import { describe, expect, it, vi } from 'vitest';

import { RpcConnection } from '../../src/background/transport/rpc.js';
import { RpcError, RpcTimeoutError } from '../../src/background/transport/types.js';

function makeConn() {
  const sent: Array<{ id: number; method: string; params: unknown }> = [];
  const conn = new RpcConnection((frame) => sent.push(frame));
  return { conn, sent };
}

describe('RpcConnection', () => {
  it('resolves a call when a matching id comes back', async () => {
    const { conn, sent } = makeConn();
    const p = conn.request('download.list', { filter: null }, 1000);
    expect(sent[0]).toMatchObject({ id: 1, method: 'download.list' });
    conn.handleInbound({ jsonrpc: '2.0', id: 1, result: { total: 0, items: [] } });
    await expect(p).resolves.toEqual({ total: 0, items: [] });
    expect(conn.inFlight).toBe(0);
  });

  it('rejects with RpcError on an error frame, carrying code and data', async () => {
    const { conn } = makeConn();
    const p = conn.request('download.get', { taskId: 'x' }, 1000);
    conn.handleInbound({ jsonrpc: '2.0', id: 1, error: { code: -32010, message: 'no such task', data: { taskId: 'x' } } });
    await expect(p).rejects.toBeInstanceOf(RpcError);
    await p.catch((e: RpcError) => {
      expect(e.code).toBe(-32010);
      expect(e.data).toEqual({ taskId: 'x' });
    });
  });

  it('matches replies to the right call when they arrive out of order', async () => {
    const { conn } = makeConn();
    const a = conn.request('download.list', {}, 1000);
    const b = conn.request('queue.list', {}, 1000);
    conn.handleInbound({ jsonrpc: '2.0', id: 2, result: 'B' });
    conn.handleInbound({ jsonrpc: '2.0', id: 1, result: 'A' });
    await expect(a).resolves.toBe('A');
    await expect(b).resolves.toBe('B');
  });

  it('ignores a reply for an unknown id and returns it as non-notification', () => {
    const { conn } = makeConn();
    expect(conn.handleInbound({ jsonrpc: '2.0', id: 999, result: 1 })).toBeNull();
  });

  it('returns notifications (no id) for the caller to route', () => {
    const { conn } = makeConn();
    const note = conn.handleInbound({ jsonrpc: '2.0', method: 'event.task.progress', params: { tasks: [] } });
    expect(note).toEqual({ jsonrpc: '2.0', method: 'event.task.progress', params: { tasks: [] } });
  });

  it('times out and then ignores the late reply', async () => {
    vi.useFakeTimers();
    const { conn } = makeConn();
    const p = conn.request('capture.offer', {}, 750);
    const assertion = expect(p).rejects.toBeInstanceOf(RpcTimeoutError);
    await vi.advanceTimersByTimeAsync(751);
    await assertion;
    // a reply that shows up after the deadline must not throw or resolve anything
    expect(conn.handleInbound({ jsonrpc: '2.0', id: 1, result: 'too late' })).toBeNull();
    vi.useRealTimers();
  });

  it('failAll rejects every pending call with the given reason', async () => {
    const { conn } = makeConn();
    const a = conn.request('download.list', {}, 1000);
    const b = conn.request('queue.list', {}, 1000);
    const reason = new Error('socket dropped');
    conn.failAll(reason);
    await expect(a).rejects.toBe(reason);
    await expect(b).rejects.toBe(reason);
    expect(conn.inFlight).toBe(0);
  });

  it('rejects when the AbortSignal fires and drops the pending entry', async () => {
    const { conn } = makeConn();
    const ac = new AbortController();
    const p = conn.request('download.probe', {}, 30_000, ac.signal);
    ac.abort(new Error('cancelled'));
    await expect(p).rejects.toThrow('cancelled');
    expect(conn.inFlight).toBe(0);
  });

  it('rejects synchronously-ish when the send callback throws', async () => {
    const conn = new RpcConnection(() => {
      throw new Error('not open');
    });
    await expect(conn.request('download.list', {}, 1000)).rejects.toThrow('not open');
    expect(conn.inFlight).toBe(0);
  });
});