1 files changed, 126 insertions, 0 deletions
diff --git a/config.go b/config.go
new file mode 100644
index 0000000..d472cee
--- /dev/null
+++ b/config.go
@@ -0,0 +1,126 @@
+// Copyright 2021, Shulhan <ms@kilabit.info>. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gotp
+
+import (
+	"crypto/rsa"
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/shuLhan/share/lib/ini"
+)
+
+const (
+	valueSeparator = ":"
+)
+
+type config struct {
+	PrivateKey string            `ini:"gotp::private_key"`
+	Issuers    map[string]string `ini:"gotp:issuer"`
+
+	file       string
+	isNotExist bool
+	privateKey *rsa.PrivateKey // Only RSA private key can do encryption.
+}
+
+func newConfig(file string) (cfg *config, err error) {
+	logp := "newConfig"
+
+	cfg = &config{
+		Issuers: make(map[string]string),
+		file:    file,
+	}
+
+	in, err := ini.Open(file)
+	if err != nil {
+		if !errors.Is(err, fs.ErrNotExist) {
+			return nil, fmt.Errorf("%s: Open %q: %w", logp, file, err)
+		}
+		cfg.isNotExist = true
+	}
+
+	if cfg.isNotExist {
+		dir := filepath.Dir(file)
+		err = os.MkdirAll(dir, 0700)
+		if err != nil {
+			return nil, fmt.Errorf("%s: MkdirAll %q: %w", logp, dir, err)
+		}
+		return cfg, nil
+	}
+
+	err = in.Unmarshal(cfg)
+	if err != nil {
+		return nil, fmt.Errorf("%s: %w", logp, err)
+	}
+
+	return cfg, nil
+}
+
+func (cfg *config) add(issuer *Issuer) (err error) {
+	var (
+		value string
+		exist bool
+	)
+
+	if issuer == nil {
+		return nil
+	}
+
+	_, exist = cfg.Issuers[issuer.Label]
+	if exist {
+		return fmt.Errorf("duplicate issuer name %q", issuer.Label)
+	}
+
+	value, err = issuer.pack(cfg.privateKey)
+	if err != nil {
+		return err
+	}
+
+	cfg.Issuers[issuer.Label] = value
+
+	return nil
+}
+
+//
+// get the issuer by its name.
+//
+func (cfg *config) get(name string) (issuer *Issuer, err error) {
+	logp := "get"
+
+	name = strings.ToLower(name)
+
+	v, ok := cfg.Issuers[name]
+	if !ok {
+		return nil, fmt.Errorf("%s: issuer %q not found", logp, name)
+	}
+
+	issuer, err = NewIssuer(name, v, cfg.privateKey)
+	if err != nil {
+		return nil, fmt.Errorf("%s %q: %w", logp, name, err)
+	}
+
+	return issuer, nil
+}
+
+// save the config to file.
+func (cfg *config) save() (err error) {
+	logp := "save"
+
+	b, err := ini.Marshal(cfg)
+	if err != nil {
+		return fmt.Errorf("%s %s: %w", logp, cfg.file, err)
+	}
+
+	err = os.WriteFile(cfg.file, b, 0600)
+	if err != nil {
+		return fmt.Errorf("%s %s: %w", logp, cfg.file, err)
+	}
+
+	return nil
+}