MISC: refactor weaken effect calculation (#1076)

so far we calculate the effect of weaken in three +1 places
ns.weaken
ns.weakenAnalyze
terminal weaken

and server.weaken where the bn mult is applied

i extracted the logic into a new netscript helper function getWeakenEffect
this gives us one place if we want to change the formula

a side effect i added the server.cpuCores to the terminal weaken to future proof it if the npc server core pr (#963) is merged

src/NetscriptFunctions.ts

@@ -36,6 +36,7 @@ import {
   processSingleServerGrowth,
   safelyCreateUniqueServer,
   getCoreBonus,
+  getWeakenEffect,
 } from "./Server/ServerHelpers";
 import {
   getPurchasedServerUpgradeCost,
@@ -380,9 +381,7 @@ export const ns: InternalAPI<NSFull> = {
         helpers.log(ctx, () => "Server is null, did it die?");
         return Promise.resolve(0);
       }
-      const cores = host.cpuCores;
-      const coreBonus = getCoreBonus(cores);
-      const weakenAmt = ServerConstants.ServerWeakenAmount * threads * coreBonus;
+      const weakenAmt = getWeakenEffect(threads, host.cpuCores);
       server.weaken(weakenAmt);
       ctx.workerScript.scriptRef.recordWeaken(server.hostname, threads);
       const expGain = calculateHackingExpGain(server, Player) * threads;
@@ -396,7 +395,7 @@ export const ns: InternalAPI<NSFull> = {
       ctx.workerScript.scriptRef.onlineExpGained += expGain;
       Player.gainHackingExp(expGain);
       // Account for hidden multiplier in Server.weaken()
-      return Promise.resolve(weakenAmt * currentNodeMults.ServerWeakenRate);
+      return Promise.resolve(weakenAmt);
     });
   },
   weakenAnalyze:
@@ -404,8 +403,7 @@ export const ns: InternalAPI<NSFull> = {
     (_threads, _cores = 1) => {
       const threads = helpers.number(ctx, "threads", _threads);
       const cores = helpers.number(ctx, "cores", _cores);
-      const coreBonus = getCoreBonus(cores);
-      return ServerConstants.ServerWeakenAmount * threads * coreBonus * currentNodeMults.ServerWeakenRate;
+      return getWeakenEffect(threads, cores);
     },
   share: (ctx) => () => {
     const cores = helpers.getServer(ctx, ctx.workerScript.hostname).cpuCores;