candles based alerts

internal/provider/provider.go

@@ -2,6 +2,7 @@ package provider
 
 import (
 	"context"
+	"time"
 
 	"gitea.computernetthings.ru/yash/crypto_alert_bot/internal/entities"
 )
@@ -10,4 +11,55 @@ type Provider interface {
 	// Price returns the current price of the pair (base currency / quote currency).
 	// e.g. BTC/USDT.
 	Price(ctx context.Context, instrument entities.Instrument) (*entities.Price, error)
+
+	// Candles returns OHLC candles for the given interval in the [from, to) range.
+	// interval is a provider-specific string (e.g. "1", "5", "60", "D", "W" for Bybit).
+	// The implementation handles pagination automatically when the range exceeds one
+	// request's capacity.
+	Candles(ctx context.Context, instrument entities.Instrument, from, to time.Time, interval KlineInterval) ([]entities.Candle, error)
+}
+
+type KlineInterval string
+
+const (
+	Kline1m  = "1"
+	Kline3m  = "3"
+	Kline5m  = "5"
+	Kline15m = "15"
+	Kline30m = "30"
+	Kline1H  = "1h"
+	Kline4H  = "4h"
+	Kline6H  = "6h"
+	Kline12H = "12h"
+	Kline1D  = "1d"
+	Kline1W  = "1w"
+)
+
+func (k KlineInterval) ToDuration() time.Duration {
+	switch k {
+	case Kline1m:
+		return time.Minute
+	case Kline3m:
+		return 3 * time.Minute
+	case Kline5m:
+		return 5 * time.Minute
+	case Kline15m:
+		return 15 * time.Minute
+	case Kline30m:
+		return 30 * time.Minute
+	case Kline1H:
+		return time.Hour
+	case Kline4H:
+		return 4 * time.Hour
+	case Kline6H:
+		return 6 * time.Hour
+	case Kline12H:
+		return 12 * time.Hour
+	case Kline1D:
+		return 24 * time.Hour
+	case Kline1W:
+		return 7 * 24 * time.Hour
+	default:
+		return time.Minute
+	}
 }