defmodule Polymarket.Data do
  @moduledoc """
  Read-only wrappers for Polymarket's public Data API.

  All endpoints are public GETs against `Polymarket.Config.data_api_host/0`
  (`https://data-api.polymarket.com`). No authentication is required —
  the wallet address is passed as a query parameter, so callers can read
  any address they have, not just their own.

  This is the source of truth for fee-inclusive trade costs (`/activity`)
  and current holdings including unredeemed winners (`/positions`). The
  CLOB fills endpoint reports `size * price` and excludes taker fees;
  prefer Data API `usdcSize` when computing P&L on completed BUY → REDEEM
  cycles.

  ## Response shape and options

  All wrappers delegate to `Polymarket.HTTP.get/3`. See its `@moduledoc`
  for the response contract and the per-call options list (`:host`,
  `:plug`, `:timeout`, `:retry`, `:max_retries`, `:headers`).

  GET requests default to Req's `:transient` retry policy; pass
  `retry: false` to disable.
  """

  @type result :: Polymarket.HTTP.result()

  # Defaults aligned with production usage — these values have shipped
  # against the live API without rejection.
  @default_size_threshold 0.1
  @default_activity_limit 1000
  @default_trades_limit 20

  @doc """
  Lists current positions for a wallet address.

  Returns positions with camelCase fields as sent by the Data API —
  including `size`, `avgPrice`, `currentValue`, and `redeemable`. This
  wrapper does **not** normalize keys to snake_case; pipe the result
  through `Polymarket.Activity` or your own mapper if you need that.

  ## Options

    * `:size_threshold` — minimum position size to return (default `0.1`).
      The Data API filters dust positions on the server side.
    * Plus any option supported by `Polymarket.HTTP.get/3`.

  > #### Pagination {: .info}
  >
  > This wrapper does not send `limit`/`offset`. The Data API defaults to
  > `limit=100`, so wallets with more than 100 positions are truncated by
  > the server. Paginated fetching is not yet exposed here.
  """
  @spec get_positions(String.t(), keyword()) :: result()
  def get_positions(address, opts \\ []) when is_binary(address) do
    {size_threshold, opts} = Keyword.pop(opts, :size_threshold, @default_size_threshold)
    params = [user: address, sizeThreshold: size_threshold]
    request("/positions", Keyword.put(opts, :params, params))
  end

  @doc """
  Lists activity (trades + redemptions) for a wallet address.

  Activity events include:

    * `TRADE` — buys and sells with fee-inclusive `usdcSize` (the actual
      wallet debit/credit, including taker fees).
    * `REDEEM` — payouts on resolved markets.

  Records are keyed by `transactionHash`, not by order hash.

  ## Options

    * `:limit` — max events to return (default `1000`).
    * `:offset` — pagination offset.
    * Plus any option supported by `Polymarket.HTTP.get/3`.
  """
  @spec get_activity(String.t(), keyword()) :: result()
  def get_activity(address, opts \\ []) when is_binary(address) do
    {limit, opts} = Keyword.pop(opts, :limit, @default_activity_limit)
    {offset, opts} = Keyword.pop(opts, :offset, nil)

    params =
      [user: address, limit: limit]
      |> maybe_put_param(:offset, offset)

    request("/activity", Keyword.put(opts, :params, params))
  end

  @doc """
  Lists public trade history for a wallet address.

  ## Options

    * `:limit` — max trades to return (default `20`).
    * `:after` — sent as-is to the API. **Note:** the live Data API
      `GET /trades` endpoint does not currently document an `after`
      filter, so this may be ignored server-side — do not rely on it for
      time-windowing until verified against the live API.
    * `:asset_id` — sent as-is. **Note:** the live `GET /trades` endpoint
      does not currently document an asset filter, so this may likewise
      be ignored server-side.
    * Plus any option supported by `Polymarket.HTTP.get/3`.
  """
  @spec get_trades(String.t(), keyword()) :: result()
  def get_trades(address, opts \\ []) when is_binary(address) do
    {limit, opts} = Keyword.pop(opts, :limit, @default_trades_limit)
    {after_ts, opts} = Keyword.pop(opts, :after, nil)
    {asset_id, opts} = Keyword.pop(opts, :asset_id, nil)

    params =
      [user: address, limit: limit]
      |> maybe_put_param(:after, after_ts)
      |> maybe_put_param(:asset_id, asset_id)

    request("/trades", Keyword.put(opts, :params, params))
  end

  # ── Private ──

  defp request(path, opts) do
    host = Keyword.get(opts, :host, Polymarket.Config.data_api_host())
    Polymarket.HTTP.get(host, path, Keyword.delete(opts, :host))
  end

  defp maybe_put_param(params, _key, nil), do: params
  defp maybe_put_param(params, key, value), do: Keyword.put(params, key, value)
end