healer-man/src/game/wow335DeathKnightSpellDeflectionRuntime.ts

import { WOW335_TALENT_NODES } from "./wow335Talents.generated";
import type { EnemyDamageSchool } from "./enemyAttacks";

export const WOW335_DEATH_KNIGHT_SPELL_DEFLECTION_TALENT_ID = "talent-2018";

const WOW335_DAMAGE_SCHOOL_MASKS: Readonly<Record<EnemyDamageSchool, number>> = {
  physical: 1,
  holy: 2,
  fire: 4,
  nature: 8,
  frost: 16,
  shadow: 32,
  arcane: 64,
};

/** Translate the incoming combat-school label into its 3.3.5 DBC school bit. */
export function wow335DeathKnightSpellDeflectionSchoolMask(school: EnemyDamageSchool): number {
  return WOW335_DAMAGE_SCHOOL_MASKS[school];
}

const SPELL_DEFLECTION_NODE = WOW335_TALENT_NODES.find(
  (node) => node.id === WOW335_DEATH_KNIGHT_SPELL_DEFLECTION_TALENT_ID,
);

export interface Wow335DeathKnightSpellDeflectionProfile {
  readonly rank: number;
  readonly absorbFraction: number;
  readonly procChanceSource: "live-parry";
  readonly auraType: 69;
  readonly schoolMask: number;
}

/** Read rank reduction and spell-school mask from generated local talent rows. */
export function wow335DeathKnightSpellDeflectionProfile(
  rank: number,
): Wow335DeathKnightSpellDeflectionProfile | null {
  const normalizedRank = Math.trunc(rank);
  const rankEffect = SPELL_DEFLECTION_NODE?.rankEffects[normalizedRank - 1];
  const description = SPELL_DEFLECTION_NODE?.rankDescriptions[normalizedRank - 1];
  if (normalizedRank < 1 || !rankEffect || !description
    || rankEffect.procCharges !== 0
    || rankEffect.recoveryTimeMs !== 0
    || rankEffect.categoryRecoveryTimeMs !== 0) return null;

  const values = description.match(
    /^You have a chance equal to your Parry chance of taking (\d+(?:\.\d+)?)% less damage from a direct damage spell\.$/,
  );
  const effect = rankEffect.effects.find((candidate) => candidate.effectType === 6 && candidate.auraType === 69);
  const reductionPercent = Number(values?.[1]);
  if (!values || !effect || effect.miscValue !== 126
    || !Number.isFinite(reductionPercent) || reductionPercent <= 0 || reductionPercent >= 100) return null;

  return {
    rank: normalizedRank,
    absorbFraction: reductionPercent / 100,
    procChanceSource: "live-parry",
    auraType: effect.auraType,
    schoolMask: effect.miscValue,
  };
}

export interface Wow335DeathKnightSpellDeflectionEvent {
  /** True only for one direct spell-damage hit; periodic ticks and weapon hits are excluded. */
  readonly directDamageSpell: boolean;
  /** DBC school mask for the incoming spell hit; Spell Deflection has mask 126. */
  readonly schoolMask: number;
  /** Defender's current, fully derived Parry chance in percentage points, such as 7.5. */
  readonly parryChancePercent: number;
  /** Deterministic unit roll in [0, 1). */
  readonly roll: number;
  /** Resolved spell damage before this talent's absorb; misses and zero-damage hits cannot proc. */
  readonly damage: number;
}

/**
 * Proc chance equals the defender's current Parry chance. The generated aura is
 * School Absorb (69), limited by school mask 126, and applies to direct hits.
 */
export function wow335DeathKnightSpellDeflectionShouldProc(
  rank: number,
  event: Wow335DeathKnightSpellDeflectionEvent,
): boolean {
  const profile = wow335DeathKnightSpellDeflectionProfile(rank);
  if (!profile
    || !event.directDamageSpell
    || !Number.isSafeInteger(event.schoolMask) || event.schoolMask <= 0
    || (event.schoolMask & profile.schoolMask) === 0
    || !Number.isFinite(event.damage) || event.damage <= 0
    || !Number.isFinite(event.parryChancePercent)
    || !Number.isFinite(event.roll) || event.roll < 0 || event.roll >= 1) return false;
  const chance = Math.min(100, Math.max(0, event.parryChancePercent)) / 100;
  return chance > 0 && event.roll < chance;
}

/**
 * Return the amount absorbed from this hit. Generated rows specify the percent,
 * not fractional-damage rounding; this simulator floors to whole damage points.
 */
export function wow335DeathKnightSpellDeflectionAbsorbedAmount(
  damage: number,
  rank: number,
): number {
  const profile = wow335DeathKnightSpellDeflectionProfile(rank);
  if (!profile || !Number.isFinite(damage) || damage <= 0) return 0;
  return Math.min(Math.floor(damage), Math.floor(Math.floor(damage) * profile.absorbFraction));
}

/** Apply the generated partial absorb after the proc roll has succeeded. */
export function wow335DeathKnightSpellDeflectionDamage(
  damage: number,
  rank: number,
): number {
  if (!Number.isFinite(damage) || damage <= 0) return Math.max(0, Number.isFinite(damage) ? Math.floor(damage) : 0);
  return Math.max(0, Math.floor(damage) - wow335DeathKnightSpellDeflectionAbsorbedAmount(damage, rank));
}