Phase Management

Phase and Step Definitions

The Commander implementation uses a hierarchical structure of phases and steps that closely follows the official Magic rules:

#![allow(unused)]
fn main() {
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Phase {
    Beginning(BeginningStep),
    Precombat(PrecombatStep),
    Combat(CombatStep),
    Postcombat(PostcombatStep),
    Ending(EndingStep),
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum BeginningStep {
    Untap,
    Upkeep,
    Draw,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum PrecombatStep {
    Main,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum CombatStep {
    Beginning,
    DeclareAttackers,
    DeclareBlockers,
    CombatDamage,
    End,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum PostcombatStep {
    Main,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum EndingStep {
    End,
    Cleanup,
}
}

Phase Transitions

Phase transitions are managed by the turn system and occur when:

All players have passed priority with an empty stack
Certain turn-based actions are completed
Special effects cause phase skipping or addition

Phase-Specific Actions

Each phase and step has specific turn-based actions that occur at its beginning:

Beginning Phase

Untap Step

The active player untaps all permanents they control
No players receive priority during this step
"At the beginning of your untap step" triggered abilities trigger

Upkeep Step

"At the beginning of your upkeep" triggered abilities trigger
Players receive priority

Draw Step

Active player draws a card
"At the beginning of your draw step" triggered abilities trigger
Players receive priority

Main Phases

Active player may play land (once per turn)
Players may cast spells and activate abilities
No automatic actions occur

Combat Phase

Detailed in the Combat System documentation

Ending Phase

End Step

"At the beginning of your end step" triggered abilities trigger
Players receive priority

Cleanup Step

Active player discards down to maximum hand size
Damage is removed from permanents
"Until end of turn" effects end
Normally, no player receives priority during this step
- If any state-based actions are performed or triggered abilities trigger, players do receive priority

Special Phase Handling

The phase system accounts for special cases:

#![allow(unused)]
fn main() {
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum TurnRestriction {
    NoUntap,
    NoUpkeep,
    NoDraw,
    NoMainPhase,
    NoCombat,
    MaxSpells(u32),
    // Other restrictions
}
}

These phase restrictions can be applied through card effects and are managed by the TurnManager.

Rummage Documentation