Add support for Xiaomi Mi Scale V1 and V2

https://github.com/esphome/feature-requests/issues/209

@tsunglung have all the rights and effort for this.

esphome/components/xiaomi_ble/xiaomi_ble.cpp

@@ -9,6 +9,31 @@ namespace xiaomi_ble {
 static const char *TAG = "xiaomi_ble";
 
 bool parse_xiaomi_data_byte(uint8_t data_type, const uint8_t *data, uint8_t data_length, XiaomiParseResult &result) {
+if (result.type == XiaomiParseResult::TYPE_MISCALE) {
+  switch(data_type) {
+    case 0x00:{
+    const uint16_t weight = uint16_t(data[1]) | (uint16_t(data[2]) << 8);
+    if (data[0] == 0x22 || data[0] == 0xa2)
+      result.weight = weight * 0.01f / 2.0f;
+    else if (data[0] == 0x03 || data[0] == 0xb2)
+      result.weight = weight * 0.01f * 0.453592;
+    else
+      return false;
+      return true;
+  }
+  case 0x01: {
+    const uint16_t weight = uint16_t(data[11]) | (uint16_t(data[12]) << 8);
+    if (data[0] == 0x02)
+      result.weight = weight * 0.01f / 2.0f;
+    else if (data[0] == 0x03)
+      result.weight = weight * 0.01f * 0.453592;
+    else
+      return false;
+      return true;
+    }
+  }
+}
+
   switch (data_type) {
     case 0x0D: {  // temperature+humidity, 4 bytes, 16-bit signed integer (LE) each, 0.1 °C, 0.1 %
       if (data_length != 4)
@@ -69,26 +94,30 @@ optional<XiaomiParseResult> parse_xiaomi(const esp32_ble_tracker::ESPBTDevice &d
     return {};
   }
 
-  if (!device.get_service_data_uuid()->contains(0x95, 0xFE)) {
+  if (!device.get_service_data_uuid()->contains(0x95, 0xFE)) and !device.get_service_data_uuid()->contains(0x1D, 0x18) and !device.get_service_data_uuid()->contains(0x1B, 0x18)) {
     // ESP_LOGVV(TAG, "Xiaomi no service data UUID magic bytes");
     return {};
   }
 
   const auto *raw = reinterpret_cast<const uint8_t *>(device.get_service_data().data());
 
-  if (device.get_service_data().size() < 14) {
+  if (device.get_service_data().size() < 9) {
     // ESP_LOGVV(TAG, "Xiaomi service data too short!");
     return {};
   }
 
   bool is_mijia = (raw[1] & 0x20) == 0x20 && raw[2] == 0xAA && raw[3] == 0x01;
   bool is_miflora = (raw[1] & 0x20) == 0x20 && raw[2] == 0x98 && raw[3] == 0x00;
-
+  bool is_miscale =  raw[3] == 0xE3 && raw[4] == 0x07 && raw[5] == 0x08;
-  if (!is_mijia && !is_miflora) {
+  bool is_mibfs = raw[2] == 0xE3 && raw[3] == 0x07 && raw[4] == 0x08;
+  if (!is_mijia && !is_miflora && !is_miscale && !is_mibfs) {
     // ESP_LOGVV(TAG, "Xiaomi no magic bytes");
     return {};
   }
 
+  bool success;
+  XiaomiParseResult result;
+if (is_mijia || is_miflora) {
   uint8_t raw_offset = is_mijia ? 11 : 12;
 
   const uint8_t raw_type = raw[raw_offset];
@@ -97,12 +126,24 @@ optional<XiaomiParseResult> parse_xiaomi(const esp32_ble_tracker::ESPBTDevice &d
   const uint8_t expected_length = data_length + raw_offset + 3;
   const uint8_t actual_length = device.get_service_data().size();
   if (expected_length != actual_length) {
-    // ESP_LOGV(TAG, "Xiaomi %s data length mismatch (%u != %d)", type, expected_length, actual_length);
+    // ESP_LOGV(TAG, "Xiaomi %s data length mismatch (%u != %d)", raw_type, expected_length, actual_length);
     return {};
   }
-  XiaomiParseResult result;
   result.type = is_miflora ? XiaomiParseResult::TYPE_MIFLORA : XiaomiParseResult::TYPE_MIJIA;
-  bool success = parse_xiaomi_data_byte(raw_type, data, data_length, result);
+  success = parse_xiaomi_data_byte(raw_type, data, data_length, result);
+} else {
+  const uint8_t *data = &raw[0];
+  const uint8_t data_length = 2;
+
+  result.type = XiaomiParseResult::TYPE_MISCALE;
+  if (device.get_service_data_uuid()->contains(0x1B, 0x18) && !is_mibfs) {
+    const uint8_t raw_type = 0x0;
+    success = parse_xiaomi_data_byte(raw_type, data, data_length, result);
+  } else {
+    const uint8_t raw_type = 0x1;
+    success = parse_xiaomi_data_byte(raw_type, data, data_length, result);
+  }
+}
   if (!success)
     return {};
   return result;
@@ -113,7 +154,7 @@ bool XiaomiListener::parse_device(const esp32_ble_tracker::ESPBTDevice &device)
   if (!res.has_value())
     return false;
 
-  const char *name = res->type == XiaomiParseResult::TYPE_MIFLORA ? "Mi Flora" : "Mi Jia";
+  const char *name = res->type == XiaomiParseResult::TYPE_MIFLORA ? "Mi Flora" : (res->type == XiaomiParseResult::TYPE_MIJIA ? "Mi Jia": "Mi Scale");
 
   ESP_LOGD(TAG, "Got Xiaomi %s (%s):", name, device.address_str().c_str());
 
@@ -135,7 +176,9 @@ bool XiaomiListener::parse_device(const esp32_ble_tracker::ESPBTDevice &device)
   if (res->moisture.has_value()) {
     ESP_LOGD(TAG, "  Moisture: %.0f%%", *res->moisture);
   }
-
+  if (res->weight.has_value()) {
+    ESP_LOGD(TAG, "  Weight: %.1fkg", *res->weight);
+  }
   return true;
 }