feat: integrate restcountries api

internal/geodata/fetcher.go

@@ -0,0 +1,57 @@
+package geodata
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+)
+
+func FetchLive() (TimezoneMap, error) {
+	client := http.Client{Timeout: 10 * time.Second}
+
+	// from: https://restcountries.com
+	url := "https://restcountries.com/v3.1/all?fields=name,population,timezones"
+
+	resp, err := client.Get(url)
+	if err != nil {
+		return nil, fmt.Errorf("failed to fetch country data")
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		return nil, fmt.Errorf("failed to fetch country data")
+	}
+
+	var apidData []countryApiReponse
+	if err := json.NewDecoder(resp.Body).Decode(&apidData); err != nil {
+		return nil, fmt.Errorf("failed to fetch ")
+	}
+
+	return buildTzMap(apidData), nil
+}
+
+func buildTzMap(data []countryApiReponse) TimezoneMap {
+	tzMap := make(TimezoneMap)
+
+	for _, countryRaw := range data {
+		country := Country{
+			Name:       countryRaw.Name.Common,
+			Population: countryRaw.Population,
+		}
+
+		for _, rawTZ := range countryRaw.Timezones {
+			rawTZ = strings.TrimPrefix(rawTZ, "UTC")
+			rawTZ = strings.ReplaceAll(rawTZ, ":", "")
+
+			if rawTZ == "" {
+				rawTZ = "+0000" // api quirk
+			}
+
+			tzMap[rawTZ] = append(tzMap[rawTZ], country)
+		}
+	}
+
+	return tzMap
+}

internal/geodata/models.go

@@ -0,0 +1,19 @@
+package geodata
+
+// Country info exposed to other packages
+type Country struct {
+	Name       string
+	Population int64
+}
+
+// Timezone to Country lookups
+type TimezoneMap map[string][]Country
+
+// internal model for https://restcountries.com/v3.1/all?fields=name,population,timezones
+type countryApiReponse struct {
+	Name struct {
+		Common string `json:"common"` // it has other fields but I don't want them
+	} `json:"name"`
+	Population int64    `json:"population"`
+	Timezones  []string `json:"timezones"` // example: [ "UTC+00:00" ]
+}