lassistanoque/backend/internal/adapter/tools/weather/tool.go

package weather

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"net/url"
	"strings"

	"trankilou.fr/lassistanoque/backend/internal/domain"
)

type WeatherTool struct {
}

type WeatherConfig struct {
}

func (t *WeatherTool) Name() string {
	return "weather"
}

func (t *WeatherTool) Description() string {
	return "Get the current weather for a given location"
}

func (t *WeatherTool) Definition(ctx context.Context) *domain.ToolDefinition {
	return &domain.ToolDefinition{
		Type: "function",
		Function: &domain.ToolFunction{
			Name:        t.Name(),
			Description: t.Description(),
			Parameters: map[string]any{
				"type": "object",
				"properties": map[string]any{
					"location": map[string]any{
						"type":        "string",
						"description": "The city name, e.g., 'Paris' or 'New York'",
					},
				},
				"required": []string{"location"},
			},
		},
	}
}

func (t *WeatherTool) Execute(ctx context.Context, input []byte) ([]byte, error) {

	var params struct {
		Location string `json:"location"`
	}
	err := json.Unmarshal(input, &params)
	if err != nil {
		return nil, err
	}

	resp, err := http.Get("https://geocoding-api.open-meteo.com/v1/search?name=" + url.QueryEscape(params.Location))
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	var location struct {
		Results []struct {
			Latitude  float64 `json:"latitude"`
			Longitude float64 `json:"longitude"`
		} `json:"results"`
	}
	err = json.NewDecoder(resp.Body).Decode(&location)
	if err != nil {
		return nil, err
	}

	if len(location.Results) == 0 {
		return nil, fmt.Errorf("location not found : %s", input)
	}

	lon := location.Results[0].Longitude
	lat := location.Results[0].Latitude

	weatherResp, err := http.Get(fmt.Sprintf("https://api.open-meteo.com/v1/forecast?latitude=%f&longitude=%f&current_weather=true&daily=weather_code,temperature_2m_max,temperature_2m_min,rain_sum,wind_speed_10m_max&hourly=temperature_2m&forecast_days=15", lat, lon))
	if err != nil {
		return nil, err
	}
	defer weatherResp.Body.Close()

	var weatherData struct {
		CurrentWeatherUnits struct {
			Temperature string `json:"temperature"`
			WindSpeed   string `json:"windspeed"`
		} `json:"current_weather_units"`
		CurrentWeather struct {
			Time        string  `json:"time"`
			Temperature float64 `json:"temperature"`
			WeatherCode int     `json:"weathercode"`
		} `json:"current_weather"`
		DailyUnits struct {
			TemperatureMax string `json:"temperature_2m_max"`
			TemperatureMin string `json:"temperature_2m_min"`
			Rain           string `json:"rain_sum"`
			WindSpeed      string `json:"wind_speed_10m_max"`
		} `json:"daily_units"`
		Daily struct {
			Time           []string  `json:"time"`
			TemperatureMax []float64 `json:"temperature_2m_max"`
			TemperatureMin []float64 `json:"temperature_2m_min"`
			Rain           []float64 `json:"rain_sum"`
			WindSpeed      []float64 `json:"wind_speed_10m_max"`
		} `json:"daily"`
	}

	err = json.NewDecoder(weatherResp.Body).Decode(&weatherData)
	if err != nil {
		return nil, err
	}

	var builder strings.Builder

	fmt.Fprintf(&builder, "Current weather in %s\n", params.Location)
	fmt.Fprintf(&builder, "- Time: %s\n", weatherData.CurrentWeather.Time)
	fmt.Fprintf(&builder, "- Temperature:  %.2f %s\n", weatherData.CurrentWeather.Temperature, weatherData.CurrentWeatherUnits.Temperature)
	fmt.Fprintf(&builder, "- Weather code: %d - %s\n", weatherData.CurrentWeather.WeatherCode, wmoCodeToDescription(weatherData.CurrentWeather.WeatherCode))
	if len(weatherData.Daily.WindSpeed) > 0 {
		fmt.Fprintf(&builder, "- Wind speed: %.2f %s\n", weatherData.Daily.WindSpeed[0], weatherData.DailyUnits.WindSpeed)
	}
	if len(weatherData.Daily.TemperatureMax) > 0 {
		fmt.Fprintf(&builder, "- Max temperature: %.2f %s\n", weatherData.Daily.TemperatureMax[0], weatherData.DailyUnits.TemperatureMax)
	}
	if len(weatherData.Daily.TemperatureMin) > 0 {
		fmt.Fprintf(&builder, "- Min temperature: %.2f %s\n", weatherData.Daily.TemperatureMin[0], weatherData.DailyUnits.TemperatureMin)
	}
	if len(weatherData.Daily.Rain) > 0 {
		fmt.Fprintf(&builder, "- Rainfall: %.2f %s\n", weatherData.Daily.Rain[0], weatherData.DailyUnits.Rain)
	}

	fmt.Fprintf(&builder, "\nForecast for the next days:\n")

	// Iterate over the daily data and append to the repor
	for i := 0; i < len(weatherData.Daily.Time); i++ {
		fmt.Fprintf(&builder, "%s: Max Temp: %.2f %s, Min Temp: %.2f %s, Rain: %.2f %s, Wind Speed: %.2f %s\n",
			weatherData.Daily.Time[i],
			weatherData.Daily.TemperatureMax[i], weatherData.DailyUnits.TemperatureMax,
			weatherData.Daily.TemperatureMin[i], weatherData.DailyUnits.TemperatureMin,
			weatherData.Daily.Rain[i], weatherData.DailyUnits.Rain,
			weatherData.Daily.WindSpeed[i], weatherData.DailyUnits.WindSpeed)
	}

	return []byte(builder.String()), nil
}

func wmoCodeToDescription(code int) string {
	switch code {
	case 0:
		return "Clear sky"
	case 1, 2, 3:
		return "Mainly clear, partly cloudy, and overcast"
	case 45, 48:
		return "Fog and depositing rime fog"
	case 51, 53, 55:
		return "Drizzle: Light, moderate, and dense intensity"
	case 56, 57:
		return "Freezing Drizzle: Light and dense intensity"
	case 61, 63, 65:
		return "Rain: Slight, moderate and heavy intensity"
	case 66, 67:
		return "Freezing Rain: Light and heavy intensity"
	case 71, 73, 75:
		return "Snowfall: Slight, moderate, and heavy intensity"
	case 77:
		return "Snow grains"
	case 80, 81, 82:
		return "Rain showers: Slight, moderate, and violent"
	case 85, 86:
		return "Snow showers slight and heavy"
	case 95:
		return "Thunderstorm: Slight and heavy intensity"
	case 96, 99:
		return "Thunderstorm with slight and heavy hail"
	default:
		return "N/A"
	}
}