feat: config command

internal/config/env_config.go

@@ -0,0 +1,76 @@
+// ALR - Any Linux Repository
+// Copyright (C) 2025 The ALR Authors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package config
+
+import (
+	"strings"
+
+	"github.com/knadh/koanf/providers/env"
+	"github.com/knadh/koanf/v2"
+	"golang.org/x/text/cases"
+	"golang.org/x/text/language"
+)
+
+type EnvConfig struct {
+	k *koanf.Koanf
+}
+
+func NewEnvConfig() *EnvConfig {
+	return &EnvConfig{
+		k: koanf.New("."),
+	}
+}
+
+func (c *EnvConfig) koanf() *koanf.Koanf {
+	return c.k
+}
+
+func (c *EnvConfig) Load() error {
+	allowedKeys := map[string]struct{}{
+		"ALR_LOG_LEVEL":   {},
+		"ALR_PAGER_STYLE": {},
+		"ALR_AUTO_PULL":   {},
+	}
+	err := c.k.Load(env.Provider("ALR_", ".", func(s string) string {
+		_, ok := allowedKeys[s]
+		if !ok {
+			return ""
+		}
+		withoutPrefix := strings.TrimPrefix(s, "ALR_")
+		lowered := strings.ToLower(withoutPrefix)
+		dotted := strings.ReplaceAll(lowered, "__", ".")
+		parts := strings.Split(dotted, ".")
+		for i, part := range parts {
+			if strings.Contains(part, "_") {
+				parts[i] = toCamelCase(part)
+			}
+		}
+		return strings.Join(parts, ".")
+	}), nil)
+
+	return err
+}
+
+func toCamelCase(s string) string {
+	parts := strings.Split(s, "_")
+	for i := 1; i < len(parts); i++ {
+		if len(parts[i]) > 0 {
+			parts[i] = cases.Title(language.Und, cases.NoLower).String(parts[i])
+		}
+	}
+	return strings.Join(parts, "")
+}