feat(onramp): cache buyable token mints from Coinbase BuyOptions API

apps/flipcash/features/contact-verification/build.gradle.kts

@@ -15,6 +15,7 @@ dependencies {
 
     implementation(project(":apps:flipcash:shared:analytics"))
     implementation(project(":apps:flipcash:shared:featureflags"))
+    implementation(project(":apps:flipcash:shared:onramp:coinbase"))
     implementation(project(":apps:flipcash:shared:phone"))
     implementation(project(":libs:messaging"))
 }

apps/flipcash/features/contact-verification/src/main/kotlin/com/flipcash/app/contact/verification/internal/phone/PhoneVerificationViewModel.kt

@@ -6,6 +6,7 @@ import androidx.lifecycle.viewModelScope
 import com.flipcash.app.core.extensions.onResult
 import com.flipcash.app.featureflags.FeatureFlag
 import com.flipcash.app.featureflags.FeatureFlagController
+import com.flipcash.app.onramp.BuyOptionsCache
 import com.flipcash.app.phone.CountryLocale
 import com.flipcash.app.phone.PhoneUtils
 import com.flipcash.features.contact.verification.R
@@ -46,6 +47,7 @@ internal class PhoneVerificationViewModel @Inject constructor(
     private val featureFlags: FeatureFlagController,
     private val resources: ResourceHelper,
     private val dispatchers: DispatcherProvider,
+    private val buyOptionsCache: BuyOptionsCache,
 ) : BaseViewModel<PhoneVerificationViewModel.State, PhoneVerificationViewModel.Event>(
     initialState = State(selectedLocale = phoneUtils.defaultCountryLocale),
     updateStateForEvent = updateStateForEvent,
@@ -182,6 +184,9 @@ internal class PhoneVerificationViewModel @Inject constructor(
                     viewModelScope.launch {
                         profileController.updateUserProfile()
                     }
+                    viewModelScope.launch {
+                        buyOptionsCache.prefetchForCurrentUser()
+                    }
 
                     viewModelScope.launch {
                         delay(1.seconds)

apps/flipcash/features/contact-verification/src/test/kotlin/com/flipcash/app/contact/verification/internal/phone/PhoneVerificationViewModelErrorTest.kt

@@ -1,6 +1,7 @@
 package com.flipcash.app.contact.verification.internal.phone
 
 import com.flipcash.app.featureflags.FeatureFlagController
+import com.flipcash.app.onramp.BuyOptionsCache
 import com.flipcash.app.phone.PhoneUtils
 import com.flipcash.features.contact.verification.R
 import com.flipcash.services.controllers.ContactVerificationController
@@ -39,6 +40,7 @@ class PhoneVerificationViewModelErrorTest {
     private val userManager = mockk<UserManager>(relaxed = true)
     private val featureFlags = mockk<FeatureFlagController>(relaxed = true)
     private val resources = mockk<ResourceHelper>(relaxed = true)
+    private val buyOptionsCache = mockk<BuyOptionsCache>(relaxed = true)
 
     private lateinit var dispatchers: TestDispatchers
 
@@ -70,6 +72,7 @@ class PhoneVerificationViewModelErrorTest {
             featureFlags = featureFlags,
             resources = resources,
             dispatchers = dispatchers,
+            buyOptionsCache = buyOptionsCache,
         )
     }
 

apps/flipcash/shared/onramp/coinbase/src/main/kotlin/com/flipcash/app/onramp/BuyOptionsCache.kt

@@ -0,0 +1,80 @@
+package com.flipcash.app.onramp
+
+import com.coinbase.onramp.api.CoinbaseApi
+import com.flipcash.services.user.UserManager
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+import kotlinx.serialization.json.JsonObject
+import kotlinx.serialization.json.jsonArray
+import kotlinx.serialization.json.jsonObject
+import kotlinx.serialization.json.jsonPrimitive
+import javax.inject.Inject
+import javax.inject.Singleton
+
+@Singleton
+class BuyOptionsCache @Inject constructor(
+    private val api: CoinbaseApi,
+    private val jwtExecutor: CoinbaseJwtExecutor,
+    private val userManager: UserManager,
+) {
+    private val cache = mutableMapOf<String, Set<BuyOptionsMint>>()
+    private val mutex = Mutex()
+
+    fun getCached(region: PhoneRegion): Set<BuyOptionsMint>? = cache[region.cacheKey]
+
+    suspend fun prefetchForCurrentUser(): Set<BuyOptionsMint>? {
+        val phone = userManager.profile?.verifiedPhoneNumber ?: return null
+        val region = regionFromPhone(phone) ?: return null
+        return prefetch(region)
+    }
+
+    fun isUsdfAvailable(region: PhoneRegion): Boolean {
+        val mints = cache[region.cacheKey] ?: return true // default to true on cache miss
+        return BuyOptionsMint.USDF in mints
+    }
+
+    suspend fun prefetch(region: PhoneRegion): Set<BuyOptionsMint>? {
+        cache[region.cacheKey]?.let { return it }
+
+        return mutex.withLock {
+            // double-check after acquiring lock
+            cache[region.cacheKey]?.let { return it }
+
+            requestAndCache(region)
+        }
+    }
+
+    private suspend fun requestAndCache(region: PhoneRegion): Set<BuyOptionsMint>? {
+        val host = "api.developer.coinbase.com/"
+        val path = "onramp/v1/buy/options"
+        val response = jwtExecutor.execute(
+            scheme = "https",
+            host = host,
+            path = path,
+            method = "GET",
+        ) { jwt ->
+            runCatching {
+                api.getBuyOptions(
+                    url = "https://$host$path",
+                    jwt = "Bearer $jwt",
+                    country = region.country,
+                    subdivision = region.subdivision,
+                )
+            }
+        }.getOrNull() ?: return null
+
+        val mints = parseMints(response)
+        cache[region.cacheKey] = mints
+        return mints
+    }
+
+    private fun parseMints(response: JsonObject): Set<BuyOptionsMint> {
+        return response["purchase_currencies"]
+            ?.jsonArray
+            ?.mapNotNull { element ->
+                element.jsonObject["symbol"]?.jsonPrimitive?.content?.let { BuyOptionsMint(it) }
+            }
+            ?.toSet()
+            ?: emptySet()
+    }
+}

apps/flipcash/shared/onramp/coinbase/src/main/kotlin/com/flipcash/app/onramp/BuyOptionsMint.kt

@@ -0,0 +1,8 @@
+package com.flipcash.app.onramp
+
+@JvmInline
+value class BuyOptionsMint(val symbol: String) {
+    companion object {
+        val USDF = BuyOptionsMint("USDF")
+    }
+}

apps/flipcash/shared/onramp/coinbase/src/main/kotlin/com/flipcash/app/onramp/CoinbaseJwtExecutor.kt

@@ -0,0 +1,57 @@
+package com.flipcash.app.onramp
+
+import com.flipcash.services.models.GetJwtError
+import com.flipcash.shared.onramp.coinbase.BuildConfig
+import com.getcode.network.jwt.ApiProvider
+import com.getcode.network.jwt.Jwt
+import com.getcode.network.jwt.JwtSecuredEndpoint
+import com.getcode.utils.trace
+import javax.inject.Inject
+import javax.inject.Singleton
+
+@Singleton
+class CoinbaseJwtExecutor @Inject constructor(
+    private val jwtProvider: OnRampJwtProvider,
+) {
+    suspend fun <T> execute(
+        scheme: String,
+        host: String,
+        path: String,
+        method: String,
+        call: suspend (Jwt) -> Result<T>,
+    ): Result<T> {
+        val apiKey = BuildConfig.COINBASE_ONRAMP_API_KEY
+        return jwtProvider.provideJwtForEndpoint(
+            apiKey = apiKey,
+            endpoint = JwtSecuredEndpoint(
+                provider = ApiProvider.Coinbase,
+                scheme = scheme,
+                host = host,
+                path = path,
+                method = method,
+            ),
+        ).fold(
+            onSuccess = { call(it) },
+            onFailure = { error ->
+                trace(
+                    message = "JWT request failed",
+                    tag = "OnRamp",
+                    metadata = {
+                        "endpoint" to "$method $host$path"
+                        "errorType" to error::class.simpleName.orEmpty()
+                    },
+                    error = error,
+                )
+                when (error) {
+                    is GetJwtError.EmailVerificationRequired -> Result.failure(
+                        OnRampAuthError.VerificationRequired(email = true)
+                    )
+                    is GetJwtError.PhoneVerificationRequired -> Result.failure(
+                        OnRampAuthError.VerificationRequired(phone = true)
+                    )
+                    else -> Result.failure(error)
+                }
+            }
+        )
+    }
+}