_BUILTIN_PARSER_H

#include "defs.h"
#include "errors.h"
#include "parser_func.h"
#include <charconv>
#include <iomanip>
#include <string>

namespace argparser::internal {

    template<typename T, parse_opt parse_opt>
    class automatic_parser {
    public:
        static parser_func<T> make_parser(const std::string &name) {
            return [name](const char *begin, const char *end, const char *&parse_end, internal::parser_allow_undelimited) {
                T val;
                auto pos = begin;
                while (pos < end && isspace(*pos)) pos++;
                auto res = std::from_chars(pos, end, val);
                if (res.ec == std::errc{}) {
                    parse_end = res.ptr;
                    return val;
                } else {
                    throw errors::type_parsing_error(name, std::string(begin, end), pos - begin, "invalid number");
                }
            };
        }
    };

    constexpr parse_opt string_parse_opt_with_default(parse_opt opt) {
        if ((opt & parse_opt::AnyString) == parse_opt::None) {
            return opt | parse_opt::AnyString;
        } else {
            return opt;
        }
    }

    constexpr bool string_parser_enable_bare(parse_opt opt) {
        return enum_flag_contains(string_parse_opt_with_default(opt), parse_opt::BareString);
    }

    constexpr bool string_parser_enable_single_quoted(parse_opt opt) {
        return enum_flag_contains(string_parse_opt_with_default(opt), parse_opt::SingleQuotedString);
    }

    constexpr bool string_parser_enable_double_quoted(parse_opt opt) {
        return enum_flag_contains(string_parse_opt_with_default(opt), parse_opt::DoubleQuotedString);
    }

    template<parse_opt parse_opt>
    class automatic_parser<std::string, parse_opt> {
        static std::string trim_string(const std::string &str) {
            auto start = str.find_first_not_of(whitespace);
            auto end = str.find_last_not_of(whitespace);
            return str.substr(start == std::string::npos ? 0 : start, end == std::string::npos ? 0 : end);
        }

    public:
        static parser_func<std::string> make_parser(const std::string &name) {

            return [name](const char *begin, const char *end, const char *&parse_end, internal::parser_allow_undelimited allow_undelimited) {
                auto str = std::string_view(begin, end);
                if (str.length() == 0) {
                    if (parse_opt == parse_opt::None || enum_flag_contains(parse_opt, parse_opt::BareString)) {
                        parse_end = begin;
                        return std::string("");
                    } else {
                        throw errors::type_parsing_error(name, std::string(""), 0, "unexpected empty input");
                    }
                }
                if (str[0] == '\'' && string_parser_enable_single_quoted(parse_opt)) {
                    auto ss = std::stringstream(std::string(str));
                    std::string val;
                    ss >> std::quoted(val, '\'', '\\');
                    auto len = ss.tellg();
                    parse_end = begin + len;
                    if (enum_flag_contains(parse_opt, parse_opt::TrimString)) {
                        return trim_string(val);
                    } else {
                        return val;
                    }
                }
                if (str[0] == '"' && string_parser_enable_double_quoted(parse_opt)) {
                    auto ss = std::stringstream(std::string(str));
                    std::string val;
                    ss >> std::quoted(val, '"', '\\');
                    auto len = ss.tellg();
                    parse_end = begin + len;
                    if (enum_flag_contains(parse_opt, parse_opt::TrimString)) {
                        return trim_string(val);
                    } else {
                        return val;
                    }
                }
                if (string_parser_enable_bare(parse_opt)) {
                    std::string illegal_characters = "\"'";
                    if (!internal::enum_flag_contains(allow_undelimited, internal::parser_allow_undelimited::Comma)) {
                        illegal_characters += ",";
                    }
                    if (!internal::enum_flag_contains(allow_undelimited, internal::parser_allow_undelimited::Parenthesis)) {
                        illegal_characters += "()";
                    }
                    if (!internal::enum_flag_contains(allow_undelimited, internal::parser_allow_undelimited::Brackets)) {
                        illegal_characters += "[]";
                    }
                    auto pos = str.find_first_of(illegal_characters);
                    if (pos == std::string_view::npos) {
                        parse_end = end;
                    } else {
                        parse_end = begin + pos;
                    }
                    std::string val{begin, parse_end};
                    if (enum_flag_contains(parse_opt, parse_opt::TrimString) || enum_flag_contains(parse_opt, parse_opt::TrimBareString)) {
                        return trim_string(val);
                    } else {
                        return val;
                    }
                }
                throw errors::type_parsing_error(name, std::string(begin, end), 0, "failed to parse string");
            };
        }
    };


    template<typename T>
    parser_func<T> make_enum_parser(const std::string &name, internal::string_map<T> values) {
        if (values.size() == 0) {
            throw errors::empty_enum_map_error(name);
        }
        return [name, values](const char *begin, const char *end, const char *&parse_end, internal::parser_allow_undelimited) {
            auto input = std::basic_string_view(begin, end);
            auto start = input.find_first_not_of(whitespace);
            if (start == std::string::npos) {
                input = "";
            } else {
                input = std::basic_string_view(begin + start, end);
            }
            T value;
            size_t value_len = 0;
            for (const auto &[str, val]: values) {
                if (str.length() <= input.length()) {
                    if (input.starts_with(str)) {
                        if (str.length() > value_len) {
                            value = val;
                            value_len = str.length();
                        }
                    }
                }
            }
            if (value_len == 0) {
                std::string expected_values = values.begin()->first;
                for (auto it = std::next(values.begin()); it != values.end(); it++) {
                    if (std::next(it) != values.end()) {
                        expected_values += ", " + it->first;
                    } else {
                        expected_values += " or " + it->first;
                    }
                }
                throw errors::type_parsing_error(name, std::string(begin, end), 0, std::format("expected {}", expected_values));
            } else {
                parse_end = begin + value_len;
                return value;
            }
        };
    }

}// namespace argparser::internal


#endif//ARGPARSER_BUILTIN_PARSER_H