support user module overrides

README.md

@@ -8,6 +8,7 @@ user-facing configuration UI is expected to live in `ximperconf shell panel`.
 ## Paths
 
 - User config: `~/.config/ximper-shell/panel/config.json`
+- User modules: `~/.config/ximper-shell/panel/modules.json`
 - System modules: `/usr/share/ximperdistro/wm/base/waybar/modules.json`
 
 ## Commands
@@ -40,8 +41,11 @@ panel, floating, islands
 
 ## Module Resolution
 
-The config stores logical module names. At generation time, the panel resolves
-them against `modules.json`.
+The config stores logical module names. At generation time, the panel merges
+system and user modules, then resolves names against the merged registry.
+User modules override system modules with the same name. Object values are
+merged recursively, so a user module can override a single option without
+copying the whole system module.
 
 Examples:
 

config.go

 package main
 
 import (
+	"bytes"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -41,6 +42,9 @@ func LoadConfig(path string) (Config, error) {
 		}
 		return cfg, err
 	}
+	if len(bytes.TrimSpace(data)) == 0 {
+		return cfg, nil
+	}
 	if err := json.Unmarshal(data, &cfg); err != nil {
 		return cfg, fmt.Errorf("parse panel config: %w", err)
 	}
@@ -73,6 +77,10 @@ func UserConfigPath() string {
 	return filepath.Join(os.Getenv("HOME"), ".config", "ximper-shell", "panel", "config.json")
 }
 
+func UserModulesPath() string {
+	return filepath.Join(os.Getenv("HOME"), ".config", "ximper-shell", "panel", "modules.json")
+}
+
 func RuntimeDir() string {
 	return filepath.Join(os.TempDir(), "ximper-shell", "panel")
 }
@@ -81,6 +89,10 @@ func RuntimeConfigPath() string {
 	return filepath.Join(RuntimeDir(), "config.jsonc")
 }
 
+func RuntimeModulesPath() string {
+	return filepath.Join(RuntimeDir(), "modules.jsonc")
+}
+
 func RuntimePIDPath() string {
 	return filepath.Join(RuntimeDir(), "waybar.pid")
 }

generate.go

@@ -19,7 +19,7 @@ func GenerateConfig(cfg Config, registry Registry) ([]byte, error) {
 		"fixed-center":           true,
 		"reload_style_on_change": true,
 		"include": []string{
-			ModulesFile,
+			RuntimeModulesPath(),
 		},
 		"modules-left":   []string{},
 		"modules-center": []string{},
@@ -66,6 +66,9 @@ func GenerateRuntimeConfig() ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
+	if err := WriteRuntimeModules(registry); err != nil {
+		return nil, err
+	}
 	return GenerateConfig(cfg, registry)
 }
 
@@ -74,11 +77,7 @@ func GenerateAndWriteRuntimeConfig() (string, error) {
 	if err != nil {
 		return "", err
 	}
-	path, err := WriteRuntimeConfig(data)
-	if err != nil {
-		return "", err
-	}
-	return path, nil
+	return WriteRuntimeConfig(data)
 }
 
 func WriteRuntimeConfig(data []byte) (string, error) {
@@ -92,12 +91,23 @@ func WriteRuntimeConfig(data []byte) (string, error) {
 	return path, nil
 }
 
+func WriteRuntimeModules(registry Registry) error {
+	data, err := registry.Marshal()
+	if err != nil {
+		return err
+	}
+	if err := os.MkdirAll(filepath.Dir(RuntimeModulesPath()), 0755); err != nil {
+		return err
+	}
+	return os.WriteFile(RuntimeModulesPath(), data, 0644)
+}
+
 func loadInputs() (Config, Registry, error) {
 	cfg, err := LoadConfig(UserConfigPath())
 	if err != nil {
 		return Config{}, Registry{}, err
 	}
-	registry, err := LoadRegistry(ModulesFile)
+	registry, err := LoadMergedRegistry(ModulesFile, UserModulesPath())
 	if err != nil {
 		return Config{}, Registry{}, err
 	}

main.go

@@ -82,7 +82,7 @@ func applyCommandSetting(cliCommand *cli.Command) {
 }
 
 func listModulesCommand(ctx context.Context, cmd *cli.Command) error {
-	registry, err := LoadRegistry(ModulesFile)
+	registry, err := LoadMergedRegistry(ModulesFile, UserModulesPath())
 	if err != nil {
 		return err
 	}

registry.go

 package main
 
 import (
+	"bytes"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"os"
 	"sort"
@@ -12,11 +14,38 @@ type Registry struct {
 	Modules map[string]json.RawMessage
 }
 
+func LoadMergedRegistry(systemPath, userPath string) (Registry, error) {
+	systemRegistry, err := LoadRegistry(systemPath)
+	if err != nil {
+		return Registry{}, err
+	}
+
+	userRegistry, err := LoadRegistry(userPath)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return systemRegistry, nil
+		}
+		return Registry{}, err
+	}
+
+	for name, raw := range userRegistry.Modules {
+		merged, err := mergeModule(systemRegistry.Modules[name], raw)
+		if err != nil {
+			return Registry{}, fmt.Errorf("merge module %q: %w", name, err)
+		}
+		systemRegistry.Modules[name] = merged
+	}
+	return systemRegistry, nil
+}
+
 func LoadRegistry(path string) (Registry, error) {
 	data, err := os.ReadFile(path)
 	if err != nil {
 		return Registry{}, err
 	}
+	if len(bytes.TrimSpace(data)) == 0 {
+		return Registry{Modules: map[string]json.RawMessage{}}, nil
+	}
 
 	var modules map[string]json.RawMessage
 	if err := json.Unmarshal(StripJSONC(data), &modules); err != nil {
@@ -26,6 +55,55 @@ func LoadRegistry(path string) (Registry, error) {
 	return Registry{Modules: modules}, nil
 }
 
+func mergeModule(base, override json.RawMessage) (json.RawMessage, error) {
+	if len(base) == 0 {
+		return override, nil
+	}
+
+	var baseValue any
+	if err := json.Unmarshal(base, &baseValue); err != nil {
+		return nil, err
+	}
+
+	var overrideValue any
+	if err := json.Unmarshal(override, &overrideValue); err != nil {
+		return nil, err
+	}
+
+	merged := mergeValue(baseValue, overrideValue)
+	data, err := json.Marshal(merged)
+	if err != nil {
+		return nil, err
+	}
+	return data, nil
+}
+
+func mergeValue(base, override any) any {
+	baseMap, baseOK := base.(map[string]any)
+	overrideMap, overrideOK := override.(map[string]any)
+	if !baseOK || !overrideOK {
+		return override
+	}
+
+	for key, overrideValue := range overrideMap {
+		if baseValue, ok := baseMap[key]; ok {
+			baseMap[key] = mergeValue(baseValue, overrideValue)
+		} else {
+			baseMap[key] = overrideValue
+		}
+	}
+
+	return baseMap
+}
+
+func (r Registry) Marshal() ([]byte, error) {
+	data, err := json.MarshalIndent(r.Modules, "", "  ")
+	if err != nil {
+		return nil, err
+	}
+	return append(data, '\n'), nil
+}
+
 func (r Registry) Names() []string {
 	names := make([]string, 0, len(r.Modules))
 	for name := range r.Modules {