Challenge property filter/chooser.

[atiannicelli]

I have recently been creating the same challenge for many different countries. Since most people like to stick to a specific country (or stay away from some specific countries) we have found that making the challenges country specific works well. But here is the issue: I end up with 20, 30, or more challenges for the same issue.

What I'd love to see is the concept of a country chooser, or even better - a generic chooser on the front page of the challenge. The chooser would be created as part of the challenge and it would basically filter the challenge to a set of tasks within the challenge.

For example: Let's say I have a challenge that identifies all ways that have highway=footway, footway=crossing, but do not have crossing=*. That's a single challenge that might have a very large number of tasks globally, but then I would configure the challenge to present the user with a choice when they start the challenge. For this specific challenge I have configured the challenge chooser to be "iso". So when the user starts the challenge a dropdown would be shown that would allow the user to choose exactly one country. The dropdown would be populated by doing a search through all the tasks in the challenge for all the different possible values for "iso" in this challenge. Then when a user chooses the specific "iso" then the challenge would filter all tasks with iso equal to that value. From there on out the challenge would look exactly the same, but they would only be working on tasks with a property of iso=.