import { describe, expect, it } from "vitest";
import {
  MAX_COMBAT_EVENT_HISTORY,
  appendCombatEvent,
  subscribeCombatEvents,
  type CombatEventInput,
  type StructuredCombatEvent,
} from "./combatEvents";

function eventInput(index: number): CombatEventInput {
  return {
    occurredAt: index * 100,
    kind: "damage",
    sourceActorId: "benchmark-source",
    targetActorId: "benchmark-target",
    abilityId: "benchmark-strike",
    school: "physical",
    rawAmount: index,
    effectiveAmount: index,
    overheal: 0,
    absorbed: 0,
    critical: false,
  };
}

describe("combat event subscriptions", () => {
  it("publishes every event while retaining only the bounded HUD history", () => {
    const published: StructuredCombatEvent[] = [];
    const unsubscribe = subscribeCombatEvents((event) => published.push(event));
    let history: readonly StructuredCombatEvent[] = [];
    const eventCount = MAX_COMBAT_EVENT_HISTORY + 75;

    try {
      for (let id = 1; id <= eventCount; id += 1) {
        history = appendCombatEvent(history, eventInput(id), id);
      }
    } finally {
      unsubscribe();
    }

    expect(published).toHaveLength(eventCount);
    expect(published.map((event) => event.id)).toEqual(
      Array.from({ length: eventCount }, (_, index) => index + 1),
    );
    expect(history).toHaveLength(MAX_COMBAT_EVENT_HISTORY);
    expect(history[0]?.id).toBe(eventCount - MAX_COMBAT_EVENT_HISTORY + 1);
    expect(history.at(-1)?.id).toBe(eventCount);

    appendCombatEvent(history, eventInput(eventCount + 1), eventCount + 1);
    expect(published).toHaveLength(eventCount);
  });

  it("isolates authoritative recording from a failing subscriber", () => {
    const published: number[] = [];
    const unsubscribeFailing = subscribeCombatEvents(() => {
      throw new Error("metrics consumer failed");
    });
    const unsubscribeHealthy = subscribeCombatEvents((event) => published.push(event.id));

    try {
      expect(appendCombatEvent([], eventInput(1), 1)).toHaveLength(1);
      expect(published).toEqual([1]);
    } finally {
      unsubscribeHealthy();
      unsubscribeFailing();
    }
  });
});