TheLastGarden/src/save/migrations.test.ts

import { describe, it, expect, vi } from 'vitest';
import { migrate, CURRENT_SCHEMA_VERSION, migrations } from './migrations';

// Tests for the forward-only migration registry. The synthetic v0 → v1
// migration (CONTEXT D-05) is the load-bearing one — Phase 4's real
// migrate_v1_to_v2 will follow the exact same shape.
//
// Phase 2 (CONTEXT D-34) extends V1Payload IN PLACE rather than introducing
// migrations[2] — Phase 1's v1 has shipped no production saves, so adding
// fields with sensible defaults is preferable. The block of "new field
// default" tests below pins the extension contract.

describe('CURRENT_SCHEMA_VERSION', () => {
  it('is 1 (Phase 2 extends v1 in place per D-34, no migrations[2])', () => {
    expect(CURRENT_SCHEMA_VERSION).toBe(1);
  });
});

describe('migrate (synthetic v0 → v1 per CONTEXT D-04 + D-05)', () => {
  it('synthetic v0 payload migrates to v1 shape', () => {
    const v0 = { garden: [{ id: 'tile-1' }, { id: 'tile-2' }] };
    const result = migrate(v0, 0);
    expect(result.toVersion).toBe(1);
    expect(result.payload).toMatchObject({
      garden: { tiles: [{ id: 'tile-1' }, { id: 'tile-2' }] },
      plants: [],
      harvestedFragmentIds: [],
      lastTickAt: expect.any(Number),
      settings: {
        musicVolume: expect.any(Number),
        ambientVolume: expect.any(Number),
        sfxVolume: expect.any(Number),
      },
    });
  });

  it('migrating from v1 is a no-op (returns payload unchanged at toVersion 1)', () => {
    const v1 = {
      garden: { tiles: [] },
      plants: [],
      harvestedFragmentIds: [],
      lastTickAt: 1234567890,
      settings: { musicVolume: 0.7, ambientVolume: 0.5, sfxVolume: 0.8 },
    };
    const result = migrate(v1, 1);
    expect(result.toVersion).toBe(1);
    expect(result.payload).toEqual(v1);
  });

  it('throws when fromVersion is in the future (no migration registered)', () => {
    expect(() => migrate({}, 99)).toThrow();
  });

  it('throws when fromVersion is negative', () => {
    expect(() => migrate({}, -1)).toThrow();
  });

  it('invokes migrations[1] exactly once when migrating v0 → v1', () => {
    const original = migrations[1];
    const spy = vi.fn(original);
    migrations[1] = spy;
    try {
      migrate({ garden: [] }, 0);
      expect(spy).toHaveBeenCalledTimes(1);
    } finally {
      migrations[1] = original;
    }
  });
});

describe('Phase 2 V1Payload extension defaults (CONTEXT D-34)', () => {
  // After D-34 every v0 → v1 migration MUST populate the new fields.
  // These tests pin the contract so a future regression that drops a
  // default is caught.

  it('migrations[1] populates unlockedPlantTypes as []', () => {
    const out = migrations[1]({ garden: ['x'] }) as Record<string, unknown>;
    expect(out.unlockedPlantTypes).toEqual([]);
  });

  it('migrations[1] populates luraBeatProgress with all-false defaults', () => {
    const out = migrations[1]({ garden: ['x'] }) as Record<string, unknown>;
    expect(out.luraBeatProgress).toEqual({
      arrived: false,
      mid: false,
      farewell: false,
      pending: null,
    });
  });

  it('migrations[1] populates offlineEvents as null (no events on a fresh save)', () => {
    const out = migrations[1]({ garden: ['x'] }) as Record<string, unknown>;
    expect(out.offlineEvents).toBeNull();
  });

  it('migrations[1] populates settings.persistenceToastShown as false (D-30 toast not yet seen)', () => {
    const out = migrations[1]({ garden: ['x'] }) as { settings: { persistenceToastShown: boolean } };
    expect(out.settings.persistenceToastShown).toBe(false);
  });

  it('migrations[1] preserves existing audio volume defaults (musicVolume 0.7)', () => {
    const out = migrations[1]({ garden: ['x'] }) as { settings: { musicVolume: number } };
    expect(out.settings.musicVolume).toBe(0.7);
  });

  it('BLOCKER 3: migrations[1] populates tickCount as 0 (sim-internal counter starts fresh)', () => {
    const out = migrations[1]({ garden: ['x'] }) as Record<string, unknown>;
    expect(out.tickCount).toBe(0);
  });
});

describe('migration registry shape (D-34 regression defense)', () => {
  it('only migrations[1] is registered (no migrations[2] sneakily added)', () => {
    expect(Object.keys(migrations).sort()).toEqual(['1']);
  });
});