Puzzle unlock system

[qiaochloe]

We could adopt DEEP (https://github.com/galacticpuzzlehunt/gph-site) or make our own. Soliciting thoughts from @guralpa or @metaterminal.

[qiaochloe]

Some engineering notes: unlocked puzzles should be recalculated every time, not stored in the database. This is more flexible & allows us to change the algorithm for each hunt. GPH seems to a lot of metadata in the puzzle database, but I feel like we can hardcode all of that in this function.

This is GPH function

    @staticmethod
    def compute_unlocks(context):
        metas_solved = []
        puzzles_unlocked = collections.OrderedDict()
        unlocks = []
        for puzzle in context.all_puzzles:
            unlocked_at = None
            if 0 <= puzzle.unlock_hours and (
                puzzle.unlock_hours == 0 or
                not context.team or
                context.team.allow_time_unlocks):
                unlock_time = context.start_time + datetime.timedelta(hours=puzzle.unlock_hours)
                if unlock_time <= context.now:
                    unlocked_at = unlock_time
            if context.hunt_is_prereleased or context.hunt_is_over:
                unlocked_at = context.start_time
            elif context.team:
                (global_solves, local_solves) = context.team.main_round_solves
                if 0 <= puzzle.unlock_global <= global_solves and (global_solves or any(metas_solved)):
                    unlocked_at = context.now
                if 0 <= puzzle.unlock_local <= local_solves[puzzle.round.slug]:
                    unlocked_at = context.now
                if puzzle.slug == META_META_SLUG and all(metas_solved):
                    unlocked_at = context.now
                if puzzle.is_meta:
                    metas_solved.append(puzzle.id in context.team.solves)
                if puzzle.id in context.team.db_unlocks:
                    unlocked_at = context.team.db_unlocks[puzzle.id].unlock_datetime
                elif unlocked_at:
                    unlocks.append(Team.unlock_puzzle(context, puzzle, unlocked_at))
            if unlocked_at:
                puzzles_unlocked[puzzle] = unlocked_at
        if unlocks:
            PuzzleUnlock.objects.bulk_create(unlocks, ignore_conflicts=True)
        return puzzles_unlocked