Added handler of EventRelayMiningDifficultyUpdated and bug fixes (#40)

## Summary

* Added handler of `EventRelayMiningDifficultyUpdated`
* Added `idx` field to Events, Messages and Transactions
* Fixed bug with applications when an application was being transferred,
and it was re-staked then the transfer info was overwritten
* Added unhandled use case when an application was being delegated to a
gateway and the gateway was unstaked, the delegate relation wasn't
removed
* Fixed `numClaimedComputedUnits`, `numEstimatedComputedUnits` and
`claimedAmount` of relays entities
* Updated `optimizedBulkCreate` util to create a transaction for every
batch instead of reuse the transaction of subql to avoid errors when
there are too many items to be saved (like in the block 72710)

Author: Alann27

schema.graphql

@@ -292,6 +292,7 @@ type Transaction @entity {
   status: TxStatus! @index
   log: String
   code: Int!
+  idx: Int!
   codespace: String
   timeoutHeight: BigInt @index
   # NB: only the first signer!
@@ -302,6 +303,7 @@ type Transaction @entity {
 
 type Message @entity {
   id: ID!
+  idx: Int!
   typeUrl: String! @index
   json: String
   transaction: Transaction!
@@ -311,6 +313,7 @@ type Message @entity {
 
 type Event @entity {
   id: ID!
+  idx: Int!
   type: String! @index
   kind: EventKind!
   attributes: [EventAttribute]!
@@ -444,6 +447,12 @@ type Service @entity {
   computeUnitsPerRelay: BigInt!
   owner: Account!
   addServiceMsgs: [MsgAddService] @derivedFrom(field: "service")
+  relayMiningDifficultyUpdatedEvents: [EventRelayMiningDifficultyUpdated] @derivedFrom(field: "service")
+  # data from the last EventRelayMiningDifficultyUpdated event
+  prevTargetHashHexEncoded: String
+  newTargetHashHexEncoded: String
+  prevNumRelaysEma: BigInt
+  newNumRelaysEma: BigInt
 }
 
 type MsgStakeApplication @entity {
@@ -738,6 +747,17 @@ type MsgAddService @entity {
   message: Message!
 }
 
+type EventRelayMiningDifficultyUpdated @entity {
+  id: ID!
+  service: Service!
+  prevTargetHashHexEncoded: String!
+  newTargetHashHexEncoded: String!
+  prevNumRelaysEma: BigInt!
+  newNumRelaysEma: BigInt!
+  block: Block!
+  event: Event!
+}
+
 type Gateway @entity {
   # id is the address of the gateway
   id: ID!

src/mappings/authz/exec.ts

@@ -42,6 +42,7 @@ function _handleAuthzExec(msg: CosmosMessage<AuthzExecMsg>): HandleAuthzExecResu
 
   result.messages.push({
     id: authzExecId,
+    idx: msg.idx,
     typeUrl,
     json: stringify(msg.msg.decodedMsg),
     transactionId: msg.tx.hash,
@@ -85,6 +86,7 @@ function _handleAuthzExec(msg: CosmosMessage<AuthzExecMsg>): HandleAuthzExecResu
       // Create a primitive message entity for a sub-message
       result.messages.push({
         id: subMsgId,
+        idx: msg.idx,
         typeUrl,
         json: stringify(decodedMsg),
         transactionId: msg.tx.hash,

src/mappings/handlers.ts

@@ -32,7 +32,7 @@ import {
   handleMsgCreateClaim,
   handleMsgSubmitProof,
 } from "./poktroll/relays";
-import { handleMsgAddService } from "./poktroll/services";
+import { handleEventRelayMiningDifficultyUpdated, handleMsgAddService } from "./poktroll/services";
 import {
   handleSupplierStakeMsg,
   handleSupplierUnbondingBeginEvent,
@@ -126,6 +126,8 @@ export const EventHandlers: Record<string, (events: Array<CosmosEvent>) => Promi
   // supplier
   "poktroll.supplier.EventSupplierUnbondingBegin": handleSupplierUnbondingBeginEvent,
   "poktroll.supplier.EventSupplierUnbondingEnd": handleSupplierUnbondingEndEvent,
+  // service
+  "poktroll.service.EventRelayMiningDifficultyUpdated": handleEventRelayMiningDifficultyUpdated,
   // gateway
   "poktroll.gateway.EventGatewayUnstaked": handleGatewayUnstakeEvent,
   "poktroll.gateway.EventGatewayUnbondingBegin": handleEventGatewayUnbondingBegin,
@@ -144,5 +146,4 @@ export const EventHandlers: Record<string, (events: Array<CosmosEvent>) => Promi
   "coinbase": noOp,
   "transfer": noOp,
   "burn": noOp,
-  "poktroll.service.EventRelayMiningDifficultyUpdated": noOp,
 };