WIP: Full restruct, seprate service and api

Signed-off-by: Asai Neko <sugar@sne.moe>

internal/authcode/authcode.go

@@ -0,0 +1,65 @@
+package authcode
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"nixcn-cms/data"
+
+	"github.com/spf13/viper"
+)
+
+type Token struct {
+	ClientId string
+	Email    string
+}
+
+func NewAuthCode(ctx context.Context, clientId string, email string) (string, error) {
+	// generate random code
+	b := make([]byte, 32)
+	if _, err := rand.Read(b); err != nil {
+		return "", err
+	}
+
+	code := base64.RawURLEncoding.EncodeToString(b)
+	key := "auth_code:" + code
+
+	ttl := viper.GetDuration("ttl.auth_code_ttl")
+
+	// store auth code metadata in Redis
+	if err := data.Redis.HSet(
+		ctx,
+		key,
+		map[string]any{
+			"client_id": clientId,
+			"email":     email,
+		},
+	).Err(); err != nil {
+		return "", err
+	}
+
+	// set expiration (one-time auth code)
+	if err := data.Redis.Expire(ctx, key, ttl).Err(); err != nil {
+		return "", err
+	}
+
+	return code, nil
+}
+
+func VerifyAuthCode(ctx context.Context, code string) (*Token, bool) {
+	key := "auth_code:" + code
+
+	// Read auth code payload
+	dataMap, err := data.Redis.HGetAll(ctx, key).Result()
+	if err != nil || len(dataMap) == 0 {
+		return nil, false
+	}
+
+	// Delete auth code immediately (one-time use)
+	_ = data.Redis.Del(ctx, key).Err()
+
+	return &Token{
+		ClientId: dataMap["client_id"],
+		Email:    dataMap["email"],
+	}, true
+}