Design a Scalable Polling and Survey Platform Frontend

[Dynamic Schema Parser] ──> [Client-Side Logic Engine] ──> [Transactional Response Queue] ──> [Real-time Live View]

   const InputRegistry: Record<string, React.LazyExoticComponent<any>> = {
     text: React.lazy(() => import('./fields/TextField')),
     mcq: React.lazy(() => import('./fields/MCQField')),
     matrix: React.lazy(() => import('./fields/MatrixField')),
   };

  const handleNextStep = () => {
    // Moves focus to the first interactive field of the next step
    requestAnimationFrame(() => {
      firstInputRef.current?.focus();
    });
  };

  interface AnswerPayload {
    surveyId: string;
    respondentId: string;
    responses: Array<{ questionId: string; val: any; timestamp: number }>;
  }

  // Component only re-renders when this specific field changes
  const answer = useResponseStore(state => state.answers[questionId]);

type Operator = 'EQUALS' | 'GREATER_THAN' | 'CONTAINS';

interface Condition {
  field: string;
  operator: Operator;
  value: any;
}

interface BranchRule {
  conditions: Condition[];
  logicalOperator: 'AND' | 'OR';
  action: {
    type: 'SHOW' | 'HIDE' | 'SKIP_TO';
    target: string;
  };
}

export class LogicEngine {
  static evaluateCondition(cond: Condition, state: Record<string, any>): boolean {
    const currentValue = state[cond.field];
    if (currentValue === undefined) return false;

    switch (cond.operator) {
      case 'EQUALS':
        return currentValue === cond.value;
      case 'GREATER_THAN':
        return Number(currentValue) > Number(cond.value);
      case 'CONTAINS':
        return Array.isArray(currentValue) && currentValue.includes(cond.value);
      default:
        return false;
    }
  }

  static evaluateRule(rule: BranchRule, state: Record<string, any>): boolean {
    const results = rule.conditions.map(c => this.evaluateCondition(c, state));
    return rule.logicalOperator === 'AND' 
      ? results.every(Boolean) 
      : results.some(Boolean);
  }
}

[Survey Runner App] ──(SSE Connection)──> [Live Ingest Platform]
       │
 (JSON POST Queue)
       ▼
 [Reliable Sync Gateway]