Issue #9838: Introduce CreditCardValidationDelegate and implement onC…

…reditCardSave in GeckoCreditCardsAddressesStorageDelegate

- Introduces `CreditCardValidationDelegate` and a default implementation in `DefaultCreditCardValidationDelegate`
- Implements `onCreditCardSave` in `GeckoCreditCardsAddressesStorageDelegate`

components/concept/storage/src/main/java/mozilla/components/concept/storage/CreditCardsAddressesStorage.kt

@@ -6,7 +6,6 @@ package mozilla.components.concept.storage
 
 import android.annotation.SuppressLint
 import android.os.Parcelable
-import kotlinx.coroutines.Deferred
 import kotlinx.parcelize.Parcelize
 
 /**
@@ -49,6 +48,7 @@ interface CreditCardsAddressesStorage {
     /**
      * Deletes the credit card with the given [guid].
      *
+     * @param guid Unique identifier for the desired credit card.
      * @return True if the deletion did anything, false otherwise.
      */
     suspend fun deleteCreditCard(guid: String): Boolean
@@ -191,10 +191,10 @@ data class CreditCard(
     val expiryMonth: Long,
     val expiryYear: Long,
     val cardType: String,
-    val timeCreated: Long,
-    val timeLastUsed: Long?,
-    val timeLastModified: Long,
-    val timesUsed: Long
+    val timeCreated: Long = 0L,
+    val timeLastUsed: Long? = 0L,
+    val timeLastModified: Long = 0L,
+    val timesUsed: Long = 0L
 ) : Parcelable {
     val obfuscatedCardNumber: String
         get() = ellipsesStart +
@@ -327,6 +327,44 @@ data class UpdatableAddressFields(
     val email: String
 )
 
+/**
+ * Provides a method for checking whether or not a given credit card can be stored.
+ */
+interface CreditCardValidationDelegate {
+
+    /**
+     * The result from validating a given [CreditCard] against the credit card storage. This will
+     * include whether or not it can be created, updated, or neither, along with an explanation
+     * of any errors.
+     */
+    sealed class Result {
+        /**
+         * Indicates that the [CreditCard] does not currently exist in the storage, and a new
+         * credit card entry can be created.
+         */
+        object CanBeCreated : Result()
+
+        /**
+         * Indicates that a matching [CreditCard] was found in the storage, and the [CreditCard]
+         * can be used to update its information.
+         */
+        data class CanBeUpdated(val foundCreditCard: CreditCard) : Result()
+
+        /**
+         * The [CreditCard] cannot be saved or updated.
+         */
+        object Error : Result()
+    }
+
+    /**
+     * Determines whether a [CreditCard] can be added or updated in the credit card storage.
+     *
+     * @param creditCard [CreditCard] to be added or updated in the credit card storage.
+     * @return [Result] that indicates whether or not the [CreditCard] should be saved or updated.
+     */
+    suspend fun validate(creditCard: CreditCard): Result
+}
+
 /**
  * Used to handle [Address] and [CreditCard] storage so that the underlying engine doesn't have to.
  * An instance of this should be attached to the Gecko runtime in order to be used.
@@ -345,22 +383,30 @@ interface CreditCardsAddressesStorageDelegate {
     /**
      * Returns all stored addresses. This is called when the engine believes an address field
      * should be autofilled.
+     *
+     * @return A list of all stored addresses.
      */
-    fun onAddressesFetch(): Deferred<List<Address>>
+    suspend fun onAddressesFetch(): List<Address>
 
     /**
      * Saves the given address to storage.
+     *
+     * @param address [Address] to be saved or updated in the address storage.
      */
     fun onAddressSave(address: Address)
 
     /**
      * Returns all stored credit cards. This is called when the engine believes a credit card
      * field should be autofilled.
+     *
+     * @return A list of all stored credit cards.
      */
-    fun onCreditCardsFetch(): Deferred<List<CreditCard>>
+    suspend fun onCreditCardsFetch(): List<CreditCard>
 
     /**
      * Saves the given credit card to storage.
+     *
+     * @param creditCard [CreditCard] to be saved or updated in the credit card storage.
      */
     fun onCreditCardSave(creditCard: CreditCard)
 }

components/service/sync-autofill/src/main/java/mozilla/components/service/sync/autofill/DefaultCreditCardValidationDelegate.kt

@@ -0,0 +1,68 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package mozilla.components.service.sync.autofill
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import mozilla.components.concept.storage.CreditCard
+import mozilla.components.concept.storage.CreditCardNumber
+import mozilla.components.concept.storage.CreditCardValidationDelegate
+import mozilla.components.concept.storage.CreditCardValidationDelegate.Result
+import mozilla.components.concept.storage.CreditCardsAddressesStorage
+
+/**
+ * A delegate that will check against the [CreditCardsAddressesStorage] to determine if a given
+ * [CreditCard] can be persisted and returns information about why it can or cannot.
+ *
+ * @param storage An instance of [CreditCardsAddressesStorage].
+ */
+class DefaultCreditCardValidationDelegate(
+    private val storage: Lazy<CreditCardsAddressesStorage>
+) : CreditCardValidationDelegate {
+
+    private val coroutineContext by lazy { Dispatchers.IO }
+
+    override suspend fun validate(creditCard: CreditCard): Result =
+        withContext(coroutineContext) {
+            val creditCards = storage.value.getAllCreditCards()
+
+            val foundCreditCard = if (creditCards.isEmpty()) {
+                // No credit cards exist in the storage, create a new credit card to the storage.
+                null
+            } else {
+                // Found a matching guid and credit card number -> update
+                creditCards.find {
+                    it.guid == creditCard.guid &&
+                        decrypt(it.encryptedCardNumber) == decrypt(creditCard.encryptedCardNumber)
+                }
+                    // Found a matching guid -> update
+                    ?: creditCards.find { it.guid == creditCard.guid }
+                    // Found a matching credit card number -> update
+                    ?: creditCards.find { decrypt(it.encryptedCardNumber) == decrypt(creditCard.encryptedCardNumber) }
+                    // Found a non-matching guid and blank credit card number -> update
+                    ?: creditCards.find { decrypt(it.encryptedCardNumber)!!.number.isEmpty() }
+                // Else create a new credit card
+            }
+
+            if (foundCreditCard == null) {
+                Result.CanBeCreated
+            } else {
+                Result.CanBeUpdated(foundCreditCard)
+            }
+        }
+
+    /**
+     * Helper function to decrypt a [CreditCardNumber.Encrypted] into its plaintext equivalent or
+     * `null` if it fails to decrypt.
+     *
+     * @param encryptedCardNumber An encrypted credit card number to be decrypted.
+     * @return A plaintext, non-encrypted credit card number.
+     */
+    private fun decrypt(encryptedCardNumber: CreditCardNumber.Encrypted): CreditCardNumber.Plaintext? {
+        val crypto = storage.value.getCreditCardCrypto()
+        val key = crypto.key()
+        return crypto.decrypt(key, encryptedCardNumber)
+    }
+}

components/service/sync-autofill/src/main/java/mozilla/components/service/sync/autofill/GeckoCreditCardsAddressesStorageDelegate.kt

@@ -4,14 +4,14 @@
 
 package mozilla.components.service.sync.autofill
 
-import kotlinx.coroutines.CompletableDeferred
 import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Deferred
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.async
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
 import mozilla.components.concept.storage.Address
 import mozilla.components.concept.storage.CreditCard
 import mozilla.components.concept.storage.CreditCardNumber
+import mozilla.components.concept.storage.CreditCardValidationDelegate
 import mozilla.components.concept.storage.CreditCardsAddressesStorage
 import mozilla.components.concept.storage.CreditCardsAddressesStorageDelegate
 
@@ -34,27 +34,43 @@ class GeckoCreditCardsAddressesStorageDelegate(
         return crypto.decrypt(key, encryptedCardNumber)
     }
 
-    override fun onAddressesFetch(): Deferred<List<Address>> {
-        return scope.async {
-            storage.value.getAllAddresses()
-        }
+    override suspend fun onAddressesFetch(): List<Address> = withContext(scope.coroutineContext) {
+        storage.value.getAllAddresses()
     }
 
     override fun onAddressSave(address: Address) {
         TODO("Not yet implemented")
     }
 
-    override fun onCreditCardsFetch(): Deferred<List<CreditCard>> {
-        if (isCreditCardAutofillEnabled().not()) {
-            return CompletableDeferred(listOf())
-        }
-
-        return scope.async {
+    override suspend fun onCreditCardsFetch(): List<CreditCard> =
+        withContext(scope.coroutineContext) {
             storage.value.getAllCreditCards()
         }
-    }
 
     override fun onCreditCardSave(creditCard: CreditCard) {
-        TODO("Not yet implemented")
+        val validationDelegate = DefaultCreditCardValidationDelegate(storage)
+
+        scope.launch {
+            when (val result = validationDelegate.validate(creditCard)) {
+                is CreditCardValidationDelegate.Result.CanBeCreated -> {
+                    decrypt(creditCard.encryptedCardNumber)?.let { plaintextCardNumber ->
+                        storage.value.addCreditCard(
+                            creditCard.intoNewCreditCardFields(
+                                plaintextCardNumber
+                            )
+                        )
+                    }
+                }
+                is CreditCardValidationDelegate.Result.CanBeUpdated -> {
+                    storage.value.updateCreditCard(
+                        guid = result.foundCreditCard.guid,
+                        creditCardFields = creditCard.intoUpdatableCreditCardFields()
+                    )
+                }
+                is CreditCardValidationDelegate.Result.Error -> {
+                    // Do nothing since an error occurred and the credit card cannot be saved.
+                }
+            }
+        }
     }
 }

components/service/sync-autofill/src/main/java/mozilla/components/service/sync/autofill/Types.kt

@@ -7,6 +7,7 @@ package mozilla.components.service.sync.autofill
 import mozilla.components.concept.storage.Address
 import mozilla.components.concept.storage.CreditCard
 import mozilla.components.concept.storage.CreditCardNumber
+import mozilla.components.concept.storage.NewCreditCardFields
 import mozilla.components.concept.storage.UpdatableAddressFields
 import mozilla.components.concept.storage.UpdatableCreditCardFields
 
@@ -94,3 +95,33 @@ internal fun mozilla.appservices.autofill.CreditCard.into(): CreditCard {
         timesUsed = this.timesUsed
     )
 }
+
+/**
+ * Conversion from [CreditCard] to [NewCreditCardFields].
+ *
+ * @param plaintextCardNumber A plaintext credit card number.
+ */
+internal fun CreditCard.intoNewCreditCardFields(plaintextCardNumber: CreditCardNumber.Plaintext): NewCreditCardFields {
+    return NewCreditCardFields(
+        billingName = this.billingName,
+        plaintextCardNumber = plaintextCardNumber,
+        cardNumberLast4 = this.cardNumberLast4,
+        expiryMonth = this.expiryMonth,
+        expiryYear = this.expiryYear,
+        cardType = this.cardType
+    )
+}
+
+/**
+ * Conversion from [CreditCard] to [UpdatableCreditCardFields].
+ */
+internal fun CreditCard.intoUpdatableCreditCardFields(): UpdatableCreditCardFields {
+    return UpdatableCreditCardFields(
+        billingName = this.billingName,
+        cardNumber = this.encryptedCardNumber,
+        cardNumberLast4 = this.cardNumberLast4,
+        expiryMonth = this.expiryMonth,
+        expiryYear = this.expiryYear,
+        cardType = this.cardType
+    )
+}