From dc719e4a157362519ea8f13e03872ecf8eb9c24f Mon Sep 17 00:00:00 2001
From: andig <andi@evcc.io>
Date: Sun, 18 Aug 2024 11:36:23 +0200
Subject: [PATCH] SolarEdge: workaround broken NaNs (#15464)

---
 provider/pipeline/pipeline.go                 |  7 ++++---
 .../definition/meter/solaredge-hybrid.yaml    |  6 +++---
 util/modbus/register.go                       |  2 ++
 util/modbus/register_test.go                  | 20 +++++++++++++++++++
 4 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/provider/pipeline/pipeline.go b/provider/pipeline/pipeline.go
index fe470e99a..00ef6de40 100644
--- a/provider/pipeline/pipeline.go
+++ b/provider/pipeline/pipeline.go
@@ -5,6 +5,7 @@ import (
 	"encoding/hex"
 	"fmt"
 	"regexp"
+	"strconv"
 	"strings"
 
 	xj "github.com/basgys/goxml2json"
@@ -140,7 +141,7 @@ func (p *Pipeline) unpackValue(value []byte) (string, error) {
 
 // decode a hex string to a proper value
 // TODO reuse similar code from Modbus
-func (p *Pipeline) decodeValue(value []byte) (interface{}, error) {
+func (p *Pipeline) decodeValue(value []byte) (float64, error) {
 	switch p.decode {
 	case "float32", "ieee754":
 		return rs485.RTUIeee754ToFloat64(value), nil
@@ -164,7 +165,7 @@ func (p *Pipeline) decodeValue(value []byte) (interface{}, error) {
 		return rs485.RTUInt32ToFloat64Swapped(value), nil
 	}
 
-	return nil, fmt.Errorf("invalid decoding: %s", p.decode)
+	return 0, fmt.Errorf("invalid decoding: %s", p.decode)
 }
 
 func (p *Pipeline) Process(in []byte) ([]byte, error) {
@@ -202,7 +203,7 @@ func (p *Pipeline) Process(in []byte) ([]byte, error) {
 		if err != nil {
 			return b, err
 		}
-		b = []byte(fmt.Sprintf("%v", v))
+		b = []byte(strconv.FormatFloat(v, 'f', -1, 64))
 	}
 
 	return b, nil
diff --git a/templates/definition/meter/solaredge-hybrid.yaml b/templates/definition/meter/solaredge-hybrid.yaml
index 2e85e0c1c..791292ad4 100644
--- a/templates/definition/meter/solaredge-hybrid.yaml
+++ b/templates/definition/meter/solaredge-hybrid.yaml
@@ -111,7 +111,7 @@ render: |
         register:
           address: 62836 # Battery 1 Instantaneous Power
           type: holding
-          decode: float32s
+          decode: float32nans
   {{- end }}
   {{- if eq .usage "battery" }}
   power:
@@ -121,7 +121,7 @@ render: |
     register:
       address: 0xE174 # Battery 1 Instantaneous Power
       type: holding
-      decode: float32s
+      decode: float32nans
     scale: -1
   soc:
     source: modbus
@@ -130,7 +130,7 @@ render: |
     register:
       address: 0xE184 # Battery 1 State of Energy (SOE)
       type: holding
-      decode: float32s
+      decode: float32nans
   batterymode:
     source: watchdog
     timeout: {{ .watchdog }}
diff --git a/util/modbus/register.go b/util/modbus/register.go
index 85e277564..d2aade888 100644
--- a/util/modbus/register.go
+++ b/util/modbus/register.go
@@ -113,6 +113,8 @@ func (r Register) DecodeFunc() (func([]byte) float64, error) {
 		return asFloat64(encoding.Float32), nil
 	case "float32s", "ieee754s":
 		return asFloat64(encoding.Float32LswFirst), nil
+	case "float32nans":
+		return decodeNaN32(asFloat64(encoding.Float32LswFirst), 0xffffff7f), nil
 
 	// 64 bit
 	case "int64":
diff --git a/util/modbus/register_test.go b/util/modbus/register_test.go
index f13ae9aee..e1ff98d77 100644
--- a/util/modbus/register_test.go
+++ b/util/modbus/register_test.go
@@ -63,3 +63,23 @@ func TestEncoding(t *testing.T) {
 		require.Equal(t, tc.out, res, tc)
 	}
 }
+
+func TestDecoding(t *testing.T) {
+	tc := []struct {
+		r   Register
+		in  []byte
+		out float64
+	}{
+		{Register{Decode: "float32"}, []byte{0x4b, 0x3c, 0x61, 0x4e}, 12345678},
+		{Register{Decode: "float32"}, []byte{0xff, 0xff, 0xff, 0x7f}, 0}, // NaN
+		{Register{Decode: "float32s"}, []byte{0x61, 0x4e, 0x4b, 0x3c}, 12345678},
+		{Register{Decode: "float32s"}, []byte{0xff, 0x7f, 0xff, 0xff}, 0},    // NaN swapped
+		{Register{Decode: "float32nans"}, []byte{0xff, 0xff, 0xff, 0x7f}, 0}, // NaN
+	}
+
+	for _, tc := range tc {
+		fun, err := tc.r.DecodeFunc()
+		require.NoError(t, err, tc)
+		require.Equal(t, tc.out, fun(tc.in), tc)
+	}
+}