import { useState, useCallback } from 'react';
import { db, Item } from '@/lib/db';
import { toast } from 'react-hot-toast';
import { syncOfflineOperations } from '@/lib/sync';

interface UseStockAdjustmentOptions {
  selectedItem: Item | null;
  isOnline: boolean;
  currentUser: any;
  onAdjustmentComplete?: () => void;
  onInventoryUpdate?: (items: Item[]) => void;
}

export function useStockAdjustment(options: UseStockAdjustmentOptions) {
  const { selectedItem, isOnline, currentUser, onAdjustmentComplete, onInventoryUpdate } = options;
  const [adjustQty, setAdjustQty] = useState<number>(1);
  const [adjustType, setAdjustType] = useState<'ADD' | 'REMOVE' | 'TRASH'>('ADD');

  const handleAdjustStock = useCallback(async () => {
    if (!selectedItem) return;

    const toastId = toast.loading("Processing...");

    try {
      const finalAdjustQty = adjustQty;
      const newQty = selectedItem.quantity + (adjustType === 'ADD' ? adjustQty : -adjustQty);

      // Create a unique ID for this operation to prevent double-counting on server
      const operationId = crypto.randomUUID();

      // Queue local operation
      const opType = adjustType === 'ADD' ? 'CHECK_IN' : (adjustType === 'TRASH' ? 'TRASH' : 'CHECK_OUT');

      await db.pendingOperations.add({
        type: opType as any,
        barcode: selectedItem.barcode,
        quantity: finalAdjustQty,
        timestamp: Date.now(),
        synced: 0,
        uuid: operationId
      } as any);

      // Update local UI & DB
      await db.items.update(selectedItem.id!, { quantity: newQty });

      // Get updated inventory
      const updated = await db.items.toArray();
      if (onInventoryUpdate) {
        onInventoryUpdate(updated);
      }

      // Trigger Sync
      if (isOnline && currentUser) {
        try {
          const result = await syncOfflineOperations(currentUser.id);
          if (result.success > 0) {
            toast.success("Inventory updated & synced", { id: toastId });
          } else {
            toast.success("Saved locally", { id: toastId });
          }
        } catch (syncError) {
          console.error("Sync failed:", syncError);
          toast.success("Saved locally (Sync pending)", { id: toastId });
        }
      } else {
        toast.success("Saved locally (Offline)", { id: toastId });
      }

      setAdjustQty(1);
      if (onAdjustmentComplete) {
        onAdjustmentComplete();
      }
    } catch (error: any) {
      console.error("Adjustment failure:", error);
      toast.error("Error saving operation", { id: toastId });
    }
  }, [selectedItem, adjustQty, adjustType, isOnline, currentUser, onAdjustmentComplete, onInventoryUpdate]);

  return {
    adjustQty,
    setAdjustQty,
    adjustType,
    setAdjustType,
    handleAdjustStock
  };
}