refactor: ATR should not be the concern of lpac-jni

...instead, use a separate interface to represent channel types that do
support reading ATR.

app-common/src/main/java/im/angry/openeuicc/core/ApduInterfaceAtrProvider.kt

@@ -0,0 +1,5 @@
+package im.angry.openeuicc.core
+
+interface ApduInterfaceAtrProvider {
+    val atr: ByteArray?
+}

app-common/src/main/java/im/angry/openeuicc/core/EuiccChannel.kt

@@ -16,6 +16,11 @@ interface EuiccChannel {
 
     val valid: Boolean
 
+    /**
+     * Answer to Reset (ATR) value of the underlying interface, if any
+     */
+    val atr: ByteArray?
+
     /**
      * Intrinsic name of this channel. For device-internal SIM slots,
      * this should be null; for USB readers, this should be the name of

app-common/src/main/java/im/angry/openeuicc/core/EuiccChannelImpl.kt

@@ -11,7 +11,7 @@ class EuiccChannelImpl(
     override val type: String,
     override val port: UiccPortInfoCompat,
     override val intrinsicChannelName: String?,
-    apduInterface: ApduInterface,
+    private val apduInterface: ApduInterface,
     verboseLoggingFlow: Flow<Boolean>,
     ignoreTLSCertificateFlow: Flow<Boolean>
 ) : EuiccChannel {
@@ -22,6 +22,9 @@ class EuiccChannelImpl(
     override val lpa: LocalProfileAssistant =
         LocalProfileAssistantImpl(apduInterface, HttpInterfaceImpl(verboseLoggingFlow, ignoreTLSCertificateFlow))
 
+    override val atr: ByteArray?
+        get() = (apduInterface as? ApduInterfaceAtrProvider)?.atr
+
     override val valid: Boolean
         get() = lpa.valid
 

app-common/src/main/java/im/angry/openeuicc/core/EuiccChannelWrapper.kt

@@ -33,6 +33,8 @@ class EuiccChannelWrapper(orig: EuiccChannel) : EuiccChannel {
         get() = channel.valid
     override val intrinsicChannelName: String?
         get() = channel.intrinsicChannelName
+    override val atr: ByteArray?
+        get() = channel.atr
 
     override fun close() = channel.close()
 

app-common/src/main/java/im/angry/openeuicc/core/OmapiApduInterface.kt

@@ -15,7 +15,7 @@ class OmapiApduInterface(
     private val service: SEService,
     private val port: UiccPortInfoCompat,
     private val verboseLoggingFlow: Flow<Boolean>
-): ApduInterface {
+): ApduInterface, ApduInterfaceAtrProvider {
     companion object {
         const val TAG = "OmapiApduInterface"
     }
@@ -26,6 +26,9 @@ class OmapiApduInterface(
     override val valid: Boolean
         get() = service.isConnected && (this::session.isInitialized && !session.isClosed)
 
+    override val atr: ByteArray?
+        get() = session.atr
+
     override fun connect() {
         session = service.getUiccReaderCompat(port.logicalSlotIndex + 1).openSession()
     }

app-common/src/main/java/im/angry/openeuicc/core/usb/UsbApduInterface.kt

@@ -3,6 +3,7 @@ package im.angry.openeuicc.core.usb
 import android.hardware.usb.UsbDeviceConnection
 import android.hardware.usb.UsbEndpoint
 import android.util.Log
+import im.angry.openeuicc.core.ApduInterfaceAtrProvider
 import im.angry.openeuicc.util.*
 import kotlinx.coroutines.flow.Flow
 import net.typeblog.lpac_jni.ApduInterface
@@ -12,7 +13,7 @@ class UsbApduInterface(
     private val bulkIn: UsbEndpoint,
     private val bulkOut: UsbEndpoint,
     private val verboseLoggingFlow: Flow<Boolean>
-): ApduInterface {
+) : ApduInterface, ApduInterfaceAtrProvider {
     companion object {
         private const val TAG = "UsbApduInterface"
     }
@@ -22,6 +23,8 @@ class UsbApduInterface(
 
     private var channelId = -1
 
+    override var atr: ByteArray? = null
+
     override fun connect() {
         ccidDescription = UsbCcidDescription.fromRawDescriptors(conn.rawDescriptors)!!
 
@@ -32,7 +35,9 @@ class UsbApduInterface(
         transceiver = UsbCcidTransceiver(conn, bulkIn, bulkOut, ccidDescription, verboseLoggingFlow)
 
         try {
-            transceiver.iccPowerOn()
+            // 6.1.1.1 PC_to_RDR_IccPowerOn (Page 20 of 40)
+            // https://www.usb.org/sites/default/files/DWG_Smart-Card_USB-ICC_ICCD_rev10.pdf
+            atr = transceiver.iccPowerOn().data
         } catch (e: Exception) {
             e.printStackTrace()
             throw e

app-common/src/main/java/im/angry/openeuicc/ui/EuiccInfoActivity.kt

@@ -41,7 +41,7 @@ class EuiccInfoActivity : BaseEuiccAccessActivity(), OpenEuiccContextMarker {
         @StringRes
         val titleResId: Int,
         val content: String?,
-        val copiedToastResId: Int? = null
+        val copiedToastResId: Int? = null,
     )
 
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -134,6 +134,13 @@ class EuiccInfoActivity : BaseEuiccAccessActivity(), OpenEuiccContextMarker {
             }
             add(Item(R.string.euicc_info_ci_type, getString(resId)))
         }
+        add(
+            Item(
+                R.string.euicc_info_atr,
+                channel.atr?.encodeHex() ?: getString(R.string.euicc_info_atr_unavailable),
+                copiedToastResId = R.string.toast_atr_copied,
+            )
+        )
     }
 
     private fun formatByBoolean(b: Boolean, res: Pair<Int, Int>): String =

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

@@ -31,6 +31,7 @@
     <string name="toast_profile_delete_confirm_text_mismatched">Confirmation string mismatch</string>
     <string name="toast_iccid_copied">ICCID copied to clipboard</string>
     <string name="toast_eid_copied">EID copied to clipboard</string>
+    <string name="toast_atr_copied">ATR copied to clipboard</string>
 
     <string name="usb_permission">Grant USB permission</string>
     <string name="usb_permission_needed">Permission is needed to access the USB smart card reader.</string>
@@ -132,6 +133,8 @@
     <string name="euicc_info_ci_gsma_live">GSMA Live CI</string>
     <string name="euicc_info_ci_gsma_test">GSMA Test CI</string>
     <string name="euicc_info_ci_unknown">Unknown eSIM CI</string>
+    <string name="euicc_info_atr">ATR (Answer To Reset)</string>
+    <string name="euicc_info_atr_unavailable">ATR unavailable</string>
 
     <string name="yes">Yes</string>
     <string name="no">No</string>