diff --git a/src/main/kotlin/com/cubetiqs/money/Money.kt b/src/main/kotlin/com/cubetiqs/money/Money.kt
index bee555f..6e22ac9 100644
--- a/src/main/kotlin/com/cubetiqs/money/Money.kt
+++ b/src/main/kotlin/com/cubetiqs/money/Money.kt
@@ -1,17 +1,21 @@
 package com.cubetiqs.money
 
 open class Money(
-    var value: Double,
-    @SpecialString(trim = true, upperCase = true) private var currency: String = "USD"
-) : StdMoney {
-
+    private var value: Double = 0.0,
+    private val currency: StdMoney.Currency = MoneyCurrency.USD,
+) : StdMoney, StdMoney.Operator<Money>, StdMoney.ExchangeOperator {
     //////////////////// - PROPERTIES - ////////////////////
 
     override fun getMoneyValue(): Double {
         return this.value
     }
 
-    override fun getMoneyCurrency(): String {
+    // not imply with exchange rate yet
+    override fun StdMoney.getExchangedTo(currency: StdMoney.Currency): Double {
+        return getMoneyValue()
+    }
+
+    override fun getMoneyCurrency(): StdMoney.Currency {
         return this.currency
     }
 
@@ -21,11 +25,48 @@ open class Money(
         return "Money(value=${getMoneyValue()}, currency='${getMoneyCurrency()}')"
     }
 
+    override fun inc(): Money = apply {
+        this.value += 1
+    }
+
+    override fun dec(): Money = apply {
+        this.value -= 1
+    }
+
+    override fun plus(other: StdMoney): Money {
+        val temp = this.value + other.getExchangedTo(this.currency)
+        return Money(value = temp, currency = this.currency)
+    }
+
+    override fun divide(other: StdMoney): Money {
+        val temp = this.value / other.getExchangedTo(this.currency)
+        return Money(value = temp, currency = this.currency)
+    }
+
+    override fun multiply(other: StdMoney): Money {
+        val temp = this.value * other.getExchangedTo(this.getMoneyCurrency())
+        return Money(value = temp, currency = this.currency)
+    }
+
+    override fun plusAssign(other: StdMoney) {
+        this.value = this.value + other.getExchangedTo(this.currency)
+    }
+
+    override fun divideAssign(other: StdMoney) {
+        this.value = this.value / other.getExchangedTo(this.currency)
+    }
+
+    override fun multiplyAssign(other: StdMoney) {
+        this.value = this.value * other.getExchangedTo(this.getMoneyCurrency())
+    }
+
     companion object {
         val ZERO: StdMoney
-            get() = Money(value = 0.0)
+            get() = Money()
+
         val ONE: StdMoney
             get() = Money(value = 1.0)
+
         val TEN: StdMoney
             get() = Money(value = 10.0)
 
@@ -33,18 +74,22 @@ open class Money(
          * Create a new money object with custom value
          *
          * @param value Double
-         * @param currency String
+         * @param currency MoneyCurrency
          */
-        fun create(value: Double, currency: String = MoneyCurrency.USD.name): StdMoney {
+        fun create(value: Double, currency: StdMoney.Currency): Money {
             return Money(value = value, currency = currency)
         }
 
-        /**
-         * Create a new money object with custom value
-         *
-         * @param value Double
-         * @param currency MoneyCurrency
-         */
-        fun create(value: Double, currency: MoneyCurrency = MoneyCurrency.USD): StdMoney = create(value, currency.name)
+        fun from(value: Double, currency: String): Money {
+            return create(value, object : StdMoney.Currency {
+                override fun getCurrency(): String {
+                    return currency.toUpperCase().trim()
+                }
+            })
+        }
+
+        fun from(money: StdMoney): Money {
+            return create(value = money.getMoneyValue(), currency = money.getMoneyCurrency())
+        }
     }
 }
diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyArithmetic.kt b/src/main/kotlin/com/cubetiqs/money/MoneyArithmetic.kt
index 0d410e2..10b3f82 100644
--- a/src/main/kotlin/com/cubetiqs/money/MoneyArithmetic.kt
+++ b/src/main/kotlin/com/cubetiqs/money/MoneyArithmetic.kt
@@ -1,5 +1,6 @@
 package com.cubetiqs.money
 
-fun StdMoney.addMoney(value: Double, currency: String): StdMoney {
-    return this + Money.create(value, currency)
+fun StdMoney.addMoney(value: Double, currency: StdMoney.Currency): StdMoney {
+    this + Money.create(value, currency)
+    return this
 }
\ No newline at end of file
diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyConfig.kt b/src/main/kotlin/com/cubetiqs/money/MoneyConfig.kt
index ef919fa..9f3b433 100644
--- a/src/main/kotlin/com/cubetiqs/money/MoneyConfig.kt
+++ b/src/main/kotlin/com/cubetiqs/money/MoneyConfig.kt
@@ -67,8 +67,8 @@ object MoneyConfig {
     fun getConfig() = config
 
     @Throws(MoneyCurrencyStateException::class)
-    fun getRate(currency: String): Double {
-        return getConfig()[currency.toUpperCase()]
+    fun getRate(currency: StdMoney.Currency): Double {
+        return getConfig()[currency.getCurrency().toUpperCase()]
             ?: throw MoneyCurrencyStateException("money currency $currency is not valid!")
     }
 
diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyCurrency.kt b/src/main/kotlin/com/cubetiqs/money/MoneyCurrency.kt
index 3bdbf45..fdf7934 100644
--- a/src/main/kotlin/com/cubetiqs/money/MoneyCurrency.kt
+++ b/src/main/kotlin/com/cubetiqs/money/MoneyCurrency.kt
@@ -1,7 +1,43 @@
 package com.cubetiqs.money
 
-enum class MoneyCurrency {
-    USD,
-    KHR,
-    EUR
+import java.io.Serializable
+
+/**
+ * Money Currency Object with flexible currency based on data and configs
+ *
+ * @author sombochea
+ * @since 1.0
+ */
+open class MoneyCurrency(
+    private val name: String,
+    private val symbol: String? = null,
+    private val configs: Map<String, Any?>? = null,
+) : Serializable, StdMoney.Currency {
+    override fun getCurrency(): String {
+        return name.toUpperCase().trim()
+    }
+
+    fun getSymbol(): String? {
+        return symbol ?: getConfigs()["symbol"]?.toString()
+    }
+
+    fun getConfigs(): Map<String, Any?> {
+        return configs ?: emptyMap()
+    }
+
+    override fun toString(): String {
+        return "MoneyCurrency(name='$name', symbol=$symbol, configs=$configs)"
+    }
+
+    companion object {
+        fun create(name: String): MoneyCurrency {
+            return MoneyCurrency(name = name)
+        }
+
+        val USD
+            get() = create("USD")
+
+        val KHR
+            get() = create("KHR")
+    }
 }
\ No newline at end of file
diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyExchangeAdapter.kt b/src/main/kotlin/com/cubetiqs/money/MoneyExchangeAdapter.kt
deleted file mode 100644
index d2cbdb9..0000000
--- a/src/main/kotlin/com/cubetiqs/money/MoneyExchangeAdapter.kt
+++ /dev/null
@@ -1,5 +0,0 @@
-package com.cubetiqs.money
-
-interface MoneyExchangeAdapter {
-    fun getRate(currency: String): Double
-}
\ No newline at end of file
diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyExchangeProvider.kt b/src/main/kotlin/com/cubetiqs/money/MoneyExchangeProvider.kt
new file mode 100644
index 0000000..96547b2
--- /dev/null
+++ b/src/main/kotlin/com/cubetiqs/money/MoneyExchangeProvider.kt
@@ -0,0 +1,5 @@
+package com.cubetiqs.money
+
+interface MoneyExchangeProvider {
+    fun getRate(currency: StdMoney.Currency): Double
+}
\ No newline at end of file
diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyExchangeUtils.kt b/src/main/kotlin/com/cubetiqs/money/MoneyExchangeUtils.kt
index 0b2f01d..7f6a3b5 100644
--- a/src/main/kotlin/com/cubetiqs/money/MoneyExchangeUtils.kt
+++ b/src/main/kotlin/com/cubetiqs/money/MoneyExchangeUtils.kt
@@ -1,7 +1,7 @@
 package com.cubetiqs.money
 
 object MoneyExchangeUtils {
-    fun exchange(exchangeFrom: StdMoney, exchangeToCurrency: String): StdMoney {
+    fun exchange(exchangeFrom: StdMoney, exchangeToCurrency: StdMoney.Currency): StdMoney {
         val rateFrom = MoneyConfig.getRate(exchangeFrom.getMoneyCurrency())
         val rateTo = MoneyConfig.getRate(exchangeToCurrency)
         return Money(value = computeRate(rateFrom, rateTo, amountFrom = exchangeFrom.getMoneyValue()), currency = exchangeToCurrency)
@@ -10,4 +10,12 @@ object MoneyExchangeUtils {
     private fun computeRate(rateFrom: Double, rateTo: Double, baseRate: Double = 1.0, amountFrom: Double = 1.0): Double {
         return amountFrom * ((baseRate / rateFrom) / (baseRate / rateTo))
     }
+
+    fun getBaseCurrency(): MoneyCurrency {
+        return MoneyCurrency.USD
+    }
+
+    fun getExchangeRate(currency: MoneyCurrency): Double {
+        return 0.0
+    }
 }
\ No newline at end of file
diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyExtension.kt b/src/main/kotlin/com/cubetiqs/money/MoneyExtension.kt
index e4d2783..2afabf3 100644
--- a/src/main/kotlin/com/cubetiqs/money/MoneyExtension.kt
+++ b/src/main/kotlin/com/cubetiqs/money/MoneyExtension.kt
@@ -1,7 +1,7 @@
 package com.cubetiqs.money
 
-fun StdMoney.exchangeTo(currency: String): StdMoney {
+fun StdMoney.exchangeTo(currency: StdMoney.Currency): StdMoney {
     return MoneyExchangeUtils.exchange(this, currency)
 }
 
-fun StdMoney.isMatchedCurrency(currency: String) = this.getMoneyCurrency().equals(currency, ignoreCase = true)
\ No newline at end of file
+fun StdMoney.isMatchedCurrency(currency: StdMoney.Currency) = this.getMoneyCurrency().getCurrency().equals(currency.getCurrency(), ignoreCase = true)
\ No newline at end of file
diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyHistory.kt b/src/main/kotlin/com/cubetiqs/money/MoneyHistory.kt
new file mode 100644
index 0000000..5af4193
--- /dev/null
+++ b/src/main/kotlin/com/cubetiqs/money/MoneyHistory.kt
@@ -0,0 +1,15 @@
+package com.cubetiqs.money
+
+import java.io.Serializable
+
+/**
+ * @author sombochea <Sambo Chea>
+ * @email sombochea@cubetiqs.com>
+ * @date 08/02/21
+ * @since 1.0
+ */
+data class MoneyHistory(
+    val valueOn: String? = null,
+    val valueOf: String? = null,
+    val currency: String? = null
+) : Serializable
\ No newline at end of file
diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyObject.kt b/src/main/kotlin/com/cubetiqs/money/MoneyObject.kt
new file mode 100644
index 0000000..00514bb
--- /dev/null
+++ b/src/main/kotlin/com/cubetiqs/money/MoneyObject.kt
@@ -0,0 +1,47 @@
+package com.cubetiqs.money
+
+import java.io.Serializable
+
+sealed class MoneyObject : Serializable, StdMoney {
+    private var value: Double = 0.0
+    private var currency: MoneyCurrency = MoneyCurrency.USD
+    private val moneyStates: MutableMap<MoneyCurrency, MoneyState> = mutableMapOf()
+
+    constructor(value: Double, currency: MoneyCurrency) {
+        this.value = value
+        this.currency = currency
+        isComputed = false
+    }
+
+    /**
+     * Check if computed, set it to true. Because we no need to add the same value again after once
+     * computed.
+     */
+    @Transient
+    var isComputed = false
+        private set
+
+    @Transient
+    var isInit = false
+        private set
+
+    /** Calculate the value. Must be call after complete add money. */
+    fun compute(): MoneyObject = apply {
+
+    }
+
+    companion object {
+        @JvmStatic
+        private fun defaultCurrency(): MoneyCurrency {
+            return MoneyExchangeUtils.getBaseCurrency()
+        }
+    }
+
+    override fun getMoneyValue(): Double {
+        return value
+    }
+
+    override fun getMoneyCurrency(): StdMoney.Currency {
+        return currency
+    }
+}
\ No newline at end of file
diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyOperator.kt b/src/main/kotlin/com/cubetiqs/money/MoneyOperator.kt
index 193b67c..d862856 100644
--- a/src/main/kotlin/com/cubetiqs/money/MoneyOperator.kt
+++ b/src/main/kotlin/com/cubetiqs/money/MoneyOperator.kt
@@ -1,12 +1,17 @@
 package com.cubetiqs.money
 
+// unary operators
 operator fun StdMoney.unaryMinus() = (-getMoneyValue())
 operator fun StdMoney.unaryPlus() = (+getMoneyValue())
-operator fun Money.inc() = Money(value++)
-operator fun Money.dec() = Money(value--)
-operator fun StdMoney.plus(other: StdMoney) = Money(getMoneyValue() + other.getMoneyValue())
-operator fun StdMoney.times(other: StdMoney) = Money(getMoneyValue() * other.getMoneyValue())
-operator fun StdMoney.div(other: StdMoney) = Money(getMoneyValue() / other.getMoneyValue())
-operator fun Money.timesAssign(other: StdMoney) {
-    this.value = this.getMoneyValue() * other.getMoneyValue()
-}
\ No newline at end of file
+
+// operators
+operator fun StdMoney.inc() = Money.from(this).inc()
+operator fun StdMoney.dec() = Money.from(this).dec()
+operator fun StdMoney.plus(other: StdMoney) = Money.from(this).plusAssign(other)
+operator fun StdMoney.times(other: StdMoney) = Money.from(this).multiplyAssign(other)
+operator fun StdMoney.div(other: StdMoney) = Money.from(this).divideAssign(other)
+
+// assign operators
+operator fun Money.timesAssign(other: StdMoney) = this.multiplyAssign(other)
+operator fun Money.plusAssign(other: StdMoney) = this.plusAssign(other)
+operator fun Money.divAssign(other: StdMoney) = this.divideAssign(other)
\ No newline at end of file
diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyState.kt b/src/main/kotlin/com/cubetiqs/money/MoneyState.kt
new file mode 100644
index 0000000..463728e
--- /dev/null
+++ b/src/main/kotlin/com/cubetiqs/money/MoneyState.kt
@@ -0,0 +1,15 @@
+package com.cubetiqs.money
+
+import java.io.Serializable
+
+/**
+ * @author sombochea <Sambo Chea>
+ * @email sombochea@cubetiqs.com
+ * @date 08/02/21
+ * @since 1.0
+ */
+data class MoneyState(
+    var value: String? = null,
+    var currency: String? = null,
+    var history: MoneyHistory? = null
+) : Serializable
\ No newline at end of file
diff --git a/src/main/kotlin/com/cubetiqs/money/StdMoney.kt b/src/main/kotlin/com/cubetiqs/money/StdMoney.kt
index 29d20cc..33074c9 100644
--- a/src/main/kotlin/com/cubetiqs/money/StdMoney.kt
+++ b/src/main/kotlin/com/cubetiqs/money/StdMoney.kt
@@ -20,6 +20,30 @@ interface StdMoney {
      *
      * @return String
      */
-    @SpecialString
-    fun getMoneyCurrency(): String
+    fun getMoneyCurrency(): Currency
+
+    /**
+     * Allow for money currency called and implemented
+     */
+    interface Currency {
+        fun getCurrency(): String
+    }
+
+    interface ExchangeOperator {
+        fun StdMoney.getExchangedTo(currency: Currency): Double
+    }
+
+    interface Operator<T : StdMoney> {
+        fun plus(other: StdMoney): T
+        fun divide(other: StdMoney): T
+
+        fun inc(): T
+        fun dec(): T
+        fun multiply(other: StdMoney): T
+
+        // assign operators
+        fun plusAssign(other: StdMoney)
+        fun divideAssign(other: StdMoney)
+        fun multiplyAssign(other: StdMoney)
+    }
 }
\ No newline at end of file
diff --git a/src/test/kotlin/MoneyTests.kt b/src/test/kotlin/MoneyTests.kt
index 56fda11..353e46c 100644
--- a/src/test/kotlin/MoneyTests.kt
+++ b/src/test/kotlin/MoneyTests.kt
@@ -2,23 +2,10 @@ import com.cubetiqs.money.Money
 import com.cubetiqs.money.MoneyConfig
 import com.cubetiqs.money.MoneyCurrency
 import com.cubetiqs.money.MoneyExchangeUtils
-import com.cubetiqs.money.SpecialStringProcessor
 import org.junit.Assert
 import org.junit.Test
 
 class MoneyTests {
-    @Test
-    fun money_operator_test() {
-        // val money = Money(10.0)
-        // val money2 = Money(20.0)
-        // money *= money
-        // println((money + money2) * money2)
-        // Assert.assertEquals(100.0, money.value, 0.0)
-
-        val test = SpecialStringProcessor().serialize(Money(1.0, "  usd   "))
-        println(test)
-    }
-
     @Test
     fun exchange_2usd_to_khr_test() {
         val properties = MoneyConfig
@@ -32,27 +19,13 @@ class MoneyTests {
             .setProperties(properties)
             .parse("USD:1,KHR:4000")
 
+        // Is valid for money config?
         Assert.assertTrue(MoneyConfig.isValid())
 
-        println(MoneyConfig.getConfig())
-
         val moneyUsd = Money(2.0)
-        val moneyKhr = MoneyExchangeUtils.exchange(moneyUsd, "KHR")
+        val moneyKhr = MoneyExchangeUtils.exchange(moneyUsd, MoneyCurrency.create("KHR"))
 
+        // Is correct exchange?
         Assert.assertEquals(8000.0, moneyKhr.getMoneyValue(), 0.0)
     }
-
-    @Test
-    fun money_exchange_config_builder_test() {
-        MoneyConfig.propertiesBuilder
-            .setDeliEqual('=')
-            .setDeliSplit(';')
-
-        MoneyConfig.parse("USD:1,KHR=4000,EUR=0.99")
-
-        val moneyUsd = Money.ONE
-        val moneyKhr = Money.create(20000.0, MoneyCurrency.KHR)
-
-        val result = moneyUsd
-    }
 }
\ No newline at end of file