add TOTP code view

app/src/main/java/sh/sar/basedbank/ui/home/HomeActivity.kt

@@ -92,6 +92,7 @@ class HomeActivity : AppCompatActivity() {
                 R.id.nav_contacts -> show(ContactsFragment())
                 R.id.nav_transfer_history -> show(TransferHistoryFragment())
                 R.id.nav_finances -> show(FinancingFragment())
+                R.id.nav_otp -> show(OtpFragment())
                 R.id.nav_settings -> show(SettingsFragment())
                 else -> Toast.makeText(this, R.string.work_in_progress, Toast.LENGTH_SHORT).show()
             }

app/src/main/java/sh/sar/basedbank/ui/home/OtpFragment.kt

@@ -0,0 +1,91 @@
+package sh.sar.basedbank.ui.home
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.fragment.app.Fragment
+import androidx.lifecycle.lifecycleScope
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.isActive
+import kotlinx.coroutines.launch
+import sh.sar.basedbank.databinding.FragmentOtpBinding
+import sh.sar.basedbank.databinding.ItemOtpCardBinding
+import sh.sar.basedbank.util.CredentialStore
+import sh.sar.basedbank.util.Totp
+
+class OtpFragment : Fragment() {
+
+    private var _binding: FragmentOtpBinding? = null
+    private val binding get() = _binding!!
+
+    private data class OtpEntry(val label: String, val seed: String)
+
+    private inner class OtpAdapter(private val entries: List<OtpEntry>) :
+        RecyclerView.Adapter<OtpAdapter.VH>() {
+
+        inner class VH(val b: ItemOtpCardBinding) : RecyclerView.ViewHolder(b.root)
+
+        override fun getItemCount() = entries.size
+
+        override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =
+            VH(ItemOtpCardBinding.inflate(LayoutInflater.from(parent.context), parent, false))
+
+        override fun onBindViewHolder(holder: VH, position: Int) {
+            holder.b.tvOtpLabel.text = entries[position].label
+            update(holder.b, entries[position].seed)
+        }
+
+        fun tick() {
+            for (i in entries.indices) {
+                val vh = (binding.recyclerView.findViewHolderForAdapterPosition(i) as? VH) ?: continue
+                update(vh.b, entries[i].seed)
+            }
+        }
+
+        private fun update(b: ItemOtpCardBinding, seed: String) {
+            val epochSeconds = System.currentTimeMillis() / 1000L
+            val secondsInPeriod = (epochSeconds % 30).toInt()
+            val remaining = 30 - secondsInPeriod
+            val code = try { Totp.generate(seed) } catch (_: Exception) { "------" }
+            b.tvOtpCode.text = "${code.take(3)} ${code.drop(3)}"
+            b.otpProgress.progress = remaining
+            b.tvOtpCountdown.text = "Refreshes in $remaining second${if (remaining == 1) "" else "s"}"
+        }
+    }
+
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
+        _binding = FragmentOtpBinding.inflate(inflater, container, false)
+        return binding.root
+    }
+
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        val store = CredentialStore(requireContext())
+        val entries = mutableListOf<OtpEntry>()
+        store.loadMibCredentials()?.let { entries.add(OtpEntry("MIB · ${it.username}", it.otpSeed)) }
+        store.loadBmlCredentials()?.let { entries.add(OtpEntry("BML · ${it.username}", it.otpSeed)) }
+
+        val adapter = OtpAdapter(entries)
+        binding.recyclerView.layoutManager = LinearLayoutManager(requireContext())
+        binding.recyclerView.adapter = adapter
+
+        viewLifecycleOwner.lifecycleScope.launch {
+            while (isActive) {
+                adapter.tick()
+                delay(1_000)
+            }
+        }
+    }
+
+    override fun onResume() {
+        super.onResume()
+        requireActivity().title = "OTP Codes"
+    }
+
+    override fun onDestroyView() {
+        super.onDestroyView()
+        _binding = null
+    }
+}

app/src/main/res/layout/fragment_otp.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <androidx.recyclerview.widget.RecyclerView
+        android:id="@+id/recyclerView"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:paddingTop="16dp"
+        android:clipToPadding="false" />
+
+</LinearLayout>

app/src/main/res/layout/item_otp_card.xml

@@ -0,0 +1,55 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.google.android.material.card.MaterialCardView
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:layout_marginHorizontal="16dp"
+    android:layout_marginBottom="12dp"
+    app:cardCornerRadius="16dp"
+    app:cardElevation="2dp">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="vertical"
+        android:padding="20dp">
+
+        <TextView
+            android:id="@+id/tvOtpLabel"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:textAppearance="?attr/textAppearanceLabelMedium"
+            android:textColor="?attr/colorOnSurfaceVariant"
+            android:layout_marginBottom="8dp" />
+
+        <TextView
+            android:id="@+id/tvOtpCode"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:textAppearance="?attr/textAppearanceDisplaySmall"
+            android:textColor="?attr/colorPrimary"
+            android:fontFamily="monospace"
+            android:letterSpacing="0.15"
+            android:layout_marginBottom="16dp" />
+
+        <com.google.android.material.progressindicator.LinearProgressIndicator
+            android:id="@+id/otpProgress"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:max="30"
+            app:trackCornerRadius="4dp"
+            app:indicatorColor="?attr/colorPrimary"
+            app:trackColor="?attr/colorSurfaceVariant" />
+
+        <TextView
+            android:id="@+id/tvOtpCountdown"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="6dp"
+            android:textAppearance="?attr/textAppearanceLabelSmall"
+            android:textColor="?attr/colorOnSurfaceVariant" />
+
+    </LinearLayout>
+
+</com.google.android.material.card.MaterialCardView>

app/src/main/res/menu/drawer_menu.xml

@@ -32,6 +32,9 @@
         <item android:id="@+id/nav_add_account"
             android:icon="@drawable/ic_nav_add_account"
             android:title="@string/nav_add_account" />
+        <item android:id="@+id/nav_otp"
+            android:icon="@drawable/ic_nav_generic"
+            android:title="@string/nav_otp" />
         <item android:id="@+id/nav_settings"
             android:icon="@drawable/ic_nav_settings"
             android:title="@string/nav_settings" />

app/src/main/res/values/strings.xml

@@ -69,6 +69,7 @@
     <string name="nav_transfer_history">Transfer History</string>
     <string name="nav_finances">Finances</string>
     <string name="nav_card_settings">Card Settings</string>
+    <string name="nav_otp">OTP Codes</string>
     <string name="nav_settings">Settings</string>
     <string name="nav_open_drawer">Open navigation</string>
     <string name="nav_close_drawer">Close navigation</string>