defmodule CPSolver.Examples.FairWeights do

alias CPSolver.IntVariable, as: Variable
  alias CPSolver.Model
  alias CPSolver.Constraint.Maximum
  alias CPSolver.Constraint.Factory

  import CPSolver.Variable.View.Factory
  alias CPSolver.Objective

  def model(node_map, weight_range \\ 32..64) do
    {weighted_values, memory_plus_load} =
      Enum.map(node_map, fn {node_id, %{memory: memory, load: load}} ->
        measure = memory + load
      #Variable.new(Enum.map(1..64, fn val -> val * (memory + load) end),
      {mul(Variable.new(weight_range,
      name: node_id), measure),
      measure}
    end)
    |> Enum.unzip()

    upper_bound = Enum.max(weight_range) * Enum.max(memory_plus_load) -
      Enum.min(weight_range) * Enum.min(memory_plus_load)

    IO.inspect(upper_bound, label: :upper_bound)

    {max_var, max_constraint} = Factory.maximum(weighted_values)
    {min_var, mix_constraint} = Factory.minimum(weighted_values)

    {difference_var, difference_constraint} = Factory.subtract(max_var, min_var)

    ub_constraint = Factory.leq(difference_var, upper_bound)
    Model.new([difference_var, max_var, min_var] ++ weighted_values, [
      ub_constraint,
      max_constraint, difference_constraint, mix_constraint],
      objective: Objective.minimize(difference_var)
    )
  end

  def test(opts \\ []) do
    model = model(sample())
    {:ok, res} = CPSolver.solve(model, opts)
  end

  def sample() do
    %{
    "fwb4" => %{memory: 233, load: 23},
    "fwb2" => %{memory: 225, load: 24},
    "slb4" => %{memory: 243, load: 12},
    "tpb4" => %{memory: 325, load: 27},
    "xra2" => %{memory: 321, load: 25},
    "tpa1" => %{memory: 306, load: 36},
    "xra4" => %{memory: 316, load: 21},
    "fwc3" => %{memory: 181, load: 6},
    "slb1" => %{memory: 246, load: 14},
    "fwa3" => %{memory: 276, load: 33},
    "xrb3" => %{memory: 321, load: 24},
    "fwc4" => %{memory: 183, load: 7},
    "tpb3" => %{memory: 342, load: 25},
    "fwb1" => %{memory: 238, load: 28},
    "xra1" => %{memory: 319, load: 24},
    "fwa2" => %{memory: 229, load: 23},
    "tpb1" => %{memory: 305, load: 23},
    "fwb3" => %{memory: 258, load: 29},
    "sla2" => %{memory: 248, load: 16},
    "sla4" => %{memory: 240, load: 14},
    "fwc2" => %{memory: 181, load: 6},
    "xrb1" => %{memory: 318, load: 26},
    "tpa3" => %{memory: 319, load: 25},
    "xrb2" => %{memory: 304, load: 25},
    "tpa2" => %{memory: 318, load: 21},
    "slb2" => %{memory: 227, load: 9},
    "fwa4" => %{memory: 238, load: 22},
    "sla1" => %{memory: 234, load: 17},
    "sla3" => %{memory: 231, load: 16},
    "fwa1" => %{memory: 258, load: 25},
    "tpa4" => %{memory: 322, load: 22},
    "slb3" => %{memory: 237, load: 14},
    "fwc1" => %{memory: 184, load: 5},
    "xra3" => %{memory: 308, load: 27},
    "xrb4" => %{memory: 329, load: 26},
    "tpb2" => %{memory: 320, load: 26}
    }
  end
end