Merge pull request #317 from kopelli/get-server-cost

Add "getPurchasedServerCost" NS function

doc/source/netscriptfunctions.rst

@@ -670,6 +670,21 @@ purchaseHacknetNode
     end of the Hacknet Node's name (e.g The Hacknet Node named 'hacknet-node-4' will have an index of 4). If the player cannot afford
     to purchase a new Hacknet Node then the function will return false.
 
+getPurchasedServerCost
+^^^^^^^^^^^^^^^^^^^^^^
+
+.. js:function:: getPurchasedServerCost(ram)
+
+    :param number ram: Amount of RAM of a potential purchased server. Must be a power of 2 (2, 4, 8, 16, etc.). Maximum value of 1048576 (2^20)
+
+    Returns the cost to purchase a server with the specified amount of *ram*.
+
+    Examples::
+
+        for (i = 1; i <= 20; i++) {
+            tprint(i + " -- " + getPurchasedServerCost(Math.pow(2, i)));
+        }
+
 purchaseServer
 ^^^^^^^^^^^^^^
 

netscript.js

@@ -72,6 +72,7 @@ let NetscriptFunctions =
     "serverExists|fileExists|isRunning|"                                       +
     "deleteServer|getPurchasedServers|"                                        +
     "getPurchasedServerLimit|getPurchasedServerMaxRam|"                        +
+    "getPurchasedServerCost|"                                                  +
     "purchaseServer|round|write|read|peek|clear|rm|getPortHandle|"             +
     "scriptRunning|scriptKill|getScriptName|getScriptRam|"                     +
     "getHackTime|getGrowTime|getWeakenTime|getScriptIncome|getScriptExpGain|"  +

src/Constants.js

@@ -70,6 +70,7 @@ let CONSTANTS = {
     ScriptHNUpgCoreRamCost:         0.8,
     ScriptGetStockRamCost:          2.0,
     ScriptBuySellStockRamCost:      2.5,
+    ScriptGetPurchaseServerRamCost: 0.25,
     ScriptPurchaseServerRamCost:    2.25,
     ScriptGetPurchasedServerLimit:  0.05,
     ScriptGetPurchasedServerMaxRam: 0.05,

src/NetscriptFunctions.js

@@ -178,7 +178,25 @@ function NetscriptFunctions(workerScript) {
             throw makeRuntimeRejectMsg(workerScript, "Index specified for Hacknet Node is out-of-bounds: " + i);
         }
         return Player.hacknetNodes[i];
-    }
+    };
+
+    /**
+     * @param {number} ram The amount of server RAM to calculate cost of.
+     * @exception {Error} If the value passed in is not numeric, out of range, or too large of a value.
+     * @returns {number} The cost of 
+     */
+    const getPurchaseServerRamCostGuard = (ram) => {
+        const guardedRam = Math.round(ram);
+        if (isNaN(guardedRam) || !powerOfTwo(guardedRam)) {
+            throw Error("failed due to invalid ram argument. Must be numeric and a power of 2");
+        }
+
+        if (guardedRam > CONSTANTS.PurchasedServerMaxRam) {
+            throw Error("failed because specified RAM was too high. Maximum RAM on a purchased server is " + CONSTANTS.PurchasedServerMaxRam + "GB");
+        }
+
+        return guardedRam * CONSTANTS.BaseCostFor1GBOfRamServer;
+    };
 
     return {
         hacknet : {
@@ -1597,6 +1615,22 @@ function NetscriptFunctions(workerScript) {
 
             return CONSTANTS.PurchasedServerMaxRam;
         },
+        getPurchasedServerCost: function(ram) {
+            if (workerScript.checkingRam) {
+                return updateStaticRam("getPurchasedServerCost", CONSTANTS.ScriptGetPurchaseServerRamCost);
+            }
+            updateDynamicRam("getPurchasedServerCost", CONSTANTS.ScriptGetPurchaseServerRamCost);
+
+            let cost = 0;
+            try {
+                cost = getPurchaseServerRamCostGuard(ram);
+            } catch (e) {
+                workerScript.scriptRef.log("ERROR: 'getPurchasedServerCost()' " + e.message);
+                return "";
+            }
+
+            return cost;
+        },
         purchaseServer : function(hostname, ram) {
             if (workerScript.checkingRam) {
                 return updateStaticRam("purchaseServer", CONSTANTS.ScriptPurchaseServerRamCost);
@@ -1615,18 +1649,14 @@ function NetscriptFunctions(workerScript) {
                 return "";
             }
 
-            ram = Math.round(ram);
+            let cost = 0;
-            if (isNaN(ram) || !isPowerOfTwo(ram)) {
+            try {
-                workerScript.scriptRef.log("ERROR: purchaseServer() failed due to invalid ram argument. Must be numeric and a power of 2");
+                cost = getPurchaseServerRamCostGuard(ram);
+            } catch (e) {
+                workerScript.scriptRef.log("ERROR: 'purchaseServer()' " + e.message);
                 return "";
             }
 
-            if (ram > CONSTANTS.PurchasedServerMaxRam) {
-                workerScript.scriptRef.log("ERROR: purchasedServer() failed because specified RAM was too high. Maximum RAM on a purchased server is " + CONSTANTS.PurchasedServerMaxRam + "GB");
-                return "";
-            }
-
-            var cost = ram * CONSTANTS.BaseCostFor1GBOfRamServer;
             if (Player.money.lt(cost)) {
                 workerScript.scriptRef.log("ERROR: Not enough money to purchase server. Need $" + formatNumber(cost, 2));
                 return "";