fix: better validations and messages

integration/nevermined/NFT1155.test.ts

@@ -107,7 +107,7 @@ describe('NFT1155 End-to-End', () => {
           },
           {
             serviceType: 'nft-access',
-            nft: { amount: numberNFTs, maxCreditsCharged: 100n, minCreditsCharged: 1n },
+            nft: { amount: numberNFTs, maxCreditsToCharge: 100n, minCreditsToCharge: 1n },
           },
         ],
         nftContractAddress: nftUpgradeable.address,
@@ -127,8 +127,8 @@ describe('NFT1155 End-to-End', () => {
       console.log(JSON.stringify(ddoAttributes))
 
       assert.equal(ddoAttributes.amount, numberNFTs)
-      assert.equal(ddoAttributes.maxCreditsCharged, 100n)
-      assert.equal(ddoAttributes.minCreditsCharged, 1n)
+      assert.equal(ddoAttributes.maxCreditsToCharge, 100n)
+      assert.equal(ddoAttributes.minCreditsToCharge, 1n)
     })
 
     it('Should be able to approve permissions', async () => {

integration/nevermined/NVMAppFlows.ts

@@ -396,8 +396,8 @@ describe('NVM App main flows using Credit NFTs (ERC-1155)', () => {
               duration: subscriptionSilverDuration,
               amount: accessCostInCreditsDataset,
               nftTransfer,
-              maxCreditsCharged: 100n,
-              minCreditsCharged: 1n,
+              maxCreditsToCharge: 100n,
+              minCreditsToCharge: 1n,
             },
           },
         ],

src/keeper/contracts/templates/NFTAccessTemplate.ts

@@ -16,6 +16,7 @@ import { AgreementInstance, AgreementTemplate } from './AgreementTemplate.abstra
 import { BaseTemplate } from './BaseTemplate.abstract'
 import { nftAccessTemplateServiceAgreementTemplate } from './NFTAccessTemplate.serviceAgreementTemplate'
 import { NFTAccessCondition, NFTHolderCondition } from '../conditions'
+import { DynamicCreditsUnderLimit } from '../../../errors/NFTError'
 
 export interface NFTAccessTemplateParams {
   holderAddress: string
@@ -168,11 +169,7 @@ export class NFTAccessTemplate extends BaseTemplate<NFTAccessTemplateParams, Ser
         : ddo.findServiceByType(this.service())
     ) as ServiceNFTAccess
 
-    // const amount = DDO.getNftAmountFromService(nftAccessService)
-    // if (amount <= 0n) return true
-
-    // params.nft_amount
-    const amount = NFTServiceAttributes.getCreditsToConsume(
+    const amount = NFTServiceAttributes.getCreditsToCharge(
       nftAccessService.attributes.main.nftAttributes,
     )
 
@@ -186,8 +183,14 @@ export class NFTAccessTemplate extends BaseTemplate<NFTAccessTemplateParams, Ser
 
     const nftContract = await this.nevermined.contracts.loadNft1155(contractAddress)
 
-    await nftContract.burnFromHolder(params.consumer_address, tokenId, amount, from, txparams)
+    const balance = await nftContract.balance(tokenId, params.consumer_address)
+    if (balance < amount) {
+      throw new DynamicCreditsUnderLimit(
+        `Balance is under the number of required credits to be burned: ${balance} < ${amount}`,
+      )
+    }
 
+    await nftContract.burnFromHolder(params.consumer_address, tokenId, amount, from, txparams)
     return true
   }
 }

src/models/NFTAttributes.ts

@@ -36,13 +36,13 @@ export class NFTServiceAttributes {
    * The maximum number of credits that can be charged to the subscriber.
    * If not specified, the subscription cost is not capped
    */
-  maxCreditsCharged?: bigint
+  maxCreditsToCharge?: bigint
 
   /**
    * The minimum number of credits that will be charged to the subscriber.
    * If not specified, the amount defined in the service agreement or 1 credit will be charged
    */
-  minCreditsCharged?: bigint
+  minCreditsToCharge?: bigint
 
   /**
    * The minimum number of credits that the subscribers needs to hold to access the asset.
@@ -57,8 +57,8 @@ export class NFTServiceAttributes {
     duration: 0, // Because it's not a subscription it doesn't have a duration
     amount: 1n, // By default just one edition
     tokenId: '', // By default no tokenId
-    maxCreditsCharged: 0n, // Max credits charged equals to 0 means the subscription cost is not capped
-    minCreditsCharged: 0n, // Min credits charged equals to 0 means the amount defined in the service agreement or 1 credit will be charged
+    maxCreditsToCharge: 0n, // Max credits to charge equals to 0 means the subscription cost is not capped
+    minCreditsToCharge: 0n, // Min credits to charge equals to 0 means the amount defined in the service agreement or 1 credit will be charged
     minCreditsRequired: 1n, // One credit required to access
   }
 
@@ -73,25 +73,30 @@ export class NFTServiceAttributes {
    * @param dynamicAmount the dynamic amount of credits asked to be consumed
    * @returns amount to consume
    */
-  static getCreditsToConsume(nftAttributes: NFTServiceAttributes, dynamicAmount?: bigint) {
+  static getCreditsToCharge(nftAttributes: NFTServiceAttributes, dynamicAmount?: bigint) {
     if (!nftAttributes) throw new NFTError('NFT attributes are not defined')
 
-    if (dynamicAmount) {
-      if (dynamicAmount > nftAttributes.maxCreditsCharged) {
-        // TODO: Evalue if thow an exception or return the max credits that can be charged
-        //throw new DynamicCreditsOverLimit(`The amount of credits to consume ${dynamicAmount} is higher than the max credits charged ${this.maxCreditsCharged}`)
-        return nftAttributes.maxCreditsCharged
-      } else if (dynamicAmount < nftAttributes.minCreditsCharged) {
-        // TODO: Evalue if thow an exception or return the min amount to be charged
-        //throw new DynamicCreditsUnderLimit(`The amount of credits to consume ${dynamicAmount} is lower than the min credits charged ${this.minCreditsCharged}`)
-        nftAttributes.minCreditsCharged
+    if (dynamicAmount !== undefined) {
+      if (dynamicAmount > nftAttributes.maxCreditsToCharge) {
+        // TODO: Evaluate if thow an exception or return the max credits that can be charged
+        //throw new DynamicCreditsOverLimit(`The amount of credits to consume ${dynamicAmount} is higher than the max credits charged ${this.maxCreditsToCharge}`)
+        return nftAttributes.maxCreditsToCharge
+      } else if (dynamicAmount < nftAttributes.minCreditsToCharge) {
+        // TODO: Evaluate if thow an exception or return the min amount to be charged
+        //throw new DynamicCreditsUnderLimit(`The amount of credits to consume ${dynamicAmount} is lower than the min credits charged ${this.minCreditsToCharge}`)
+        nftAttributes.minCreditsToCharge
       }
       return dynamicAmount
     }
-    if (nftAttributes.minCreditsCharged && nftAttributes.minCreditsCharged >= 0n)
-      return nftAttributes.amount > nftAttributes.minCreditsCharged
+
+    if (dynamicAmount === 0n || nftAttributes.amount === 0n)
+      // If the amount is 0 means the access is Free
+      return 0n
+
+    if (nftAttributes.minCreditsToCharge && nftAttributes.minCreditsToCharge >= 0n)
+      return nftAttributes.amount > nftAttributes.minCreditsToCharge
         ? nftAttributes.amount
-        : nftAttributes.minCreditsCharged
+        : nftAttributes.minCreditsToCharge
     else return nftAttributes.amount
   }
 
@@ -124,17 +129,17 @@ export class NFTServiceAttributes {
       if (service.nft.amount === undefined) service.nft.amount = this.defaultValues.amount
 
       if (service.serviceType === 'nft-access') {
-        if (!service.nft.minCreditsCharged) service.nft.minCreditsCharged = service.nft.amount
-        if (!service.nft.maxCreditsCharged) service.nft.maxCreditsCharged = service.nft.amount
+        if (!service.nft.minCreditsToCharge) service.nft.minCreditsToCharge = service.nft.amount
+        if (!service.nft.maxCreditsToCharge) service.nft.maxCreditsToCharge = service.nft.amount
         if (!service.nft.minCreditsRequired)
-          service.nft.minCreditsRequired = service.nft.minCreditsCharged
+          service.nft.minCreditsRequired = service.nft.minCreditsToCharge
 
         if (
-          service.nft.amount < service.nft.minCreditsCharged ||
-          service.nft.amount > service.nft.maxCreditsCharged
+          service.nft.amount < service.nft.minCreditsToCharge ||
+          service.nft.amount > service.nft.maxCreditsToCharge
         )
           throw new NFTError(
-            `The amount of credits to consume ${service.nft.amount} is not between the min credits charged ${service.nft.minCreditsCharged} and the max credits charged ${service.nft.maxCreditsCharged}`,
+            `The amount of credits to consume ${service.nft.amount} is not between the min credits charged ${service.nft.minCreditsToCharge} and the max credits charged ${service.nft.maxCreditsToCharge}`,
           )
       } else if (service.serviceType === 'nft-sales') {
         if (nftAttributes.ercType == 721) service.nft.amount = 1n