feat: add config and credential storage

internal/config/config.go

@@ -0,0 +1,89 @@
+package config
+
+import (
+	"encoding/json"
+	"errors"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"sgg-ai-skill-manager/internal/domain"
+)
+
+const (
+	AuthPassword = "password"
+	AuthToken    = "token"
+)
+
+func Default() domain.Config {
+	return domain.Config{
+		Gitea: domain.GiteaConfig{
+			AuthType:      AuthPassword,
+			CredentialKey: "sgg-ai-skill-manager:gitea",
+		},
+		Update: domain.UpdateConfig{
+			AutoUpdate:      true,
+			CheckOnStartup:  true,
+			IntervalMinutes: 60,
+		},
+	}
+}
+
+func Load(path string) (domain.Config, error) {
+	cfg := Default()
+	raw, err := os.ReadFile(path)
+	if errors.Is(err, os.ErrNotExist) {
+		return cfg, nil
+	}
+	if err != nil {
+		return cfg, err
+	}
+	if strings.TrimSpace(string(raw)) == "" {
+		return cfg, nil
+	}
+	if err := json.Unmarshal(raw, &cfg); err != nil {
+		return cfg, err
+	}
+	applyDefaults(&cfg)
+	return cfg, nil
+}
+
+func Save(path string, cfg domain.Config) error {
+	applyDefaults(&cfg)
+	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
+		return err
+	}
+	raw, err := json.MarshalIndent(cfg, "", "  ")
+	if err != nil {
+		return err
+	}
+	return os.WriteFile(path, append(raw, '\n'), 0o600)
+}
+
+func Validate(cfg domain.Config) error {
+	if strings.TrimSpace(cfg.Gitea.BaseURL) == "" {
+		return errors.New("gitea baseURL is required")
+	}
+	if strings.TrimSpace(cfg.Gitea.Org) == "" {
+		return errors.New("gitea org is required")
+	}
+	if cfg.Gitea.AuthType != AuthPassword && cfg.Gitea.AuthType != AuthToken {
+		return errors.New("authType must be password or token")
+	}
+	if cfg.Update.IntervalMinutes <= 0 {
+		return errors.New("update interval must be positive")
+	}
+	return nil
+}
+
+func applyDefaults(cfg *domain.Config) {
+	if cfg.Gitea.AuthType == "" {
+		cfg.Gitea.AuthType = AuthPassword
+	}
+	if cfg.Gitea.CredentialKey == "" {
+		cfg.Gitea.CredentialKey = "sgg-ai-skill-manager:gitea"
+	}
+	if cfg.Update.IntervalMinutes <= 0 {
+		cfg.Update.IntervalMinutes = 60
+	}
+}