🏗 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/esp32_ble_beacon/__init__.py

@@ -0,0 +1,29 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.const import CONF_ID, CONF_TYPE, CONF_UUID, ESP_PLATFORM_ESP32
+
+ESP_PLATFORMS = [ESP_PLATFORM_ESP32]
+CONFLICTS_WITH = ['esp32_ble_tracker']
+
+esp32_ble_beacon_ns = cg.esphome_ns.namespace('esp32_ble_beacon')
+ESP32BLEBeacon = esp32_ble_beacon_ns.class_('ESP32BLEBeacon', cg.Component)
+
+CONF_MAJOR = 'major'
+CONF_MINOR = 'minor'
+
+CONFIG_SCHEMA = cv.Schema({
+    cv.GenerateID(): cv.declare_variable_id(ESP32BLEBeacon),
+    cv.Required(CONF_TYPE): cv.one_of('IBEACON', upper=True),
+    cv.Required(CONF_UUID): cv.uuid,
+    cv.Optional(CONF_MAJOR, default=10167): cv.uint16_t,
+    cv.Optional(CONF_MINOR, default=61958): cv.uint16_t,
+}).extend(cv.COMPONENT_SCHEMA)
+
+
+def to_code(config):
+    uuid = config[CONF_UUID].hex
+    uuid_arr = [cg.RawExpression('0x{}'.format(uuid[i:i + 2])) for i in range(0, len(uuid), 2)]
+    var = cg.new_Pvariable(config[CONF_ID], uuid_arr)
+    yield cg.register_component(var, config)
+    cg.add(var.set_major(config[CONF_MAJOR]))
+    cg.add(var.set_minor(config[CONF_MINOR]))

esphome/components/esp32_ble_beacon/esp32_ble_beacon.cpp

@@ -0,0 +1,134 @@
+#include "esp32_ble_beacon.h"
+#include "esphome/core/log.h"
+
+#ifdef ARDUINO_ARCH_ESP32
+
+#include <nvs_flash.h>
+#include <freertos/FreeRTOSConfig.h>
+#include <esp_bt_main.h>
+#include <esp_bt.h>
+#include <freertos/task.h>
+#include <esp_gap_ble_api.h>
+
+namespace esphome {
+namespace esp32_ble_beacon {
+
+static const char *TAG = "esp32_ble_beacon";
+
+static esp_ble_adv_params_t ble_adv_params = {
+    .adv_int_min = 0x20,
+    .adv_int_max = 0x40,
+    .adv_type = ADV_TYPE_NONCONN_IND,
+    .own_addr_type = BLE_ADDR_TYPE_PUBLIC,
+    .peer_addr = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
+    .peer_addr_type = BLE_ADDR_TYPE_PUBLIC,
+    .channel_map = ADV_CHNL_ALL,
+    .adv_filter_policy = ADV_FILTER_ALLOW_SCAN_ANY_CON_ANY,
+};
+
+#define ENDIAN_CHANGE_U16(x) ((((x) &0xFF00) >> 8) + (((x) &0xFF) << 8))
+
+static esp_ble_ibeacon_head_t ibeacon_common_head = {
+    .flags = {0x02, 0x01, 0x06}, .length = 0x1A, .type = 0xFF, .company_id = 0x004C, .beacon_type = 0x1502};
+
+void ESP32BLEBeacon::setup() {
+  ESP_LOGCONFIG(TAG, "Setting up ESP32 BLE beacon...");
+  global_esp32_ble_beacon = this;
+
+  xTaskCreatePinnedToCore(ESP32BLEBeacon::ble_core_task,
+                          "ble_task",  // name
+                          10000,       // stack size (in words)
+                          nullptr,     // input params
+                          1,           // priority
+                          nullptr,     // Handle, not needed
+                          0            // core
+  );
+}
+
+float ESP32BLEBeacon::get_setup_priority() const { return setup_priority::DATA; }
+void ESP32BLEBeacon::ble_core_task(void *params) {
+  ble_setup();
+
+  while (true) {
+    delay(1000);
+  }
+}
+void ESP32BLEBeacon::ble_setup() {
+  // Initialize non-volatile storage for the bluetooth controller
+  esp_err_t err = nvs_flash_init();
+  if (err != ESP_OK) {
+    ESP_LOGE(TAG, "nvs_flash_init failed: %d", err);
+    return;
+  }
+
+  if (!btStart()) {
+    ESP_LOGE(TAG, "btStart failed: %d", esp_bt_controller_get_status());
+    return;
+  }
+
+  esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT);
+
+  err = esp_bluedroid_init();
+  if (err != ESP_OK) {
+    ESP_LOGE(TAG, "esp_bluedroid_init failed: %d", err);
+    return;
+  }
+  err = esp_bluedroid_enable();
+  if (err != ESP_OK) {
+    ESP_LOGE(TAG, "esp_bluedroid_enable failed: %d", err);
+    return;
+  }
+  err = esp_ble_gap_register_callback(ESP32BLEBeacon::gap_event_handler);
+  if (err != ESP_OK) {
+    ESP_LOGE(TAG, "esp_ble_gap_register_callback failed: %d", err);
+    return;
+  }
+
+  esp_ble_ibeacon_t ibeacon_adv_data;
+  memcpy(&ibeacon_adv_data.ibeacon_head, &ibeacon_common_head, sizeof(esp_ble_ibeacon_head_t));
+  memcpy(&ibeacon_adv_data.ibeacon_vendor.proximity_uuid, global_esp32_ble_beacon->uuid_.data(),
+         sizeof(ibeacon_adv_data.ibeacon_vendor.proximity_uuid));
+  ibeacon_adv_data.ibeacon_vendor.minor = ENDIAN_CHANGE_U16(global_esp32_ble_beacon->minor_);
+  ibeacon_adv_data.ibeacon_vendor.major = ENDIAN_CHANGE_U16(global_esp32_ble_beacon->major_);
+  ibeacon_adv_data.ibeacon_vendor.measured_power = 0xC5;
+
+  esp_ble_gap_config_adv_data_raw((uint8_t *) &ibeacon_adv_data, sizeof(ibeacon_adv_data));
+}
+
+void ESP32BLEBeacon::gap_event_handler(esp_gap_ble_cb_event_t event, esp_ble_gap_cb_param_t *param) {
+  esp_err_t err;
+  switch (event) {
+    case ESP_GAP_BLE_ADV_DATA_RAW_SET_COMPLETE_EVT: {
+      err = esp_ble_gap_start_advertising(&ble_adv_params);
+      if (err != ESP_OK) {
+        ESP_LOGE(TAG, "esp_ble_gap_start_advertising failed: %d", err);
+      }
+      break;
+    }
+    case ESP_GAP_BLE_ADV_START_COMPLETE_EVT: {
+      err = param->adv_start_cmpl.status;
+      if (err != ESP_BT_STATUS_SUCCESS) {
+        ESP_LOGE(TAG, "BLE adv start failed: %s", esp_err_to_name(err));
+      }
+      break;
+    }
+    case ESP_GAP_BLE_ADV_STOP_COMPLETE_EVT: {
+      err = param->adv_start_cmpl.status;
+      if (err != ESP_BT_STATUS_SUCCESS) {
+        ESP_LOGE(TAG, "BLE adv stop failed: %s", esp_err_to_name(err));
+      } else {
+        ESP_LOGD(TAG, "BLE stopped advertising successfully");
+      }
+      break;
+    }
+    default:
+      break;
+  }
+}
+
+ESP32BLEBeacon *global_esp32_ble_beacon = nullptr;
+
+}  // namespace esp32_ble_beacon
+}  // namespace esphome
+
+#endif

esphome/components/esp32_ble_beacon/esp32_ble_beacon.h

@@ -0,0 +1,57 @@
+#pragma once
+
+#include "esphome/core/component.h"
+
+#ifdef ARDUINO_ARCH_ESP32
+
+#include <esp_gap_ble_api.h>
+
+namespace esphome {
+namespace esp32_ble_beacon {
+
+typedef struct {
+  uint8_t flags[3];
+  uint8_t length;
+  uint8_t type;
+  uint16_t company_id;
+  uint16_t beacon_type;
+} __attribute__((packed)) esp_ble_ibeacon_head_t;
+
+typedef struct {
+  uint8_t proximity_uuid[16];
+  uint16_t major;
+  uint16_t minor;
+  uint8_t measured_power;
+} __attribute__((packed)) esp_ble_ibeacon_vendor_t;
+
+typedef struct {
+  esp_ble_ibeacon_head_t ibeacon_head;
+  esp_ble_ibeacon_vendor_t ibeacon_vendor;
+} __attribute__((packed)) esp_ble_ibeacon_t;
+
+class ESP32BLEBeacon : public Component {
+ public:
+  explicit ESP32BLEBeacon(const std::array<uint8_t, 16> &uuid) : uuid_(uuid) {}
+
+  void setup() override;
+  float get_setup_priority() const override;
+
+  void set_major(uint16_t major) { this->major_ = major; }
+  void set_minor(uint16_t minor) { this->minor_ = minor; }
+
+ protected:
+  static void gap_event_handler(esp_gap_ble_cb_event_t event, esp_ble_gap_cb_param_t *param);
+  static void ble_core_task(void *params);
+  static void ble_setup();
+
+  std::array<uint8_t, 16> uuid_;
+  uint16_t major_{};
+  uint16_t minor_{};
+};
+
+extern ESP32BLEBeacon *global_esp32_ble_beacon;
+
+}  // namespace esp32_ble_beacon
+}  // namespace esphome
+
+#endif