private static Link GetLastLink(Link self, int size, PagingParameters pagingOptions)
{
if (pagingOptions?.Limit == null)
{
return(null);
}
var limit = pagingOptions.Limit.Value;
if (size <= limit)
{
return(null);
}
var offset = Math.Ceiling((size - (double)limit) / limit) * limit;
var parameters = new RouteValueDictionary(self.RouteValues)
{
["limit"] = limit,
["offset"] = offset
};
var newLink = Link.ToCollection(self.RouteName, parameters);
return(newLink);
}
private static Link GetNextLink(Link self, int size, PagingParameters pagingOptions)
{
if (pagingOptions?.Limit == null)
{
return(null);
}
if (pagingOptions?.Offset == null)
{
return(null);
}
var limit = pagingOptions.Limit.Value;
var offset = pagingOptions.Offset.Value;
var next = offset + limit;
if (next >= size)
{
return(null);
}
var parameters = new RouteValueDictionary(self.RouteValues)
{
["limit"] = limit,
["offset"] = next
};
var newLink = Link.ToCollection(self.RouteName, parameters);
return(newLink);
}
public static TResponse Create <TResponse>(Link self, T[] items, int size, PagingParameters pagingOptions)
where TResponse : PagedCollection <T>, new()
=> new TResponse
{
Self = self,
Value = items,
Size = size,
Offset = pagingOptions.Offset,
Limit = pagingOptions.Limit,
First = self,
Next = GetNextLink(self, size, pagingOptions),
Previous = GetPreviousLink(self, size, pagingOptions),
Last = GetLastLink(self, size, pagingOptions)
};
private static Link GetPreviousLink(Link self, int size, PagingParameters pagingOptions)
{
if (pagingOptions?.Limit == null)
{
return(null);
}
if (pagingOptions?.Offset == null)
{
return(null);
}
var limit = pagingOptions.Limit.Value;
var offset = pagingOptions.Offset.Value;
if (offset == 0)
{
return(null);
}
if (offset > size)
{
return(GetLastLink(self, size, pagingOptions));
}
var previousPage = Math.Max(offset - limit, 0);
if (previousPage <= 0)
{
return(self);
}
var parameters = new RouteValueDictionary(self.RouteValues)
{
["limit"] = limit,
["offset"] = previousPage
};
var newLink = Link.ToCollection(self.RouteName, parameters);
return(newLink);
}
