time.pat

#pragma once

import std.io;

/*!
    Library to handle time and date related operations.
*/

namespace auto std::time {

    /**
        A structured representation of a time and date.
    */
    struct Time {
        u8 sec;
        u8 min;
        u8 hour;
        u8 mday;
        u8 mon;
        u16 year;
        u8 wday;
        u16 yday;
        bool isdst;
    } [[sealed]];

    /**
        A helper type to convert between Time and u128.
    */
    union TimeConverter {
        Time time;
        u128 value;
    };

    /**
        A type to represent a time in seconds since the epoch.
    */
    using EpochTime = u32;

    /**
        A type to represent a time zone.
    */
    enum TimeZone : u8 {
        Local,
        UTC
    };

    /**
        A type to represent a DOS date.
    */
    bitfield DOSDate {
        day: 5;
        month: 4;
        year: 7;
    } [[sealed]];

    /**
        A type to represent a DOS time.
    */
    bitfield DOSTime {
        seconds: 5;
        minutes: 6;
        hours: 5;
    } [[sealed]];

    namespace impl {

        union DOSDateConverter {
            DOSDate date;
            u16 value;
        };

        union DOSTimeConverter {
            DOSTime time;
            u16 value;
        };

    }


    /**
        Returns the current time in seconds since the epoch.
        @return The current time in seconds since the epoch.
    */
    fn epoch() {
        return builtin::std::time::epoch();
    };

    /**
        Converts a time in seconds since the epoch to a local time.
        @param epoch_time The time in seconds since the epoch.
        @return The local time.
    */
    fn to_local(EpochTime epoch_time) {
        le TimeConverter converter;

        converter.value = builtin::std::time::to_local(epoch_time);

        return converter.time;
    };

    /**
        Converts a time in seconds since the epoch to a UTC time.
        @param epoch_time The time in seconds since the epoch.
        @return The UTC time.
    */
    fn to_utc(EpochTime epoch_time) {
        le TimeConverter converter;

        converter.value = builtin::std::time::to_utc(epoch_time);

        return converter.time;
    };

    /**
        Queries the current time in the specified time zone.
        @param [time_zone] The time zone to query. Defaults to local.
        @return The current time in the specified time zone.
    */
    fn now(TimeZone time_zone = TimeZone::Local) {
        le TimeConverter converter;

        if (time_zone == TimeZone::Local)
            converter.value = builtin::std::time::to_local(std::time::epoch());
        else if (time_zone == TimeZone::UTC)
            converter.value = builtin::std::time::to_utc(std::time::epoch());
        else
            converter.value = 0x00;

        return converter.time;
    };

    /**
        Converts a value to a DOS date.
        @param value The value to convert.
        @return The DOS date.
    */
    fn to_dos_date(u16 value) {
        le impl::DOSDateConverter converter;

        converter.value = value;

        return converter.date;
    };

    /**
        Converts a value to a DOS time.
        @param value The value to convert.
        @return The DOS time.
    */
    fn to_dos_time(u16 value) {
        le impl::DOSTimeConverter converter;

        converter.value = value;

        return converter.time;
    };

    /**
        Converts a FILETIME to unix time.
        @param value The value to convert.
        @return Timestamp formatted as unix time.
    */
    fn filetime_to_unix(u64 value) {
        return value / 10000000 - 11644473600;
    };

    /**
        Formats a time according to the specified format string.
        @param time The time to format.
        @param [format_string] The format string to use. Defaults to "%c".
        @return The formatted time.
    */
    fn format(Time time, str format_string = "%c") {
        le TimeConverter converter;
        converter.time = time;

        return builtin::std::time::format(format_string, converter.value);
    };

    /**
        Formats a DOS date according to the specified format string.
        @param date The DOS date to format.
        @param [format_string] The format string to use. Defaults to "{}/{}/{}".
        @return The formatted DOS date.
    */
    fn format_dos_date(DOSDate date, str format_string = "{}/{}/{}") {
        return std::format(format_string, date.day, date.month, date.year + 1980);
    };

    /**
        Formats a DOS time according to the specified format string.
        @param time The DOS time to format.
        @param [format_string] The format string to use. Defaults to "{:02}:{:02}:{:02}".
        @return The formatted DOS time.
    */
    fn format_dos_time(DOSTime time, str format_string = "{:02}:{:02}:{:02}") {
        return std::format(format_string, time.hours, time.minutes, time.seconds * 2);
    };

}