import { describe, expect, it } from "vitest";
import {
  applyMigrations,
  CURRENT_SAVE_VERSION,
  migrateSave,
  saveDocumentSchema,
  type SaveMigration,
} from "../src/index";
import { fullSave } from "./save-fixture";

describe("save document (Step 14.2)", () => {
  it("validates a fully populated save", () => {
    expect(saveDocumentSchema.safeParse(fullSave()).success).toBe(true);
    expect(CURRENT_SAVE_VERSION).toBe(2);
  });

  it("rejects an invalid save with a readable error naming the field", () => {
    const broken = fullSave() as unknown as { company: { credits: unknown } };
    broken.company.credits = "lots";
    const result = migrateSave(broken);
    expect(result.ok).toBe(false);
    if (!result.ok) {
      expect(result.error).toContain("The save is damaged");
      expect(result.error).toContain("company.credits");
    }
  });

  it("rejects things that aren't saves, and saves from a newer build", () => {
    expect(migrateSave("hello")).toEqual({ ok: false, error: "The save isn't a save document." });
    expect(migrateSave({ company: {} })).toEqual({
      ok: false,
      error: "The save has no valid saveVersion.",
    });
    const future = migrateSave({ ...fullSave(), saveVersion: CURRENT_SAVE_VERSION + 1 });
    expect(future.ok).toBe(false);
    if (!future.ok) expect(future.error).toContain("newer version");
  });

  it("reads a current save as it is", () => {
    const result = migrateSave(JSON.parse(JSON.stringify(fullSave())));
    expect(result).toEqual({ ok: true, save: fullSave() });
  });

  it("chains migrations in order, one version at a time", () => {
    const seen: number[] = [];
    const migrations: SaveMigration[] = [
      { from: 2, migrate: (s) => (seen.push(2), { ...s, extra: [...(s.extra as number[]), 2] }) },
      { from: 1, migrate: (s) => (seen.push(1), { ...s, extra: [1] }) },
    ];
    const result = applyMigrations({ saveVersion: 1 }, migrations, 3);
    expect(result).toEqual({ ok: true, save: { saveVersion: 3, extra: [1, 2] } });
    expect(seen).toEqual([1, 2]);
    expect(applyMigrations({ saveVersion: 1 }, [], 2)).toEqual({
      ok: false,
      error: "No migration from save version 1.",
    });
  });
});

/** The fixture as a version-1 save: before fuel tanks (CR-015). */
type Loose = Record<string, unknown> & {
  ships: Record<string, unknown>[];
  dispatches: { record: Record<string, unknown>; resolution: Record<string, unknown> | null }[];
};

function versionOne(): Record<string, unknown> {
  const save = JSON.parse(JSON.stringify(fullSave())) as Loose;
  save.saveVersion = 1;
  for (const ship of save.ships) {
    delete ship.fuelFu;
    delete ship.fuelAvgPrice;
    delete ship.refuelPolicy;
  }
  for (const dispatch of save.dispatches) {
    delete dispatch.record.fuelBurnedFu;
    if (dispatch.resolution) delete dispatch.resolution.topUp;
  }
  return save;
}

describe("save migration 1 → 2: fuel tanks (CR-015 §5)", () => {
  it("fills every ship's tank, on Auto top-up, and changes nothing else", () => {
    const result = migrateSave(versionOne());
    if (!result.ok) throw new Error(result.error);
    const { save } = result;
    const before = fullSave();
    expect(save.saveVersion).toBe(2);
    // The Courier has Extended Fuel Tanks 1 (40 fu × 4.8) and is in flight: the base
    // price, 5 cr/fu since CR-018 (decision 0.5.110).
    expect(save.ships[0]).toMatchObject({ fuelFu: 192, fuelAvgPrice: 5, refuelPolicy: "auto" });
    // The Clipper is at Earth: a full 1,170 fu at Earth's 8 cr/fu.
    expect(save.ships[1]).toMatchObject({ fuelFu: 1170, fuelAvgPrice: 8, refuelPolicy: "auto" });
    // Earlier trips paid fuel in credits: nothing came out of a tank, nothing topped up.
    for (const dispatch of save.dispatches) {
      expect(dispatch.record.fuelBurnedFu).toBe(0);
      if (dispatch.resolution) expect(dispatch.resolution.topUp).toBeNull();
    }
    // In-flight dispatches keep their arrival times; everything else is as it was.
    expect(save.dispatches.map((d) => d.arrivalAt)).toEqual(
      before.dispatches.map((d) => d.arrivalAt),
    );
    expect(save.company).toEqual(before.company);
    expect(save.pilots).toEqual(before.pilots);
  });
});