import { expect } from "vitest";
import type { GameWorld } from "../src/game/world/world";
import { settle } from "./world-driver";

/** Acknowledge pages up to the next choice; returns the pages seen. */
export function until(world: GameWorld) {
  const pages: string[] = [];
  for (let tick = 0; tick < 500; tick++) {
    const dialogue = world.dialogue;
    if (!dialogue) {
      if (!world.busy) return pages;
      world.tick();
      continue;
    }
    const page = dialogue.pages[dialogue.index].replace(/\n/g, " ");
    if (page && pages.at(-1) !== page) pages.push(page);
    const last = dialogue.index === dialogue.pages.length - 1;
    if (last && dialogue.choice) return pages;
    if (last && dialogue.holdTicks !== undefined) world.tick();
    else world.advanceDialogue();
  }
  throw new Error("No choice appeared.");
}

export function menuItems(world: GameWorld) {
  const choice = world.dialogue?.choice;
  return choice?.kind === "menu" ? choice.items : [];
}

/** Choose the menu item matching `label` (the whole label, or a regex). */
export function pick(world: GameWorld, label: string | RegExp) {
  const items = menuItems(world);
  const index = items.findIndex((item) =>
    typeof label === "string" ? item === label : label.test(item),
  );
  expect(index, `${label} in ${items.join(", ")}`).toBeGreaterThanOrEqual(0);
  world.choose(index);
  return until(world);
}

/** Choose the pack entry for `item` in its pocket. */
export function pickItem(world: GameWorld, item: number) {
  const choice = world.dialogue?.choice;
  if (choice?.kind !== "pack")
    throw new Error(`Expected the pack, got ${choice?.kind}`);
  for (const [pocket, { entries }] of choice.pockets.entries()) {
    const index = entries.findIndex((entry) => entry.item === item);
    if (index >= 0) {
      world.choosePackEntry(pocket, index);
      return until(world);
    }
  }
  throw new Error(`Item ${item} is not in the pack.`);
}

export function open(world: GameWorld) {
  expect(world.openStartMenu()).toBe(true);
  return until(world);
}

/** PACK, the item, then USE: the pages shown up to the next choice. */
export function useItem(world: GameWorld, item: number) {
  open(world);
  pick(world, "PACK");
  pickItem(world, item);
  return pick(world, "USE");
}

/** B until every menu has closed; returns the pages shown meanwhile. */
export function close(world: GameWorld) {
  const pages: string[] = [];
  for (let i = 0; i < 20 && world.busy; i++) {
    if (world.dialogue?.choice) world.advanceDialogue();
    pages.push(...until(world));
  }
  pages.push(...settle(world));
  expect(world.diagnostic).toBe("");
  return pages;
}