// Cache des listes de fichiers modifiés : invalidation par jeton, plafond de chargements simultanés,
// et erreur qui reste visible au lieu d'être avalée (le défaut de l'ancien panneau Git).
import { beforeEach, describe, expect, it, vi } from 'vitest';
import { createPinia, setActivePinia } from 'pinia';
import type { FileChange, WorktreeChangesResponse } from '@arboretum/shared';

interface Deferred {
  resolve: (res: WorktreeChangesResponse) => void;
  reject: (err: Error) => void;
}

let calls: string[] = [];
let inFlight = 0;
let maxInFlight = 0;
let deferreds: Deferred[] = [];
/** Quand true, chaque appel reste en vol jusqu'à résolution explicite (test du plafond). */
let manual = false;
let failNext = false;

vi.mock('../src/lib/git-api', () => ({
  gitApi: {
    changes: (repoId: string, wt: string): Promise<WorktreeChangesResponse> => {
      calls.push(`${repoId}\0${wt}`);
      inFlight++;
      maxInFlight = Math.max(maxInFlight, inFlight);
      const settle = <T,>(p: Promise<T>): Promise<T> =>
        p.finally(() => {
          inFlight--;
        });
      if (manual) {
        return settle(
          new Promise<WorktreeChangesResponse>((resolve, reject) => {
            deferreds.push({ resolve, reject });
          }),
        );
      }
      if (failNext) {
        failNext = false;
        return settle(Promise.reject(new Error('boom')));
      }
      return settle(Promise.resolve({ repoId, path: wt, changes: [], truncated: false }));
    },
  },
}));

const { useChangesStore, MAX_CONCURRENT_LOADS } = await import('../src/stores/changes');
const { useWorktreesStore } = await import('../src/stores/worktrees');

function fakeStorage() {
  const m = new Map<string, string>();
  return {
    getItem: (k: string) => (m.has(k) ? (m.get(k) as string) : null),
    setItem: (k: string, v: string) => void m.set(k, v),
    removeItem: (k: string) => void m.delete(k),
    clear: () => m.clear(),
  };
}

/** Laisse la file se dépiler (les chargements sont enchaînés par des microtâches). */
const settle = async (): Promise<void> => {
  for (let i = 0; i < 20; i++) await Promise.resolve();
};

describe('store changes', () => {
  beforeEach(() => {
    calls = [];
    deferreds = [];
    inFlight = 0;
    maxInFlight = 0;
    manual = false;
    failNext = false;
    (globalThis as unknown as { localStorage: unknown }).localStorage = fakeStorage();
    setActivePinia(createPinia());
  });

  it('ne recharge pas une entrée fraîche, recharge dès que le jeton bouge', async () => {
    const changes = useChangesStore();
    const worktrees = useWorktreesStore();

    changes.request('r1', '/wt/a');
    await settle();
    expect(calls).toHaveLength(1);

    changes.request('r1', '/wt/a'); // rien n'a bougé
    await settle();
    expect(calls).toHaveLength(1);

    worktrees.noteChange('r1', '/wt/a'); // le disque a bougé
    changes.request('r1', '/wt/a');
    await settle();
    expect(calls).toHaveLength(2);
  });

  it('invalidate force le rechargement sans jeton', async () => {
    const changes = useChangesStore();
    changes.request('r1', '/wt/a');
    await settle();
    changes.invalidate('r1', '/wt/a');
    await settle();
    expect(calls).toHaveLength(2);
  });

  it('une erreur reste visible et la liste précédente est conservée', async () => {
    const changes = useChangesStore();
    const seeded: FileChange[] = [
      {
        path: 'src/x.ts',
        indexStatus: '.',
        worktreeStatus: 'M',
        staged: false,
        unstaged: true,
        untracked: false,
        conflicted: false,
        insertions: 1,
        deletions: 0,
        binary: false,
      },
    ];
    // premier chargement réussi, puis échec
    changes.request('r1', '/wt/a');
    await settle();
    changes.entries['r1\0/wt/a'] = { ...changes.entries['r1\0/wt/a']!, changes: seeded };

    failNext = true;
    changes.invalidate('r1', '/wt/a');
    await settle();

    const entry = changes.entry('r1', '/wt/a');
    expect(entry?.error).toBe('boom');
    expect(entry?.changes).toEqual(seeded); // pas d'écran qui se vide
    expect(entry?.loading).toBe(false);
  });

  it('ne dépasse jamais le plafond de chargements simultanés', async () => {
    manual = true;
    const changes = useChangesStore();
    for (let i = 0; i < 10; i++) changes.request('r1', `/wt/${i}`);
    await settle();
    expect(maxInFlight).toBe(MAX_CONCURRENT_LOADS);
    expect(calls).toHaveLength(MAX_CONCURRENT_LOADS);

    // on libère tout : la file se dépile jusqu'au bout
    while (deferreds.length > 0) {
      const d = deferreds.shift();
      d?.resolve({ repoId: 'r1', path: '/wt/x', changes: [], truncated: false });
      await settle();
    }
    expect(calls).toHaveLength(10);
    expect(maxInFlight).toBe(MAX_CONCURRENT_LOADS);
  });

  it('forget libère, invalidateAll repérime, reset vide', async () => {
    const changes = useChangesStore();
    changes.request('r1', '/wt/a');
    changes.request('r1', '/wt/b');
    await settle();
    expect(Object.keys(changes.entries)).toHaveLength(2);

    changes.forget('r1', '/wt/a');
    expect(changes.entry('r1', '/wt/a')).toBeNull();

    expect(changes.isStale('r1', '/wt/b')).toBe(false);
    changes.invalidateAll();
    expect(changes.isStale('r1', '/wt/b')).toBe(true);

    changes.reset();
    expect(Object.keys(changes.entries)).toHaveLength(0);
  });
});