import { CUSTOM_MODULE_PRELOAD_MAX } from '@tessera/shared';
import { beforeEach, describe, expect, it } from 'vitest';
import {
  CUSTOM_MODULE_KEEP_ALIVE_MAX,
  touchLru,
  useCustomModuleCacheStore,
} from './custom-module-cache-store';

describe('touchLru', () => {
  it('setzt ein neues Modul nach vorn ohne zu verwerfen', () => {
    expect(touchLru(['a', 'b'], 'c', 5)).toEqual({ recent: ['c', 'a', 'b'], evicted: [] });
  });

  it('holt ein vorhandenes Modul nach vorn, ohne es zu verdoppeln', () => {
    expect(touchLru(['a', 'b', 'c'], 'c', 5)).toEqual({ recent: ['c', 'a', 'b'], evicted: [] });
  });

  it('verwirft ueber der Grenze das am laengsten unbenutzte', () => {
    expect(touchLru(['e', 'd', 'c', 'b', 'a'], 'f', 5)).toEqual({
      recent: ['f', 'e', 'd', 'c', 'b'],
      evicted: ['a'],
    });
  });

  it('haelt das gerade benutzte Modul auch bei unsinniger Grenze', () => {
    expect(touchLru(['a'], 'b', 0)).toEqual({ recent: ['b'], evicted: ['a'] });
  });
});

describe('useCustomModuleCacheStore', () => {
  const slot = () => document.createElement('div');
  const remember = (id: string) =>
    useCustomModuleCacheStore.getState().remember({ id, name: id, url: `https://x.test/${id}` });

  beforeEach(() => {
    useCustomModuleCacheStore.getState().clear();
  });

  it('haelt die Einhaengereihenfolge stabil und verwirft nach LRU', () => {
    const ids = Array.from({ length: CUSTOM_MODULE_KEEP_ALIVE_MAX + 1 }, (_, i) => `m${i}`);
    for (const id of ids) remember(id);
    const { activate } = useCustomModuleCacheStore.getState();
    for (const id of ids.slice(0, CUSTOM_MODULE_KEEP_ALIVE_MAX)) activate(id, slot());
    // m0 erneut benutzen -> m1 ist jetzt am laengsten unbenutzt.
    activate('m0', slot());
    expect(useCustomModuleCacheStore.getState().openIds).toEqual(['m0', 'm1', 'm2', 'm3', 'm4']);

    activate('m5', slot());
    const state = useCustomModuleCacheStore.getState();
    expect(state.openIds).toEqual(['m0', 'm2', 'm3', 'm4', 'm5']);
    expect(state.recent[0]).toBe('m5');
    // Metadaten bleiben — nur der offene Rahmen wird verworfen.
    expect(state.modules.m1).toBeDefined();
  });

  it('aktiviert kein Modul ohne Metadaten', () => {
    useCustomModuleCacheStore.getState().activate('unbekannt', slot());
    expect(useCustomModuleCacheStore.getState().openIds).toEqual([]);
    expect(useCustomModuleCacheStore.getState().active).toBeNull();
  });

  it('deaktiviert nur den eigenen Platzhalter', () => {
    remember('a');
    const first = slot();
    const { activate, deactivate } = useCustomModuleCacheStore.getState();
    activate('a', first);
    deactivate(slot());
    expect(useCustomModuleCacheStore.getState().active?.slot).toBe(first);
    deactivate(first);
    expect(useCustomModuleCacheStore.getState().active).toBeNull();
    expect(useCustomModuleCacheStore.getState().openIds).toEqual(['a']);
  });

  it('vergisst ein Modul samt offenem Rahmen', () => {
    remember('a');
    useCustomModuleCacheStore.getState().activate('a', slot());
    useCustomModuleCacheStore.getState().forget('a');
    const state = useCustomModuleCacheStore.getState();
    expect(state.modules).toEqual({});
    expect(state.openIds).toEqual([]);
    expect(state.recent).toEqual([]);
    expect(state.active).toBeNull();
  });
});

describe('useCustomModuleCacheStore — preload (quick-261008-who)', () => {
  const mod = (id: string) => ({ id, name: id, url: `https://x.test/${id}` });

  beforeEach(() => {
    useCustomModuleCacheStore.getState().clear();
  });

  it('merkt Metadaten, haengt hinten an openIds, pinnt und laesst active unberuehrt', () => {
    useCustomModuleCacheStore.getState().preload(mod('a'));
    useCustomModuleCacheStore.getState().preload(mod('b'));
    const s = useCustomModuleCacheStore.getState();
    expect(s.modules.a).toEqual(mod('a'));
    expect(s.openIds).toEqual(['a', 'b']);
    expect(s.pinned).toEqual(['a', 'b']);
    expect(s.active).toBeNull();
  });

  it('zweimal aufgerufen aendert nichts', () => {
    useCustomModuleCacheStore.getState().preload(mod('a'));
    const before = useCustomModuleCacheStore.getState();
    useCustomModuleCacheStore.getState().preload(mod('a'));
    expect(useCustomModuleCacheStore.getState()).toBe(before);
  });

  it('ignoriert mehr als CUSTOM_MODULE_PRELOAD_MAX gepinnte', () => {
    for (let i = 0; i < CUSTOM_MODULE_PRELOAD_MAX + 2; i++) {
      useCustomModuleCacheStore.getState().preload(mod(`m${i}`));
    }
    const s = useCustomModuleCacheStore.getState();
    expect(s.pinned).toHaveLength(CUSTOM_MODULE_PRELOAD_MAX);
    expect(s.openIds).toHaveLength(CUSTOM_MODULE_PRELOAD_MAX);
  });

  it('forget und clear entfernen auch aus pinned', () => {
    useCustomModuleCacheStore.getState().preload(mod('a'));
    useCustomModuleCacheStore.getState().preload(mod('b'));
    useCustomModuleCacheStore.getState().forget('a');
    expect(useCustomModuleCacheStore.getState().pinned).toEqual(['b']);
    useCustomModuleCacheStore.getState().clear();
    expect(useCustomModuleCacheStore.getState().pinned).toEqual([]);
  });

  it('activate eines gepinnten Moduls laesst es gepinnt', () => {
    useCustomModuleCacheStore.getState().preload(mod('a'));
    useCustomModuleCacheStore.getState().activate('a', document.createElement('div'));
    const s = useCustomModuleCacheStore.getState();
    expect(s.pinned).toEqual(['a']);
    expect(s.openIds).toEqual(['a']);
    expect(s.active?.id).toBe('a');
  });
});