feat: track battery levels per device

agent/battery/battery.go

@@ -1,6 +1,13 @@
-// Package battery provides functions to check if the system has a battery and return the charge state and percentage.
+// Package battery provides battery information for the host and connected devices.
 package battery
 
+import (
+	"errors"
+	"sort"
+	"strconv"
+	"strings"
+)
+
 const (
 	stateUnknown uint8 = iota
 	stateEmpty
@@ -9,3 +16,55 @@ const (
 	stateDischarging
 	stateIdle
 )
+
+// Battery is a readable battery reported by the operating system.
+type Battery struct {
+	Name                  string
+	Percent               uint8
+	State                 uint8
+	FullChargeCapacity    uint64
+	HasFullChargeCapacity bool
+	System                bool
+}
+
+var errNoBatteries = errors.New("no readable batteries")
+
+// normalizeBatteries supplies stable fallback names and disambiguates duplicates.
+func normalizeBatteries(batteries []Battery) []Battery {
+	nameCounts := make(map[string]int, len(batteries))
+	for i := range batteries {
+		name := strings.TrimSpace(batteries[i].Name)
+		if name == "" {
+			name = "Battery " + strconv.Itoa(i+1)
+		}
+		nameCounts[name]++
+		if nameCounts[name] > 1 {
+			name += " (" + strconv.Itoa(nameCounts[name]) + ")"
+		}
+		batteries[i].Name = name
+	}
+	return batteries
+}
+
+// Primary returns the representative battery. Reported full-charge capacity wins,
+// then system-scoped devices, then name for deterministic ties.
+func Primary(batteries []Battery) (Battery, bool) {
+	if len(batteries) == 0 {
+		return Battery{}, false
+	}
+	ordered := append([]Battery(nil), batteries...)
+	sort.SliceStable(ordered, func(i, j int) bool {
+		a, b := ordered[i], ordered[j]
+		if a.HasFullChargeCapacity != b.HasFullChargeCapacity {
+			return a.HasFullChargeCapacity
+		}
+		if a.HasFullChargeCapacity && a.FullChargeCapacity != b.FullChargeCapacity {
+			return a.FullChargeCapacity > b.FullChargeCapacity
+		}
+		if a.System != b.System {
+			return a.System
+		}
+		return a.Name < b.Name
+	})
+	return ordered[0], true
+}

agent/battery/battery_darwin.go

@@ -3,11 +3,7 @@
 package battery
 
 import (
-	"errors"
-	"log/slog"
-	"math"
 	"os/exec"
-	"sync"
 
 	"howett.net/plist"
 )
@@ -35,62 +31,46 @@ func readMacBatteries() ([]macBattery, error) {
 	return batteries, nil
 }
 
-// HasReadableBattery checks if the system has a battery and returns true if it does.
-var HasReadableBattery = sync.OnceValue(func() bool {
-	systemHasBattery := false
-	batteries, err := readMacBatteries()
-	slog.Debug("Batteries", "batteries", batteries, "err", err)
-	for _, bat := range batteries {
-		if bat.MaxCapacity > 0 {
-			systemHasBattery = true
-			break
-		}
-	}
-	return systemHasBattery
-})
+func HasReadableBattery() bool {
+	batteries, _ := GetBatteryStats()
+	return len(batteries) > 0
+}
 
-// GetBatteryStats returns the current battery percent and charge state.
-// Uses CurrentCapacity/MaxCapacity to match the value macOS displays.
-func GetBatteryStats() (batteryPercent uint8, batteryState uint8, err error) {
-	if !HasReadableBattery() {
-		return batteryPercent, batteryState, errors.ErrUnsupported
-	}
+// GetBatteryStats returns every readable battery reported by macOS.
+func GetBatteryStats() ([]Battery, error) {
 	batteries, err := readMacBatteries()
+	if err != nil {
+		return nil, err
+	}
 	if len(batteries) == 0 {
-		return batteryPercent, batteryState, errors.New("no batteries")
+		return nil, errNoBatteries
 	}
-
-	totalCapacity := 0
-	totalCharge := 0
-	batteryState = math.MaxUint8
-
+	result := make([]Battery, 0, len(batteries))
 	for _, bat := range batteries {
-		if bat.MaxCapacity == 0 {
+		if bat.MaxCapacity <= 0 {
 			// skip ghost batteries with 0 capacity
 			// https://github.com/distatus/battery/issues/34
 			continue
 		}
-		totalCapacity += bat.MaxCapacity
-		totalCharge += min(bat.CurrentCapacity, bat.MaxCapacity)
-
+		percent := min(max(float64(bat.CurrentCapacity)/float64(bat.MaxCapacity)*100, 0), 100)
+		state := stateUnknown
 		switch {
 		case !bat.ExternalConnected:
-			batteryState = stateDischarging
+			state = stateDischarging
 		case bat.IsCharging:
-			batteryState = stateCharging
+			state = stateCharging
 		case bat.CurrentCapacity == 0:
-			batteryState = stateEmpty
+			state = stateEmpty
 		case !bat.FullyCharged:
-			batteryState = stateIdle
+			state = stateIdle
 		default:
-			batteryState = stateFull
+			state = stateFull
 		}
+		result = append(result, Battery{Name: "Primary", Percent: uint8(percent), State: state,
+			FullChargeCapacity: uint64(bat.MaxCapacity), HasFullChargeCapacity: true, System: true})
 	}
-
-	if totalCapacity == 0 || batteryState == math.MaxUint8 {
-		return batteryPercent, batteryState, errors.New("no battery capacity")
+	if len(result) == 0 {
+		return nil, errNoBatteries
 	}
-
-	batteryPercent = uint8(float64(totalCharge) / float64(totalCapacity) * 100)
-	return batteryPercent, batteryState, nil
+	return normalizeBatteries(result), nil
 }

agent/battery/battery_linux.go

@@ -3,58 +3,19 @@
 package battery
 
 import (
-	"errors"
-	"log/slog"
-	"math"
 	"os"
 	"path/filepath"
 	"strconv"
-	"sync"
 
 	"github.com/henrygd/beszel/agent/utils"
 )
 
-// getBatteryPaths returns the paths of all batteries in /sys/class/power_supply
-var getBatteryPaths func() ([]string, error)
+var batteryRoot = "/sys/class/power_supply"
 
-// HasReadableBattery checks if the system has a battery and returns true if it does.
-var HasReadableBattery func() bool
-
-func init() {
-	resetBatteryState("/sys/class/power_supply")
-}
-
-// resetBatteryState resets the sync.Once functions to a fresh state.
-// Tests call this after swapping sysfsPowerSupply so the new path is picked up.
-func resetBatteryState(sysfsPowerSupplyPath string) {
-	getBatteryPaths = sync.OnceValues(func() ([]string, error) {
-		entries, err := os.ReadDir(sysfsPowerSupplyPath)
-		if err != nil {
-			return nil, err
-		}
-		var paths []string
-		for _, e := range entries {
-			path := filepath.Join(sysfsPowerSupplyPath, e.Name())
-			if utils.ReadStringFile(filepath.Join(path, "type")) == "Battery" {
-				paths = append(paths, path)
-			}
-		}
-		return paths, nil
-	})
-	HasReadableBattery = sync.OnceValue(func() bool {
-		systemHasBattery := false
-		paths, err := getBatteryPaths()
-		for _, path := range paths {
-			if _, ok := utils.ReadStringFileOK(filepath.Join(path, "capacity")); ok {
-				systemHasBattery = true
-				break
-			}
-		}
-		if !systemHasBattery {
-			slog.Debug("No battery found", "err", err)
-		}
-		return systemHasBattery
-	})
+// HasReadableBattery reports whether collection currently finds a readable battery.
+func HasReadableBattery() bool {
+	batteries, _ := GetBatteryStats()
+	return len(batteries) > 0
 }
 
 func parseSysfsState(status string) uint8 {
@@ -74,26 +35,18 @@ func parseSysfsState(status string) uint8 {
 	}
 }
 
-// GetBatteryStats returns the current battery percent and charge state.
-// Reads /sys/class/power_supply/*/capacity directly so the kernel-reported
-// value is used, which is always 0-100 and matches what the OS displays.
-func GetBatteryStats() (batteryPercent uint8, batteryState uint8, err error) {
-	if !HasReadableBattery() {
-		return batteryPercent, batteryState, errors.ErrUnsupported
-	}
-	paths, err := getBatteryPaths()
+// GetBatteryStats re-enumerates power supplies and returns every readable battery.
+func GetBatteryStats() ([]Battery, error) {
+	entries, err := os.ReadDir(batteryRoot)
 	if err != nil {
-		return batteryPercent, batteryState, err
+		return nil, err
 	}
-	if len(paths) == 0 {
-		return batteryPercent, batteryState, errors.New("no batteries")
-	}
-
-	batteryState = math.MaxUint8
-	totalPercent := 0
-	count := 0
-
-	for _, path := range paths {
+	batteries := make([]Battery, 0, len(entries))
+	for _, entry := range entries {
+		path := filepath.Join(batteryRoot, entry.Name())
+		if utils.ReadStringFile(filepath.Join(path, "type")) != "Battery" {
+			continue
+		}
 		capStr, ok := utils.ReadStringFileOK(filepath.Join(path, "capacity"))
 		if !ok {
 			continue
@@ -103,19 +56,30 @@ func GetBatteryStats() (batteryPercent uint8, batteryState uint8, err error) {
 			continue
 		}
 		cap = min(max(cap, 0), 100)
-		totalPercent += cap
-		count++
-
-		state := parseSysfsState(utils.ReadStringFile(filepath.Join(path, "status")))
-		if state != stateUnknown {
-			batteryState = state
+		name := utils.ReadStringFile(filepath.Join(path, "model_name"))
+		if name == "" {
+			name = utils.ReadStringFile(filepath.Join(path, "model"))
 		}
+		if name == "" {
+			name = entry.Name()
+		}
+		battery := Battery{
+			Name:    name,
+			Percent: uint8(cap),
+			State:   parseSysfsState(utils.ReadStringFile(filepath.Join(path, "status"))),
+			System:  utils.ReadStringFile(filepath.Join(path, "scope")) != "Device",
+		}
+		for _, fullName := range []string{"charge_full", "energy_full"} {
+			if parsed, ok := utils.ReadUintFile(filepath.Join(path, fullName)); ok && parsed > 0 {
+				battery.FullChargeCapacity = parsed
+				battery.HasFullChargeCapacity = true
+				break
+			}
+		}
+		batteries = append(batteries, battery)
 	}
-
-	if count == 0 || batteryState == math.MaxUint8 {
-		return batteryPercent, batteryState, errors.New("no battery capacity")
+	if len(batteries) == 0 {
+		return nil, errNoBatteries
 	}
-
-	batteryPercent = uint8(totalPercent / count)
-	return batteryPercent, batteryState, nil
+	return normalizeBatteries(batteries), nil
 }

agent/battery/battery_linux_test.go

@@ -8,204 +8,102 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
-// setupFakeSysfs creates a temporary sysfs-like tree under t.TempDir(),
-// swaps sysfsPowerSupply, resets the sync.Once caches, and restores
-// everything on cleanup. Returns a helper to create battery directories.
-func setupFakeSysfs(t *testing.T) (tmpDir string, addBattery func(name, capacity, status string)) {
+type fakeBattery struct{ id, name, capacity, status, full, scope string }
+
+func setupFakeSysfs(t *testing.T) (string, func(fakeBattery)) {
 	t.Helper()
-
-	tmp := t.TempDir()
-	resetBatteryState(tmp)
-
-	write := func(path, content string) {
+	root := t.TempDir()
+	previousRoot := batteryRoot
+	batteryRoot = root
+	t.Cleanup(func() { batteryRoot = previousRoot })
+	write := func(path, value string) {
 		t.Helper()
-		dir := filepath.Dir(path)
-		if err := os.MkdirAll(dir, 0o755); err != nil {
-			t.Fatal(err)
+		require.NoError(t, os.MkdirAll(filepath.Dir(path), 0o755))
+		require.NoError(t, os.WriteFile(path, []byte(value), 0o644))
+	}
+	add := func(b fakeBattery) {
+		t.Helper()
+		dir := filepath.Join(root, b.id)
+		write(filepath.Join(dir, "type"), "Battery")
+		if b.capacity != "" {
+			write(filepath.Join(dir, "capacity"), b.capacity)
 		}
-		if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
-			t.Fatal(err)
+		write(filepath.Join(dir, "status"), b.status)
+		if b.name != "" {
+			write(filepath.Join(dir, "model_name"), b.name)
+		}
+		if b.full != "" {
+			write(filepath.Join(dir, "energy_full"), b.full)
+		}
+		if b.scope != "" {
+			write(filepath.Join(dir, "scope"), b.scope)
 		}
 	}
-
-	addBattery = func(name, capacity, status string) {
-		t.Helper()
-		batDir := filepath.Join(tmp, name)
-		write(filepath.Join(batDir, "type"), "Battery")
-		write(filepath.Join(batDir, "capacity"), capacity)
-		write(filepath.Join(batDir, "status"), status)
-	}
-
-	return tmp, addBattery
+	return root, add
 }
 
 func TestParseSysfsState(t *testing.T) {
-	tests := []struct {
-		input string
-		want  uint8
-	}{
-		{"Empty", stateEmpty},
-		{"Full", stateFull},
-		{"Charging", stateCharging},
-		{"Discharging", stateDischarging},
-		{"Not charging", stateIdle},
-		{"", stateUnknown},
-		{"SomethingElse", stateUnknown},
-	}
-	for _, tt := range tests {
-		assert.Equal(t, tt.want, parseSysfsState(tt.input), "parseSysfsState(%q)", tt.input)
-	}
+	assert.Equal(t, stateEmpty, parseSysfsState("Empty"))
+	assert.Equal(t, stateFull, parseSysfsState("Full"))
+	assert.Equal(t, stateCharging, parseSysfsState("Charging"))
+	assert.Equal(t, stateDischarging, parseSysfsState("Discharging"))
+	assert.Equal(t, stateIdle, parseSysfsState("Not charging"))
+	assert.Equal(t, stateUnknown, parseSysfsState("SomethingElse"))
 }
 
-func TestGetBatteryStats_SingleBattery(t *testing.T) {
-	_, addBattery := setupFakeSysfs(t)
-	addBattery("BAT0", "72", "Discharging")
-
-	pct, state, err := GetBatteryStats()
-	assert.NoError(t, err)
-	assert.Equal(t, uint8(72), pct)
-	assert.Equal(t, stateDischarging, state)
+func TestGetBatteryStatsMultipleNamedAndPrimary(t *testing.T) {
+	_, add := setupFakeSysfs(t)
+	add(fakeBattery{id: "BAT0", name: "Primary", capacity: "105", status: "Charging", full: "5000", scope: "System"})
+	add(fakeBattery{id: "hidpp_battery_0", name: "MX Keys S", capacity: "55", status: "Unknown", full: "900", scope: "Device"})
+	batteries, err := GetBatteryStats()
+	require.NoError(t, err)
+	require.Len(t, batteries, 2)
+	assert.Equal(t, "Primary", batteries[0].Name)
+	assert.Equal(t, uint8(100), batteries[0].Percent)
+	assert.Equal(t, stateUnknown, batteries[1].State)
+	primary, ok := Primary(batteries)
+	require.True(t, ok)
+	assert.Equal(t, "Primary", primary.Name)
 }
 
-func TestGetBatteryStats_MultipleBatteries(t *testing.T) {
-	_, addBattery := setupFakeSysfs(t)
-	addBattery("BAT0", "80", "Charging")
-	addBattery("BAT1", "40", "Charging")
-
-	pct, state, err := GetBatteryStats()
-	assert.NoError(t, err)
-	// average of 80 and 40 = 60
-	assert.EqualValues(t, 60, pct)
-	assert.Equal(t, stateCharging, state)
+func TestGetBatteryStatsFallbackDuplicatesAndUnreadable(t *testing.T) {
+	root, add := setupFakeSysfs(t)
+	add(fakeBattery{id: "BAT0", name: "Keyboard", capacity: "80", status: "Discharging"})
+	add(fakeBattery{id: "BAT1", name: "Keyboard", capacity: "-4", status: "SomethingWeird"})
+	add(fakeBattery{id: "BAT2", capacity: "not-a-number", status: "Charging"})
+	add(fakeBattery{id: "BAT3", capacity: "42", status: "Full"})
+	ac := filepath.Join(root, "AC0")
+	require.NoError(t, os.MkdirAll(ac, 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(ac, "type"), []byte("Mains"), 0o644))
+	batteries, err := GetBatteryStats()
+	require.NoError(t, err)
+	require.Len(t, batteries, 3)
+	assert.Equal(t, "Keyboard", batteries[0].Name)
+	assert.Equal(t, "Keyboard (2)", batteries[1].Name)
+	assert.Equal(t, uint8(0), batteries[1].Percent)
+	assert.Equal(t, "BAT3", batteries[2].Name)
 }
 
-func TestGetBatteryStats_FullBattery(t *testing.T) {
-	_, addBattery := setupFakeSysfs(t)
-	addBattery("BAT0", "100", "Full")
-
-	pct, state, err := GetBatteryStats()
-	assert.NoError(t, err)
-	assert.Equal(t, uint8(100), pct)
-	assert.Equal(t, stateFull, state)
-}
-
-func TestGetBatteryStats_CapacityClamped(t *testing.T) {
-	_, addBattery := setupFakeSysfs(t)
-	addBattery("BAT0", "105", "Charging")
-
-	pct, state, err := GetBatteryStats()
-	assert.NoError(t, err)
-	assert.Equal(t, uint8(100), pct)
-	assert.Equal(t, stateCharging, state)
-}
-
-func TestGetBatteryStats_EmptyBattery(t *testing.T) {
-	_, addBattery := setupFakeSysfs(t)
-	addBattery("BAT0", "0", "Empty")
-
-	pct, state, err := GetBatteryStats()
-	assert.NoError(t, err)
-	assert.Equal(t, uint8(0), pct)
-	assert.Equal(t, stateEmpty, state)
-}
-
-func TestGetBatteryStats_NotCharging(t *testing.T) {
-	_, addBattery := setupFakeSysfs(t)
-	addBattery("BAT0", "80", "Not charging")
-
-	pct, state, err := GetBatteryStats()
-	assert.NoError(t, err)
-	assert.Equal(t, uint8(80), pct)
-	assert.Equal(t, stateIdle, state)
-}
-
-func TestGetBatteryStats_NoBatteries(t *testing.T) {
-	setupFakeSysfs(t) // empty directory, no batteries
-
-	_, _, err := GetBatteryStats()
+func TestGetBatteryStatsHotPlugReenumerates(t *testing.T) {
+	_, add := setupFakeSysfs(t)
+	_, err := GetBatteryStats()
 	assert.Error(t, err)
-}
-
-func TestGetBatteryStats_NonBatterySupplyIgnored(t *testing.T) {
-	tmp, addBattery := setupFakeSysfs(t)
-
-	// Add a real battery
-	addBattery("BAT0", "55", "Charging")
-
-	// Add an AC adapter (type != Battery) - should be ignored
-	acDir := filepath.Join(tmp, "AC0")
-	if err := os.MkdirAll(acDir, 0o755); err != nil {
-		t.Fatal(err)
-	}
-	if err := os.WriteFile(filepath.Join(acDir, "type"), []byte("Mains"), 0o644); err != nil {
-		t.Fatal(err)
-	}
-
-	pct, state, err := GetBatteryStats()
-	assert.NoError(t, err)
-	assert.Equal(t, uint8(55), pct)
-	assert.Equal(t, stateCharging, state)
-}
-
-func TestGetBatteryStats_InvalidCapacitySkipped(t *testing.T) {
-	tmp, addBattery := setupFakeSysfs(t)
-
-	// One battery with valid capacity
-	addBattery("BAT0", "90", "Discharging")
-
-	// Another with invalid capacity text
-	badDir := filepath.Join(tmp, "BAT1")
-	if err := os.MkdirAll(badDir, 0o755); err != nil {
-		t.Fatal(err)
-	}
-	if err := os.WriteFile(filepath.Join(badDir, "type"), []byte("Battery"), 0o644); err != nil {
-		t.Fatal(err)
-	}
-	if err := os.WriteFile(filepath.Join(badDir, "capacity"), []byte("not-a-number"), 0o644); err != nil {
-		t.Fatal(err)
-	}
-	if err := os.WriteFile(filepath.Join(badDir, "status"), []byte("Discharging"), 0o644); err != nil {
-		t.Fatal(err)
-	}
-
-	pct, _, err := GetBatteryStats()
-	assert.NoError(t, err)
-	// Only BAT0 counted
-	assert.Equal(t, uint8(90), pct)
-}
-
-func TestGetBatteryStats_UnknownStatusOnly(t *testing.T) {
-	_, addBattery := setupFakeSysfs(t)
-	addBattery("BAT0", "50", "SomethingWeird")
-
-	_, _, err := GetBatteryStats()
-	assert.Error(t, err)
-}
-
-func TestHasReadableBattery_True(t *testing.T) {
-	_, addBattery := setupFakeSysfs(t)
-	addBattery("BAT0", "50", "Charging")
-
+	assert.False(t, HasReadableBattery())
+	add(fakeBattery{id: "BAT0", capacity: "64", status: "Discharging"})
+	batteries, err := GetBatteryStats()
+	require.NoError(t, err)
 	assert.True(t, HasReadableBattery())
+	require.Len(t, batteries, 1)
+	assert.Equal(t, uint8(64), batteries[0].Percent)
 }
 
-func TestHasReadableBattery_False(t *testing.T) {
-	setupFakeSysfs(t) // no batteries
-
-	assert.False(t, HasReadableBattery())
-}
-
-func TestHasReadableBattery_NoCapacityFile(t *testing.T) {
-	tmp, _ := setupFakeSysfs(t)
-
-	// Battery dir with type file but no capacity file
-	batDir := filepath.Join(tmp, "BAT0")
-	err := os.MkdirAll(batDir, 0o755)
-	assert.NoError(t, err)
-	err = os.WriteFile(filepath.Join(batDir, "type"), []byte("Battery"), 0o644)
-	assert.NoError(t, err)
-
+func TestGetBatteryStatsNoReadableCapacity(t *testing.T) {
+	_, add := setupFakeSysfs(t)
+	add(fakeBattery{id: "BAT0", status: "Charging"})
+	_, err := GetBatteryStats()
+	assert.Error(t, err)
 	assert.False(t, HasReadableBattery())
 }

agent/battery/battery_stub.go

@@ -8,6 +8,6 @@ func HasReadableBattery() bool {
 	return false
 }
 
-func GetBatteryStats() (uint8, uint8, error) {
-	return 0, 0, errors.ErrUnsupported
+func GetBatteryStats() ([]Battery, error) {
+	return nil, errors.ErrUnsupported
 }

agent/battery/battery_test.go

@@ -0,0 +1,35 @@
+package battery
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestPrimarySelection(t *testing.T) {
+	tests := []struct {
+		name string
+		bats []Battery
+		want string
+	}{
+		{"largest reported capacity", []Battery{{Name: "Small", FullChargeCapacity: 20, HasFullChargeCapacity: true, System: true}, {Name: "Large", FullChargeCapacity: 80, HasFullChargeCapacity: true}}, "Large"},
+		{"reported ranks over missing", []Battery{{Name: "Unknown", System: true}, {Name: "Known", FullChargeCapacity: 1, HasFullChargeCapacity: true}}, "Known"},
+		{"system wins capacity tie", []Battery{{Name: "Peripheral", FullChargeCapacity: 50, HasFullChargeCapacity: true}, {Name: "System", FullChargeCapacity: 50, HasFullChargeCapacity: true, System: true}}, "System"},
+		{"name resolves final tie", []Battery{{Name: "Zed"}, {Name: "Alpha"}}, "Alpha"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, ok := Primary(tt.bats)
+			require.True(t, ok)
+			assert.Equal(t, tt.want, got.Name)
+		})
+	}
+	_, ok := Primary(nil)
+	assert.False(t, ok)
+}
+
+func TestNormalizeBatteriesFallbackNames(t *testing.T) {
+	bats := normalizeBatteries([]Battery{{}, {}, {Name: "Mouse"}, {Name: "Mouse"}})
+	assert.Equal(t, []string{"Battery 1", "Battery 2", "Mouse", "Mouse (2)"}, []string{bats[0].Name, bats[1].Name, bats[2].Name, bats[3].Name})
+}

agent/battery/battery_windows.go

@@ -7,9 +7,6 @@ package battery
 
 import (
 	"errors"
-	"log/slog"
-	"math"
-	"sync"
 	"syscall"
 	"unsafe"
 
@@ -79,7 +76,7 @@ var (
 	setupDiDestroyDeviceInfoList     = setupapi.NewProc("SetupDiDestroyDeviceInfoList")
 )
 
-// winBatteryGet reads one battery by index. Returns (fullCapacity, currentCapacity, state, error).
+// winBatteryGet reads one battery by index.
 // Returns error == errNotFound when there are no more batteries.
 var errNotFound = errors.New("no more batteries")
 
@@ -122,7 +119,7 @@ func readWinBatteryState(powerState uint32) uint8 {
 	}
 }
 
-func winBatteryGet(idx int) (full, current uint32, state uint8, err error) {
+func winBatteryGet(idx int) (Battery, error) {
 	hdev, err := setupDiSetup(
 		setupDiGetClassDevsW,
 		4,
@@ -132,7 +129,7 @@ func winBatteryGet(idx int) (full, current uint32, state uint8, err error) {
 		0, 0,
 	)
 	if err != nil {
-		return 0, 0, stateUnknown, err
+		return Battery{}, err
 	}
 	defer syscall.SyscallN(setupDiDestroyDeviceInfoList.Addr(), hdev)
 
@@ -148,10 +145,10 @@ func winBatteryGet(idx int) (full, current uint32, state uint8, err error) {
 		0,
 	)
 	if errno == 259 { // ERROR_NO_MORE_ITEMS
-		return 0, 0, stateUnknown, errNotFound
+		return Battery{}, errNotFound
 	}
 	if errno != 0 {
-		return 0, 0, stateUnknown, errno
+		return Battery{}, errno
 	}
 
 	var cbRequired uint32
@@ -165,7 +162,7 @@ func winBatteryGet(idx int) (full, current uint32, state uint8, err error) {
 		0,
 	)
 	if errno != 0 && errno != 122 { // ERROR_INSUFFICIENT_BUFFER
-		return 0, 0, stateUnknown, errno
+		return Battery{}, errno
 	}
 	didd := make([]uint16, cbRequired/2)
 	cbSize := (*uint32)(unsafe.Pointer(&didd[0]))
@@ -185,7 +182,7 @@ func winBatteryGet(idx int) (full, current uint32, state uint8, err error) {
 		0,
 	)
 	if errno != 0 {
-		return 0, 0, stateUnknown, errno
+		return Battery{}, errno
 	}
 	devicePath := &didd[2:][0]
 
@@ -199,7 +196,7 @@ func winBatteryGet(idx int) (full, current uint32, state uint8, err error) {
 		0,
 	)
 	if err != nil {
-		return 0, 0, stateUnknown, err
+		return Battery{}, err
 	}
 	defer windows.CloseHandle(handle)
 
@@ -216,7 +213,7 @@ func winBatteryGet(idx int) (full, current uint32, state uint8, err error) {
 		&dwOut, nil,
 	)
 	if err != nil || bqi.BatteryTag == 0 {
-		return 0, 0, stateUnknown, errors.New("battery tag not returned")
+		return Battery{}, errors.New("battery tag not returned")
 	}
 
 	var bi batteryInformation
@@ -229,7 +226,21 @@ func winBatteryGet(idx int) (full, current uint32, state uint8, err error) {
 		uint32(unsafe.Sizeof(bi)),
 		&dwOut, nil,
 	); err != nil {
-		return 0, 0, stateUnknown, err
+		return Battery{}, err
+	}
+
+	// BatteryDeviceName is optional, so retain the deterministic fallback on error.
+	name := ""
+	nameQuery := bqi
+	nameQuery.InformationLevel = 4 // BatteryDeviceName
+	nameBuffer := make([]uint16, 128)
+	if err := windows.DeviceIoControl(
+		handle, 2703428,
+		(*byte)(unsafe.Pointer(&nameQuery)), uint32(unsafe.Sizeof(nameQuery)),
+		(*byte)(unsafe.Pointer(&nameBuffer[0])), uint32(len(nameBuffer)*2),
+		&dwOut, nil,
+	); err == nil {
+		name = windows.UTF16ToString(nameBuffer)
 	}
 
 	bws := batteryWaitStatus{BatteryTag: bqi.BatteryTag}
@@ -243,56 +254,38 @@ func winBatteryGet(idx int) (full, current uint32, state uint8, err error) {
 		uint32(unsafe.Sizeof(bs)),
 		&dwOut, nil,
 	); err != nil {
-		return 0, 0, stateUnknown, err
+		return Battery{}, err
 	}
 
-	if bs.Capacity == 0xffffffff { // BATTERY_UNKNOWN_CAPACITY
-		return 0, 0, stateUnknown, errors.New("battery capacity unknown")
+	if bs.Capacity == 0xffffffff || bi.FullChargedCapacity == 0 || bi.FullChargedCapacity == 0xffffffff {
+		return Battery{}, errors.New("battery capacity unknown")
 	}
-
-	return bi.FullChargedCapacity, bs.Capacity, readWinBatteryState(bs.PowerState), nil
+	percent := min(float64(bs.Capacity)/float64(bi.FullChargedCapacity)*100, 100)
+	return Battery{Name: name, Percent: uint8(percent), State: readWinBatteryState(bs.PowerState),
+		FullChargeCapacity: uint64(bi.FullChargedCapacity), HasFullChargeCapacity: true, System: true}, nil
 }
 
 // HasReadableBattery checks if the system has a battery and returns true if it does.
-var HasReadableBattery = sync.OnceValue(func() bool {
-	systemHasBattery := false
-	full, _, _, err := winBatteryGet(0)
-	if err == nil && full > 0 {
-		systemHasBattery = true
-	}
-	if !systemHasBattery {
-		slog.Debug("No battery found", "err", err)
-	}
-	return systemHasBattery
-})
-
-// GetBatteryStats returns the current battery percent and charge state.
-func GetBatteryStats() (batteryPercent uint8, batteryState uint8, err error) {
-	if !HasReadableBattery() {
-		return batteryPercent, batteryState, errors.ErrUnsupported
-	}
-
-	totalFull := uint32(0)
-	totalCurrent := uint32(0)
-	batteryState = math.MaxUint8
+func HasReadableBattery() bool {
+	batteries, _ := GetBatteryStats()
+	return len(batteries) > 0
+}
 
+// GetBatteryStats returns every readable battery reported by Windows.
+func GetBatteryStats() ([]Battery, error) {
+	batteries := make([]Battery, 0, 2)
 	for i := 0; ; i++ {
-		full, current, state, bErr := winBatteryGet(i)
+		battery, bErr := winBatteryGet(i)
 		if errors.Is(bErr, errNotFound) {
 			break
 		}
-		if bErr != nil || full == 0 {
+		if bErr != nil {
 			continue
 		}
-		totalFull += full
-		totalCurrent += min(current, full)
-		batteryState = state
+		batteries = append(batteries, battery)
 	}
-
-	if totalFull == 0 || batteryState == math.MaxUint8 {
-		return batteryPercent, batteryState, errors.New("no battery capacity")
+	if len(batteries) == 0 {
+		return nil, errNoBatteries
 	}
-
-	batteryPercent = uint8(float64(totalCurrent) / float64(totalFull) * 100)
-	return batteryPercent, batteryState, nil
+	return normalizeBatteries(batteries), nil
 }

agent/system.go

@@ -132,9 +132,14 @@ func (a *Agent) getSystemStats(cacheTimeMs uint16) system.Stats {
 	var systemStats system.Stats
 
 	// battery
-	if batteryPercent, batteryState, err := battery.GetBatteryStats(); err == nil {
-		systemStats.Battery[0] = batteryPercent
-		systemStats.Battery[1] = batteryState
+	if batteries, err := battery.GetBatteryStats(); err == nil {
+		systemStats.Batteries = make(map[string]uint8, len(batteries))
+		for _, device := range batteries {
+			systemStats.Batteries[device.Name] = device.Percent
+		}
+		if primary, ok := battery.Primary(batteries); ok {
+			systemStats.Battery = [2]uint8{primary.Percent, primary.State}
+		}
 	}
 
 	// cpu metrics