import fs from 'node:fs/promises';
import os from 'node:os';
import path from 'node:path';
import { afterAll, beforeAll, describe, expect, it } from 'vitest';
import { getGameDb } from '@/lib/db/client';
import * as schema from '@/lib/db/schema';
import { POST } from './route';

let dir: string;

beforeAll(async () => {
  // Same pattern as app/api/state/route.test.ts: point the DB singleton at a
  // throwaway file (fresh module registry per test file → fresh singleton).
  dir = await fs.mkdtemp(path.join(os.tmpdir(), 'flight-sim-api-'));
  process.env.FLIGHT_DB_PATH = path.join(dir, 'sim.db');
});

afterAll(async () => {
  delete process.env.FLIGHT_DB_PATH;
  await fs.rm(dir, { recursive: true, force: true });
});

const post = (body: unknown) => POST(new Request('http://localhost/api/sim', { method: 'POST', body: JSON.stringify(body) }));
const postRaw = (text: string) => POST(new Request('http://localhost/api/sim', { method: 'POST', body: text }));

describe('POST /api/sim', () => {
  it('returns the current simState for an empty body (tick + no-op)', async () => {
    const res = await post({});
    expect(res.status).toBe(200);
    const body = (await res.json()) as { clockMs: number; timeScale: number; paused: boolean };
    expect(typeof body.clockMs).toBe('number');
    expect(body.timeScale).toBe(1); // seeded default
    expect(body.paused).toBe(false);
  });

  it('sets and clamps timeScale into [1, 1000]', async () => {
    const hi = await post({ timeScale: 2000 });
    expect(hi.status).toBe(200);
    expect(((await hi.json()) as { timeScale: number }).timeScale).toBe(1000);

    const lo = await post({ timeScale: 0.1 });
    expect(lo.status).toBe(200);
    expect(((await lo.json()) as { timeScale: number }).timeScale).toBe(1);

    // The top of the ladder passes through unclamped (v0.14.0).
    const max = await post({ timeScale: 1000 });
    expect(max.status).toBe(200);
    expect(((await max.json()) as { timeScale: number }).timeScale).toBe(1000);

    // In-range values pass through unclamped — ladder and off-ladder alike.
    const ladder = await post({ timeScale: 500 });
    expect(ladder.status).toBe(200);
    expect(((await ladder.json()) as { timeScale: number }).timeScale).toBe(500);

    const mid = await post({ timeScale: 37 });
    expect(mid.status).toBe(200);
    expect(((await mid.json()) as { timeScale: number }).timeScale).toBe(37);

    // Restore the default for later tests.
    await post({ timeScale: 1 });
  });

  it('toggles paused and freezes the clock across ticks', async () => {
    const pause = await post({ paused: true });
    expect(pause.status).toBe(200);
    expect(((await pause.json()) as { paused: boolean }).paused).toBe(true);

    // Two reads while paused → identical clock (tick-on-read advances nothing).
    const a = await post({});
    const b = await post({});
    expect(((await a.json()) as { clockMs: number }).clockMs).toBe(
      ((await b.json()) as { clockMs: number }).clockMs,
    );

    const resume = await post({ paused: false });
    expect(resume.status).toBe(200);
    expect(((await resume.json()) as { paused: boolean }).paused).toBe(false);
  });

  it('applies both fields in one call', async () => {
    const res = await post({ timeScale: 64, paused: true });
    expect(res.status).toBe(200);
    const body = (await res.json()) as { timeScale: number; paused: boolean };
    expect(body.timeScale).toBe(64);
    expect(body.paused).toBe(true);
    await post({ timeScale: 1, paused: false }); // restore
  });

  it('records lastSelectedTimeScale when timeScale is posted; a paused-only post leaves it untouched (ISS-057)', async () => {
    const inst = await getGameDb(); // same singleton the route's applyTimeControls writes through
    const row = async () => (await inst.db.select().from(schema.simState))[0];

    await post({ timeScale: 250 });
    expect((await row()).lastSelectedTimeScale).toBe(250); // manual intent recorded…

    await post({ paused: true });
    expect((await row()).paused).toBe(true);
    expect((await row()).lastSelectedTimeScale).toBe(250); // …and a {paused}-only post does not touch it

    await post({ timeScale: 1, paused: false }); // restore
    expect((await row()).lastSelectedTimeScale).toBe(1);
  });

  it('rejects invalid input with 400', async () => {
    for (const body of [{ timeScale: 'fast' }, { timeScale: Infinity }, { paused: 'yes' }, { bogus: 1 }]) {
      const res = await post(body);
      expect(res.status).toBe(400);
      expect(((await res.json()) as { error: string }).error).toBeTruthy();
    }

    for (const text of ['nope{', '[1,2]', '"str"', 'null']) {
      const res = await postRaw(text);
      expect(res.status).toBe(400);
    }
  });
});