core: Duux Whisper Flex Ultimate fan no longer working in new Tuya integration (`fs`)

@frenck this PR solves all fan speed and control issues i am aware of https://github.com/tuya/tuya-home-assistant/pull/490 except for fan direction (forward/reverse)

I’m seeing a similar issue (if not the same) with a Fanco Infinity-ID DC fan:

Logger: homeassistant.components.fan
Source: components/tuya/fan.py:165 
Integration: Fan (documentation, issues) 
First occurred: 6:49:35 PM (2 occurrences) 
Last logged: 6:49:35 PM

Error adding entities for domain fan with platform tuya
Error while setting up tuya platform for fan
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/helpers/entity_platform.py", line 382, in async_add_entities
    await asyncio.gather(*tasks)
  File "/usr/src/homeassistant/homeassistant/helpers/entity_platform.py", line 607, in _async_add_entity
    await entity.add_to_platform_finish()
  File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 715, in add_to_platform_finish
    self.async_write_ha_state()
  File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 486, in async_write_ha_state
    self._async_write_ha_state()
  File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 521, in _async_write_ha_state
    attr.update(self.state_attributes or {})
  File "/usr/src/homeassistant/homeassistant/components/fan/__init__.py", line 617, in state_attributes
    data[ATTR_SPEED] = self.speed
  File "/usr/src/homeassistant/homeassistant/components/fan/__init__.py", line 461, in speed
    if self._implemented_preset_mode and (preset_mode := self.preset_mode):
  File "/usr/src/homeassistant/homeassistant/components/tuya/fan.py", line 165, in preset_mode
    return self.device.status[DPCode.MODE]
KeyError: <DPCode.MODE: 'mode'>

I tried to get the device info as posted above but couldn’t figure out how to retrieve that. If anyone could post a link or instructions I can provide more details on the device.

@frenck I was able to gather device info using the method from tuya-home-assistant github. Hope this will help. To summarize: this fan was working partially in tuya-home-assistant v1.5 (HACS), and seems to be broken in the same way as of tuya-home-assistant v1.6 (HACS) and the latest Tuya integration (in core).

{
"active_time": 1628696958,
"biz_type": 0,
"category": "fs",
"create_time": 1628696958,
"icon": "smart/icon/001441070657466AAETE/a3de89a299843127e4d716cd35e5fd4e.png",
"id": "ebbc7c0bf2c73d0e33d7xp",
"ip": "***",
"lat": "***",
"local_key": "***",
"lon": "***",
"model": "DXCF14/15",
"name": "Whisper Flex Ultimate",
"online": true,
"owner_id": "34993017",
"product_id": "cjsa4k7tqbpuyq3l",
"product_name": "",
"status": [
{
"code": "switch",
"value": false
},
{
"code": "fan_speed_percent",
"value": 1
},
{
"code": "temp",
"value": 17
}
],
"sub": false,
"time_zone": "+02:00",
"uid": "***",
"update_time": 1634031730,
"uuid": "00588b1fb206c170"
}

2021-10-16 15:02:03 DEBUG (SyncWorker_2) [tuya iot] Request: method = GET, url = https://openapi.tuyaus.com/v1.0/devices/ebbc7c0bf2c73d0e33d7xp/specifications, params = None, body = None, t = 1634389323950
2021-10-16 15:02:03 DEBUG (Thread-4) [tuya iot] _on_log: Received SUBACK
2021-10-16 15:02:03 DEBUG (Thread-4) [tuya iot] _on_subscribe: 1
2021-10-16 15:02:04 DEBUG (SyncWorker_2) [tuya iot] Response: {
"result": {
"category": "fs",
"functions": [
{
"code": "switch",
"type": "Boolean",
"values": "{}"
},
{
"code": "fan_speed_percent",
"type": "Integer",
"values": "{\"min\":\"1\",\"max\":\"30\",\"scale\":\"0\",\"step\":\"1\"}"
},
{
"code": "temp",
"type": "Integer",
"values": "{\"unit\":\"℃\",\"min\":\"17\",\"max\":\"28\",\"scale\":\"0\",\"step\":\"1\"}"
}
],
"status": [
{
"code": "switch",
"type": "Boolean",
"values": "{}"
},
{
"code": "fan_speed_percent",
"type": "Integer",
"values": "{\"min\":\"1\",\"max\":\"30\",\"scale\":\"0\",\"step\":\"1\"}"
},
{
"code": "temp",
"type": "Integer",
"values": "{\"unit\":\"℃\",\"min\":\"17\",\"max\":\"28\",\"scale\":\"0\",\"step\":\"1\"}"
}
]
},
"success": true,
"t": 1634389324061
}

This is already helpful! If can try again later, that would be great. Otherwise, we have to do it with what is available 😉