feat: set up project

internal/services/price/conversor.go

@@ -0,0 +1,143 @@
+package price
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+
+	"gitea.urkob.com/urko/btc-pay-checker/internal/domain"
+	"gitea.urkob.com/urko/btc-pay-checker/kit"
+)
+
+type CoinPriceResponse struct {
+	Coins map[string]map[string]interface{} `json:"coins"`
+}
+
+type PriceConversor struct {
+	apiUrl        string
+	dollarRateApi string
+	client        *http.Client
+}
+
+func NewPriceConversor(apiUrl, dollarRateApi string) *PriceConversor {
+	return &PriceConversor{
+		apiUrl:        apiUrl,
+		client:        &http.Client{},
+		dollarRateApi: dollarRateApi,
+	}
+}
+
+type usdConversorResponse struct {
+	Result             string             `json:"result"`
+	Provider           string             `json:"provider"`
+	Documentation      string             `json:"documentation"`
+	TermsOfUse         string             `json:"terms_of_use"`
+	TimeLastUpdateUnix int                `json:"time_last_update_unix"`
+	TimeLastUpdateUtc  string             `json:"time_last_update_utc"`
+	TimeNextUpdateUnix int                `json:"time_next_update_unix"`
+	TimeNextUpdateUtc  string             `json:"time_next_update_utc"`
+	TimeEolUnix        int                `json:"time_eol_unix"`
+	BaseCode           string             `json:"base_code"`
+	Rates              map[string]float64 `json:"rates"`
+}
+
+func (p *PriceConversor) USDTo(c domain.Coin) (float64, error) {
+	usd := 0.0
+	reqURL := fmt.Sprintf(p.dollarRateApi)
+	req, err := http.NewRequest("GET", reqURL, nil)
+	if err != nil {
+		return usd, fmt.Errorf("http.NewRequest: %s", err)
+	}
+
+	kit.WithJSONHeaders(req)
+
+	resp, err := p.client.Do(req)
+	if err != nil {
+		return usd, fmt.Errorf("client.Do: %s", err)
+	}
+
+	bts, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return usd, fmt.Errorf("iokit.ReadAll: %s", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return usd, fmt.Errorf("error %d: %s", resp.StatusCode, string(bts))
+	}
+
+	var respBody usdConversorResponse
+	if err = json.Unmarshal(bts, &respBody); err != nil {
+		return usd, fmt.Errorf("json.Unmarshal: %s", err)
+	}
+
+	v, ok := respBody.Rates[string(c)]
+	if !ok {
+		return usd, fmt.Errorf("coin isn't found")
+	}
+
+	return v, nil
+}
+
+func (p *PriceConversor) USD(c domain.Coin) (float64, error) {
+	usd := 0.0
+	reqURL := fmt.Sprintf(p.apiUrl+"/prices/current/%s", c)
+	req, err := http.NewRequest("GET", reqURL, nil)
+	if err != nil {
+		return usd, fmt.Errorf("http.NewRequest: %s", err)
+	}
+
+	kit.WithJSONHeaders(req)
+
+	resp, err := p.client.Do(req)
+	if err != nil {
+		return usd, fmt.Errorf("client.Do: %s", err)
+	}
+
+	bts, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return usd, fmt.Errorf("iokit.ReadAll: %s", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return usd, fmt.Errorf("error %d: %s", resp.StatusCode, string(bts))
+	}
+
+	var respBody CoinPriceResponse
+	if err = json.Unmarshal(bts, &respBody); err != nil {
+		return usd, fmt.Errorf("json.Unmarshal: %s", err)
+	}
+
+	if _, hasKey := respBody.Coins[string(c)]; !hasKey {
+		return usd, fmt.Errorf("coin isn't found")
+	}
+
+	if _, hasKey := respBody.Coins[string(c)]["price"]; !hasKey {
+		return usd, fmt.Errorf("coin price isn't found")
+	}
+
+	usd, ok := respBody.Coins[string(c)]["price"].(float64)
+	if !ok {
+		return usd, fmt.Errorf("cannot cast price to float64")
+	}
+
+	return usd, nil
+}
+
+func (p *PriceConversor) UsdToBtc(usdAmount float64) (float64, error) {
+	usd, err := p.USD(domain.CoinBTC)
+	if err != nil {
+		return usdAmount, fmt.Errorf("USDToBtc: %s", err)
+	}
+
+	return usdAmount / usd, nil
+}
+
+func (p *PriceConversor) BtcToUsd(btcAmount float64) (float64, error) {
+	usd, err := p.USD(domain.CoinBTC)
+	if err != nil {
+		return btcAmount, fmt.Errorf("USDToBtc: %s", err)
+	}
+
+	return btcAmount * usd, nil
+}