feat(as-sdk): add Tally convenience methods

To help with decoding the reveal bytes into JSON objects and merging it
with the consensus results. This does not decode the actual reveal
bodies as this is implementation specific and up to the developer
creating the tally binary.

libs/as-sdk/assembly/index.ts

@@ -1,5 +1,13 @@
 import Process from './process';
+import Tally from './tally';
+
+export {
+  httpFetch,
+  HttpFetchMethod,
+  HttpFetchOptions,
+  HttpResponse,
+} from './http';
 
-export { httpFetch, HttpFetchMethod, HttpFetchOptions, HttpResponse } from './http';
 export { PromiseStatus } from './promise';
-export { Process };
+export { Process, Tally };
+export { RevealBody } from './tally';

libs/as-sdk/assembly/process.ts

@@ -1,3 +1,4 @@
+import { VM_MODE_TALLY, VM_MODE_DR, VM_MODE_ENV_KEY } from './vm-modes';
 import { Process as WasiProcess, CommandLine, Environ } from 'as-wasi/assembly';
 import { execution_result } from './bindings/seda_v1';
 
@@ -39,6 +40,35 @@ export default class Process {
     return result;
   }
 
+  /**
+   * Gets the mode of the VM instance.
+   *
+   * @returns {string} The mode of the VM, either 'dr' or 'tally'.
+   */
+  static getVmMode(): string {
+    const env = Process.envs();
+
+    return env.get(VM_MODE_ENV_KEY);
+  }
+
+  /**
+   * Returns true when the VM instance is in 'tally' mode.
+   *
+   * @returns {boolean}
+   */
+  static isTallyVmMode(): boolean {
+    return Process.getVmMode() === VM_MODE_TALLY;
+  }
+
+  /**
+   * Returns true when the VM instance is in 'dr' mode.
+   *
+   * @returns {boolean}
+   */
+  static isDrVmMode(): boolean {
+    return Process.getVmMode() === VM_MODE_DR;
+  }
+
   /**
    * Exits the process with a message
    * This sets the result of the Data Request execution to the message

libs/as-sdk/assembly/tally.ts

@@ -0,0 +1,63 @@
+import { JSON } from "json-as/assembly";
+import Process from "./process";
+
+const REVEALS_ARGUMENT_POSITION = 2;
+const CONSENSUS_ARGUMENT_POSITION = 3;
+
+@json
+export class RevealBody {
+  salt!: u8[];
+  exit_code!: u8;
+  gas_used!: string;
+  reveal!: u8[];
+}
+
+@json
+export class RevealResult {
+  salt!: u8[];
+  exit_code!: u8;
+  gas_used!: string;
+  reveal!: u8[];
+  inConsensus!: u8;
+}
+
+export default class Tally {
+  static getReveals(): RevealResult[] {
+    const encodedReveals = Process.args().at(REVEALS_ARGUMENT_POSITION);
+    const reveals = JSON.parse<RevealBody[]>(encodedReveals);
+
+    const encodedConsensus = Process.args().at(CONSENSUS_ARGUMENT_POSITION);
+    const consensus = JSON.parse<u8[]>(encodedConsensus);
+
+    const revealsAmount = reveals.length;
+    const consensusAmount = consensus.length;
+    if (revealsAmount !== consensusAmount) {
+      throw new Error(
+        `Number of reveals (${revealsAmount}) does not equal number of consensus reports (${consensusAmount}).`
+      );
+    }
+
+    const revealResults: RevealResult[] = [];
+    for (let index = 0; index < reveals.length; index++) {
+      const reveal = reveals[index];
+
+      revealResults.push({
+        exit_code: reveal.exit_code,
+        gas_used: reveal.gas_used,
+        reveal: reveal.reveal,
+        salt: reveal.salt,
+        inConsensus: consensus.at(index),
+      });
+    }
+
+    return revealResults;
+  }
+
+  static getConsensusReveals(): RevealResult[] {
+    const revealResults = Tally.getReveals();
+
+    return revealResults.filter(
+      (revealResult) => revealResult.inConsensus === 0
+    );
+  }
+}

libs/as-sdk/assembly/vm-modes.ts

@@ -0,0 +1,3 @@
+export const VM_MODE_ENV_KEY = "VM_MODE";
+export const VM_MODE_TALLY = "tally";
+export const VM_MODE_DR = "dr";