index.community/backend/lib/backend_web/views/graph_view.ex

defmodule BackendWeb.GraphView do
  use BackendWeb, :view
  alias BackendWeb.GraphView

  def render("index.json", %{nodes: nodes, edges: edges}) do
    %{
      nodes: render_many(nodes, GraphView, "node.json"),
      edges: render_many(edges, GraphView, "edge.json")
    }
  end

  def render("node.json", %{graph: node}) do
    size =
      case node.user_count > 1 do
        true -> :math.log(node.user_count)
        false -> 1
      end

    # This is the format that cytoscape.js expects.
    %{
      data: %{
        id: node.domain,
        label: node.domain,
        size: size
      },
      position: %{
        x: node.x,
        y: node.y
      }
    }
  end

  def render("edge.json", %{graph: edge}) do
    %{
      data: %{
        id: edge.id,
        source: edge.source_domain,
        target: edge.target_domain,
        weight: edge.weight
      }
    }
  end
end