// Memory leak prevention utilities

class RequestTracker {
  private activeRequests = new Set<AbortController>();

  addRequest(controller: AbortController) {
    this.activeRequests.add(controller);
  }

  removeRequest(controller: AbortController) {
    this.activeRequests.delete(controller);
  }

  cancelAllRequests() {
    this.activeRequests.forEach(controller => {
      try {
        controller.abort();
      } catch (error) {
        console.warn('Failed to abort request:', error);
      }
    });
    this.activeRequests.clear();
  }

  getActiveRequestCount(): number {
    return this.activeRequests.size;
  }
}

export const requestTracker = new RequestTracker();

// Enhanced fetch with automatic tracking
export function trackedFetch(input: RequestInfo | URL, init?: RequestInit): Promise<Response> {
  const controller = new AbortController();
  const timeoutId = setTimeout(() => {
    controller.abort();
  }, 30000); // 30 second timeout

  // Merge abort signals
  if (init?.signal) {
    init.signal.addEventListener('abort', () => {
      controller.abort();
    });
  }

  const trackedInit = {
    ...init,
    signal: controller.signal,
  };

  requestTracker.addRequest(controller);

  return fetch(input, trackedInit).finally(() => {
    clearTimeout(timeoutId);
    requestTracker.removeRequest(controller);
  });
}

// Cleanup utility for components
export function useCleanup() {
  const cleanupFunctions = new Set<() => void>();

  const addCleanup = (cleanup: () => void) => {
    cleanupFunctions.add(cleanup);
  };

  const executeCleanup = () => {
    cleanupFunctions.forEach(cleanup => {
      try {
        cleanup();
      } catch (error) {
        console.warn('Cleanup function failed:', error);
      }
    });
    cleanupFunctions.clear();
  };

  return { addCleanup, executeCleanup };
}

// Memory monitoring for development
export function startMemoryMonitoring() {
  if (process.env.NODE_ENV === 'development' && typeof window !== 'undefined') {
    setInterval(() => {
      if ('memory' in performance) {
        const memory = (performance as Performance & { memory?: { usedJSHeapSize: number; totalJSHeapSize: number; jsHeapSizeLimit: number } }).memory;
        if (!memory) return;
        const usedMB = Math.round(memory.usedJSHeapSize / 1048576);

        const limitMB = Math.round(memory.jsHeapSizeLimit / 1048576);
        
        // Log memory usage every 30 seconds
        if (usedMB > limitMB * 0.9) {
          console.warn(`High memory usage: ${usedMB}MB / ${limitMB}MB`);
        }
      }
    }, 30000);
  }
}

// Debounced function with cleanup
export function debounceWithCleanup<T extends (...args: unknown[]) => unknown>(
  func: T,
  wait: number
): { debouncedFn: (...args: Parameters<T>) => void; cancel: () => void } {
  let timeoutId: NodeJS.Timeout | null = null;

  const debouncedFn = (...args: Parameters<T>) => {
    if (timeoutId) {
      clearTimeout(timeoutId);
    }
    timeoutId = setTimeout(() => {
      func(...args);
      timeoutId = null;
    }, wait);
  };

  const cancel = () => {
    if (timeoutId) {
      clearTimeout(timeoutId);
      timeoutId = null;
    }
  };

  return { debouncedFn, cancel };
}