[BiometricsV2] Refactor model code to kotlin

Bug: 286196884
Test: atest FingerprintEnrollmentActivityTest CredentialModelTest
      EnrollmentRequestTest FingerprintEnrollIntroViewModelTest
      FingerprintEnrollmentViewModelTest
Test: atest biometrics-enrollment-test
Change-Id: I2bdae4d2dd052d3664a790cd982edf51fcebec09

src/com/android/settings/biometrics2/ui/model/CredentialModel.kt

@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.settings.biometrics2.ui.model
+
+import android.content.Intent.EXTRA_USER_ID
+import android.os.Bundle
+import android.os.UserHandle
+import androidx.annotation.VisibleForTesting
+import com.android.settings.biometrics.BiometricEnrollBase.EXTRA_KEY_CHALLENGE
+import com.android.settings.password.ChooseLockSettingsHelper.EXTRA_KEY_CHALLENGE_TOKEN
+import com.android.settings.password.ChooseLockSettingsHelper.EXTRA_KEY_GK_PW_HANDLE
+import java.time.Clock
+
+/**
+ * Secret credential data including
+ * 1. userId
+ * 2. challenge
+ * 3. token
+ * 4. gkPwHandle
+ */
+class CredentialModel(bundle: Bundle?, private val clock: Clock) {
+
+    private val mInitMillis = clock.millis()
+
+    /** userId for this credential */
+    val userId: Int = (bundle ?: Bundle()).getInt(EXTRA_USER_ID, UserHandle.myUserId())
+
+    private var clearGkPwHandleMillis: Long? = null
+
+    /** Gatekeeper password handle */
+    var gkPwHandle: Long = (bundle ?: Bundle()).getLong(EXTRA_KEY_GK_PW_HANDLE, INVALID_GK_PW_HANDLE)
+        private set
+
+    val isValidGkPwHandle: Boolean
+        get() = gkPwHandle != INVALID_GK_PW_HANDLE
+
+    /** Clear gatekeeper password handle data */
+    fun clearGkPwHandle() {
+        clearGkPwHandleMillis = clock.millis()
+        gkPwHandle = INVALID_GK_PW_HANDLE
+    }
+
+    /** Check user id is valid or not */
+    val isValidUserId: Boolean
+        get() = userId != UserHandle.USER_NULL
+
+    private var updateChallengeMillis: Long? = null
+
+    var challenge: Long = (bundle ?: Bundle()).getLong(EXTRA_KEY_CHALLENGE, INVALID_CHALLENGE)
+        set(value) {
+            updateChallengeMillis = clock.millis()
+            field = value
+        }
+
+    val isValidChallenge: Boolean
+        get() = challenge != INVALID_CHALLENGE
+
+    private var updateTokenMillis: Long? = null
+
+    /** Challenge token */
+    var token: ByteArray? = (bundle ?: Bundle()).getByteArray(EXTRA_KEY_CHALLENGE_TOKEN)
+        set(value) {
+            updateTokenMillis = clock.millis()
+            field = value
+        }
+
+    val isValidToken: Boolean
+        get() = token != null
+
+    val bundle: Bundle
+        /**
+         * Get a bundle which can be used to recreate CredentialModel
+         */
+        get() {
+            val bundle = Bundle()
+            bundle.putInt(EXTRA_USER_ID, userId)
+            bundle.putLong(EXTRA_KEY_CHALLENGE, challenge)
+            bundle.putByteArray(EXTRA_KEY_CHALLENGE_TOKEN, token)
+            bundle.putLong(EXTRA_KEY_GK_PW_HANDLE, gkPwHandle)
+            return bundle
+        }
+
+
+    /** Returns a string representation of the object */
+    override fun toString(): String {
+        val gkPwHandleLen = "$gkPwHandle".length
+        val tokenLen = token?.size ?: 0
+        val challengeLen = "$challenge".length
+        return (javaClass.simpleName + ":{initMillis:$mInitMillis"
+                + ", userId:$userId"
+                + ", challenge:{len:$challengeLen"
+                + ", updateMillis:$updateChallengeMillis}"
+                + ", token:{len:$tokenLen, isValid:$isValidToken"
+                + ", updateMillis:$updateTokenMillis}"
+                + ", gkPwHandle:{len:$gkPwHandleLen, isValid:$isValidGkPwHandle"
+                + ", clearMillis:$clearGkPwHandleMillis}"
+                + " }")
+    }
+
+    companion object {
+        /** Default value for an invalid challenge */
+        @VisibleForTesting
+        const val INVALID_CHALLENGE = -1L
+
+        /** Default value if GkPwHandle is invalid */
+        @VisibleForTesting
+        const val INVALID_GK_PW_HANDLE = 0L
+    }
+}