feat: include daily percentage variation

pkg/coinapi/coinapi.go

@@ -0,0 +1,80 @@
+package coinapi
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/araujo88/bitcoin-price-bot-nostr/pkg/config"
+	"github.com/araujo88/bitcoin-price-bot-nostr/pkg/responses"
+)
+
+const BASE_URL = "https://rest.coinapi.io/v1/"
+
+var API_KEY = config.GetDotEnvVariable("API_KEY")
+
+// makeRequest handles the common operations of making an HTTP request to the CoinAPI
+func makeRequest(url string) ([]byte, error) {
+	client := &http.Client{}
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("creating request: %w", err)
+	}
+
+	req.Header.Set("X-CoinAPI-Key", API_KEY)
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("executing request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("unexpected status code: %d", resp.StatusCode)
+	}
+
+	response, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("reading response: %w", err)
+	}
+
+	return response, nil
+}
+
+// FetchRate retrieves the current rate of Bitcoin in the specified currency
+func FetchRate(currency string) (float64, error) {
+	url := BASE_URL + "exchangerate/BTC/" + currency
+	response, err := makeRequest(url)
+	if err != nil {
+		return 0, err
+	}
+
+	var message responses.CurrencyRate
+	if err := json.Unmarshal(response, &message); err != nil {
+		return 0, fmt.Errorf("unmarshal response: %w", err)
+	}
+
+	return message.Rate, nil
+}
+
+// FetchDailyVariation retrieves the daily variation in percentage of the Bitcoin price for a specified currency
+func FetchDailyVariation(currency string) (float64, error) {
+	url := fmt.Sprintf("%sohlcv/BTC/%s/latest?period_id=1DAY&limit=1", BASE_URL, currency)
+	response, err := makeRequest(url)
+	if err != nil {
+		return 0, err
+	}
+
+	var data []responses.OHLCVData
+	if err := json.Unmarshal(response, &data); err != nil {
+		return 0, fmt.Errorf("unmarshal OHLCV data: %w", err)
+	}
+
+	if len(data) > 0 {
+		ohlcv := data[0]
+		variation := ((ohlcv.PriceClose - ohlcv.PriceOpen) / ohlcv.PriceOpen) * 100
+		return variation, nil
+	}
+
+	return 0, fmt.Errorf("no data found")
+}

pkg/post/post.go

@@ -8,7 +8,7 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/araujo88/bitcoin-price-bot-nostr/pkg/btcrate"
+	"github.com/araujo88/bitcoin-price-bot-nostr/pkg/coinapi"
 	"github.com/araujo88/bitcoin-price-bot-nostr/pkg/config"
 	"github.com/araujo88/bitcoin-price-bot-nostr/pkg/relay"
 	"github.com/nbd-wtf/go-nostr"
@@ -40,14 +40,42 @@ func Post() error {
 		return err
 	}
 
-	rate_usd := 1 / btcrate.FetchRate("USD") / 0.00000001
-	rate_eur := 1 / btcrate.FetchRate("EUR") / 0.00000001
-	rate_jpy := 1 / btcrate.FetchRate("JPY") / 0.00000001
-	rate_gbp := 1 / btcrate.FetchRate("GBP") / 0.00000001
-	rate_brl := 1 / btcrate.FetchRate("BRL") / 0.00000001
+	rate_usd, err := coinapi.FetchRate("USD")
+	if err != nil {
+		return errors.New("error fetching rate for USD")
+	}
+	rate_eur, err := coinapi.FetchRate("EUR")
+	if err != nil {
+		return errors.New("error fetching rate for EUR")
+	}
+	rate_brl, err := coinapi.FetchRate("BRL")
+	if err != nil {
+		return errors.New("error fetching rate for BRL")
+	}
+
+	daily_variation_usd, err := coinapi.FetchDailyVariation("USD")
+	if err != nil {
+		return errors.New("error fetching daily vartion for USD")
+	}
+
+	daily_variation_eur, err := coinapi.FetchDailyVariation("EUR")
+	if err != nil {
+		return errors.New("error fetching daily vartion for EUR")
+	}
+
+	daily_variation_brl, err := coinapi.FetchDailyVariation("BRL")
+	if err != nil {
+		return errors.New("error fetching daily vartion for BRL")
+	}
+
+	content := fmt.Sprintf(`1 BTC = %.0f USD (%.2f %%)\n
+	1 BTC = %0.f EUR (%.2f %%)\n
+	1 BTC = %0.f BRL (%.2f %%)\n`,
+		rate_usd, daily_variation_usd,
+		rate_eur, daily_variation_eur,
+		rate_brl, daily_variation_brl)
 
-	price_string := fmt.Sprintf("1 USD = %.0f sats\n1 EUR = %0.f sats\n1 JPY = %0.f sats\n1 GBP = %0.f sats\n1 BRL = %0.f sats", rate_usd, rate_eur, rate_jpy, rate_gbp, rate_brl)
-	ev.Content = price_string
+	ev.Content = content
 
 	ev.CreatedAt = time.Now()
 	ev.Kind = nostr.KindTextNote

pkg/responses/resposes.go

@@ -0,0 +1,21 @@
+package responses
+
+type CurrencyRate struct {
+	Time         string  `json:"time"`
+	AssetIdBase  string  `json:"asset_id_base"`
+	AssetIdQuote string  `json:"asset_id_quote"`
+	Rate         float64 `json:"rate"`
+}
+
+type OHLCVData struct {
+	TimePeriodStart string  `json:"time_period_start"`
+	TimePeriodEnd   string  `json:"time_period_end"`
+	TimeOpen        string  `json:"time_open"`
+	TimeClose       string  `json:"time_close"`
+	PriceOpen       float64 `json:"price_open"`
+	PriceHigh       float64 `json:"price_high"`
+	PriceLow        float64 `json:"price_low"`
+	PriceClose      float64 `json:"price_close"`
+	VolumeTraded    float64 `json:"volume_traded"`
+	TradesCount     int     `json:"trades_count"`
+}