fix: always consider user input when performing swap (#572)

* fix: always consider user input when performing swap

* refactor: extract decimal places constants

* refactor: extract minimumOptimalValue

* fix: handle bzz precision and tweak message

src/models/BzzToken.ts

@@ -1,8 +1,14 @@
 import { BigNumber } from 'bignumber.js'
 import { Token } from './Token'
 
+export const BZZ_DECIMAL_PLACES = 16
+
 export class BzzToken extends Token {
-  constructor(amount: BigNumber | string | bigint) {
-    super(amount, 16)
+  constructor(value: BigNumber | string | bigint) {
+    super(value, BZZ_DECIMAL_PLACES)
+  }
+
+  static fromDecimal(value: BigNumber | string | bigint): BzzToken {
+    return Token.fromDecimal(value, BZZ_DECIMAL_PLACES)
   }
 }

src/models/DaiToken.ts

@@ -1,8 +1,14 @@
 import { BigNumber } from 'bignumber.js'
 import { Token } from './Token'
 
+const DAI_DECIMAL_PLACES = 18
+
 export class DaiToken extends Token {
-  constructor(amount: BigNumber | string | bigint) {
-    super(amount, 18)
+  constructor(value: BigNumber | string | bigint) {
+    super(value, DAI_DECIMAL_PLACES)
+  }
+
+  static fromDecimal(value: BigNumber | string | bigint): DaiToken {
+    return Token.fromDecimal(value, DAI_DECIMAL_PLACES)
   }
 }

src/models/Token.ts

@@ -87,4 +87,11 @@ export class Token {
       this.decimals,
     )
   }
+
+  plusBaseUnits(amount: string): Token {
+    return new Token(
+      this.toBigNumber.plus(new BigNumber(amount).multipliedBy(new BigNumber(10).pow(this.decimals))),
+      this.decimals,
+    )
+  }
 }