InfiniTime/src/components/ble/SimpleWeatherService.h

/*  Copyright (C) 2023 Jean-François Milants

    This file is part of InfiniTime.

    InfiniTime is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published
    by the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    InfiniTime is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/
#pragma once

#include <cstdint>
#include <string>
#include <array>
#include <memory>

#define min // workaround: nimble's min/max macros conflict with libstdc++
#define max
#include <host/ble_gap.h>
#include <host/ble_uuid.h>
#include <optional>
#include <cstring>
#undef max
#undef min

#include "components/datetime/DateTimeController.h"

int WeatherCallback(uint16_t connHandle, uint16_t attrHandle, struct ble_gatt_access_ctxt* ctxt, void* arg);

namespace Pinetime {
  namespace Controllers {

    class SimpleWeatherService {
    public:
      explicit SimpleWeatherService(DateTime& dateTimeController);

      void Init();

      int OnCommand(struct ble_gatt_access_ctxt* ctxt);

      static constexpr uint8_t MaxNbForecastDays = 5;

      enum class Icons : uint8_t {
        Sun = 0,       // ClearSky
        CloudsSun = 1, // FewClouds
        Clouds = 2,    // Scattered clouds
        BrokenClouds = 3,
        CloudShowerHeavy = 4, // shower rain
        CloudSunRain = 5,     // rain
        Thunderstorm = 6,
        Snow = 7,
        Smog = 8, // Mist
        Unknown = 255
      };

      class Temperature {
      public:
        explicit Temperature(int16_t raw = 0) : raw {raw} {
        }

        [[nodiscard]] int16_t PreciseCelsius() const {
          return raw;
        }

        [[nodiscard]] int16_t PreciseFahrenheit() const {
          return raw * 9 / 5 + 3200;
        }

        [[nodiscard]] int16_t Celsius() const {
          return (PreciseCelsius() + 50) / 100;
        }

        [[nodiscard]] int16_t Fahrenheit() const {
          return (PreciseFahrenheit() + 50) / 100;
        }

        bool operator==(const Temperature& other) const {
          return raw == other.raw;
        }

      private:
        int16_t raw;
      };

      using Location = std::array<char, 33>; // 32 char + \0 (end of string)

      struct CurrentWeather {
        CurrentWeather(uint64_t timestamp,
                       Temperature temperature,
                       Temperature minTemperature,
                       Temperature maxTemperature,
                       Icons iconId,
                       Location&& location)
          : timestamp {timestamp},
            temperature {temperature},
            minTemperature {minTemperature},
            maxTemperature {maxTemperature},
            iconId {iconId},
            location {std::move(location)} {
        }

        uint64_t timestamp;
        Temperature temperature;
        Temperature minTemperature;
        Temperature maxTemperature;
        Icons iconId;
        Location location;

        bool operator==(const CurrentWeather& other) const;
      };

      struct Forecast {
        uint64_t timestamp;
        uint8_t nbDays;

        struct Day {
          Temperature minTemperature;
          Temperature maxTemperature;
          Icons iconId;

          bool operator==(const Day& other) const;
        };

        std::array<Day, MaxNbForecastDays> days;

        bool operator==(const Forecast& other) const;
      };

      std::optional<CurrentWeather> Current() const;
      std::optional<Forecast> GetForecast() const;

    private:
      // 00050000-78fc-48fe-8e23-433b3a1942d0
      static constexpr ble_uuid128_t BaseUuid() {
        return CharUuid(0x00, 0x00);
      }

      // 0005yyxx-78fc-48fe-8e23-433b3a1942d0
      static constexpr ble_uuid128_t CharUuid(uint8_t x, uint8_t y) {
        return ble_uuid128_t {.u = {.type = BLE_UUID_TYPE_128},
                              .value = {0xd0, 0x42, 0x19, 0x3a, 0x3b, 0x43, 0x23, 0x8e, 0xfe, 0x48, 0xfc, 0x78, y, x, 0x05, 0x00}};
      }

      ble_uuid128_t weatherUuid {BaseUuid()};

      ble_uuid128_t weatherDataCharUuid {CharUuid(0x00, 0x01)};

      const struct ble_gatt_chr_def characteristicDefinition[2] = {{.uuid = &weatherDataCharUuid.u,
                                                                    .access_cb = WeatherCallback,
                                                                    .arg = this,
                                                                    .flags = BLE_GATT_CHR_F_WRITE,
                                                                    .val_handle = &eventHandle},
                                                                   {0}};
      const struct ble_gatt_svc_def serviceDefinition[2] = {
        {.type = BLE_GATT_SVC_TYPE_PRIMARY, .uuid = &weatherUuid.u, .characteristics = characteristicDefinition},
        {0}};

      uint16_t eventHandle {};

      Pinetime::Controllers::DateTime& dateTimeController;

      std::optional<CurrentWeather> currentWeather;
      std::optional<Forecast> forecast;
    };
  }
}