Can register Authenticator app

src/data/totp_key.rs

@@ -1,14 +1,19 @@
+use std::io::ErrorKind;
+
 use base32::Alphabet;
 use rand::Rng;
+use totp_rfc6238::{HashAlgorithm, TotpGenerator};
 
 use crate::data::app_config::AppConfig;
 use crate::data::user::User;
+use crate::utils::err::Res;
+use crate::utils::time::time;
 
 const BASE32_ALPHABET: Alphabet = Alphabet::RFC4648 { padding: true };
-const NUM_DIGITS: i32 = 6;
-const PERIOD: i32 = 30;
+const NUM_DIGITS: usize = 6;
+const PERIOD: u64 = 30;
 
-#[derive(serde::Serialize, serde::Deserialize, Debug)]
+#[derive(Clone, serde::Serialize, serde::Deserialize, Debug)]
 pub struct TotpKey {
     encoded: String,
 }
@@ -17,11 +22,16 @@ impl TotpKey {
     /// Generate a new TOTP key
     pub fn new_random() -> Self {
         let random_bytes = rand::thread_rng().gen::<[u8; 10]>();
-        TotpKey {
+        Self {
             encoded: base32::encode(BASE32_ALPHABET, &random_bytes)
         }
     }
 
+    /// Get a key from an encoded secret
+    pub fn from_encoded_secret(s: &str) -> Self {
+        Self { encoded: s.to_string() }
+    }
+
     /// Get QrCode URL for user
     ///
     /// Based on https://github.com/google/google-authenticator/wiki/Key-Uri-Format
@@ -50,4 +60,38 @@ impl TotpKey {
     pub fn get_secret(&self) -> String {
         self.encoded.to_string()
     }
+
+    /// Get current code
+    pub fn current_code(&self) -> Res<String> {
+        self.get_code_at(|| time())
+    }
+
+    /// Get previous code
+    pub fn previous_code(&self) -> Res<String> {
+        self.get_code_at(|| time() - PERIOD)
+    }
+
+    /// Get the code at a specific time
+    fn get_code_at<F: Fn() -> u64>(&self, get_time: F) -> Res<String> {
+        let gen = TotpGenerator::new()
+            .set_digit(NUM_DIGITS).unwrap()
+            .set_step(PERIOD).unwrap()
+            .set_hash_algorithm(HashAlgorithm::SHA1)
+            .build();
+
+        let key = match base32::decode(BASE32_ALPHABET, &self.encoded) {
+            None => {
+                return Err(Box::new(
+                    std::io::Error::new(ErrorKind::Other, "Failed to decode base32 secret!")));
+            }
+            Some(k) => k,
+        };
+
+        Ok(gen.get_code_with(&key, get_time))
+    }
+
+    /// Check a code's validity
+    pub fn check_code(&self, code: &str) -> Res<bool> {
+        Ok(self.current_code()?.eq(code) || self.previous_code()?.eq(code))
+    }
 }