From e7caa50932036a01325f547be410f4543557e699 Mon Sep 17 00:00:00 2001
From: Derrick Hammer <derrick@derrickhammer.com>
Date: Mon, 11 Mar 2024 06:42:51 -0400
Subject: [PATCH] fix: don't store MaxRPCSCPrice as a float, and use big.Rat to
 compute it

---
 config/sia.go           | 18 ++++++++++++------
 renter/price_tracker.go | 21 +++++++++++++++------
 2 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/config/sia.go b/config/sia.go
index dd72afb..739fb86 100644
--- a/config/sia.go
+++ b/config/sia.go
@@ -1,6 +1,9 @@
 package config
 
-import "errors"
+import (
+	"errors"
+	"math/big"
+)
 
 var _ Validator = (*SiaConfig)(nil)
 var _ Defaults = (*SiaConfig)(nil)
@@ -13,7 +16,7 @@ type SiaConfig struct {
 	MaxDownloadPrice   float64 `mapstructure:"max_download_price"`
 	MaxStoragePrice    float64 `mapstructure:"max_storage_price"`
 	MaxContractSCPrice float64 `mapstructure:"max_contract_sc_price"`
-	MaxRPCSCPrice      float64 `mapstructure:"max_rpc_sc_price"`
+	MaxRPCSCPrice      string  `mapstructure:"max_rpc_sc_price"`
 }
 
 func (s SiaConfig) Defaults() map[string]interface{} {
@@ -44,12 +47,15 @@ func (s SiaConfig) Validate() error {
 		return errors.New("core.storage.sia.max_storage_price must be greater than 0")
 	}
 
-	if s.MaxRPCSCPrice <= 0 {
-		return errors.New("core.storage.sia.max_rpc_sc_price must be greater than 0")
+	err := errors.New("failed to parse core.storage.sia.max_rpc_sc_price ")
+
+	rat, ok := new(big.Rat).SetString(s.MaxRPCSCPrice)
+	if !ok {
+		return err
 	}
 
-	if s.MaxRPCSCPrice <= 0 {
-		return errors.New("core.storage.sia.max_contract_sc_price must be greater than 0")
+	if rat.Cmp(new(big.Rat).SetUint64(0)) <= 0 {
+		return err
 	}
 
 	return nil
diff --git a/renter/price_tracker.go b/renter/price_tracker.go
index 15e4846..ef6f9e4 100644
--- a/renter/price_tracker.go
+++ b/renter/price_tracker.go
@@ -139,12 +139,17 @@ SELECT AVG(rate) as average_rate FROM (
 		return err
 	}
 
-	maxRPCPrice := p.config.Config().Core.Storage.Sia.MaxRPCSCPrice
-	maxRPCPrice = maxRPCPrice / 1_000_000
+	maxRPCPrice, ok := new(big.Rat).SetString(p.config.Config().Core.Storage.Sia.MaxRPCSCPrice)
 
-	p.logger.Debug("Setting max RPC price", zap.Float64("maxRPCPrice", maxRPCPrice))
+	if !ok {
+		return errors.New("failed to parse max rpc price")
+	}
 
-	gouge.MaxRPCPrice, err = siacoinsFromFloat(maxRPCPrice)
+	maxRPCPrice = new(big.Rat).Quo(maxRPCPrice, new(big.Rat).SetUint64(1_000_000))
+
+	p.logger.Debug("Setting max RPC price", zap.String("maxRPCPrice", maxRPCPrice.FloatString(2)))
+
+	gouge.MaxRPCPrice, err = siacoinsFromRat(maxRPCPrice)
 	if err != nil {
 		return err
 	}
@@ -260,8 +265,7 @@ func NewPriceTracker(params PriceTrackerParams) *PriceTracker {
 	}
 }
 
-func siacoinsFromFloat(f float64) (types.Currency, error) {
-	r := new(big.Rat).SetFloat64(f)
+func siacoinsFromRat(r *big.Rat) (types.Currency, error) {
 	r.Mul(r, new(big.Rat).SetInt(types.HastingsPerSiacoin.Big()))
 	i := new(big.Int).Div(r.Num(), r.Denom())
 	if i.Sign() < 0 {
@@ -271,3 +275,8 @@ func siacoinsFromFloat(f float64) (types.Currency, error) {
 	}
 	return types.NewCurrency(i.Uint64(), new(big.Int).Rsh(i, 64).Uint64()), nil
 }
+
+func siacoinsFromFloat(f float64) (types.Currency, error) {
+	r := new(big.Rat).SetFloat64(f)
+	return siacoinsFromRat(r)
+}