🏗 Merge C++ into python codebase (#504)

## Description:

Move esphome-core codebase into esphome (and a bunch of other refactors). See https://github.com/esphome/feature-requests/issues/97

Yes this is a shit ton of work and no there's no way to automate it :( But it will be worth it 👍

Progress:
- Core support (file copy etc): 80%
- Base Abstractions (light, switch): ~50%
- Integrations: ~10%
- Working? Yes, (but only with ported components).

Other refactors:
- Moves all codegen related stuff into a single class: `esphome.codegen` (imported as `cg`)
- Rework coroutine syntax
- Move from `component/platform.py` to `domain/component.py` structure as with HA
- Move all defaults out of C++ and into config validation.
- Remove `make_...` helpers from Application class. Reason: Merge conflicts with every single new integration.
- Pointer Variables are stored globally instead of locally in setup(). Reason: stack size limit.

Future work:
- Rework const.py - Move all `CONF_...` into a conf class (usage `conf.UPDATE_INTERVAL` vs `CONF_UPDATE_INTERVAL`). Reason: Less convoluted import block
- Enable loading from `custom_components` folder.

**Related issue (if applicable):** https://github.com/esphome/feature-requests/issues/97

**Pull request in [esphome-docs](https://github.com/esphome/esphome-docs) with documentation (if applicable):** esphome/esphome-docs#<esphome-docs PR number goes here>

## Checklist:
  - [ ] The code change is tested and works locally.
  - [ ] Tests have been added to verify that the new code works (under `tests/` folder).

If user exposed functionality or configuration variables are added/changed:
  - [ ] Documentation added/updated in [esphomedocs](https://github.com/OttoWinter/esphomedocs).

esphome/components/xiaomi_miflora/sensor.py

@@ -0,0 +1,69 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.components import sensor
+from esphome.components.esp32_ble_tracker import CONF_ESP32_BLE_ID, ESPBTDeviceListener, \
+    ESP_BLE_DEVICE_SCHEMA
+from esphome.const import CONF_BATTERY_LEVEL, CONF_MAC_ADDRESS, CONF_TEMPERATURE, \
+    CONF_UNIT_OF_MEASUREMENT, CONF_ICON, CONF_ACCURACY_DECIMALS, \
+    UNIT_CELSIUS, ICON_THERMOMETER, UNIT_PERCENT, ICON_WATER_PERCENT, ICON_BATTERY, CONF_ID, \
+    CONF_MOISTURE, CONF_ILLUMINANCE, ICON_BRIGHTNESS_5, UNIT_LUX, CONF_CONDUCTIVITY, \
+    UNIT_MICROSIEMENS_PER_CENTIMETER, ICON_FLOWER
+
+DEPENDENCIES = ['esp32_ble_tracker']
+AUTO_LOAD = ['xiaomi_ble']
+
+xiaomi_miflora_ns = cg.esphome_ns.namespace('xiaomi_miflora')
+XiaomiMiflora = xiaomi_miflora_ns.class_('XiaomiMiflora', ESPBTDeviceListener, cg.Component)
+
+CONFIG_SCHEMA = cv.Schema({
+    cv.GenerateID(): cv.declare_variable_id(XiaomiMiflora),
+    cv.Required(CONF_MAC_ADDRESS): cv.mac_address,
+    cv.Optional(CONF_TEMPERATURE): cv.nameable(sensor.SENSOR_SCHEMA.extend({
+        cv.Optional(CONF_UNIT_OF_MEASUREMENT, default=UNIT_CELSIUS): sensor.unit_of_measurement,
+        cv.Optional(CONF_ICON, default=ICON_THERMOMETER): sensor.icon,
+        cv.Optional(CONF_ACCURACY_DECIMALS, default=1): sensor.accuracy_decimals
+    })),
+    cv.Optional(CONF_MOISTURE): cv.nameable(sensor.SENSOR_SCHEMA.extend({
+        cv.Optional(CONF_UNIT_OF_MEASUREMENT, default=UNIT_PERCENT): sensor.unit_of_measurement,
+        cv.Optional(CONF_ICON, default=ICON_WATER_PERCENT): sensor.icon,
+        cv.Optional(CONF_ACCURACY_DECIMALS, default=0): sensor.accuracy_decimals
+    })),
+    cv.Optional(CONF_ILLUMINANCE): cv.nameable(sensor.SENSOR_SCHEMA.extend({
+        cv.Optional(CONF_UNIT_OF_MEASUREMENT, default=UNIT_LUX): sensor.unit_of_measurement,
+        cv.Optional(CONF_ICON, default=ICON_BRIGHTNESS_5): sensor.icon,
+        cv.Optional(CONF_ACCURACY_DECIMALS, default=0): sensor.accuracy_decimals
+    })),
+    cv.Optional(CONF_CONDUCTIVITY): cv.nameable(sensor.SENSOR_SCHEMA.extend({
+        cv.Optional(CONF_UNIT_OF_MEASUREMENT, default=UNIT_MICROSIEMENS_PER_CENTIMETER):
+            sensor.unit_of_measurement,
+        cv.Optional(CONF_ICON, default=ICON_FLOWER): sensor.icon,
+        cv.Optional(CONF_ACCURACY_DECIMALS, default=0): sensor.accuracy_decimals
+    })),
+    cv.Optional(CONF_BATTERY_LEVEL): cv.nameable(sensor.SENSOR_SCHEMA.extend({
+        cv.Optional(CONF_UNIT_OF_MEASUREMENT, default=UNIT_PERCENT): sensor.unit_of_measurement,
+        cv.Optional(CONF_ICON, default=ICON_BATTERY): sensor.icon,
+        cv.Optional(CONF_ACCURACY_DECIMALS, default=0): sensor.accuracy_decimals
+    })),
+}).extend(ESP_BLE_DEVICE_SCHEMA)
+
+
+def to_code(config):
+    hub = yield cg.get_variable(config[CONF_ESP32_BLE_ID])
+    var = cg.new_Pvariable(config[CONF_ID], hub, config[CONF_MAC_ADDRESS].as_hex)
+    yield cg.register_component(var, config)
+
+    if CONF_TEMPERATURE in config:
+        sens = yield sensor.new_sensor(config[CONF_TEMPERATURE])
+        cg.add(var.set_temperature(sens))
+    if CONF_MOISTURE in config:
+        sens = yield sensor.new_sensor(config[CONF_MOISTURE])
+        cg.add(var.set_moisture(sens))
+    if CONF_ILLUMINANCE in config:
+        sens = yield sensor.new_sensor(config[CONF_ILLUMINANCE])
+        cg.add(var.set_illuminance(sens))
+    if CONF_CONDUCTIVITY in config:
+        sens = yield sensor.new_sensor(config[CONF_CONDUCTIVITY])
+        cg.add(var.set_conductivity(sens))
+    if CONF_BATTERY_LEVEL in config:
+        sens = yield sensor.new_sensor(config[CONF_BATTERY_LEVEL])
+        cg.add(var.set_battery_level(sens))

esphome/components/xiaomi_miflora/xiaomi_miflora.cpp

@@ -0,0 +1,23 @@
+#include "xiaomi_miflora.h"
+#include "esphome/core/log.h"
+
+#ifdef ARDUINO_ARCH_ESP32
+
+namespace esphome {
+namespace xiaomi_miflora {
+
+static const char *TAG = "xiaomi_miflora";
+
+void XiaomiMiflora::dump_config() {
+  ESP_LOGCONFIG(TAG, "Xiaomi Mijia");
+  LOG_SENSOR("  ", "Temperature", this->temperature_);
+  LOG_SENSOR("  ", "Moisture", this->moisture_);
+  LOG_SENSOR("  ", "Conductivity", this->conductivity_);
+  LOG_SENSOR("  ", "Illuminance", this->illuminance_);
+  LOG_SENSOR("  ", "Battery Level", this->battery_level_);
+}
+
+}  // namespace xiaomi_miflora
+}  // namespace esphome
+
+#endif

esphome/components/xiaomi_miflora/xiaomi_miflora.h

@@ -0,0 +1,59 @@
+#pragma once
+
+#include "esphome/core/component.h"
+#include "esphome/components/sensor/sensor.h"
+#include "esphome/components/esp32_ble_tracker/esp32_ble_tracker.h"
+#include "esphome/components/xiaomi_ble/xiaomi_ble.h"
+
+#ifdef ARDUINO_ARCH_ESP32
+
+namespace esphome {
+namespace xiaomi_miflora {
+
+class XiaomiMiflora : public Component, public esp32_ble_tracker::ESPBTDeviceListener {
+ public:
+  XiaomiMiflora(esp32_ble_tracker::ESP32BLETracker *parent, uint64_t address)
+      : ESPBTDeviceListener(parent), address_(address) {}
+
+  bool parse_device(const esp32_ble_tracker::ESPBTDevice &device) override {
+    if (device.address_uint64() != this->address_)
+      return false;
+
+    auto res = xiaomi_ble::parse_xiaomi(device);
+    if (!res.has_value())
+      return false;
+
+    if (res->temperature.has_value() && this->temperature_ != nullptr)
+      this->temperature_->publish_state(*res->temperature);
+    if (res->moisture.has_value() && this->moisture_ != nullptr)
+      this->moisture_->publish_state(*res->moisture);
+    if (res->conductivity.has_value() && this->conductivity_ != nullptr)
+      this->conductivity_->publish_state(*res->conductivity);
+    if (res->illuminance.has_value() && this->illuminance_ != nullptr)
+      this->illuminance_->publish_state(*res->illuminance);
+    if (res->battery_level.has_value() && this->battery_level_ != nullptr)
+      this->battery_level_->publish_state(*res->battery_level);
+    return true;
+  }
+
+  void dump_config() override;
+  float get_setup_priority() const override { return setup_priority::DATA; }
+  void set_temperature(sensor::Sensor *temperature) { temperature_ = temperature; }
+  void set_moisture(sensor::Sensor *moisture) { moisture_ = moisture; }
+  void set_conductivity(sensor::Sensor *conductivity) { conductivity_ = conductivity; }
+  void set_illuminance(sensor::Sensor *illuminance) { illuminance_ = illuminance; }
+  void set_battery_level(sensor::Sensor *battery_level) { battery_level_ = battery_level; }
+
+ protected:
+  uint64_t address_;
+  sensor::Sensor *temperature_{nullptr};
+  sensor::Sensor *moisture_{nullptr};
+  sensor::Sensor *conductivity_{nullptr};
+  sensor::Sensor *illuminance_{nullptr};
+  sensor::Sensor *battery_level_{nullptr};
+};
+
+}  // namespace xiaomi_miflora
+}  // namespace esphome
+
+#endif