feat: config system — TOML load/save with provider auth map

internal/config/config.go

@@ -0,0 +1,67 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+
+	"github.com/BurntSushi/toml"
+)
+
+type ProviderConfig struct {
+	APIKey          string `toml:"api_key,omitempty"`
+	AccessKeyID     string `toml:"access_key_id,omitempty"`
+	AccessKeySecret string `toml:"access_key_secret,omitempty"`
+	Endpoint        string `toml:"endpoint,omitempty"`
+}
+
+type Config struct {
+	CurrentProvider string                    `toml:"current_provider"`
+	Output          string                    `toml:"output"`
+	Providers       map[string]ProviderConfig `toml:"providers"`
+}
+
+func Load(path string) (*Config, error) {
+	cfg := &Config{
+		Output:    "table",
+		Providers: make(map[string]ProviderConfig),
+	}
+	data, err := os.ReadFile(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return cfg, nil
+		}
+		return nil, err
+	}
+	if err := toml.Unmarshal(data, cfg); err != nil {
+		return nil, err
+	}
+	if cfg.Providers == nil {
+		cfg.Providers = make(map[string]ProviderConfig)
+	}
+	if cfg.Output == "" {
+		cfg.Output = "table"
+	}
+	return cfg, nil
+}
+
+func Save(path string, cfg *Config) error {
+	dir := filepath.Dir(path)
+	if err := os.MkdirAll(dir, 0700); err != nil {
+		return err
+	}
+	f, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	enc := toml.NewEncoder(f)
+	return enc.Encode(cfg)
+}
+
+func DefaultPath() string {
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return "config.toml"
+	}
+	return filepath.Join(home, ".config", "ry", "config.toml")
+}