healer-man/src/game/combatResults.test.ts

import { describe, expect, it } from "vitest";
import { EMPTY_ITEM_STATS } from "./itemStats";
import {
  baseMissChancePercent,
  combatAttackTable,
  combatAttackerFromCharacterStats,
  combatDefenderFromCharacterStats,
  resolveCombatResult,
  type CombatRollSource,
  type ResolveCombatResultInput,
} from "./combatResults";
import { deriveCharacterStats } from "./wotlkStats";

function fixedRoll(outcome: number, resistance = 0.5): CombatRollSource {
  return (stage) => stage === "outcome" ? outcome : resistance;
}

function physicalAttack(overrides: Partial<ResolveCombatResultInput> = {}): ResolveCombatResultInput {
  return {
    amount: 100,
    attackKind: "melee",
    damageSchool: "physical",
    attacker: { level: 80, criticalChancePercent: 20 },
    defender: {
      level: 80,
      dodgePercent: 10,
      parryPercent: 10,
      blockPercent: 10,
      blockValue: 20,
    },
    ...overrides,
  };
}

describe("discrete combat results", () => {
  it("builds WotLK-shaped special, spell, and dual-wield miss chances", () => {
    expect(baseMissChancePercent("melee", 80, 80)).toBe(5);
    expect(baseMissChancePercent("melee", 80, 83)).toBe(8);
    expect(baseMissChancePercent("spell", 80, 83)).toBe(17);
    expect(baseMissChancePercent("melee", 80, 80, true)).toBe(24);
  });

  it.each([
    [0.01, "miss"],
    [0.10, "dodge"],
    [0.20, "parry"],
    [0.30, "block"],
    [0.40, "crit"],
    [0.80, "hit"],
  ] as const)("resolves roll %s as %s on a single attack table", (roll, outcome) => {
    const result = resolveCombatResult({ ...physicalAttack(), roll: fixedRoll(roll) });
    expect(result.outcome).toBe(outcome);
    expect(result.landed).toBe(["block", "crit", "hit"].includes(outcome));
    expect(result.avoided).toBe(["miss", "dodge", "parry"].includes(outcome));
    if (outcome === "block") expect(result.blockedAmount).toBe(20);
    if (outcome === "crit") expect(result.damageBeforeMitigation).toBe(200);
  });

  it("applies hit and expertise before rolling and exposes the resulting table", () => {
    const input = physicalAttack({
      attacker: {
        level: 80,
        hitPercent: 5,
        expertiseReductionPercent: 10,
        criticalChancePercent: 20,
      },
    });
    expect(combatAttackTable(input)).toEqual({
      missPercent: 0,
      dodgePercent: 0,
      parryPercent: 0,
      blockPercent: 10,
      criticalPercent: 20,
      hitPercent: 70,
    });
  });

  it("reduces physical damage with effective armor after armor penetration", () => {
    const result = resolveCombatResult({
      ...physicalAttack({
        attacker: { level: 80, hitPercent: 100, armorPenetrationPercent: 50 },
        defender: { level: 80, armor: 2_000 },
      }),
      roll: fixedRoll(0.5),
    });
    expect(result.outcome).toBe("hit");
    expect(result.effectiveArmor).toBe(1_000);
    expect(result.armorReductionPercent).toBeGreaterThan(0);
    expect(result.armorMitigatedAmount).toBeGreaterThan(0);
    expect(result.finalDamage).toBe(100 - result.armorMitigatedAmount);
  });

  it("fully resists binary spells using a separate deterministic resistance roll", () => {
    const result = resolveCombatResult({
      amount: 100,
      attackKind: "spell",
      damageSchool: "fire",
      attacker: { level: 80, hitPercent: 4 },
      defender: { level: 80, resistances: { fire: 400 } },
      rules: { resistanceMode: "binary" },
      roll: fixedRoll(0.5, 0.2),
    });
    expect(result.outcome).toBe("resist");
    expect(result.fullyResisted).toBe(true);
    expect(result.avoided).toBe(true);
    expect(result.resistedAmount).toBe(100);
    expect(result.damageBeforeMitigation).toBe(100);
    expect(result.finalDamage).toBe(0);
  });

  it("rolls partial resistance in 10% buckets and honors spell penetration", () => {
    const resisted = resolveCombatResult({
      amount: 100,
      attackKind: "spell",
      damageSchool: "frost",
      attacker: { level: 80, hitPercent: 4, spellPenetration: 100 },
      defender: { level: 80, resistances: { frost: 500 } },
      roll: fixedRoll(0.5, 0.5),
    });
    expect(resisted.outcome).toBe("hit");
    expect(resisted.resistanceFraction).toBeCloseTo(0.4);
    expect(resisted.resistedAmount).toBe(40);
    expect(resisted.finalDamage).toBe(60);
    expect(resisted.partiallyResisted).toBe(true);
  });

  it("reports critical, block, resistance, and flat damage-reduction metadata exactly", () => {
    const result = resolveCombatResult({
      amount: 100,
      attackKind: "melee",
      damageSchool: "physical",
      attacker: { level: 80, hitPercent: 100, criticalChancePercent: 100 },
      defender: { level: 80, damageReductionPercent: 25 },
      roll: fixedRoll(0.5),
    });
    expect(result).toMatchObject({
      outcome: "crit",
      landed: true,
      critical: true,
      avoided: false,
      rawDamage: 100,
      damageBeforeMitigation: 200,
      armorMitigatedAmount: 0,
      blockedAmount: 0,
      resistedAmount: 0,
      damageReductionAmount: 50,
      finalDamage: 150,
    });
  });

  it("adapts derived character stats for outgoing and incoming attacks", () => {
    const stats = deriveCharacterStats("warrior", 80, {
      ...EMPTY_ITEM_STATS,
      armor: 1_000,
      hitRating: 100,
      criticalStrikeRating: 100,
      expertiseRating: 100,
      armorPenetrationRating: 100,
      blockValue: 50,
      fireResistance: 40,
    });
    const attacker = combatAttackerFromCharacterStats(stats, "melee");
    const defender = combatDefenderFromCharacterStats(stats);
    expect(attacker.hitPercent).toBe(stats.meleeHitPercent);
    expect(attacker.criticalChancePercent).toBe(stats.meleeCritPercent);
    expect(attacker.expertiseReductionPercent).toBe(stats.expertiseReductionPercent);
    expect(defender).toMatchObject({
      level: 80,
      armor: stats.armor,
      blockValue: stats.blockValue,
      resistances: { fire: 40 },
    });
  });
});