feat: add exclusivity period check (#105)

src/fusion-order/fusion-order.ts

@@ -442,4 +442,13 @@ export class FusionOrder {
             wallet
         )
     }
+
+    /**
+     * Check if the auction has exclusive resolver, and it is in the exclusivity period
+     */
+    public isExclusivityPeriod(time = now()): boolean {
+        return this.fusionExtension.postInteractionData.isExclusivityPeriod(
+            time
+        )
+    }
 }

src/fusion-order/settlement-post-interaction-data/settlement-post-interaction-data.ts

@@ -5,6 +5,7 @@ import {IntegratorFee, SettlementSuffixData} from './types'
 import {isHexBytes} from '../../validations'
 import {add0x} from '../../utils'
 import {UINT_16_MAX} from '../../constants'
+import {now} from '../../utils/time'
 
 export class SettlementPostInteractionData {
     public readonly whitelist: WhitelistItem[]
@@ -226,6 +227,18 @@ export class SettlementPostInteractionData {
         return false
     }
 
+    public isExclusivityPeriod(time = now()): boolean {
+        if (this.whitelist.length === 1) {
+            return true
+        }
+
+        if (this.whitelist[0].delay === this.whitelist[1].delay) {
+            return false
+        }
+
+        return time <= this.resolvingStartTime + this.whitelist[0].delay
+    }
+
     public isExclusiveResolver(wallet: Address): boolean {
         const addressHalf = wallet.toString().slice(-20)