Merge pull request #11 from prosolis/forex-crypto-coingecko

Forex: convert to/from crypto via CoinGecko (keyless)

internal/plugin/forex.go

@@ -113,6 +113,7 @@ const fxHelpText = "**Forex Commands**\n\n" +
 	"`!fx rate EUR/USD` — cross-pair rate from first currency's perspective\n" +
 	"`!fx report [EUR|JPY|CAD]` — full analysis (averages, 52w range, buy score)\n" +
 	"`!fx 1500 USD to EUR` — convert an amount (also: `!fx convert 1500 USD EUR`)\n" +
+	"`!fx 100 USD to BTC` — convert to/from crypto (BTC, ETH, SOL, XRP, DOGE, ADA, LTC)\n" +
 	"`!fx setalert <currency> <rate>` — alert when USD/currency reaches threshold\n" +
 	"`!fx alerts` — list active alerts in this room\n" +
 	"`!fx delalert <currency> <rate>` — remove an alert\n" +
@@ -122,7 +123,7 @@ const fxHelpText = "**Forex Commands**\n\n" +
 
 func (p *ForexPlugin) cmdRate(ctx MessageContext, args []string) error {
 	// Check for cross-pair syntax like EUR/USD or USD/JPY
-	if pair := fxParsePair(args); pair != nil {
+	if pair := fxParsePair(args, false); pair != nil {
 		return p.cmdPairRateOrReport(ctx, pair, false)
 	}
 
@@ -156,8 +157,10 @@ type fxPair struct {
 }
 
 // fxParsePair detects "XXX/YYY" syntax in args. Both sides must be USD or a
-// tracked currency. Returns nil if no pair is found.
+// tracked currency; when allowCrypto is set, supported crypto assets are
-func fxParsePair(args []string) *fxPair {
+// accepted too (used by the conversion path, not by analysis). Returns nil if
+// no pair is found.
+func fxParsePair(args []string, allowCrypto bool) *fxPair {
 	if len(args) == 0 {
 		return nil
 	}
@@ -174,7 +177,11 @@ func fxParsePair(args []string) *fxPair {
 		return nil
 	}
 	base, quote := parts[0], parts[1]
-	if !fxIsSupported(base) || !fxIsSupported(quote) {
+	ok := fxIsSupported
+	if allowCrypto {
+		ok = fxIsConvertible
+	}
+	if !ok(base) || !ok(quote) {
 		return nil
 	}
 	if base == quote {
@@ -215,46 +222,62 @@ func (p *ForexPlugin) cmdPairRateOrReport(ctx MessageContext, pair *fxPair, full
 	return p.SendReply(ctx.RoomID, ctx.EventID, sig.FormatQuick())
 }
 
-// fxLivePairRate computes the live cross-pair rate from USD-base rates.
+// fxLivePairRate computes the live cross-pair rate (how many Quote per 1 Base).
+// Each side is resolved to a "units per USD" figure, then crossed; this handles
+// USD, fiat (Frankfurter), and crypto (CoinGecko) sides uniformly.
 func (p *ForexPlugin) fxLivePairRate(pair *fxPair) (float64, error) {
-	var currencies []string
+	// Batch the fiat sides into a single Frankfurter call.
-	if pair.Base != "USD" {
+	var fiat []string
-		currencies = append(currencies, pair.Base)
+	for _, c := range []string{pair.Base, pair.Quote} {
+		if c != "USD" && !fxIsCrypto(c) {
+			fiat = append(fiat, c)
+		}
 	}
-	if pair.Quote != "USD" {
+	var fiatRates map[string]float64
-		currencies = append(currencies, pair.Quote)
+	if len(fiat) > 0 {
+		var err error
+		if fiatRates, err = p.fxLiveRates(fiat); err != nil {
+			return 0, err
+		}
 	}
 
-	rates, err := p.fxLiveRates(currencies)
+	basePer, err := p.fxPerUSD(pair.Base, fiatRates)
 	if err != nil {
 		return 0, err
 	}
+	quotePer, err := p.fxPerUSD(pair.Quote, fiatRates)
+	if err != nil {
+		return 0, err
+	}
+	if basePer == 0 {
+		return 0, fmt.Errorf("missing rate data for cross-pair")
+	}
+	return quotePer / basePer, nil
+}
 
+// fxPerUSD returns how many units of cur equal 1 USD. Fiat rates are taken from
+// the pre-fetched fiatRates map; crypto is fetched live from CoinGecko.
+func (p *ForexPlugin) fxPerUSD(cur string, fiatRates map[string]float64) (float64, error) {
 	switch {
-	case pair.Base == "USD":
+	case cur == "USD":
-		r, ok := rates[pair.Quote]
+		return 1.0, nil
-		if !ok {
+	case fxIsCrypto(cur):
-			return 0, fmt.Errorf("no rate data for %s", pair.Quote)
+		price, err := p.cgSpotUSD(cur)
+		if err != nil {
+			return 0, err
+		}
+		return 1.0 / price, nil
+	default:
+		r, ok := fiatRates[cur]
+		if !ok || r == 0 {
+			return 0, fmt.Errorf("no rate data for %s", cur)
 		}
 		return r, nil
-	case pair.Quote == "USD":
-		r, ok := rates[pair.Base]
-		if !ok || r == 0 {
-			return 0, fmt.Errorf("no rate data for %s", pair.Base)
-		}
-		return 1.0 / r, nil
-	default:
-		br, ok1 := rates[pair.Base]
-		qr, ok2 := rates[pair.Quote]
-		if !ok1 || !ok2 || br == 0 {
-			return 0, fmt.Errorf("missing rate data for cross-pair")
-		}
-		return qr / br, nil
 	}
 }
 
 func (p *ForexPlugin) cmdReport(ctx MessageContext, args []string) error {
-	if pair := fxParsePair(args); pair != nil {
+	if pair := fxParsePair(args, false); pair != nil {
 		return p.cmdPairRateOrReport(ctx, pair, true)
 	}
 	currencies := fxParseCurrencies(args)

internal/plugin/forex_api.go

@@ -34,8 +34,12 @@ func fxIsTracked(cur string) bool {
 	return false
 }
 
-// fxFormatRate formats a rate: JPY uses 2 decimal places, others use 4.
+// fxFormatRate formats a rate: crypto uses up to 8 decimals (trailing zeros
+// trimmed) for tiny per-USD figures, JPY uses 2, others use 4.
 func fxFormatRate(currency string, rate float64) string {
+	if fxIsCrypto(currency) {
+		return fxTrimZeros(fmt.Sprintf("%.8f", rate))
+	}
 	if currency == "JPY" {
 		return fmt.Sprintf("%.2f", rate)
 	}

internal/plugin/forex_convert.go

@@ -58,7 +58,7 @@ func fxParseConvert(args []string) (amount float64, base, quote string, err erro
 	for _, tok := range tokens {
 		// Pair form: USD/EUR
 		if strings.ContainsAny(tok, "/|-") {
-			pair := fxParsePair([]string{tok})
+			pair := fxParsePair([]string{tok}, true)
 			if pair != nil {
 				if base != "" {
 					return 0, "", "", fmt.Errorf("multiple currency pairs")
@@ -76,9 +76,9 @@ func fxParseConvert(args []string) (amount float64, base, quote string, err erro
 			amountSet = true
 			continue
 		}
-		// Currency code?
+		// Currency or crypto code?
 		up := strings.ToUpper(tok)
-		if fxIsSupported(up) {
+		if fxIsConvertible(up) {
 			currencies = append(currencies, up)
 			continue
 		}
@@ -127,12 +127,15 @@ func (p *ForexPlugin) cmdConvert(ctx MessageContext, args []string) error {
 	return p.SendReply(ctx.RoomID, ctx.EventID, msg)
 }
 
-// fxEmoji returns the flag emoji for a supported currency, falling back
+// fxEmoji returns the flag/symbol emoji for a supported currency or crypto
-// to USD's flag.
+// asset, falling back to USD's flag.
 func fxEmoji(cur string) string {
 	if m, ok := fxMeta[cur]; ok && m.Emoji != "" {
 		return m.Emoji
 	}
+	if c, ok := fxCryptoMeta[strings.ToUpper(cur)]; ok && c.Emoji != "" {
+		return c.Emoji
+	}
 	if cur == "USD" {
 		return "🇺🇸"
 	}
@@ -140,9 +143,13 @@ func fxEmoji(cur string) string {
 }
 
 // fxFormatAmount formats a converted amount with thousands separators.
-// JPY uses 0 decimal places (yen are not subdivided in practice for display),
+// Crypto uses up to 8 decimals (trailing zeros trimmed) since amounts are
-// other currencies use 2.
+// often fractional; JPY uses 0 (yen are not subdivided in practice for
+// display); other currencies use 2.
 func fxFormatAmount(currency string, amount float64) string {
+	if fxIsCrypto(currency) {
+		return fxTrimZeros(fxAddCommas(amount, 8))
+	}
 	decimals := 2
 	if currency == "JPY" {
 		decimals = 0
@@ -150,6 +157,16 @@ func fxFormatAmount(currency string, amount float64) string {
 	return fxAddCommas(amount, decimals)
 }
 
+// fxTrimZeros drops trailing fractional zeros (and a bare trailing dot) from a
+// formatted decimal string, leaving integers untouched.
+func fxTrimZeros(s string) string {
+	if !strings.Contains(s, ".") {
+		return s
+	}
+	s = strings.TrimRight(s, "0")
+	return strings.TrimRight(s, ".")
+}
+
 // fxAddCommas formats a float with N decimal places and thousands separators.
 func fxAddCommas(v float64, decimals int) string {
 	s := strconv.FormatFloat(v, 'f', decimals, 64)

internal/plugin/forex_crypto.go

@@ -0,0 +1,119 @@
+package plugin
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strings"
+	"sync"
+	"time"
+)
+
+// ── Crypto support (CoinGecko, keyless) ──────────────────────────────────────
+//
+// CoinGecko's public simple/price endpoint needs no API key and no usage tier,
+// matching Frankfurter's keyless model. Crypto is wired into the *conversion*
+// path only (`!fx 100 USD to BTC`). The rate/report/alert analysis stays
+// fiat-only on purpose: a daily-snapshot "buy signal" or 52-week range is
+// meaningless for 24/7 crypto markets.
+
+type fxCryptoInfo struct {
+	CoinGeckoID string
+	Emoji       string
+	Label       string
+}
+
+// fxCryptoMeta maps a ticker to its CoinGecko coin ID and display metadata.
+// Add a row here to support another asset.
+var fxCryptoMeta = map[string]fxCryptoInfo{
+	"BTC":  {"bitcoin", "₿", "Bitcoin"},
+	"ETH":  {"ethereum", "Ξ", "Ethereum"},
+	"SOL":  {"solana", "◎", "Solana"},
+	"XRP":  {"ripple", "✕", "XRP"},
+	"DOGE": {"dogecoin", "🐕", "Dogecoin"},
+	"ADA":  {"cardano", "₳", "Cardano"},
+	"LTC":  {"litecoin", "Ł", "Litecoin"},
+}
+
+// fxIsCrypto reports whether sym is a supported crypto asset.
+func fxIsCrypto(sym string) bool {
+	_, ok := fxCryptoMeta[strings.ToUpper(sym)]
+	return ok
+}
+
+// fxIsConvertible reports whether a symbol can appear in a conversion —
+// USD, a tracked fiat currency, or a supported crypto asset.
+func fxIsConvertible(cur string) bool {
+	return fxIsSupported(cur) || fxIsCrypto(cur)
+}
+
+const coinGeckoBaseURL = "https://api.coingecko.com/api/v3"
+
+// Short-TTL price cache to stay well under CoinGecko's public rate limit and
+// keep repeated conversions snappy.
+const cgCacheTTL = 60 * time.Second
+
+var (
+	cgMu    sync.Mutex
+	cgCache = map[string]cgCacheEntry{}
+)
+
+type cgCacheEntry struct {
+	priceUSD float64
+	at       time.Time
+}
+
+// cgSpotUSD returns the USD spot price for one unit of the given crypto symbol.
+func (p *ForexPlugin) cgSpotUSD(sym string) (float64, error) {
+	sym = strings.ToUpper(sym)
+	info, ok := fxCryptoMeta[sym]
+	if !ok {
+		return 0, fmt.Errorf("unsupported crypto %s", sym)
+	}
+
+	cgMu.Lock()
+	if e, ok := cgCache[sym]; ok && time.Since(e.at) < cgCacheTTL {
+		cgMu.Unlock()
+		return e.priceUSD, nil
+	}
+	cgMu.Unlock()
+
+	ctx, cancel := context.WithTimeout(context.Background(), 8*time.Second)
+	defer cancel()
+
+	url := fmt.Sprintf("%s/simple/price?ids=%s&vs_currencies=usd", coinGeckoBaseURL, info.CoinGeckoID)
+	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
+	if err != nil {
+		return 0, err
+	}
+
+	resp, err := p.httpClient.Do(req)
+	if err != nil {
+		return 0, fmt.Errorf("coingecko API error: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return 0, fmt.Errorf("coingecko API returned %d", resp.StatusCode)
+	}
+
+	var data map[string]map[string]float64
+	if err := json.NewDecoder(resp.Body).Decode(&data); err != nil {
+		return 0, fmt.Errorf("coingecko decode error: %w", err)
+	}
+	entry, ok := data[info.CoinGeckoID]
+	if !ok {
+		return 0, fmt.Errorf("no price for %s", sym)
+	}
+	price, ok := entry["usd"]
+	if !ok || price <= 0 {
+		return 0, fmt.Errorf("invalid price for %s", sym)
+	}
+
+	cgMu.Lock()
+	cgCache[sym] = cgCacheEntry{priceUSD: price, at: time.Now()}
+	cgMu.Unlock()
+
+	return price, nil
+}