feat: introduced unified currency mode, with options to set custom currency and exchange rates #83,#113, #116, #132

Author: ritesh-kanwar

app/schemas/com.ritesh.cashiro.data.database.CashiroDatabase/52.json

@@ -2,7 +2,7 @@
   "formatVersion": 1,
   "database": {
     "version": 52,
-    "identityHash": "7af7c786b43a1ea50bbb1592e2df5bfb",
+    "identityHash": "8cdd5bb3c827a51203352bce87918a53",
     "entities": [
       {
         "tableName": "transactions",
@@ -313,7 +313,7 @@
       },
       {
         "tableName": "merchant_mappings",
-        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`merchant_name` TEXT NOT NULL, `category` TEXT NOT NULL, `subcategory` TEXT, `created_at` TEXT NOT NULL, `updated_at` TEXT NOT NULL, PRIMARY KEY(`merchant_name`))",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`merchant_name` TEXT NOT NULL, `category` TEXT NOT NULL, `created_at` TEXT NOT NULL, `updated_at` TEXT NOT NULL, PRIMARY KEY(`merchant_name`))",
         "fields": [
           {
             "fieldPath": "merchantName",
@@ -327,11 +327,6 @@
             "affinity": "TEXT",
             "notNull": true
           },
-          {
-            "fieldPath": "subcategory",
-            "columnName": "subcategory",
-            "affinity": "TEXT"
-          },
           {
             "fieldPath": "createdAt",
             "columnName": "created_at",
@@ -1004,7 +999,7 @@
       },
       {
         "tableName": "exchange_rates",
-        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, `from_currency` TEXT NOT NULL, `to_currency` TEXT NOT NULL, `rate` TEXT NOT NULL, `provider` TEXT NOT NULL, `updated_at` TEXT NOT NULL, `updated_at_unix` INTEGER NOT NULL DEFAULT 0, `expires_at` TEXT NOT NULL, `expires_at_unix` INTEGER NOT NULL DEFAULT 0)",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, `from_currency` TEXT NOT NULL, `to_currency` TEXT NOT NULL, `rate` TEXT NOT NULL, `provider` TEXT NOT NULL, `updated_at` TEXT NOT NULL, `updated_at_unix` INTEGER NOT NULL DEFAULT 0, `expires_at` TEXT NOT NULL, `expires_at_unix` INTEGER NOT NULL DEFAULT 0, `is_custom` INTEGER NOT NULL DEFAULT 0)",
         "fields": [
           {
             "fieldPath": "id",
@@ -1061,6 +1056,13 @@
             "affinity": "INTEGER",
             "notNull": true,
             "defaultValue": "0"
+          },
+          {
+            "fieldPath": "isCustom",
+            "columnName": "is_custom",
+            "affinity": "INTEGER",
+            "notNull": true,
+            "defaultValue": "0"
           }
         ],
         "primaryKey": {
@@ -1691,7 +1693,7 @@
     ],
     "setupQueries": [
       "CREATE TABLE IF NOT EXISTS room_master_table (id INTEGER PRIMARY KEY,identity_hash TEXT)",
-      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, '7af7c786b43a1ea50bbb1592e2df5bfb')"
+      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, '8cdd5bb3c827a51203352bce87918a53')"
     ]
   }
 }

app/src/main/java/com/ritesh/cashiro/MainActivity.kt

@@ -14,6 +14,8 @@ import androidx.appcompat.app.AppCompatActivity
 import com.ritesh.cashiro.receiver.SmsBroadcastReceiver
 import com.ritesh.cashiro.data.manager.NotificationScheduler
 import androidx.lifecycle.lifecycleScope
+import com.ritesh.cashiro.data.currency.model.CurrencySymbols
+import com.ritesh.cashiro.data.preferences.UserPreferencesRepository
 import com.ritesh.cashiro.presentation.ui.features.accounts.AccountDetailViewModel
 import com.ritesh.cashiro.presentation.ui.features.accounts.ManageAccountsViewModel
 import com.ritesh.cashiro.presentation.ui.features.add.AddViewModel
@@ -53,6 +55,9 @@ class MainActivity : AppCompatActivity() {
     @Inject
     lateinit var notificationScheduler: NotificationScheduler
 
+    @Inject
+    lateinit var userPreferencesRepository: UserPreferencesRepository
+
     // Transaction ID to edit when launched from notification
     var editTransactionId by mutableStateOf<Long?>(null)
         private set
@@ -89,6 +94,14 @@ class MainActivity : AppCompatActivity() {
             notificationScheduler.scheduleDailyReminder()
         }
 
+        // Load custom currencies into CurrencySymbols
+        lifecycleScope.launch {
+            userPreferencesRepository.customCurrencies.collect { customCurrencies ->
+                val customMap = customCurrencies.associate { it.code to it.symbol }
+                CurrencySymbols.setCustomSymbols(customMap)
+            }
+        }
+
         setContent {
             CashiroApp(
                 editTransactionId = editTransactionId,

app/src/main/java/com/ritesh/cashiro/data/backup/BackupExporter.kt

@@ -121,6 +121,7 @@ class BackupExporter @Inject constructor(
         val budgetCategoryLimits = if (config.includeBudgets) database.budgetDao().getAllCategoryLimits().first() else emptyList()
         val subcategories = if (config.includeProfileData) database.subcategoryDao().getAllSubcategories().first() else emptyList()
         val rules = if (config.includeAppPreferences) database.ruleDao().getAllRules().first() else emptyList()
+        val exchangeRates = if (config.includeAppPreferences) database.exchangeRateDao().getAllRates().first() else emptyList()
         val ruleApplications = if (config.includeTransactionalData) database.ruleApplicationDao().getRecentApplications(1000).first() else emptyList() // Limit to recent apps for backup size
         val webhookProfiles = if (config.includeAppPreferences) {
             database.webhookProfileDao().getAllProfiles().first().map { profile ->
@@ -204,7 +205,8 @@ class BackupExporter @Inject constructor(
                 subcategories = subcategories,
                 rules = rules,
                 ruleApplications = ruleApplications,
-                webhookProfiles = webhookProfiles
+                webhookProfiles = webhookProfiles,
+                exchangeRates = exchangeRates
             ),
             preferences = PreferencesSnapshot(
                 theme = ThemePreferences(
@@ -250,6 +252,20 @@ class BackupExporter @Inject constructor(
                         order = order.map { it.name },
                         hidden = hidden.map { it.name }
                     )
+                } else null,
+                currency = if (config.includeAppPreferences) {
+                    val unifiedCurrencyEnabled = userPreferencesRepository.unifiedCurrencyEnabled.first()
+                    val unifiedCurrencyCode = userPreferencesRepository.unifiedCurrencyCode.first()
+                    val defaultCurrencyEnabled = userPreferencesRepository.defaultCurrencyEnabled.first()
+                    val defaultCurrencyCode = userPreferencesRepository.defaultCurrencyCode.first()
+                    val customCurrencies = userPreferencesRepository.customCurrencies.first()
+                    CurrencyPreferences(
+                        unifiedCurrencyEnabled = unifiedCurrencyEnabled,
+                        unifiedCurrencyCode = unifiedCurrencyCode,
+                        defaultCurrencyEnabled = defaultCurrencyEnabled,
+                        defaultCurrencyCode = defaultCurrencyCode,
+                        customCurrencies = customCurrencies
+                    )
                 } else null
             )
         )

app/src/main/java/com/ritesh/cashiro/data/backup/BackupImporter.kt

@@ -172,6 +172,7 @@ class BackupImporter @Inject constructor(
                 }
                 database.ruleDao().deleteAllRules()
                 database.ruleApplicationDao().deleteAllApplications()
+                database.exchangeRateDao().deleteAllRates()
 
                 // Import all data
                 backup.database.categories.forEach { category ->
@@ -208,6 +209,10 @@ class BackupImporter @Inject constructor(
                     database.chatDao().insertMessage(message)
                 }
 
+                backup.database.exchangeRates.forEach { rate ->
+                    database.exchangeRateDao().insertExchangeRate(rate)
+                }
+                
                 backup.database.budgets.forEach { budget ->
                     database.budgetDao().insertBudget(budget.sanitize())
                 }
@@ -366,6 +371,7 @@ class BackupImporter @Inject constructor(
                 importMerchantMappingsWithMerge(backup.database.merchantMappings)
                 importBudgetsWithMerge(backup.database.budgets, backup.database.budgetCategoryLimits)
                 importWebhookProfilesWithMerge(backup.database.webhookProfiles)
+                importExchangeRatesWithMerge(backup.database.exchangeRates)
 
                 // Import preferences (merge with existing)
                 importPreferences(backup.preferences)
@@ -487,6 +493,12 @@ class BackupImporter @Inject constructor(
         }
     }
 
+    private suspend fun importExchangeRatesWithMerge(rates: List<ExchangeRateEntity>) {
+        rates.forEach { rate ->
+            database.exchangeRateDao().insertExchangeRate(rate)
+        }
+    }
+
     private fun parseRangePreset(value: String): WebhookRangePreset =
         runCatching { WebhookRangePreset.valueOf(value) }
             .getOrElse { WebhookRangePreset.SINCE_LAST_SUCCESS }
@@ -642,5 +654,20 @@ class BackupImporter @Inject constructor(
 
             userPreferencesRepository.updateShowBannerImage(profile.showBannerImage)
         }
+
+        // Currency Preferences
+        preferences.currency?.let { currencyPrefs ->
+            userPreferencesRepository.setUnifiedCurrencyEnabled(currencyPrefs.unifiedCurrencyEnabled)
+            currencyPrefs.unifiedCurrencyCode?.let {
+                userPreferencesRepository.setUnifiedCurrencyCode(it)
+            }
+            userPreferencesRepository.setDefaultCurrencyEnabled(currencyPrefs.defaultCurrencyEnabled)
+            currencyPrefs.defaultCurrencyCode?.let {
+                userPreferencesRepository.setDefaultCurrencyCode(it)
+            }
+            currencyPrefs.customCurrencies.forEach { customCurrency ->
+                userPreferencesRepository.addCustomCurrency(customCurrency)
+            }
+        }
     }
 }

app/src/main/java/com/ritesh/cashiro/data/backup/BackupModels.kt

@@ -132,7 +132,10 @@ data class DatabaseSnapshot(
     val webhookProfiles: List<WebhookProfileBackup> = emptyList(),
 
     @SerializedName("chat_messages")
-    val chatMessages: List<ChatMessage>
+    val chatMessages: List<ChatMessage>,
+
+    @SerializedName("exchange_rates")
+    val exchangeRates: List<ExchangeRateEntity> = emptyList()
 )
 
 data class WebhookProfileBackup(
@@ -178,7 +181,10 @@ data class PreferencesSnapshot(
     val profile: ProfilePreferences? = null,
 
     @SerializedName("home_widgets")
-    val homeWidgets: HomeWidgetPreferences? = null
+    val homeWidgets: HomeWidgetPreferences? = null,
+
+    @SerializedName("currency")
+    val currency: CurrencyPreferences? = null
 )
 
 /**
@@ -192,6 +198,26 @@ data class HomeWidgetPreferences(
     val hidden: List<String>
 )
 
+/**
+ * Currency preferences
+ */
+data class CurrencyPreferences(
+    @SerializedName("unified_currency_enabled")
+    val unifiedCurrencyEnabled: Boolean,
+    
+    @SerializedName("unified_currency_code")
+    val unifiedCurrencyCode: String?,
+    
+    @SerializedName("default_currency_enabled")
+    val defaultCurrencyEnabled: Boolean,
+    
+    @SerializedName("default_currency_code")
+    val defaultCurrencyCode: String?,
+
+    @SerializedName("custom_currencies")
+    val customCurrencies: List<com.ritesh.cashiro.data.model.CustomCurrency> = emptyList()
+)
+
 /**
  * Theme-related preferences
  */

app/src/main/java/com/ritesh/cashiro/data/currency/CurrencyConversionService.kt

@@ -5,6 +5,9 @@ import com.ritesh.cashiro.data.database.entity.ExchangeRateEntity
 import com.ritesh.cashiro.data.preferences.UserPreferencesRepository
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.launch
 import java.math.BigDecimal
@@ -28,6 +31,10 @@ class CurrencyConversionService @Inject constructor(
     private val rateCache = mutableMapOf<String, BigDecimal>()
     private var lastCacheUpdate: LocalDateTime = LocalDateTime.MIN
 
+    // Emits a new value whenever a custom rate is saved or reset, so ViewModels can react
+    private val _rateChangeTrigger = MutableStateFlow(0L)
+    val rateChangeTrigger: StateFlow<Long> = _rateChangeTrigger.asStateFlow()
+
     /**
      * Convert amount from one currency to another
      */
@@ -64,6 +71,25 @@ class CurrencyConversionService @Inject constructor(
             rateCache[cacheKey]?.let { return it }
         }
 
+        // Check database for custom rates first (always takes priority)
+        if (!forceRefresh) {
+            val customRate = exchangeRateDao.getCustomRate(fromCurrency.uppercase(), toCurrency.uppercase())
+            if (customRate != null) {
+                updateCache(cacheKey, customRate.rate)
+                return customRate.rate
+            }
+
+            val reverseCustomRate = exchangeRateDao.getCustomRate(toCurrency.uppercase(), fromCurrency.uppercase())
+            if (reverseCustomRate != null) {
+                try {
+                    val invertedRate = BigDecimal.ONE.divide(reverseCustomRate.rate, MathContext(10))
+                    updateCache(cacheKey, invertedRate)
+                    return invertedRate
+                } catch (_: ArithmeticException) {
+                }
+            }
+        }
+
         // Check database for fresh rates
         val currentTime = LocalDateTime.now()
         val dbRate = exchangeRateDao.getExchangeRate(fromCurrency, toCurrency, currentTime)
@@ -93,6 +119,18 @@ class CurrencyConversionService @Inject constructor(
             }
         }
 
+        // Check reverse pair (e.g., custom rate stored as INR→USD when looking for USD→INR)
+        val reverseRate = exchangeRateDao.getExchangeRate(toCurrency, fromCurrency, currentTime)
+        if (reverseRate != null && !forceRefresh) {
+            try {
+                val invertedRate = BigDecimal.ONE.divide(reverseRate.rate, MathContext(10))
+                updateCache(cacheKey, invertedRate)
+                return invertedRate
+            } catch (_: ArithmeticException) {
+                // Division by zero or non-terminating decimal — fall through to API
+            }
+        }
+
         // Fetch from API if not found, forced refresh, or rates are stale
         return fetchAndCacheRate(fromCurrency, toCurrency)
     }
@@ -185,11 +223,44 @@ class CurrencyConversionService @Inject constructor(
             }
 
             if (entities.isNotEmpty()) {
-                exchangeRateDao.insertExchangeRates(entities)
+                val customRates = exchangeRateDao.getCustomRatesForCurrency(baseCurrency.uppercase())
+                val customPairs = customRates.map { it.fromCurrency.uppercase() to it.toCurrency.uppercase() }.toSet()
+
+                val filteredEntities = entities.filterNot { entity ->
+                    (entity.fromCurrency.uppercase() to entity.toCurrency.uppercase()) in customPairs
+                }
+
+                if (filteredEntities.isNotEmpty()) {
+                    exchangeRateDao.insertExchangeRates(filteredEntities)
+                }
             }
         }
     }
 
+    suspend fun saveCustomRate(fromCurrency: String, toCurrency: String, rate: BigDecimal) {
+        val now = LocalDateTime.now()
+        val entity = ExchangeRateEntity(
+            fromCurrency = fromCurrency.uppercase(),
+            toCurrency = toCurrency.uppercase(),
+            rate = rate,
+            provider = "custom",
+            updatedAt = now,
+            updatedAtUnix = now.atZone(ZoneId.systemDefault()).toEpochSecond(),
+            expiresAt = now.plusYears(100),
+            expiresAtUnix = now.plusYears(100).atZone(ZoneId.systemDefault()).toEpochSecond(),
+            isCustom = true
+        )
+        exchangeRateDao.upsertCustomRate(entity)
+        rateCache.clear()
+        _rateChangeTrigger.value++
+    }
+
+    suspend fun resetCustomRate(fromCurrency: String, toCurrency: String) {
+        exchangeRateDao.resetCustomRate(fromCurrency.uppercase(), toCurrency.uppercase())
+        rateCache.clear()
+        _rateChangeTrigger.value++
+    }
+
     /**
      * Retrieve stored conversions for a base currency from the local database.
      */

app/src/main/java/com/ritesh/cashiro/data/currency/model/CurrencyConversion.kt

@@ -3,8 +3,10 @@ package com.ritesh.cashiro.data.currency.model
 data class CurrencyConversion(
     val currencyCode: String,
     val rate: Double,
-    val lastUpdated: Long = 0L
+    val lastUpdated: Long = 0L,
+    val isCustom: Boolean = false,
+    val customSymbol: String? = null
 ) {
-    val symbol: String get() = CurrencySymbols.getSymbol(currencyCode)
+    val symbol: String get() = customSymbol ?: CurrencySymbols.getSymbol(currencyCode)
     val displayRate: String get() = String.format("%.6f", rate)
 }