import { describe, expect, it } from "vitest";
import { existsSync, readFileSync } from "node:fs";
import { CrystalAssets } from "../src/game/rom/assets";
import { GameWorld } from "../src/game/world/world";
import { generatePartyMon } from "../src/game/party/pokemon";
import { flypoints, landmarkPosition, regionAtlas } from "../src/game/world/atlas";
import { defaultTextContext } from "../src/game/scripts/text";
import { OW } from "../src/game/world/constants";

const romPath =
  process.env.CRYSTAL_ROM_PATH ??
  "Pokemon - Crystal Version (UE) (V1.1) [C][!].gbc";
const pret = ".reference/pokecrystal";
const NEW_BARK_TOWN = "24:4",
  LANDMARK_NEW_BARK_TOWN = 1,
  LANDMARK_ROUTE_29 = 2,
  LANDMARK_CHERRYGROVE_CITY = 3,
  LANDMARK_VIOLET_CITY = 6,
  LANDMARK_AZALEA_TOWN = 12,
  LANDMARK_PALLET_TOWN = 47;

describe.skipIf(!existsSync(romPath) || !existsSync(`${pret}/data/maps/landmarks.asm`))(
  "the atlas data against the pinned PRET source",
  () => {
    const assets = new CrystalAssets(new Uint8Array(readFileSync(romPath)));
    const read = (path: string) => readFileSync(`${pret}/${path}`, "utf8");
    // const_def counts from 0, or from the value given.
    const constants = (path: string, prefix: string) => {
      const values = new Map<string, number>();
      let next = 0;
      for (const [, start, name] of read(path).matchAll(/^\s+(?:const_def(?: (\d+))?|const (\w+))/gm)) {
        if (name === undefined) next = Number(start ?? 0);
        else values.set(name, next++);
      }
      return new Map([...values].filter(([name]) => name.startsWith(prefix)));
    };

    it("places every landmark where data/maps/landmarks.asm does", () => {
      const rows = [...read("data/maps/landmarks.asm").matchAll(/^\s+landmark\s+(-?\d+),\s*(-?\d+),/gm)];
      expect(rows).toHaveLength(OW.LANDMARK_FAST_SHIP + 1);
      rows.forEach(([, x, y], landmark) =>
        expect(landmarkPosition(assets.reader, landmark), String(landmark)).toEqual({
          x: Number(x),
          y: Number(y),
        }),
      );
    });

    it("reads the flypoints of data/maps/flypoints.asm", () => {
      const landmarks = constants("constants/landmark_constants.asm", "LANDMARK_");
      const spawns = constants("constants/map_data_constants.asm", "SPAWN_");
      const rows = [...read("data/maps/flypoints.asm").matchAll(/^\s+db (LANDMARK_\w+),\s*(SPAWN_\w+)/gm)].map(
        ([, landmark, spawn]) => ({ landmark: landmarks.get(landmark), spawn: spawns.get(spawn) }),
      );
      expect(rows).toHaveLength(OW.NUM_FLYPOINTS);
      expect(flypoints(assets.reader)).toEqual(rows);
    });
  },
);

describe.skipIf(!existsSync(romPath))("the region atlas", () => {
  const assets = new CrystalAssets(new Uint8Array(readFileSync(romPath)));
  function fixture(visited: number[]) {
    const world = new GameWorld(assets, () => new Date("2026-09-25T12:00:00"), () => 0x42);
    world.state.party = [
      generatePartyMon(assets.pokemon, {
        species: 155, level: 8, item: 0, otId: world.playerId,
        ot: "GOLD", dvs: 0x9abc, caughtData: 0,
      }),
    ];
    world.restore({ ...world.save(), map: NEW_BARK_TOWN, x: 13, y: 7, direction: "down", objects: [] });
    for (const spawn of visited) world.state.flags.add(assets.spawnEngineFlag(spawn)!);
    return world;
  }
  const spawnOf = (landmark: number) =>
    flypoints(assets.reader).find((point) => point.landmark === landmark)!.spawn;

  it("shows Johto with the player, the visited flypoints and the open areas", () => {
    const world = fixture([spawnOf(LANDMARK_NEW_BARK_TOWN), spawnOf(LANDMARK_CHERRYGROVE_CITY)]);
    const atlas = world.atlas();
    expect(atlas).toMatchObject({ region: "johto", regions: ["johto"], player: LANDMARK_NEW_BARK_TOWN });
    expect(atlas.landmarks.map((landmark) => landmark.landmark)).toEqual(
      Array.from({ length: OW.JOHTO_LANDMARK_LAST }, (_, i) => i + 1),
    );
    const at = (landmark: number) => atlas.landmarks[landmark - 1];
    expect(at(LANDMARK_NEW_BARK_TOWN)).toMatchObject({
      name: "NEW BARK TOWN",
      open: true,
      flypoint: { visited: true },
    });
    expect(at(LANDMARK_CHERRYGROVE_CITY).flypoint?.visited).toBe(true);
    expect(at(LANDMARK_VIOLET_CITY)).toMatchObject({ open: true, flypoint: { visited: false } });
    expect(at(LANDMARK_ROUTE_29)).toMatchObject({ open: true });
    expect(at(LANDMARK_ROUTE_29).flypoint).toBeUndefined();
    expect(at(LANDMARK_AZALEA_TOWN)).toMatchObject({ open: false, flypoint: { visited: false } });
    // Kanto stays closed, so asking for it shows Johto.
    expect(world.atlas("kanto").region).toBe("johto");
  });

  it("opens Kanto once Indigo Plateau is visited, without the player", () => {
    const world = fixture([OW.SPAWN_INDIGO]);
    expect(world.atlas().regions).toEqual(["johto", "kanto"]);
    const kanto = world.atlas("kanto");
    expect(kanto.region).toBe("kanto");
    expect(kanto.player).toBeUndefined();
    expect(kanto.landmarks[0]).toMatchObject({ landmark: LANDMARK_PALLET_TOWN, open: false });
    expect(kanto.landmarks).toHaveLength(OW.KANTO_LANDMARK_LAST - OW.KANTO_LANDMARK + 1);
  });

  it("starts on Kanto when the player stands there", () => {
    const atlas = regionAtlas({
      reader: assets.reader,
      text: () => defaultTextContext("GOLD"),
      landmark: LANDMARK_PALLET_TOWN,
      visited: () => false,
      open: new Set(),
    });
    expect(atlas).toMatchObject({ region: "kanto", regions: ["johto", "kanto"], player: LANDMARK_PALLET_TOWN });
  });

  it("leaves the Fast Ship's landmark outside both regions", () => {
    const ship = regionAtlas({
      reader: assets.reader,
      text: () => defaultTextContext("GOLD"),
      landmark: OW.LANDMARK_FAST_SHIP,
      visited: () => false,
      open: new Set(),
    });
    expect(ship.region).toBe("johto");
    expect(ship.player).toBeUndefined();
  });
});