defmodule TradeMachine.GMGradeV2.Pillars.AssetManagement.DraftCapitalValue do
  @moduledoc """
  Scores the post-scenario draft inventory against the frozen 30-team DAV total.

  `DAV.Inventory` is the shared Phase 7 implementation of AVC's controlled-claim
  rules: it resolves part-level ownership, excludes out-of-window and duplicate
  claims, values swaps as inventory holdings, and preserves incremental swap DAV
  separately for the expanded view.
  """

  alias TradeMachine.GMGradeV2.Benchmark
  alias TradeMachine.GMGradeV2.DAV.Inventory
  alias TradeMachine.GMGradeV2.Percentile
  alias TradeMachine.GMGradeV2.Pillars.AssetManagement.JSONSafe
  alias TradeMachine.GMGradeV2.Result.MetricResult

  @doc "Builds and scores one team's final seven-draft inventory."
  @spec score(binary(), Inventory.graph(), map(), Benchmark.t()) :: MetricResult.t()
  def score(team_id, graph, dav_context, %Benchmark{} = benchmark) do
    team_id
    |> Inventory.value(graph, dav_context)
    |> score_inventory(benchmark)
  end

  @doc "Scores an already-built Phase 7 inventory against the frozen benchmark."
  @spec score_inventory(Inventory.t(), Benchmark.t()) :: MetricResult.t()
  def score_inventory(inventory, %Benchmark{} = benchmark) do
    benchmark_values = benchmark_values(benchmark, "total")

    %MetricResult{
      key: :draft_capital_value,
      version: benchmark.version,
      score: Percentile.score(inventory.total, benchmark_values),
      inputs: %{
        total_dav: inventory.total,
        asset_count: inventory.asset_count,
        window: %{first_year: inventory.window.first, last_year: inventory.window.last},
        benchmark: benchmark_values
      },
      supporting: %{
        first_round_dav: inventory.first_round,
        second_round_dav: inventory.second_round,
        swap_dav: inventory.swap_gain,
        by_year: breakdown(inventory.assets, & &1.year),
        by_origin_team: breakdown(inventory.assets, &(&1.original_team_id || :swap_pool)),
        assets: JSONSafe.value(inventory.assets)
      },
      explanation:
        "Draft Capital Value percentiles #{inventory.total} total DAV across " <>
          "#{inventory.asset_count} controlled assets against the frozen league inventory."
    }
  end

  defp benchmark_values(benchmark, metric) do
    benchmark
    |> Benchmark.section(:dav)
    |> Map.fetch!("metrics")
    |> Map.fetch!(metric)
  end

  defp breakdown(assets, key_fun) do
    assets
    |> Enum.group_by(key_fun)
    |> Enum.map(fn {key, grouped} ->
      {key, Enum.reduce(grouped, 0.0, &(&2 + &1.inventory_dav))}
    end)
    |> Map.new()
  end
end