import { describe, expect, it } from "vitest";
import type { CombatPresentationEvent } from "../game/combatPresentation";
import {
  COMBAT_EFFECT_SYSTEM_LIMIT,
  addOriginalInstantCastEffect,
  addOriginalOnlyEffect,
  advanceCombatEffectFrame,
  originalInstantCastEvent,
  originalInstantTerminalEvent,
  updateCombatEffectQueue,
  type ActiveCombatEffect,
} from "./combatEffectRuntime";

function event(
  id: number,
  patch: Partial<CombatPresentationEvent> = {},
): CombatPresentationEvent {
  return {
    id,
    sessionId: 1,
    occurredAt: id,
    phase: "impact",
    actorGroup: "enemy",
    sourceActorId: `enemy-${id}`,
    targetActorId: "player",
    abilityId: "fixture",
    name: "Fixture",
    source: "fallback",
    school: "shadow",
    delivery: "projectile",
    origin: [0, 0, 0],
    targetPosition: [1, 0, 0],
    ...patch,
  };
}

function enqueue(
  events: readonly CombatPresentationEvent[],
  quality: "off" | "low" | "high",
): readonly ActiveCombatEffect[] {
  return events.reduce<readonly ActiveCombatEffect[]>(
    (current, next) => updateCombatEffectQueue(current, next, quality),
    [],
  );
}

describe("combat-effect runtime budget", () => {
  it("expires effects by wall time while bounding motion after a hitch", () => {
    let frame = advanceCombatEffectFrame(0, 1 / 60, 420);
    frame = advanceCombatEffectFrame(frame.elapsedMs, 1 / 60, 420);
    frame = advanceCombatEffectFrame(frame.elapsedMs, 0.5, 420);

    expect(frame.elapsedMs).toBeCloseTo(533.333, 2);
    expect(frame.motionDeltaSeconds).toBe(0.05);
    expect(frame.progress).toBe(1);
    expect(frame.done).toBe(true);
    expect(advanceCombatEffectFrame(frame.elapsedMs, Number.NaN, 420).elapsedMs)
      .toBe(frame.elapsedMs);
  });

  it("bounds large bursts while retaining player feedback and the newest event", () => {
    const player = event(1, {
      actorGroup: "player",
      sourceActorId: "player",
      school: "holy",
    });
    const enemies = Array.from({ length: 512 }, (_, index) => event(index + 2, {
      phase: "tick",
    }));

    const high = enqueue([player, ...enemies], "high");
    const low = enqueue([player, ...enemies], "low");

    expect(high).toHaveLength(COMBAT_EFFECT_SYSTEM_LIMIT.high);
    expect(low).toHaveLength(COMBAT_EFFECT_SYSTEM_LIMIT.low);
    expect(enqueue([player], "off")).toEqual([]);
    expect(updateCombatEffectQueue(enqueue([player], "high"), enemies[0], "off"))
      .toEqual([]);
    expect(high.some(({ event: active }) => active.id === player.id)).toBe(true);
    expect(high.at(-1)?.event.id).toBe(enemies.at(-1)?.id);
    expect(new Set(high.map(({ key }) => key)).size).toBe(high.length);
  });

  it("keeps combat-significant enemy casts ahead of low-value friendly ticks", () => {
    const partyTicks = Array.from({ length: COMBAT_EFFECT_SYSTEM_LIMIT.low }, (_, index) => event(index + 1, {
      actorGroup: "party",
      sourceActorId: `party-${index}`,
      phase: "tick",
    }));
    const enemyCast = event(100, {
      actorGroup: "enemy",
      sourceActorId: "boss",
      phase: "cast-start",
    });

    const effects = enqueue([...partyTicks, enemyCast], "low");
    expect(effects).toHaveLength(COMBAT_EFFECT_SYSTEM_LIMIT.low);
    expect(effects.some(({ event: active }) => active.id === enemyCast.id)).toBe(true);
    expect(effects.filter(({ event: active }) => active.phase === "tick"))
      .toHaveLength(COMBAT_EFFECT_SYSTEM_LIMIT.low - 1);
  });

  it("coalesces a single area burst but preserves projectile phases", () => {
    const areaRelease = event(1, {
      occurredAt: 100,
      phase: "release",
      delivery: "area",
      sourceActorId: "caster",
    });
    const areaImpacts = Array.from({ length: 5 }, (_, index) => event(index + 2, {
      occurredAt: 100,
      phase: "impact",
      delivery: "area",
      sourceActorId: "caster",
      targetActorId: `target-${index}`,
    }));
    const area = enqueue([areaRelease, ...areaImpacts], "high");
    expect(area).toHaveLength(1);
    expect(area[0].event.phase).toBe("impact");

    const projectile = enqueue([
      event(10, { occurredAt: 200, phase: "release", sourceActorId: "caster" }),
      event(11, { occurredAt: 200, phase: "impact", sourceActorId: "caster" }),
    ], "high");
    expect(projectile).toHaveLength(2);
  });

  it("lets an instant source cast overlap its release while completing timed casts", () => {
    const release = event(2, {
      phase: "release",
      sourceActorId: "instant-caster",
      instantCast: true,
    });
    const sourceCast = originalInstantCastEvent(release);
    expect(sourceCast).toMatchObject({
      id: -2,
      phase: "cast-start",
      sourceActorId: "instant-caster",
      instantCast: true,
    });
    const instant = updateCombatEffectQueue(
      addOriginalInstantCastEffect([], release, "high"),
      release,
      "high",
    );
    expect(instant.map(({ event: active }) => active.phase)).toEqual(["cast-start", "release"]);
    expect(instant[0].originalOnly).toBe(true);

    const timed = enqueue([
      event(3, { phase: "cast-start", sourceActorId: "timed-caster" }),
      event(4, { phase: "release", sourceActorId: "timed-caster" }),
    ], "high");
    expect(timed.map(({ event: active }) => active.phase)).toEqual(["release"]);
    expect(originalInstantCastEvent(timed[0].event)).toBeNull();
  });

  it("preserves source terminal semantics for instant impact and aura fallbacks", () => {
    const impact = event(20, { phase: "impact", instantCast: true, delivery: "area" });
    const auraFallback = originalInstantTerminalEvent(impact);
    expect(auraFallback).toMatchObject({ id: -20, phase: "aura-start", instantCast: true });

    const aura = event(21, { phase: "aura-start", instantCast: true, delivery: "aura" });
    const impactFallback = originalInstantTerminalEvent(aura);
    expect(impactFallback).toMatchObject({ id: -21, phase: "impact", instantCast: true });
    expect(addOriginalOnlyEffect([], impactFallback!, "high")[0]).toMatchObject({
      originalOnly: true,
      event: { phase: "impact" },
    });
    expect(originalInstantTerminalEvent(event(22, { phase: "impact" }))).toBeNull();
  });
});