wshub: persist calibration alongside sources; add config reload

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Common/Client/go/wshub/sources.go

@@ -1,12 +1,12 @@
 package wshub
 
 import (
-	"encoding/json"
 	"fmt"
 	"io"
 	"log"
 	"net"
 	"os"
+	"sort"
 	"strconv"
 	"strings"
 	"sync"
@@ -95,11 +95,16 @@ func (sm *SourceManager) Remove(id string) {
 	}
 }
 
-// Save writes the current source list to filePath.
-func (sm *SourceManager) Save() error {
-	if sm.filePath == "" {
-		return fmt.Errorf("no sources-file configured")
-	}
+// Path returns the configured config-file path ("" when none).
+func (sm *SourceManager) Path() string {
+	sm.mu.RLock()
+	defer sm.mu.RUnlock()
+	return sm.filePath
+}
+
+// snapshotSources returns the current sources sorted by label, so the written
+// file is byte-stable across runs (the map iteration order is not).
+func (sm *SourceManager) snapshotSources() []SourceConfig {
 	sm.mu.RLock()
 	cfgs := make([]SourceConfig, 0, len(sm.sources))
 	for _, ms := range sm.sources {
@@ -111,26 +116,86 @@ func (sm *SourceManager) Save() error {
 		})
 	}
 	sm.mu.RUnlock()
+	sort.Slice(cfgs, func(i, j int) bool {
+		if cfgs[i].Label != cfgs[j].Label {
+			return cfgs[i].Label < cfgs[j].Label
+		}
+		return cfgs[i].Addr < cfgs[j].Addr
+	})
+	return cfgs
+}
 
-	data, err := json.MarshalIndent(cfgs, "", "  ")
+// Save writes the current source list and calibration table to filePath as one
+// flat JSON array.
+func (sm *SourceManager) Save() error {
+	path := sm.Path()
+	if path == "" {
+		return fmt.Errorf("no sources-file configured")
+	}
+	data, err := encodeConfigFile(sm.snapshotSources(), sm.hub.cal.List())
 	if err != nil {
 		return err
 	}
-	return os.WriteFile(sm.filePath, data, 0644)
+	return os.WriteFile(path, data, 0644)
 }
 
-// Load reads sources from path and adds them.
+// Load reads the config file at path, replaces the calibration table with its
+// contents and starts every source it lists.
 func (sm *SourceManager) Load(path string) error {
 	data, err := os.ReadFile(path)
 	if err != nil {
 		return err
 	}
-	var cfgs []SourceConfig
-	if err := json.Unmarshal(data, &cfgs); err != nil {
+	srcs, cals, err := parseConfigFile(data)
+	if err != nil {
 		return err
 	}
+	sm.mu.Lock()
 	sm.filePath = path
-	for _, cfg := range cfgs {
+	sm.mu.Unlock()
+
+	sm.hub.cal.Replace(cals)
+	for _, cfg := range srcs {
+		sm.Add(cfg.Label, cfg.Addr, cfg.MulticastGroup, cfg.DataPort)
+	}
+	return nil
+}
+
+// Reload re-reads the config file.  The calibration table is replaced wholesale
+// and sources listed in the file that are not already running are started; no
+// live source is ever stopped, restarted or reconnected, because a reload must
+// not interrupt streaming.  The asymmetry is deliberate: calibration is cheap
+// to reapply, a source is a live UDP session.
+func (sm *SourceManager) Reload() error {
+	path := sm.Path()
+	if path == "" {
+		return fmt.Errorf("no sources-file configured")
+	}
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return err
+	}
+	srcs, cals, err := parseConfigFile(data)
+	if err != nil {
+		return err
+	}
+	sm.hub.cal.Replace(cals)
+
+	sm.mu.RLock()
+	live := make(map[string]bool, len(sm.sources))
+	for _, ms := range sm.sources {
+		live[ms.label+"\x00"+ms.addr] = true
+	}
+	sm.mu.RUnlock()
+
+	for _, cfg := range srcs {
+		label := cfg.Label
+		if label == "" {
+			label = cfg.Addr // Add() applies the same default
+		}
+		if live[label+"\x00"+cfg.Addr] {
+			continue
+		}
 		sm.Add(cfg.Label, cfg.Addr, cfg.MulticastGroup, cfg.DataPort)
 	}
 	return nil