feat: migrate FiatRateCache to DataStore

This commit is contained in:
2026-06-02 00:56:02 +02:00
parent 93332dc683
commit 712722120c
7 changed files with 162 additions and 51 deletions
@@ -0,0 +1,116 @@
package com.bitcointxoko.gudariwallet.data
import android.content.Context
import android.util.Log
import androidx.datastore.core.DataStore
import androidx.datastore.preferences.core.Preferences
import androidx.datastore.preferences.core.edit
import androidx.datastore.preferences.core.emptyPreferences
import androidx.datastore.preferences.core.floatPreferencesKey
import androidx.datastore.preferences.core.longPreferencesKey
import androidx.datastore.preferences.core.stringPreferencesKey
import androidx.datastore.preferences.preferencesDataStore
import com.google.gson.Gson
import com.google.gson.reflect.TypeToken
import kotlinx.coroutines.flow.catch
import kotlinx.coroutines.flow.first
import java.io.IOException
private const val TAG = "FiatDataStore"
private const val DATASTORE_NAME = "fiat_prefs"
// Top-level extension — one instance per process
private val Context.fiatDataStore: DataStore<Preferences> by preferencesDataStore(
name = DATASTORE_NAME
)
class FiatDataStore(context: Context) {
private val dataStore = context.applicationContext.fiatDataStore
private val gson = Gson()
// ── Key factories ─────────────────────────────────────────────────────────
private fun rateKey(currency: String) = floatPreferencesKey("fiat_rate_$currency")
private fun rateFetchedAtKey(currency: String) = longPreferencesKey("fiat_rate_fetched_at_$currency")
private val currenciesKey = stringPreferencesKey("fiat_currencies_json")
// ── Rate ──────────────────────────────────────────────────────────────────
/**
* Returns the last persisted rate for [currency], or null if none exists.
* Used as a cold-start fallback while a fresh network fetch is in flight.
*/
suspend fun getPersistedRate(currency: String): Double? {
val prefs = dataStore.data
.catch { e ->
if (e is IOException) {
Log.w(TAG, "FIAT [RATE STALE ] read error — ${e.message}")
emit(emptyPreferences())
} else throw e
}
.first()
val value = prefs[rateKey(currency)]?.toDouble()
if (value != null && value > 0.0) {
Log.d(TAG, "FIAT [RATE STALE ] $currency — using persisted rate $value")
}
return value?.takeIf { it > 0.0 }
}
/**
* Persists a freshly fetched [rate] for [currency].
* Always called alongside the in-memory update in [FiatRateCache.putRate].
*/
suspend fun persistRate(currency: String, rate: Double) {
runCatching {
dataStore.edit { prefs ->
prefs[rateKey(currency)] = rate.toFloat()
prefs[rateFetchedAtKey(currency)] = System.currentTimeMillis()
}
}.onFailure { e ->
Log.w(TAG, "FIAT [RATE FRESH ] persist failed for $currency${e.message}")
}
Log.d(TAG, "FIAT [RATE FRESH ] $currency = $rate — persisted to DataStore")
}
// ── Currency list ─────────────────────────────────────────────────────────
/**
* Returns the persisted currency list, or null if none has been stored yet.
*/
suspend fun getPersistedCurrencies(): List<String>? {
val prefs = dataStore.data
.catch { e ->
if (e is IOException) {
Log.w(TAG, "FIAT [CURRENCIES] read error — ${e.message}")
emit(emptyPreferences())
} else throw e
}
.first()
val json = prefs[currenciesKey] ?: return null
return runCatching {
val type = object : TypeToken<List<String>>() {}.type
val list: List<String> = gson.fromJson(json, type)
Log.d(TAG, "FIAT [CURRENCIES] DataStore hit (${list.size} currencies)")
list
}.getOrElse { e ->
Log.w(TAG, "FIAT [CURRENCIES] parse failed — ${e.message}")
null
}
}
/**
* Persists [currencies] to DataStore.
*/
suspend fun persistCurrencies(currencies: List<String>) {
if (currencies.isEmpty()) return
runCatching {
dataStore.edit { prefs ->
prefs[currenciesKey] = gson.toJson(currencies)
}
}.onFailure { e ->
Log.w(TAG, "FIAT [CURRENCIES] persist failed — ${e.message}")
}
Log.d(TAG, "FIAT [CURRENCIES] persisted ${currencies.size} currencies to DataStore")
}
}
@@ -1,24 +1,19 @@
package com.bitcointxoko.gudariwallet.data
import android.content.SharedPreferences
import android.util.Log
import androidx.core.content.edit
import com.google.gson.Gson
import com.google.gson.reflect.TypeToken
private const val TAG = "FiatRateCache"
/**
* Two-tier (in-memory + SharedPreferences) cache for fiat exchange rates
* Two-tier (in-memory + DataStore) cache for fiat exchange rates
* and the supported-currency list.
*
* Receives the already-open [prefs] instance from [BalancePrefsStore] so that
* all wallet prefs stay in a single file.
* Disk persistence is delegated to [FiatDataStore]; this class owns
* only the in-memory (L1) layer and the cache-coordination logic.
*/
class FiatRateCache(store: BalancePrefsStore) {
private val prefs = store.prefs
class FiatRateCache(private val fiatDataStore: FiatDataStore) {
// ── Rate ─────────────────────────────────────────────────────────────────
// ── Rate ─────────────────────────────────────────────────────────────────
private var cachedRate : Double? = null
private var rateLastFetchedAt : Long = 0L
@@ -26,9 +21,10 @@ class FiatRateCache(store: BalancePrefsStore) {
/**
* Returns a fresh in-memory rate for [currency] if it is younger than
* [ttlMs], then falls back to the last persisted float, then returns null.
* [ttlMs], then falls back to the last persisted value via DataStore,
* then returns null.
*/
fun getRate(currency: String, ttlMs: Long): Double? {
suspend fun getRate(currency: String, ttlMs: Long): Double? {
val now = System.currentTimeMillis()
val age = now - rateLastFetchedAt
@@ -37,9 +33,9 @@ class FiatRateCache(store: BalancePrefsStore) {
return cachedRate
}
// Cold-start fallback: last persisted rate
val persisted = prefs.getFloat("fiat_rate_$currency", 0f).toDouble()
if (persisted > 0.0) {
// Cold-start fallback: last persisted rate from DataStore
val persisted = fiatDataStore.getPersistedRate(currency)
if (persisted != null) {
Log.d(TAG, "FIAT [RATE STALE ] $currency — using persisted rate $persisted")
return persisted
}
@@ -50,15 +46,12 @@ class FiatRateCache(store: BalancePrefsStore) {
/**
* Stores a freshly fetched [rate] for [currency] in memory and on disk.
*/
fun putRate(currency: String, rate: Double) {
suspend fun putRate(currency: String, rate: Double) {
val now = System.currentTimeMillis()
cachedRate = rate
rateLastFetchedAt = now
cachedRateCurrency = currency
prefs.edit {
putFloat("fiat_rate_$currency", rate.toFloat())
putLong("fiat_rate_fetched_at_$currency", now)
}
fiatDataStore.persistRate(currency, rate)
Log.d(TAG, "FIAT [RATE FRESH ] 1 $currency = $rate sats — cached + persisted")
}
@@ -72,38 +65,32 @@ class FiatRateCache(store: BalancePrefsStore) {
// ── Currency list ─────────────────────────────────────────────────────────
private var cachedCurrencies: List<String>? = null
private val gson = Gson()
/**
* Returns the cached currency list (memory → disk → null).
* Returns the cached currency list (memory → DataStore → null).
* Callers are responsible for fetching from the network on a null result.
*/
fun getCurrencies(): List<String>? {
suspend fun getCurrencies(): List<String>? {
cachedCurrencies?.let {
Log.d(TAG, "FIAT [CURRENCIES] in-memory hit (${it.size} currencies)")
return it
}
val json = prefs.getString("fiat_currencies_json", null) ?: return null
return runCatching {
val type = object : TypeToken<List<String>>() {}.type
val list: List<String> = gson.fromJson(json, type)
Log.d(TAG, "FIAT [CURRENCIES] prefs hit (${list.size} currencies)")
list.also { cachedCurrencies = it }
}.getOrElse { e ->
Log.w(TAG, "FIAT [CURRENCIES] prefs parse failed — ${e.message}")
null
val persisted = fiatDataStore.getPersistedCurrencies()
if (persisted != null) {
cachedCurrencies = persisted
}
return persisted
}
/** Stores [currencies] in memory and on disk. */
fun putCurrencies(currencies: List<String>) {
suspend fun putCurrencies(currencies: List<String>) {
if (currencies.isEmpty()) return
cachedCurrencies = currencies
prefs.edit { putString("fiat_currencies_json", gson.toJson(currencies)) }
fiatDataStore.persistCurrencies(currencies)
Log.d(TAG, "FIAT [CURRENCIES] cached ${currencies.size} currencies")
}
val currentRate: Double?
get() = cachedRate.takeIf { cachedRateCurrency.isNotBlank() }
}
}