Premium Players Support Reworked

[scaik]

Pull Request Etiquette

• I have checked the PRs for upcoming features/bug fixes.

Changes

• Internal code
• API (affecting end-user code, backwards compatible)
• Other: _____

Closes Issue: #39

Description

This pull request implements the following features:

• Nickname length max & min limit
• Premium account auto-detection on login
• Separated authentication scenarios for premium and cracked players
• Premium nickname change handling
• Cracked and premium conflict handling

Now this works a bit different compared to previous PR.
The PreLogin scenario look like this:

1. Validate nickname (Moved from PostLogin)
2. Check if player's IP + Nickname is in the PendingLoginBucket
   • If found, it means that this is a cracked player
   • Continue to regular authorization
3. Retrieve player UUID from mojang
   • If not found, continue to regular authorization
4. If there is no account with player's nickname or there is a non-premium account,
   we should check player's mode, because that can be just a cracked player with premium name.
   (By the way, there is an option in config to prevent such players from connecting)
   • Add player to PendingLoginBucket
   • Force online mode
5. Otherwise we force offline mode

There is a slight downsight in this approach, which is that whenever a cracked player
with a premium name logs in, he will get kicked and he will have to reconnect,
but i couldn't manage to find any workarounds.

Inspired by LibreLogin and FastLogin

I really hope that this is what the plugin needs and my code will work as expected :)

[bivashy]

First of all, great job! I reviewed your code and you nailed it. I'm going to test your changes and then try to fix some issues you mentioned. I will modify the code if I find any bugs or minor fixes.

This will definitely be merged, so you can be sure that the next release will include this feature.

Testing TODO:

• Test with id-type: NAME and premium enabled.
  Expected behavior: Plugin should behave as usual, commands with player name should work as expected.

• Enable premium, change player name in database to wrong one (without profile-conflict)
  Expected behavior: Plugin should change player name in database to valid one

• Test every profile-conflict.
  Expected behavior: Plugin should work depending on profile-conflict.

• Try to enter with enabled premium mode without online account
  Expected behavior: Plugin should kick player with error

• Use wrong name when entering premium mode account
  Expected behavior: Plugin should kick player with error

• Test Mojang rate limit and premium account auto-detection
  Expected behavior: Plugin should work without premium functionality.

If you have other test cases, reply to this comment.

[scaik]

Thanks for reviewing my code, i’m glad to hear that! tbh i tested it and it worked as expected, but my tests were very superficial. i think there is another test case with premium auth steps.

[scaik]

Relocation didn't help, idk why. So i just let bungee download the library.