ynab-portfolio-monitor/providers/bitcoin/fiat.go

package bitcoin

import (
	"fmt"
	"net/http"
)

const fiatConvertURL = "https://api.coingecko.com/api/v3/coins/bitcoin?localization=false&tickers=false&market_data=true&community_data=false&developer_data=false&sparkline=false"

type coinGeckoResponse struct {
	MarketData struct {
		CurrentPrice struct {
			CAD int `json:"cad"`
		} `json:"current_price"`
	} `json:"market_data"`
}

func (c *client) convertBTCToCAD(amount int) (int, error) {
	coinGeckoData := &coinGeckoResponse{}

	req, err := http.NewRequest("GET", fmt.Sprintf("%s&x-cg-demo-api-key=%s", fiatConvertURL, c.coinGeckoApiKey), nil)
	if err != nil {
		return 0, fmt.Errorf("failed to create new GET request: %v", err)
	}

	res, err := c.httpClient.Do(req)
	if err != nil {
		return 0, fmt.Errorf("http GET request failed: %v", err)
	}

	err = c.processResponse(res, coinGeckoData)
	if err != nil {
		return 0, fmt.Errorf("failed to process response: %v", err)
	}

	return (amount * int(coinGeckoData.MarketData.CurrentPrice.CAD*1000)) / 100000000, nil // one BTC = one hundred million satoshi's
}