defmodule BearCli.AuditLogs do
  @moduledoc """
  `bear audit-logs` 指令群（稽核日誌；docs/commands.md §3.10、issue #12）。

  對應伺服器端稽核日誌 JSON API（alterminal/bear#46，`/api/v1/audit-logs`、
  PAT Bearer、admin 限定）。認證沿用既有 PAT 憑證（`BEAR_TOKEN` 或憑證檔）。

  退出碼：0 成功；2 用法錯誤；3 未登入或 401；6 網路／伺服器錯誤；
  8 權限不足（403，僅限 admin）。
  """

  import BearCli.Admin, only: [context: 1, fail: 3, format_api_error: 2]
  alias BearCli.Api

  # -- 入口 --

  @doc """
  執行 `bear audit-logs <動詞>`，回傳退出碼。`opts[:audit_logs_api]` 可注入
  假 API 模組供測試（需實作 `audit_logs_list/3`）。
  """
  def run(:list, opts) do
    api = opts[:audit_logs_api] || Api

    with {:ok, ctx} <- context(opts) do
      params =
        [page: opts[:page] || 1, per_page: opts[:per_page] || 50]
        |> maybe_put(:category, opts[:category])

      case api.audit_logs_list(ctx.issuer, ctx.token, params) do
        {:ok, body} ->
          entries = body["data"] || []

          if opts[:json] do
            IO.puts(
              Jason.encode!(
                Map.take(body, ["page", "per_page", "total", "total_pages", "emails"])
                |> Map.merge(%{ok: true, entries: entries})
              )
            )
          else
            print_table(entries, body["emails"] || %{})
          end

          0

        {:error, _kind, _detail} = error ->
          {message, code} = format_api_error(ctx, error)
          fail(opts, message, code)
      end
    else
      {:error, message, code} -> fail(opts, message, code)
    end
  end

  defp maybe_put(params, _key, nil), do: params
  defp maybe_put(params, _key, ""), do: params
  defp maybe_put(params, key, value), do: Keyword.put(params, key, value)

  # -- 輸出 --

  @table_headers ["TIME", "CATEGORY", "EVENT", "ACTOR", "ACCOUNT"]

  defp print_table(entries, emails) do
    rows =
      Enum.map(entries, fn entry ->
        [
          entry["created_at"] || "",
          entry["category"] || "",
          entry["event"] || "",
          email_of(emails, entry["actor_id"]),
          email_of(emails, entry["account_id"])
        ]
      end)

    widths =
      Enum.with_index(@table_headers, fn _header, i ->
        Enum.max([
          String.length(Enum.at(@table_headers, i))
          | Enum.map(rows, &String.length(Enum.at(&1, i)))
        ])
      end)

    render_row = fn cells ->
      cells
      |> Enum.with_index()
      |> Enum.map(fn {cell, i} -> String.pad_trailing(cell, Enum.at(widths, i)) end)
      |> Enum.join("  ")
      |> String.trim_trailing()
    end

    IO.puts(render_row.(@table_headers))
    Enum.each(rows, fn cells -> IO.puts(render_row.(cells)) end)
  end

  defp email_of(_emails, nil), do: "-"

  defp email_of(emails, id) do
    case Map.get(emails, id) do
      nil -> String.slice(id || "", 0, 8)
      email -> email
    end
  end
end