import { describe, expect, it } from "vitest";
import {
  selectEnemyChainTargets,
  type EnemyChainTargetCandidate,
} from "./enemyChainTargeting";

const target = (
  id: string,
  x: number,
  alive = true,
): EnemyChainTargetCandidate => ({
  id,
  alive,
  position: [x, 0, 0],
});

describe("enemy chain target selection", () => {
  it("keeps the primary first and selects the nearest target from each prior hit", () => {
    const primary = target("primary", 0);
    const hits = selectEnemyChainTargets({
      primaryTarget: primary,
      candidates: [target("east", 6), target("west", -5), target("west-next", -13)],
      maximumTargets: 3,
      jumpRange: 10,
      damageMultiplierPerBounce: 0.6,
      hasLineOfSight: () => true,
    });

    expect(hits.map(({ target: hit, jumpIndex, damageMultiplier }) => ({
      id: hit.id,
      jumpIndex,
      damageMultiplier,
    }))).toEqual([
      { id: "primary", jumpIndex: 0, damageMultiplier: 1 },
      { id: "west", jumpIndex: 1, damageMultiplier: 0.6 },
      { id: "west-next", jumpIndex: 2, damageMultiplier: 0.36 },
    ]);
  });

  it("skips dead, out-of-pool, and blocked candidates without repeating actor IDs", () => {
    const primary = target("primary", 0);
    const hits = selectEnemyChainTargets({
      primaryTarget: primary,
      candidates: [
        target("blocked", 1),
        target("first", 3),
        target("first", 3.1),
        target("dead", 3.2, false),
        target("second", 7),
        target("outside-search-pool", 41),
      ],
      maximumTargets: 4,
      jumpRange: 10,
      damageMultiplierPerBounce: 0.7,
      hasLineOfSight: (_source, destination) => destination[0] !== 1,
    });

    expect(hits.map(({ target: hit }) => hit.id)).toEqual(["primary", "first", "second"]);
    expect(hits.map(({ damageMultiplier }) => damageMultiplier)).toEqual([1, 0.7, 0.7 * 0.7]);
  });

  it("aborts for a dead primary and never replaces a living primary with a nearer candidate", () => {
    const deadPrimary = target("dead-primary", 0, false);
    expect(selectEnemyChainTargets({
      primaryTarget: deadPrimary,
      candidates: [target("nearby", 0.1)],
      maximumTargets: 3,
      jumpRange: 10,
      damageMultiplierPerBounce: 0.6,
      hasLineOfSight: () => true,
    })).toEqual([]);

    const primary = target("primary", 0);
    const hits = selectEnemyChainTargets({
      primaryTarget: primary,
      candidates: [target("nearby", 0.1)],
      maximumTargets: 3,
      jumpRange: 10,
      damageMultiplierPerBounce: 0.6,
      hasLineOfSight: () => true,
    });
    expect(hits.map(({ target: hit }) => hit.id)).toEqual(["primary", "nearby"]);
  });
});