Crystal/tests/battle-world.test.ts

import { describe, expect, it } from "vitest";
import { existsSync, readFileSync } from "node:fs";
import { CrystalAssets } from "../src/game/rom/assets";
import { battleFixtureWorld, ENCOUNTER_WALK, type BattleScenario } from "./battle-fixture";
import type { GameWorld } from "../src/game/world/world";
import { generatePartyMon, calcStats } from "../src/game/party/pokemon";

const romPath = process.env.CRYSTAL_ROM_PATH ?? "Pokemon - Crystal Version (UE) (V1.1) [C][!].gbc";
const fixture = (scenario: BattleScenario = "win") =>
  battleFixtureWorld(new CrystalAssets(new Uint8Array(readFileSync(romPath))), scenario);

function encounter(world: GameWorld) {
  for (const direction of ENCOUNTER_WALK) expect(world.move(direction)).toBe(true);
  expect(world.battle).toBeDefined();
}

function finish(world: GameWorld, action: "fight" | "run" = "fight") {
  const messages = new Set<string>();
  for (let tick = 0; tick < 10000; tick++) {
    if (world.battle) {
      const view = world.battle;
      if (view.message) messages.add(view.message.text);
      if (view.prompt?.kind === "action") world.battleAction({ action, move: 0 });
      else if (view.prompt?.kind === "yesno") world.battleChoose(1);
      else if (view.prompt?.kind === "forget") world.battleChoose(3);
      else if (view.prompt?.kind === "stats" || view.message?.prompt) world.interact();
      else world.tick();
    } else if (world.dialogue) {
      messages.add(world.dialogue.pages[world.dialogue.index]);
      world.advanceDialogue();
      world.tick();
    } else if (world.busy) world.tick();
    else return [...messages].join("\n");
  }
  throw new Error(`Battle did not settle: ${world.diagnostic}`);
}

describe.skipIf(!existsSync(romPath))("world battle integration with the local ROM", () => {
  it("commits a victory, level-up, move learning and Pokédex sighting", () => {
    const world = fixture();
    encounter(world);
    const before = world.save();
    expect(before.party[0].level).toBe(5);
    expect(before.pokedex.seen).toEqual([155]);
    const messages = finish(world);
    expect(world.notice, world.diagnostic).toBe("");
    expect(messages).toContain("SMOKESCREEN");
    expect(world.state.party[0].level).toBe(6);
    expect(world.state.party[0].moves).toContain(108);
    expect(world.state.pokedex.seen.has(16)).toBe(true);
    expect(world.state.pokedex.caught.has(16)).toBe(false);
    const saved = world.save();
    world.restore(saved);
    expect(world.save()).toEqual(saved);
  });

  it("evolves a Pokémon that levelled up once the battle is won", () => {
    const world = fixture();
    const data = world.assets.pokemon;
    const mon = generatePartyMon(data, {
      species: 155, level: 13, item: 0, otId: world.playerId,
      ot: "CHRIS", dvs: 0x823b, caughtData: 0,
    });
    mon.exp = data.expAtLevel(data.baseData(155).growthRate, 14) - 1;
    world.state.party[0] = mon;
    encounter(world);
    const messages = finish(world);
    expect(world.notice, world.diagnostic).toBe("");
    expect(messages).toContain("What? CYNDAQUIL\nis evolving!");
    expect(messages).toContain("evolved into\nQUILAVA!");
    const evolved = world.state.party[0];
    expect([evolved.species, evolved.nickname, evolved.level]).toEqual([156, "QUILAVA", 14]);
    expect(evolved.stats).toEqual(calcStats(data, 156, evolved.dvs, 14, evolved.statExp));
    expect(world.state.pokedex.caught.has(156)).toBe(true);
    const saved = world.save();
    world.restore(saved);
    expect(world.save()).toEqual(saved);
  });

  it("considers only the Pokémon that levelled up (wEvolvableFlags)", () => {
    const world = fixture();
    const data = world.assets.pokemon;
    // A level-14 Cyndaquil that does not take part could evolve, but
    // EvolveAfterBattle only checks the one that grew to level 6.
    world.state.party.push(generatePartyMon(data, {
      species: 155, level: 14, item: 0, otId: world.playerId,
      ot: "CHRIS", dvs: 0x823b, caughtData: 0,
    }));
    encounter(world);
    const messages = finish(world);
    expect(world.notice, world.diagnostic).toBe("");
    expect(world.state.party[0].level).toBe(6);
    expect(messages).not.toContain("evolving");
    expect(world.state.party.map((mon) => mon.species)).toEqual([155, 155]);
  });

  it("struggles with recoil once every move is out of PP", () => {
    const world = fixture();
    world.state.party[0].pp = [0, 0, 0, 0];
    encounter(world);
    const messages = finish(world);
    expect(world.notice, world.diagnostic).toBe("");
    expect(messages).toMatch(/STRUGGLE/);
    expect(messages).toMatch(/recoil/i);
  });

  it("escapes without awarding experience and returns to walking", () => {
    const world = fixture();
    encounter(world);
    expect(finish(world, "run")).toMatch(/Got away safely/);
    expect(world.notice, world.diagnostic).toBe("");
    expect(world.state.party[0].exp).toBe(178);
    expect(world.state.pokedex.seen.has(16)).toBe(true);
    expect(world.move("down")).toBe(true);
  });

  it("restores earned stat experience before the next stat recalculation", () => {
    const world = fixture();
    const mon = generatePartyMon(world.assets.pokemon, {
      species: 155, level: 100, item: 0, otId: world.playerId,
      ot: "CHRIS", dvs: 0x823b, caughtData: 0,
    });
    mon.moves = [33, 0, 0, 0];
    mon.pp = [35, 0, 0, 0];
    world.state.party = [mon];
    encounter(world);
    finish(world);
    expect(world.notice, world.diagnostic).toBe("");
    const saved = world.save();
    expect(saved.party[0].statExp.some((value) => value > 0)).toBe(true);
    expect(saved.party[0].stats).not.toEqual(calcStats(world.assets.pokemon, 155, mon.dvs, 100, saved.party[0].statExp));
    expect(() => world.restore(saved)).not.toThrow();
    expect(world.save()).toEqual(saved);
    const corrupt = structuredClone(saved);
    corrupt.party[0].stats[1] = 999;
    expect(() => world.restore(corrupt)).toThrow("Invalid native save");
  });

  it("whiteout heals the party, halves money and returns home", () => {
    const world = fixture("loss");
    encounter(world);
    const messages = finish(world);
    expect(world.notice, world.diagnostic).toBe("");
    expect(messages).toMatch(/whited\s+out/i);
    expect(world.save()).toMatchObject({ map: "24:7", x: 3, y: 3, money: 1500 });
    const mon = world.state.party[0];
    expect(mon.hp).toBe(mon.stats[0]);
    expect(mon.pp[0]).toBe(35);
    expect(mon.status).toBe(0);
  });

  it("a mid-battle save restores the committed party and position", () => {
    const world = fixture();
    encounter(world);
    const committed = world.save();
    for (let tick = 0; tick < 5000; tick++) {
      if (world.battle?.prompt?.kind === "action") {
        world.battleAction({ action: "fight", move: 0 });
        break;
      }
      if (world.battle?.message?.prompt) world.interact();
      else world.tick();
    }
    expect(world.save()).toEqual(committed);
    world.restore(committed);
    expect(world.battle).toBeUndefined();
    expect(world.save()).toEqual(committed);
    expect(world.move("right")).toBe(true);
  });

  it("a failed whiteout map callback cannot commit healing or money loss", () => {
    const world = fixture("loss");
    encounter(world);
    const before = world.save();
    // A malformed callback models a destination whose logic is not supported.
    world.assets.map("24:7").callbacks.push({ kind: 5, script: world.assets.reader.bytes.length });
    finish(world);
    expect(world.notice).toContain("not been ported");
    expect(world.save().money).toBe(before.money);
    expect(world.save().party).toEqual(before.party);
    expect(world.save().pokedex).toEqual(before.pokedex);
  });

  it("unsupported effects discard all battle party and Pokédex changes", () => {
    const world = fixture("unsupported");
    encounter(world);
    const before = world.save();
    finish(world);
    expect(world.notice).toContain("not been ported");
    expect(world.save().party).toEqual(before.party);
    expect(world.save().pokedex).toEqual(before.pokedex);
    expect(world.save().money).toBe(before.money);
  });
});