# API and Cache Patterns

## Mutation Pattern (PREFERRED)

Always use `useMutation` hooks for data modifications instead of direct Supabase calls.

### ✅ CORRECT Pattern

```typescript
import { useMutation, useQueryClient } from '@tanstack/react-query';
import { supabase } from '@/integrations/supabase/client';
import { toast } from 'sonner';
import { getErrorMessage } from '@/lib/errorHandler';
import { useQueryInvalidation } from '@/lib/queryInvalidation';

export function useMyMutation() {
  const queryClient = useQueryClient();
  const { invalidateRelatedCache } = useQueryInvalidation();

  return useMutation({
    mutationFn: async (params) => {
      const { error } = await supabase
        .from('table')
        .insert(params);
      
      if (error) throw error;
    },
    onMutate: async (params) => {
      // Optional: Optimistic updates
      await queryClient.cancelQueries({ queryKey: ['my-data'] });
      const previous = queryClient.getQueryData(['my-data']);
      
      queryClient.setQueryData(['my-data'], (old) => {
        // Update optimistically
      });
      
      return { previous };
    },
    onError: (error, variables, context) => {
      // Rollback optimistic updates
      if (context?.previous) {
        queryClient.setQueryData(['my-data'], context.previous);
      }
      
      toast.error("Error", {
        description: getErrorMessage(error),
      });
    },
    onSuccess: () => {
      invalidateRelatedCache();
      toast.success("Success", {
        description: "Operation completed successfully.",
      });
    },
  });
}
```

### ❌ INCORRECT Pattern (Direct Supabase)

```typescript
// DON'T DO THIS
const handleSubmit = async () => {
  try {
    const { error } = await supabase.from('table').insert(data);
    if (error) throw error;
    toast.success('Success');
  } catch (error) {
    toast.error(error.message);
  }
};
```

## Error Handling Pattern

### ✅ CORRECT: Use onError callback

```typescript
const mutation = useMutation({
  mutationFn: async (data) => {
    const { error } = await supabase.from('table').insert(data);
    if (error) throw error;
  },
  onError: (error: unknown) => {
    toast.error("Error", {
      description: getErrorMessage(error),
    });
  },
});
```

### ❌ INCORRECT: try/catch in component

```typescript
// Avoid this pattern
const handleSubmit = async () => {
  try {
    await mutation.mutateAsync(data);
  } catch (error) {
    // Error already handled in mutation
  }
};
```

## Query Keys Pattern

### ✅ CORRECT: Use centralized queryKeys

```typescript
import { queryKeys } from '@/lib/queryKeys';

const { data } = useQuery({
  queryKey: queryKeys.parks.detail(slug),
  queryFn: fetchParkDetail,
});
```

### ❌ INCORRECT: Inline query keys

```typescript
// Don't do this
const { data } = useQuery({
  queryKey: ['parks', 'detail', slug],
  queryFn: fetchParkDetail,
});
```

## Cache Invalidation Pattern

### ✅ CORRECT: Use invalidation helpers

```typescript
import { useQueryInvalidation } from '@/lib/queryInvalidation';

const { invalidateParks, invalidateHomepageData } = useQueryInvalidation();

// In mutation onSuccess:
onSuccess: () => {
  invalidateParks();
  invalidateHomepageData('parks');
}
```

### ❌ INCORRECT: Manual invalidation

```typescript
// Avoid this
queryClient.invalidateQueries({ queryKey: ['parks'] });
```

## Benefits of This Pattern

1. **Automatic retry logic**: Failed mutations can be retried automatically
2. **Loading states**: `isPending` flag for UI feedback
3. **Optimistic updates**: Update UI before server confirms
4. **Consistent error handling**: Centralized error handling
5. **Cache coordination**: Proper invalidation timing
6. **Testing**: Easier to mock and test
7. **Type safety**: Better TypeScript support

## Migration Checklist

When migrating a component:

- [ ] Create custom mutation hook in appropriate directory
- [ ] Use `useMutation` instead of direct Supabase calls
- [ ] Implement `onError` callback with toast notifications
- [ ] Implement `onSuccess` callback with cache invalidation
- [ ] Use centralized `queryKeys` for query identification
- [ ] Use `useQueryInvalidation` helpers for cache management
- [ ] Replace loading state with `mutation.isPending`
- [ ] Remove try/catch blocks from component
- [ ] Test optimistic updates if applicable