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

import { describe, expect, it, vi } from "vitest";
import {
  absorbDamage,
  applyAura,
  dispelAuras,
  evaluateAuraProcs,
  expireAuras,
  resolveDamageValue,
  resolveResourceValue,
  resolveStatValue,
  type ActiveAura,
  type AuraDefinition,
} from "./combatAuras";

const buff = (overrides: Partial<AuraDefinition> = {}): AuraDefinition => ({
  id: "test-buff",
  name: "Test Buff",
  disposition: "buff",
  durationMs: 5_000,
  ...overrides,
});

function apply(
  definition: AuraDefinition,
  now = 0,
  current: readonly ActiveAura[] = [],
  stacks = 1,
): readonly ActiveAura[] {
  return applyAura(current, {
    definition,
    sourceId: "caster",
    targetId: "player",
    now,
    stacks,
  }).auras;
}

describe("combat auras", () => {
  it("adds stacks to the cap and refreshes the duration", () => {
    const definition = buff({ maxStacks: 3, stackBehavior: "add" });
    let auras = apply(definition, 100, [], 2);
    auras = apply(definition, 1_000, auras, 2);

    expect(auras).toHaveLength(1);
    expect(auras[0]).toMatchObject({ stacks: 3, appliedAt: 1_000, expiresAt: 6_000 });
  });

  it("refreshes without adding stacks and replaces when requested", () => {
    const refreshing = buff({ maxStacks: 4, stackBehavior: "refresh" });
    let auras = apply(refreshing, 0, [], 2);
    auras = apply(refreshing, 500, auras, 1);
    expect(auras[0]).toMatchObject({ stacks: 2, expiresAt: 5_500 });

    const replacing = buff({ maxStacks: 4, stackBehavior: "replace" });
    auras = apply(replacing, 1_000, auras, 1);
    expect(auras[0]).toMatchObject({ stacks: 1, appliedAt: 1_000, expiresAt: 6_000 });
  });

  it("applies typed stat, resource, and damage modifiers", () => {
    const auras = apply(buff({
      maxStacks: 2,
      modifiers: [
        { kind: "stat", stat: "strength", operation: "flat", value: 5 },
        { kind: "resource", resource: "mana", property: "cost", operation: "percent", value: -0.1 },
        { kind: "damage", direction: "dealt", school: "fire", operation: "percent", value: 0.2, perStack: false },
      ],
    }), 0, [], 2);

    expect(resolveStatValue(10, auras, "strength")).toBe(20);
    expect(resolveResourceValue(100, auras, "mana", "cost")).toBe(80);
    expect(resolveDamageValue(100, auras, { direction: "dealt", school: "fire", attackKind: "spell" })).toBe(120);
    expect(resolveDamageValue(100, auras, { direction: "dealt", school: "frost", attackKind: "spell" })).toBe(100);
  });

  it("selectively dispels debuffs for allies and buffs for hostile purges", () => {
    const magicDebuff = buff({ id: "magic-dot", disposition: "debuff", dispelCategory: "magic" });
    const poisonDebuff = buff({ id: "poison", disposition: "debuff", dispelCategory: "poison" });
    const magicBuff = buff({ id: "power", dispelCategory: "magic" });
    let auras: readonly ActiveAura[] = [];
    auras = apply(magicDebuff, 0, auras);
    auras = apply(poisonDebuff, 1, auras);
    auras = apply(magicBuff, 2, auras);

    const cleanse = dispelAuras(auras, { relationship: "friendly", categories: ["magic"] });
    expect(cleanse.removed.map((aura) => aura.definition.id)).toEqual(["magic-dot"]);
    expect(cleanse.auras.map((aura) => aura.definition.id)).toEqual(["poison", "power"]);

    const purge = dispelAuras(cleanse.auras, { relationship: "hostile", categories: ["magic"] });
    expect(purge.removed.map((aura) => aura.definition.id)).toEqual(["power"]);
    expect(purge.auras.map((aura) => aura.definition.id)).toEqual(["poison"]);
  });

  it("expires finite auras while retaining permanent ones", () => {
    let auras: readonly ActiveAura[] = [];
    auras = apply(buff({ id: "short", durationMs: 1_000 }), 100, auras);
    auras = apply(buff({ id: "permanent", durationMs: null }), 100, auras);

    const atBoundary = expireAuras(auras, 1_100);
    expect(atBoundary.expired.map((aura) => aura.definition.id)).toEqual(["short"]);
    expect(atBoundary.active.map((aura) => aura.definition.id)).toEqual(["permanent"]);
  });

  it("consumes only matching absorbs and reports damage left over", () => {
    let auras: readonly ActiveAura[] = [];
    auras = apply(buff({
      id: "wards",
      absorbs: [
        { id: "fire-ward", amount: 30, school: "fire" },
        { id: "barrier", amount: 25 },
      ],
    }), 0, auras);

    const result = absorbDamage(auras, {
      targetId: "player",
      amount: 70,
      school: "fire",
      now: 100,
    });
    expect(result).toMatchObject({ absorbed: 55, remainingDamage: 15 });
    expect(result.consumptions.map(({ absorbId, amount }) => [absorbId, amount])).toEqual([
      ["fire-ward", 30],
      ["barrier", 25],
    ]);
    expect(result.auras[0].absorbs.map((absorb) => absorb.remaining)).toEqual([0, 0]);
  });

  it("supports guaranteed and failed deterministic proc rolls", () => {
    const definition = buff({
      procs: [{
        id: "spark",
        triggers: "hit",
        chance: 0.25,
        action: { kind: "damage", amount: 10, school: "fire", target: "event-other" },
      }],
    });
    const auras = apply(definition);
    const guaranteed = evaluateAuraProcs(auras, {
      trigger: "hit",
      subjectId: "player",
      otherId: "mob",
    }, 100, () => 0.24);
    expect(guaranteed.triggered).toHaveLength(1);

    const failed = evaluateAuraProcs(auras, {
      trigger: "hit",
      subjectId: "player",
      otherId: "mob",
    }, 100, () => 0.25);
    expect(failed.triggered).toHaveLength(0);
  });

  it("enforces proc internal cooldowns and consumes charges only on success", () => {
    const roll = vi.fn(() => 0);
    const definition = buff({
      durationMs: 20_000,
      procs: [{
        id: "echo",
        triggers: ["cast", "heal"],
        chance: 1,
        internalCooldownMs: 1_000,
        charges: 2,
        action: { kind: "custom", id: "echo-cast" },
      }],
    });
    let auras = apply(definition);
    let result = evaluateAuraProcs(auras, { trigger: "cast", subjectId: "player" }, 100, roll);
    expect(result.triggered).toHaveLength(1);
    expect(result.auras[0].procStates[0]).toMatchObject({ readyAt: 1_100, remainingCharges: 1 });

    result = evaluateAuraProcs(result.auras, { trigger: "heal", subjectId: "player" }, 500, roll);
    expect(result.triggered).toHaveLength(0);
    expect(roll).toHaveBeenCalledTimes(1);

    result = evaluateAuraProcs(result.auras, { trigger: "heal", subjectId: "player" }, 1_100, roll);
    expect(result.triggered).toHaveLength(1);
    expect(result.auras[0].procStates[0].remainingCharges).toBe(0);

    result = evaluateAuraProcs(result.auras, { trigger: "cast", subjectId: "player" }, 3_000, roll);
    expect(result.triggered).toHaveLength(0);
    expect(roll).toHaveBeenCalledTimes(2);
  });
});