feat(config): config at XDG dir

cmd/config.go

@@ -0,0 +1,67 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/BurntSushi/toml"
+	gap "github.com/muesli/go-app-paths"
+)
+
+type Config struct {
+	DefaultDB string `toml:"default_db"`
+}
+
+var (
+	config    Config
+	configErr error
+)
+
+func init() {
+	config, configErr = loadConfig()
+}
+
+func defaultConfig() Config {
+	return Config{
+		DefaultDB: "default",
+	}
+}
+
+func loadConfig() (Config, error) {
+	cfg := defaultConfig()
+
+	path, err := configPath()
+	if err != nil {
+		return cfg, err
+	}
+
+	if _, err := os.Stat(path); err != nil {
+		if os.IsNotExist(err) {
+			return cfg, nil
+		}
+		return cfg, err
+	}
+
+	if _, err := toml.DecodeFile(path, &cfg); err != nil {
+		return cfg, fmt.Errorf("parse %s: %w", path, err)
+	}
+
+	if cfg.DefaultDB == "" {
+		cfg.DefaultDB = defaultConfig().DefaultDB
+	}
+
+	return cfg, nil
+}
+
+func configPath() (string, error) {
+	if override := os.Getenv("PDA_CONFIG"); override != "" {
+		return override, nil
+	}
+	scope := gap.NewVendorScope(gap.User, "pda", "config")
+	dir, err := scope.ConfigPath("")
+	if err != nil {
+		return "", err
+	}
+	return filepath.Join(dir, "config.toml"), nil
+}

cmd/keyspec.go

@@ -15,7 +15,7 @@ type KeySpec struct {
 }
 
 // ParseKey parses "KEY[@DB]" into a normalized KeySpec.
-// When defaults is true, a missing DB defaults to "default".
+// When defaults is true, a missing DB defaults to the configured default.
 func ParseKey(raw string, defaults bool) (KeySpec, error) {
 	parts := strings.Split(raw, "@")
 	if len(parts) > 2 {
@@ -34,7 +34,7 @@ func ParseKey(raw string, defaults bool) (KeySpec, error) {
 	key := strings.ToLower(rawKey)
 	db := strings.ToLower(rawDB)
 	if db == "" && defaults {
-		db = "default"
+		db = config.DefaultDB
 	}
 
 	return KeySpec{
@@ -57,7 +57,7 @@ func (k KeySpec) Full() string {
 // Display returns the normalized key reference
 // but omits the default database if none was set manually
 func (k KeySpec) Display() string {
-	if k.DB == "" || k.DB == "default" {
+	if k.DB == "" || k.DB == config.DefaultDB {
 		return k.Key
 	}
 	return fmt.Sprintf("%s@%s", k.Key, k.DB)

cmd/root.go

@@ -22,6 +22,7 @@ THE SOFTWARE.
 package cmd
 
 import (
+	"fmt"
 	"os"
 
 	"github.com/spf13/cobra"
@@ -42,6 +43,10 @@ var rootCmd = &cobra.Command{
 `}
 
 func Execute() {
+	if configErr != nil {
+		fmt.Fprintln(os.Stderr, "failed to load config:", configErr)
+		os.Exit(1)
+	}
 	err := rootCmd.Execute()
 	if err != nil {
 		os.Exit(1)

cmd/shared.go

@@ -173,7 +173,7 @@ func (s *Store) parseDB(v string, defaults bool) (string, error) {
 	}
 	if db == "" {
 		if defaults {
-			return "default", nil
+			return config.DefaultDB, nil
 		}
 		return "", fmt.Errorf("cannot parse db: bad db format, use DB or @DB")
 	}
@@ -182,7 +182,7 @@ func (s *Store) parseDB(v string, defaults bool) (string, error) {
 
 func (s *Store) open(name string) (*badger.DB, error) {
 	if name == "" {
-		name = "default"
+		name = config.DefaultDB
 	}
 	path, err := s.path(name)
 	if err != nil {