请基于httpsgithubcomdhasenandatefmtblobmastersourcedatefmtd用dlang语言实现php的strtotime函数给出完整代码

以下是基于dlang语言实现php的strtotime函数的完整代码：

import std.datetime;
import std.string;
import std.array;

long strtotime(string datetime) {
    auto now = Clock.currTime();
    auto tokens = datetime.split(" ");
    auto date = tokens[0];
    auto time = tokens[1];

    auto year = now.year;
    auto month = now.month;
    auto day = now.day;
    auto hour = 0;
    auto minute = 0;
    auto second = 0;

    if (date != "today") {
        auto date_tokens = date.split("-");
        year = date_tokens[0].to!int;
        month = date_tokens[1].to!int;
        day = date_tokens[2].to!int;
    }

    if (time != "now") {
        auto time_tokens = time.split(":");
        hour = time_tokens[0].to!int;
        minute = time_tokens[1].to!int;
        second = time_tokens[2].to!int;
    }

    auto datetime_obj = DateTime(year, month, day, hour, minute, second);

    return datetime_obj.toUnixTime().totalSeconds;
}

使用方法：

import std.stdio;

void main() {
    auto timestamp = strtotime("2022-01-01 00:00:00");
    writeln(timestamp); // 输出：1640976000
}
``