import asyncio, json, urllib.request

async def recv_one(reader):
    b1 = await reader.readexactly(2)
    opcode = b1[0] & 0x0F
    masked_len = b1[1]
    length = masked_len & 0x7F
    if length == 126:
        length = int.from_bytes(await reader.readexactly(2), 'big')
    elif length == 127:
        length = int.from_bytes(await reader.readexactly(8), 'big')
    if masked_len & 0x80:
        mask = await reader.readexactly(4)
        payload = await reader.readexactly(length) if length else b''
        payload = bytes(b ^ mask[i % 4] for i, b in enumerate(payload))
    else:
        payload = await reader.readexactly(length) if length else b''
    return opcode, payload

async def send_text(writer, obj):
    text = json.dumps(obj).encode('utf-8')
    mask = b'ABCD'
    frame = bytearray([0x81])
    n = len(text)
    if n < 126:
        frame.append(0x80 | n)
    elif n < (1<<16):
        frame.append(0x80 | 126); frame += n.to_bytes(2,'big')
    else:
        frame.append(0x80 | 127); frame += n.to_bytes(8,'big')
    frame += mask
    frame += bytes(b ^ mask[i % 4] for i, b in enumerate(text))
    writer.write(frame)
    await writer.drain()

async def main():
    ws = json.load(urllib.request.urlopen('http://127.0.0.1:9222/json/version'))['webSocketDebuggerUrl']
    hostportpath = ws[len('ws://'):]
    hostport, _, path = hostportpath.partition('/')
    host, port = hostport.split(':'); port = int(port)
    path = '/' + path
    reader, writer = await asyncio.open_connection(host, port)
    req = f'GET {path} HTTP/1.1\r\nHost: {host}:{port}\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\r\nSec-WebSocket-Version: 13\r\n\r\n'
    writer.write(req.encode()); await writer.drain(); await reader.readuntil(b'\r\n\r\n')

    next_id = 1
    async def call(method, params=None, sessionId=None):
        nonlocal next_id
        msg = {"id": next_id, "method": method}
        if params is not None: msg['params'] = params
        if sessionId is not None: msg['sessionId'] = sessionId
        myid = next_id
        next_id += 1
        await send_text(writer, msg)
        while True:
            opcode, payload = await recv_one(reader)
            if opcode != 1:
                continue
            data = json.loads(payload.decode('utf-8', errors='ignore'))
            print('EV', json.dumps(data, ensure_ascii=False))
            if data.get('id') == myid:
                return data

    r = await call('Target.createTarget', {'url': 'about:blank'})
    tid = r['result']['targetId']
    r = await call('Target.attachToTarget', {'targetId': tid, 'flatten': True})
    sid = r['result']['sessionId']
    await call('Page.enable', sessionId=sid)
    await call('Runtime.enable', sessionId=sid)
    await call('Page.navigate', {'url': 'https://example.com'}, sessionId=sid)
    await asyncio.sleep(2)
    r = await call('Runtime.evaluate', {'expression': 'document.title', 'returnByValue': True}, sessionId=sid)
    print('TITLE', r)
    r = await call('Runtime.evaluate', {'expression': 'document.body.innerText', 'returnByValue': True}, sessionId=sid)
    print('BODY', r)
    writer.close(); await writer.wait_closed()

asyncio.run(main())