// COMB-02: Death Save Logic Extraction
// ============================================================
/**
* Simplified death save tracker for the evaluateDeathSave helper.
* Contains only the essential success/failure counts.
*/
interface DeathSaveTracker {
successes: number;
failures: number;
}
/**
* Possible outcomes of a death saving throw.
*
* D&D 5e PHB p.197 defines these outcomes:
* - success: Roll 10+ (with modifiers) - one step closer to stability
* - failure: Roll 9- (with modifiers) - one step closer to death
* - stable: Third success reached - stable but unconscious
* - dead: Third failure reached - character dies
* - revived: Natural 20 - regain consciousness at 1 HP
*/
type DeathSaveOutcome =
| { status: 'success'; message: string }
| { status: 'failure'; message: string }
| { status: 'stable'; message: string }
| { status: 'dead'; message: string }
| { status: 'revived'; message: string };
/**
* Evaluate a death saving throw and return the outcome.
*
* This is the core death save logic extracted from rollDeathSave for reusability.
* It handles all D&D 5e death save rules (PHB p.197):
* 1. Natural 20: Immediate revival at 1 HP
* 2. Natural 1: Counts as TWO failures (can cause instant death)
* 3. Total >= 10: One success
* 4. Total < 10: One failure
* 5. Three successes: Character becomes stable
* 6. Three failures: Character dies
*
* @param roll - The natural d20 roll (1-20, before modifiers)
* @param tracker - Current death save tracker (successes and failures)
* @param modifier - Optional modifier to add to the roll (default 0)
* @returns Object with the outcome and updated tracker
*/
function evaluateDeathSave(
roll: number,
tracker: DeathSaveTracker,
modifier: number = 0
): { outcome: DeathSaveOutcome; updatedTracker: DeathSaveTracker } {
// Clone tracker to avoid mutation
const updatedTracker: DeathSaveTracker = {
successes: tracker.successes,
failures: tracker.failures
};
// Handle natural 20 (revive with 1 HP)
if (roll === 20) {
// Natural 20 clears all death saves and revives
updatedTracker.successes = 0;
updatedTracker.failures = 0;
return {
outcome: { status: 'revived', message: '✨ NATURAL 20! ✨ Regains consciousness at 1 HP!' },
updatedTracker
};
}
// Handle natural 1 (2 failures)
if (roll === 1) {
updatedTracker.failures += 2;
if (updatedTracker.failures >= 3) {
updatedTracker.failures = 3;
return {
outcome: { status: 'dead', message: '💀 NATURAL 1! Two failures - DEATH! 💀' },
updatedTracker
};
}
return {
outcome: { status: 'failure', message: '⚠️ NATURAL 1! Two failures added!' },
updatedTracker
};
}
// Calculate total with modifier
const total = roll + modifier;
// Handle 10+ (success)
if (total >= 10) {
updatedTracker.successes += 1;
// Check for stabilization (3 successes)
if (updatedTracker.successes >= 3) {
updatedTracker.successes = 3;
return {
outcome: { status: 'stable', message: '★ STABILIZED! ★ No longer dying.' },
updatedTracker
};
}
return {
outcome: { status: 'success', message: 'Success! Holding on...' },
updatedTracker
};
}
// Handle <10 (failure)
updatedTracker.failures += 1;
// Check for death (3 failures)
if (updatedTracker.failures >= 3) {
updatedTracker.failures = 3;
return {
outcome: { status: 'dead', message: '💀 Three failures - DEATH! 💀' },
updatedTracker
};
}
return {
outcome: { status: 'failure', message: 'Failure. Slipping away...' },
updatedTracker
};
}
// Legacy internal type for backward compatibility with existing formatting functions
type DeathSaveOutcomeInternal =
| { type: 'nat20'; message: string }
| { type: 'nat1'; message: string }
| { type: 'success'; message: string }
| { type: 'failure'; message: string }
| { type: 'stabilized'; message: string }
| { type: 'death'; message: string };
