This is a specification of an initiative system that would allow for the creation of parallel attacks and defenses. This solves many issues such as prioritization and queuing.

Here are some new parameters:

MinAttackTime: minimum length of the attack phase.
MaxAttackTime: maximum length of the attack phase.
MinDefenseTime: minimum length of the defense phase.
MaxDefenseTime: minimum length of the defense phase.
BattlePriority: a numerical DB key for faction roles that allows that role to preferentially join battles.

Some terminology:

A battle is a set of players who are trying to form a group to attack or defend. Battles have a capacity which at the moment is either 3 or 2.
An invasion is what you get when an attack battle is turned into an attack challenge.
A game is a ZK game. They occur on planets.
An adjacent planet is one that is attackable by the faction even if dropships are ignored.

Attacking

The attack phase proceeds mostly as usual. Players of the attacking faction can join any valid planet using the MM UIs or the ATTACK PLANET button. The attack phase ends with the creation of at least one invasion if both of the following are satisfied:

At least one battle is at capacity.
It is at least MinAttackTime since the start of the phase.

The attack phase is forfeit (no invasions are created) if the two conditions remain unsatisfied for MaxAttackTime.

If the attack phase ends and it has gone for longer than MinAttackTime then a single invasion is launched, exactly like the current system. If the attack phase ends because there was at least one full battle at MinAttackTime then multiple invasions may be launched like so:

Launch an invasion for every battle which is at capacity.
Reshuffle the remaining players into complete battles to try to make a battle for everyone. Use the fact that 2 and 3 are co-prime to find a battle for everyone (provided that there are at least 2 players left over and the faction has access to both a 2v2 and 3v3 planet). Launch an invasion with each of these battles.
Start the defense phase.

Retaining the players preferences through the reshuffle would be nice but is not required.

Multiple invasions targeting the same planet should be able to be launched simultaneously. These changes are required:

Allow players to join battles on adjacent planets regardless of whether there are games in progress there.
If a battle on an adjacent planet is filled up during the attack phase then the MM should spawn another battle for that planet. These battles will require some sort of indexing for the sake of displaying them in chobby.
If a game ends on a planet with dropships then only use floor(1/(N + 1)) of the dropships, where N is the number of other games in progress (started by this faction) on the planet.

Note that these rules explicitly only allow factions to start multiple games on adjacent planets. A planet that is only accessible via warp should not have simultaneous games started by the same faction.

Defending

The defense phase can now contain multiple planets, with the added complication that attacks on multiple different factions can occur.

If the phase has not yet reached MaxDefenseTime then a battle turns into a game when both the following two conditions are satisfied:

The battle is at capacity.
It is at least MinDefenseTime since the start of the phase.

The defense phase ends when either all battles are turned into games or MaxDefenseTime is reached. If MaxDefenseTime is reached then:

Turn all battles with (capacity - 1) players in them into games.
Reshuffle the remaining players into battles with (capacity - 1) players. The method is not particularly important since 3v3 planets are rare.

Booting

Faction officials want to be able to push their way into particularly important battles. They are especially interested in getting the most out of warp attacks. This can be achieved with the booting system. It works the same way in the attack and defend phase.

Any player can attempt to join a battle which is already at capacity.
If there are any players in the battle with a lower rank than the player that attempted to join then remove the lowest ranked player from the battle.
Move the removed player to another battle, one that is closet to reaching its capacity.

The rank of a player is determined by the following list. Top is the best with lower entries breaking ties.

Compare highest BattlePriority gained from faction role. Higher has a higher rank.
Compare whether you are the owner of the planet associated with the battle. Owner has higher rank.
Compare whether you have any friends in the battle. If one of the two players in the comparison has any friends in the battle then they have higher rank.
Compare when you joined the battle. Whoever joined earlier has higher rank, If you are not in the battle you have lower rank.

Lobby Interface

Chobby needs to know MinDefenseTime and MinAttackTime
The list of planets in the defense phase need to specify which factions can join the defense on a per-planet basis.
If you are booted from a battle then a server message should be sent containing keys for which battle you were booted from and informing you of your new battle.
If you attempt to join a full battle but were unable to boot anyone then a server message should be sent telling you that you failed to boot anyone.
An even better lobby interface would be one that encoded the minimum rank required to boot someone from a game and gave the player a way to calculate their rank in each of the games they could join.

Notes

MinDefenseTime and MinAttackTime exist to give the faction a few minutes to plan and discuss their battles. It also allows for people to shuffle and boot each other before any battles are created, resulting in the most flexible creation of battles.

ZeroK-RTS / Zero-K-Infrastructure

Parallel attack and defense queues #2132

Attacking

Defending

Booting

Lobby Interface

Notes