Implemented audit log system

api/src/services/logging/auditLog.ts

@@ -0,0 +1,50 @@
+import pool from "../../db";
+import { logger } from "./logger";
+
+export type AuditArea = 'member' | 'calendar' | 'unit' | 'auth' | 'admin' | 'application';
+
+export interface AuditContext {
+    actorId: number;       // The person doing the action (created_by)
+    targetId?: number;     // The ID of the thing being changed (target_id)
+}
+
+class AuditLogger {
+    async record(
+        area: AuditArea,
+        action: string,
+        context: AuditContext,
+        data: Record<string, any> = {} // Already optional with default {}
+    ) {
+        const actionType = `${area}.${action}`;
+
+        try {
+            await pool.query(
+                `INSERT INTO audit_log (action_type, payload, target_id, created_by) 
+                 VALUES (?, ?, ?, ?)`, // Fixed: removed extra comma/placeholder
+                [
+                    actionType,
+                    JSON.stringify(data),
+                    context.targetId || null,
+                    context.actorId,
+                ]
+            );
+        } catch (err) {
+            logger.error('audit', `AUDIT_FAILURE: Failed to log ${actionType}`, { error: err });
+        }
+    }
+
+    // Making data optional using '?' and default parameter
+    member(action: 'update_rank' | 'status_change' | 'create', context: AuditContext, data: any = {}) {
+        return this.record('member', action, context, data);
+    }
+
+    calendar(action: 'event_signup' | 'event_create' | 'attendance', context: AuditContext, data: any = {}) {
+        return this.record('calendar', action, context, data);
+    }
+
+    application(action: 'created' | 'approved' | 'denied' | 'restarted', context: AuditContext, data: any = {}) {
+        return this.record('application', action, context, data);
+    }
+}
+
+export const audit = new AuditLogger();