import { tap, expect } from '@git.zone/tstest/tapbundle';
import * as smartstate from '../ts/index.js';
import { Subject, of, Observable, throwError, concat } from 'rxjs';

// ── Lifecycle ──────────────────────────────────────────────────────────
tap.test('process should start in idle status', async () => {
  const state = new smartstate.Smartstate<'test'>();
  const part = await state.getStatePart<{ v: number }>('test', { v: 0 });
  const process = part.createProcess<number>({
    producer: () => of(1),
    reducer: (s, v) => ({ v: s.v + v }),
  });
  expect(process.status).toEqual('idle');
  process.dispose();
});

tap.test('start/pause/resume/dispose lifecycle', async () => {
  const state = new smartstate.Smartstate<'lifecycle'>();
  const part = await state.getStatePart<{ v: number }>('lifecycle', { v: 0 });
  const subject = new Subject<number>();
  const process = part.createProcess<number>({
    producer: () => subject.asObservable(),
    reducer: (s, v) => ({ v: s.v + v }),
  });

  expect(process.status).toEqual('idle');
  process.start();
  expect(process.status).toEqual('running');
  process.pause();
  expect(process.status).toEqual('paused');
  process.resume();
  expect(process.status).toEqual('running');
  process.dispose();
  expect(process.status).toEqual('disposed');
});

// ── Producer → state integration ───────────────────────────────────────
tap.test('producer values should update state through reducer', async () => {
  const state = new smartstate.Smartstate<'producer'>();
  const part = await state.getStatePart<{ values: number[] }>('producer', { values: [] });
  const subject = new Subject<number>();

  const process = part.createProcess<number>({
    producer: () => subject.asObservable(),
    reducer: (s, v) => ({ values: [...s.values, v] }),
  });
  process.start();

  subject.next(1);
  subject.next(2);
  subject.next(3);
  await new Promise((r) => setTimeout(r, 100));

  expect(part.getState()!.values).toEqual([1, 2, 3]);
  process.dispose();
});

// ── Pause stops producer, resume restarts ──────────────────────────────
tap.test('pause should stop receiving values, resume should restart', async () => {
  const state = new smartstate.Smartstate<'pauseResume'>();
  const part = await state.getStatePart<{ count: number }>('pauseResume', { count: 0 });
  const subject = new Subject<number>();

  const process = part.createProcess<number>({
    producer: () => subject.asObservable(),
    reducer: (s, v) => ({ count: s.count + v }),
  });
  process.start();

  subject.next(1);
  await new Promise((r) => setTimeout(r, 50));
  expect(part.getState()!.count).toEqual(1);

  process.pause();
  subject.next(1); // should be ignored — producer unsubscribed
  await new Promise((r) => setTimeout(r, 50));
  expect(part.getState()!.count).toEqual(1); // unchanged

  process.resume();
  subject.next(1);
  await new Promise((r) => setTimeout(r, 50));
  expect(part.getState()!.count).toEqual(2);

  process.dispose();
});

// ── Auto-pause with custom Observable ──────────────────────────────────
tap.test('auto-pause with custom Observable<boolean> signal', async () => {
  const state = new smartstate.Smartstate<'autoPause'>();
  const part = await state.getStatePart<{ count: number }>('autoPause', { count: 0 });
  const producer = new Subject<number>();
  const pauseSignal = new Subject<boolean>();

  const process = part.createProcess<number>({
    producer: () => producer.asObservable(),
    reducer: (s, v) => ({ count: s.count + v }),
    autoPause: pauseSignal.asObservable(),
  });
  process.start();

  producer.next(1);
  await new Promise((r) => setTimeout(r, 50));
  expect(part.getState()!.count).toEqual(1);

  // Signal pause
  pauseSignal.next(false);
  await new Promise((r) => setTimeout(r, 50));
  expect(process.status).toEqual('paused');

  producer.next(1); // ignored
  await new Promise((r) => setTimeout(r, 50));
  expect(part.getState()!.count).toEqual(1);

  // Signal resume
  pauseSignal.next(true);
  await new Promise((r) => setTimeout(r, 50));
  expect(process.status).toEqual('running');

  producer.next(1);
  await new Promise((r) => setTimeout(r, 50));
  expect(part.getState()!.count).toEqual(2);

  process.dispose();
});

// ── Auto-pause 'visibility' in Node.js (no document) ──────────────────
tap.test('autoPause visibility should be always-active in Node.js', async () => {
  const state = new smartstate.Smartstate<'vis'>();
  const part = await state.getStatePart<{ v: number }>('vis', { v: 0 });
  const subject = new Subject<number>();

  const process = part.createProcess<number>({
    producer: () => subject.asObservable(),
    reducer: (s, v) => ({ v: v }),
    autoPause: 'visibility',
  });
  process.start();
  expect(process.status).toEqual('running');

  subject.next(42);
  await new Promise((r) => setTimeout(r, 50));
  expect(part.getState()!.v).toEqual(42);
  process.dispose();
});

// ── Scheduled action ───────────────────────────────────────────────────
tap.test('createScheduledAction should dispatch action on interval', async () => {
  const state = new smartstate.Smartstate<'scheduled'>();
  const part = await state.getStatePart<{ ticks: number }>('scheduled', { ticks: 0 });

  const tickAction = part.createAction<void>(async (sp) => {
    return { ticks: sp.getState()!.ticks + 1 };
  });

  const scheduled = part.createScheduledAction({
    action: tickAction,
    payload: undefined,
    intervalMs: 50,
  });

  await new Promise((r) => setTimeout(r, 280));
  scheduled.dispose();

  // Should have ticked at least 3 times in ~280ms with 50ms interval
  expect(part.getState()!.ticks).toBeGreaterThanOrEqual(3);
});

// ── StatePart.dispose cascades ─────────────────────────────────────────
tap.test('StatePart.dispose should dispose all processes', async () => {
  const state = new smartstate.Smartstate<'cascade'>();
  const part = await state.getStatePart<{ v: number }>('cascade', { v: 0 });

  const p1 = part.createProcess<number>({
    producer: () => new Subject<number>().asObservable(),
    reducer: (s, v) => ({ v }),
  });
  const p2 = part.createProcess<number>({
    producer: () => new Subject<number>().asObservable(),
    reducer: (s, v) => ({ v }),
  });
  p1.start();
  p2.start();

  part.dispose();
  expect(p1.status).toEqual('disposed');
  expect(p2.status).toEqual('disposed');
});

// ── status$ observable ─────────────────────────────────────────────────
tap.test('status$ should emit lifecycle transitions', async () => {
  const state = new smartstate.Smartstate<'status$'>();
  const part = await state.getStatePart<{ v: number }>('status$', { v: 0 });
  const subject = new Subject<number>();

  const process = part.createProcess<number>({
    producer: () => subject.asObservable(),
    reducer: (s, v) => ({ v }),
  });

  const statuses: string[] = [];
  process.status$.subscribe((s) => statuses.push(s));

  process.start();
  process.pause();
  process.resume();
  process.dispose();

  expect(statuses).toEqual(['idle', 'running', 'paused', 'running', 'disposed']);
});

// ── Producer error → graceful pause ────────────────────────────────────
tap.test('producer error should pause process gracefully', async () => {
  const state = new smartstate.Smartstate<'error'>();
  const part = await state.getStatePart<{ v: number }>('error', { v: 0 });

  let callCount = 0;
  const process = part.createProcess<number>({
    producer: () => {
      callCount++;
      if (callCount === 1) {
        // First subscription: emit 1, then error
        return concat(of(1), throwError(() => new Error('boom')));
      }
      // After resume: emit 2 successfully
      return of(2);
    },
    reducer: (s, v) => ({ v }),
  });
  process.start();
  await new Promise((r) => setTimeout(r, 50));

  expect(process.status).toEqual('paused');
  expect(part.getState()!.v).toEqual(1); // got the value before error

  // Resume creates a fresh subscription
  process.resume();
  await new Promise((r) => setTimeout(r, 50));
  expect(part.getState()!.v).toEqual(2);

  process.dispose();
});

// ── Disposed guards ────────────────────────────────────────────────────
tap.test('start/pause/resume on disposed process should throw', async () => {
  const state = new smartstate.Smartstate<'guards'>();
  const part = await state.getStatePart<{ v: number }>('guards', { v: 0 });

  const process = part.createProcess<number>({
    producer: () => of(1),
    reducer: (s, v) => ({ v }),
  });
  process.dispose();

  let errors = 0;
  try { process.start(); } catch { errors++; }
  try { process.pause(); } catch { errors++; }
  try { process.resume(); } catch { errors++; }
  expect(errors).toEqual(3);
});

// ── autoStart option ───────────────────────────────────────────────────
tap.test('autoStart should start process immediately', async () => {
  const state = new smartstate.Smartstate<'autoStart'>();
  const part = await state.getStatePart<{ v: number }>('autoStart', { v: 0 });

  const process = part.createProcess<number>({
    producer: () => of(42),
    reducer: (s, v) => ({ v }),
    autoStart: true,
  });

  await new Promise((r) => setTimeout(r, 50));
  expect(process.status).toEqual('running');
  expect(part.getState()!.v).toEqual(42);
  process.dispose();
});

export default tap.start();