feat: add zod validation to config

src/lib/config.ts

@@ -1,5 +1,6 @@
 import { readFileSync, existsSync, writeFileSync } from 'node:fs';
 import { join } from 'node:path';
+import { z } from 'zod';
 
 const configPath = join(import.meta.dir, '..', '..', 'config', 'config.json');
 
@@ -45,6 +46,56 @@ export interface GameConfigType {
 // Initial default config state
 export const config: GameConfigType = {} as GameConfigType;
 
+const bigIntSchema = z.union([z.string(), z.number(), z.bigint()])
+    .refine((val) => {
+        try {
+            BigInt(val);
+            return true;
+        } catch {
+            return false;
+        }
+    }, { message: "Must be a valid integer" })
+    .transform((val) => BigInt(val));
+
+const configSchema = z.object({
+    leveling: z.object({
+        base: z.number(),
+        exponent: z.number(),
+        chat: z.object({
+            cooldownMs: z.number(),
+            minXp: z.number(),
+            maxXp: z.number(),
+        })
+    }),
+    economy: z.object({
+        daily: z.object({
+            amount: bigIntSchema,
+            streakBonus: bigIntSchema,
+            cooldownMs: z.number(),
+        }),
+        transfers: z.object({
+            allowSelfTransfer: z.boolean(),
+            minAmount: bigIntSchema,
+        })
+    }),
+    inventory: z.object({
+        maxStackSize: bigIntSchema,
+        maxSlots: z.number(),
+    }),
+    commands: z.record(z.string(), z.boolean()),
+    lootdrop: z.object({
+        activityWindowMs: z.number(),
+        minMessages: z.number(),
+        spawnChance: z.number(),
+        cooldownMs: z.number(),
+        reward: z.object({
+            min: z.number(),
+            max: z.number(),
+            currency: z.string(),
+        })
+    })
+});
+
 export function reloadConfig() {
     if (!existsSync(configPath)) {
         throw new Error(`Config file not found at ${configPath}`);
@@ -82,7 +133,10 @@ reloadConfig();
 // Backwards compatibility alias
 export const GameConfig = config;
 
-export function saveConfig(newConfig: GameConfigType) {
+export function saveConfig(newConfig: unknown) {
+    // Validate and transform input
+    const validatedConfig = configSchema.parse(newConfig);
+
     const replacer = (key: string, value: any) => {
         if (typeof value === 'bigint') {
             return value.toString();
@@ -90,7 +144,7 @@ export function saveConfig(newConfig: GameConfigType) {
         return value;
     };
 
-    const jsonString = JSON.stringify(newConfig, replacer, 4);
+    const jsonString = JSON.stringify(validatedConfig, replacer, 4);
     writeFileSync(configPath, jsonString, 'utf-8');
     reloadConfig();
 }