Reminder + planner + todo list?

Question

Task Management

Recommend a program with the following functionality.
List or tree of tasks. Tasks can be of the following types:
- either just a description of the case (do this and that),
- or a task with a one-time reference to absolute time (January 1, 2020; today at 22:00; tomorrow at 8:00; 25 date of the current month),
- or a one-time task with reference to relative time (essentially a timer - for example, after 10 days; after 5 minutes; after 100 years :) )
- or a periodic task that triggers according to a specific time pattern (every month on the 20th; every Monday, every year on June 1, every hour, on the first business day of the month, etc.)
For events, there should be notifications of the following types to choose from - a pop-up window, a tooltip in the tray, a sound signal (on Android - also some kind of notification and sound signal).
The program sits in the tray and is called by clicking on the icon. In addition to the actual account registration, access to the program must have a password (such as a pincode, protection from random curious); a password should also be set for an arbitrary task, that is, if the task is password-protected and an event occurs, a window pops up with the message "Private event; enter password" but without the event text.
The event, when it fires, should be able to delay it according to a certain time pattern: for a day, for an hour, for 10 minutes, etc. That is, in fact - the buttons in the event window: "OK", "Delay for a day", "
Spent events (without time and periodic - if the user manually deletes them, with time - one-time, for which the user clicked "OK") are sent to the archive. From there they can be manually removed permanently.
The program must be cross-platform, with native clients for Windows, Linux, Android; with data synchronization via the Internet. Should be free. Open source whenever possible.
Do not add or subtract anything, all the listed functions are needed; therefore, there is an idea to write it yourself (to store tasks in ordinary text files with synchronization via dropbox), but still there is a chance that something ready already exists ...

Answer 1

look at doit.im , they praised it on Habré , it didn’t suit me for some reason, but I tried it on about three years ago, now, it seems, it’s alive. Maybe even OpenSource.
you can also choose from:
1) Remeberthemilk is the first of its kind. Free. But a full-fledged mobile client is only paid, there is no Desktop client (via a browser)
2) Wunderlist, there are clients, there is free.
3) well, the closest to GTD is mylifeorganized.net, I bought it, the same three years ago, because of problems with encoding on English Windows, I had to refuse, but - remains the closest to GTD
, I use RTM

Answer 2

The description is very Google calendar reminds...

Answer 3

Almost everything you described is in LeaderTask . Unless there are no reminders with the preliminary introduction of a password, as far as I remember. You can write to the developers and offer to implement this option. Their support is good and responds quickly.
You can try to come up with a special technique for entering tasks for some secret cases, which will allow you to achieve the goal (so that the text of the task is displayed not immediately, but upon request), but do not look for an uber program (suitable for all of the above requirements) and do not write it yourself from - for one feature. For example, you can make some kind of conditional description of the task (which will be shown when reminded), and hide its real text in the notes for the task. With this approach, when a reminder pops up, you can go to the task and its notes (and do what you need with the task), and outsiders do not see the real text of the task.
I will assume that you need a feature with secrecy of tasks so that colleagues who approach your monitor do not see notifications about your personal affairs. If there is any other purpose for it, write. It is interesting to think about how you can get what you need.