feat: support named switchable layouts

internal/config/config.go

@@ -12,13 +12,14 @@ import (
 )
 
 type Config struct {
-	Version   int      `yaml:"version"`
-	Gap       int      `yaml:"gap"`
-	ShiftDrag bool     `yaml:"shift_drag"`
-	Overlay   Overlay  `yaml:"overlay"`
-	Layouts   []Layout `yaml:"layouts"`
-	Excluded  []string `yaml:"excluded_apps"`
-	Hotkeys   []Hotkey `yaml:"hotkeys"`
+	Version      int      `yaml:"version"`
+	Gap          int      `yaml:"gap"`
+	ShiftDrag    bool     `yaml:"shift_drag"`
+	ActiveLayout string   `yaml:"active_layout"`
+	Overlay      Overlay  `yaml:"overlay"`
+	Layouts      []Layout `yaml:"layouts"`
+	Excluded     []string `yaml:"excluded_apps"`
+	Hotkeys      []Hotkey `yaml:"hotkeys"`
 }
 
 type Overlay struct {
@@ -29,6 +30,7 @@ type Overlay struct {
 }
 
 type Layout struct {
+	Name    string `yaml:"name"`
 	Monitor string `yaml:"monitor"`
 	Zones   []Zone `yaml:"zones"`
 }
@@ -49,8 +51,9 @@ type Hotkey struct {
 func Default() Config {
 	return Config{
 		Version: 1, Gap: 8, ShiftDrag: true,
-		Overlay: Overlay{Enabled: true, Color: "#00AEEF", Opacity: 90, BorderWidth: 3},
-		Layouts: []Layout{{Monitor: "*", Zones: []Zone{
+		ActiveLayout: "columns",
+		Overlay:      Overlay{Enabled: true, Color: "#00AEEF", Opacity: 90, BorderWidth: 10},
+		Layouts: []Layout{{Name: "columns", Monitor: "*", Zones: []Zone{
 			{Name: "left", X: 0, Y: 0, Width: 50, Height: 100},
 			{Name: "right", X: 50, Y: 0, Width: 50, Height: 100},
 		}}},
@@ -73,6 +76,7 @@ func Load(path string) (Config, error) {
 	if err := d.Decode(&c); err != nil {
 		return Config{}, fmt.Errorf("parse YAML: %w", err)
 	}
+	c.upgradeLegacyLayouts()
 	if err := c.Validate(); err != nil {
 		return Config{}, err
 	}
@@ -100,15 +104,27 @@ func (c Config) Validate() error {
 	if len(c.Layouts) == 0 {
 		return errors.New("at least one layout is required")
 	}
+	active := strings.TrimSpace(c.ActiveLayout)
+	if active == "" {
+		return errors.New("active_layout is required")
+	}
 	seenMonitors := map[string]bool{}
+	activeExists := false
 	for li, l := range c.Layouts {
+		layoutName := strings.TrimSpace(l.Name)
+		if layoutName == "" {
+			return fmt.Errorf("layouts[%d].name is required", li)
+		}
+		if strings.EqualFold(layoutName, active) {
+			activeExists = true
+		}
 		name := strings.TrimSpace(l.Monitor)
 		if name == "" {
 			return fmt.Errorf("layouts[%d].monitor is required", li)
 		}
-		key := strings.ToLower(name)
+		key := strings.ToLower(layoutName) + "\x00" + strings.ToLower(name)
 		if seenMonitors[key] {
-			return fmt.Errorf("duplicate layout for monitor %q", name)
+			return fmt.Errorf("duplicate layout named %q for monitor %q", layoutName, name)
 		}
 		seenMonitors[key] = true
 		if len(l.Zones) == 0 {
@@ -120,6 +136,9 @@ func (c Config) Validate() error {
 			}
 		}
 	}
+	if !activeExists {
+		return fmt.Errorf("active_layout %q does not match any layout name", c.ActiveLayout)
+	}
 	for i, h := range c.Hotkeys {
 		a := strings.ToLower(strings.TrimSpace(h.Action))
 		if a != "next_zone" && a != "previous_zone" && !strings.HasPrefix(a, "zone_") {
@@ -138,6 +157,21 @@ func (c Config) Validate() error {
 	return nil
 }
 
+func (c *Config) upgradeLegacyLayouts() {
+	if strings.TrimSpace(c.ActiveLayout) != "" || len(c.Layouts) == 0 {
+		return
+	}
+	for _, l := range c.Layouts {
+		if strings.TrimSpace(l.Name) != "" {
+			return
+		}
+	}
+	c.ActiveLayout = "default"
+	for i := range c.Layouts {
+		c.Layouts[i].Name = "default"
+	}
+}
+
 func validHexColor(s string) bool {
 	if len(s) != 7 || s[0] != '#' {
 		return false
@@ -151,14 +185,15 @@ func DefaultPath(exePath string) string {
 }
 
 func (c Config) LayoutFor(device string) (Layout, bool) {
+	active := strings.TrimSpace(c.ActiveLayout)
 	for _, l := range c.Layouts {
 		monitor := strings.TrimSpace(l.Monitor)
-		if monitor != "*" && strings.EqualFold(monitor, strings.TrimSpace(device)) {
+		if strings.EqualFold(strings.TrimSpace(l.Name), active) && monitor != "*" && strings.EqualFold(monitor, strings.TrimSpace(device)) {
 			return l, true
 		}
 	}
 	for _, l := range c.Layouts {
-		if strings.TrimSpace(l.Monitor) == "*" {
+		if strings.EqualFold(strings.TrimSpace(l.Name), active) && strings.TrimSpace(l.Monitor) == "*" {
 			return l, true
 		}
 	}

internal/config/config_test.go

@@ -1,6 +1,10 @@
 package config
 
-import "testing"
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
 
 func TestDefaultValid(t *testing.T) {
 	if err := Default().Validate(); err != nil {
@@ -15,6 +19,51 @@ func TestLayoutFallback(t *testing.T) {
 	}
 }
 
+func TestActiveLayoutSelection(t *testing.T) {
+	c := Default()
+	c.Layouts = append(c.Layouts, Layout{Name: "wide", Monitor: "*", Zones: []Zone{{Name: "wide", Width: 100, Height: 100}}})
+	c.ActiveLayout = "wide"
+	got, ok := c.LayoutFor(`\\.\DISPLAY1`)
+	if !ok || got.Name != "wide" || len(got.Zones) != 1 {
+		t.Fatalf("wrong active layout: %+v, %v", got, ok)
+	}
+}
+
+func TestLegacyLayoutUpgrade(t *testing.T) {
+	c := Default()
+	c.ActiveLayout = ""
+	for i := range c.Layouts {
+		c.Layouts[i].Name = ""
+	}
+	c.upgradeLegacyLayouts()
+	if c.ActiveLayout != "default" || c.Layouts[0].Name != "default" {
+		t.Fatalf("legacy layout was not upgraded: %+v", c)
+	}
+}
+
+func TestLoadLegacyUnnamedLayout(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "legacy.yaml")
+	data := []byte("version: 1\ngap: 8\nshift_drag: true\nlayouts:\n  - monitor: '*'\n    zones:\n      - {x: 0, y: 0, width: 100, height: 100}\n")
+	if err := os.WriteFile(path, data, 0o600); err != nil {
+		t.Fatal(err)
+	}
+	c, err := Load(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if c.ActiveLayout != "default" || c.Layouts[0].Name != "default" {
+		t.Fatalf("legacy file was not upgraded: %+v", c)
+	}
+}
+
+func TestMissingActiveLayoutFails(t *testing.T) {
+	c := Default()
+	c.ActiveLayout = "missing"
+	if err := c.Validate(); err == nil {
+		t.Fatal("expected missing active layout to fail")
+	}
+}
+
 func TestExcluded(t *testing.T) {
 	c := Default()
 	c.Excluded = []string{"notepad", "exact.exe"}