Initial commit

internal/feed/openmeteo.go

@@ -0,0 +1,151 @@
+package feed
+
+import (
+	"fmt"
+	"math"
+	"net/http"
+	"net/url"
+	"slices"
+	"time"
+
+	_ "time/tzdata"
+)
+
+type PlacesResponseJson struct {
+	Results []PlaceJson
+}
+
+type PlaceJson struct {
+	Name      string
+	Latitude  float64
+	Longitude float64
+	Timezone  string
+	Country   string
+	location  *time.Location
+}
+
+type WeatherResponseJson struct {
+	Daily struct {
+		Sunrise []int64 `json:"sunrise"`
+		Sunset  []int64 `json:"sunset"`
+	} `json:"daily"`
+
+	Hourly struct {
+		Temperature              []float64 `json:"temperature_2m"`
+		PrecipitationProbability []int     `json:"precipitation_probability"`
+	} `json:"hourly"`
+
+	Current struct {
+		Temperature         float64 `json:"temperature_2m"`
+		ApparentTemperature float64 `json:"apparent_temperature"`
+		WeatherCode         int     `json:"weather_code"`
+	} `json:"current"`
+}
+
+type weatherColumn struct {
+	Temperature      int
+	Scale            float64
+	HasPrecipitation bool
+}
+
+func FetchPlaceFromName(location string) (*PlaceJson, error) {
+	requestUrl := fmt.Sprintf("https://geocoding-api.open-meteo.com/v1/search?name=%s&count=1&language=en&format=json", url.QueryEscape(location))
+	request, _ := http.NewRequest("GET", requestUrl, nil)
+	responseJson, err := decodeJsonFromRequest[PlacesResponseJson](defaultClient, request)
+
+	if err != nil {
+		return nil, fmt.Errorf("could not fetch places data: %v", err)
+	}
+
+	if len(responseJson.Results) == 0 {
+		return nil, fmt.Errorf("no places found for %s", location)
+	}
+
+	place := &responseJson.Results[0]
+
+	loc, err := time.LoadLocation(place.Timezone)
+
+	if err != nil {
+		return nil, fmt.Errorf("could not load location: %v", err)
+	}
+
+	place.location = loc
+
+	return place, nil
+}
+
+func barIndexFromHour(h int) int {
+	return h / 2
+}
+
+// TODO: bunch of spaget, refactor
+// TODO: allow changing between C and F
+func FetchWeatherForPlace(place *PlaceJson) (*Weather, error) {
+	query := url.Values{}
+
+	query.Add("latitude", fmt.Sprintf("%f", place.Latitude))
+	query.Add("longitude", fmt.Sprintf("%f", place.Longitude))
+	query.Add("timeformat", "unixtime")
+	query.Add("timezone", place.Timezone)
+	query.Add("forecast_days", "1")
+	query.Add("current", "temperature_2m,apparent_temperature,weather_code,wind_speed_10m")
+	query.Add("hourly", "temperature_2m,precipitation_probability")
+	query.Add("daily", "sunrise,sunset")
+
+	requestUrl := "https://api.open-meteo.com/v1/forecast?" + query.Encode()
+	request, _ := http.NewRequest("GET", requestUrl, nil)
+	responseJson, err := decodeJsonFromRequest[WeatherResponseJson](defaultClient, request)
+
+	if err != nil {
+		return nil, fmt.Errorf("%w: %v", ErrNoContent, err)
+	}
+
+	now := time.Now().In(place.location)
+	bars := make([]weatherColumn, 0, 24)
+	currentBar := barIndexFromHour(now.Hour())
+	sunriseBar := barIndexFromHour(time.Unix(int64(responseJson.Daily.Sunrise[0]), 0).In(place.location).Hour())
+	sunsetBar := barIndexFromHour(time.Unix(int64(responseJson.Daily.Sunset[0]), 0).In(place.location).Hour()) - 1
+
+	if sunsetBar < 0 {
+		sunsetBar = 0
+	}
+
+	if len(responseJson.Hourly.Temperature) == 24 {
+		temperatures := make([]int, 12)
+		precipitations := make([]bool, 12)
+
+		t := responseJson.Hourly.Temperature
+		p := responseJson.Hourly.PrecipitationProbability
+
+		for i := 0; i < 24; i += 2 {
+			if i/2 == currentBar {
+				temperatures[i/2] = int(responseJson.Current.Temperature)
+			} else {
+				temperatures[i/2] = int(math.Round((t[i] + t[i+1]) / 2))
+			}
+
+			precipitations[i/2] = (p[i]+p[i+1])/2 > 75
+		}
+
+		minT := slices.Min(temperatures)
+		maxT := slices.Max(temperatures)
+
+		for i := 0; i < 12; i++ {
+			bars = append(bars, weatherColumn{
+				Temperature:      temperatures[i],
+				Scale:            float64(temperatures[i]-minT) / float64(maxT-minT),
+				HasPrecipitation: precipitations[i],
+			})
+		}
+	}
+
+	return &Weather{
+		Temperature:         int(responseJson.Current.Temperature),
+		ApparentTemperature: int(responseJson.Current.ApparentTemperature),
+		WeatherCode:         responseJson.Current.WeatherCode,
+		CurrentColumn:       currentBar,
+		SunriseColumn:       sunriseBar,
+		SunsetColumn:        sunsetBar,
+		Columns:             bars,
+	}, nil
+}