defmodule QueryBuilder.Extension do
  @moduledoc ~S"""
  Use this module to create an extension module to `QueryBuilder` for app specific query utilities.
  Use your query builder extension module wherever you would normally use `QueryBuilder`

  Example:
  ```
  defmodule MyApp.QueryBuilder do
    use QueryBuilder.Extension, from_opts_full_ops: [:where_initcap]
    import Ecto.Query

    defmacro __using__(opts) do
      quote do
        require QueryBuilder
        QueryBuilder.__using__(unquote(opts))
      end
    end

    # Add app specific query functions
    #---------------------------------

    def where_initcap(query, field, value) do
      text_equals_condition = fn field, value, get_binding_fun ->
        {field, binding} = get_binding_fun.(field)
        dynamic([{^binding, x}], fragment("initcap(?)", ^value) == field(x, ^field))
      end

      query
      |> where(&text_equals_condition.(field, value, &1))
    end
  end

  defmodule MyApp.Accounts.User do
    use MyApp.QueryBuilder

    schema "users" do
      field :name, :string
      field :active, :boolean
    end
  end

  defmodule MyApp.Accounts do
    alias MyApp.QueryBuilder, as: QB

    def list_users(opts \\ []) do
      # Query list can include custom query functions as well:
      # [where_initcap: QB.args(:name, "john"), where: [active: true]]
      MyApp.Accounts.User
      |> QB.from_opts(opts, mode: :full)
      |> Repo.all()
    end
  end
  ```
  """

  defmacro __using__(opts) do
    opts = validate_extension_opts!(opts)

    from_opts_full_ops = Keyword.get(opts, :from_opts_full_ops, [])
    boundary_ops_user_asserted = Keyword.get(opts, :boundary_ops_user_asserted, [])

    quote do
      # Expose all QueryBuilder functions: QueryBuilder.__info__(:functions)

      @doc false
      def __query_builder_extension_from_opts_config__() do
        %{
          from_opts_full_ops: unquote(from_opts_full_ops),
          boundary_ops_user_asserted: unquote(boundary_ops_user_asserted)
        }
      end

      defdelegate left_join(query, assoc_fields, filters \\ [], or_filters \\ []),
        to: QueryBuilder

      defdelegate inner_join(query, assoc_fields), to: QueryBuilder

      defdelegate left_join_leaf(query, assoc_fields, filters \\ [], or_filters \\ []),
        to: QueryBuilder

      defdelegate left_join_path(query, assoc_fields, filters \\ [], or_filters \\ []),
        to: QueryBuilder

      defdelegate left_join_latest(query, assoc_field, opts \\ []), to: QueryBuilder
      defdelegate left_join_top_n(query, assoc_field, opts \\ []), to: QueryBuilder

      defdelegate maybe_where(query, bool, filters), to: QueryBuilder

      defdelegate maybe_where(query, condition, assoc_fields, filters, or_filters \\ []),
        to: QueryBuilder

      defdelegate maybe_order_by(query, bool, value), to: QueryBuilder

      defdelegate maybe_order_by(query, condition, assoc_fields, value),
        to: QueryBuilder

      defdelegate args(args), to: QueryBuilder
      defdelegate args(arg1, arg2), to: QueryBuilder
      defdelegate args(arg1, arg2, arg3), to: QueryBuilder
      defdelegate args(arg1, arg2, arg3, arg4), to: QueryBuilder

      defdelegate new(ecto_query), to: QueryBuilder
      defdelegate subquery(queryable, opts \\ []), to: QueryBuilder
      defdelegate paginate(query, repo, opts \\ []), to: QueryBuilder
      defdelegate distinct(query, value), to: QueryBuilder
      defdelegate distinct(query, assoc_fields, value), to: QueryBuilder
      defdelegate distinct_roots(query, enabled \\ true), to: QueryBuilder
      defdelegate top_n_per(query, opts), to: QueryBuilder
      defdelegate top_n_per(query, assoc_fields, opts), to: QueryBuilder
      defdelegate first_per(query, opts), to: QueryBuilder
      defdelegate first_per(query, assoc_fields, opts), to: QueryBuilder
      defdelegate group_by(query, expr), to: QueryBuilder
      defdelegate group_by(query, assoc_fields, expr), to: QueryBuilder
      defdelegate having(query, filters), to: QueryBuilder
      defdelegate having(query, assoc_fields, filters, or_filters \\ []), to: QueryBuilder
      defdelegate having_any(query, or_groups), to: QueryBuilder
      defdelegate having_any(query, assoc_fields, or_groups), to: QueryBuilder
      defdelegate order_by(query, value), to: QueryBuilder
      defdelegate order_by(query, assoc_fields, value), to: QueryBuilder
      defdelegate preload_separate(query, assoc_fields), to: QueryBuilder
      defdelegate preload_separate_scoped(query, assoc_field, opts \\ []), to: QueryBuilder
      defdelegate preload_through_join(query, assoc_fields), to: QueryBuilder
      defdelegate select(query, selection), to: QueryBuilder
      defdelegate select(query, assoc_fields, selection), to: QueryBuilder
      defdelegate select_merge(query, selection), to: QueryBuilder
      defdelegate select_merge(query, assoc_fields, selection), to: QueryBuilder
      defdelegate count(), to: QueryBuilder
      defdelegate count(token), to: QueryBuilder
      defdelegate count(token, modifier), to: QueryBuilder
      defdelegate count_distinct(token), to: QueryBuilder
      defdelegate avg(token), to: QueryBuilder
      defdelegate sum(token), to: QueryBuilder
      defdelegate min(token), to: QueryBuilder
      defdelegate max(token), to: QueryBuilder
      defdelegate array_agg(token, opts \\ []), to: QueryBuilder
      defdelegate where(query, filters), to: QueryBuilder
      defdelegate where(query, assoc_fields, filters, or_filters \\ []), to: QueryBuilder
      defdelegate where_any(query, or_groups), to: QueryBuilder
      defdelegate where_any(query, assoc_fields, or_groups), to: QueryBuilder
      defdelegate where_has(query, assoc_fields, filters \\ []), to: QueryBuilder
      defdelegate where_missing(query, assoc_fields, filters \\ []), to: QueryBuilder
      defdelegate where_exists(query, assoc_fields, filters, or_filters \\ []), to: QueryBuilder

      defdelegate where_not_exists(query, assoc_fields, filters, or_filters \\ []),
        to: QueryBuilder

      defdelegate where_exists_subquery(query, assoc_fields, opts \\ []), to: QueryBuilder

      defdelegate where_not_exists_subquery(query, assoc_fields, opts \\ []),
        to: QueryBuilder

      defdelegate offset(query, value), to: QueryBuilder
      defdelegate limit(query, value), to: QueryBuilder

      @doc ~S"""
      Applies a keyword list of operations to a query.

      Like `QueryBuilder.from_opts/*`, this defaults to boundary mode.

      To use the full `from_opts` surface, pass `mode: :full`. Custom extension
      operations are rejected by default in full mode; allowlist them via
      `use QueryBuilder.Extension, from_opts_full_ops: [...]`.

      Note: operations allowlisted via `boundary_ops_user_asserted: [...]` are also
      accepted in full mode (full is a superset).
      """
      def from_opts(query, opts) do
        from_opts(query, opts, mode: :boundary)
      end

      def from_opts(query, opts, from_opts_opts) do
        QueryBuilder.__from_opts__(query, opts, __MODULE__, from_opts_opts)
      end

      # Migration shim: v1 exposed from_list/2. Keep it to raise with a clear upgrade hint.
      def from_list(_query, _opts) do
        raise ArgumentError,
              "from_list/2 was renamed to from_opts/2; please update your call sites"
      end
    end
  end

  defp validate_extension_opts!(opts) when is_list(opts) do
    unless Keyword.keyword?(opts) do
      raise ArgumentError,
            "use QueryBuilder.Extension expects options to be a keyword list, got: #{inspect(opts)}"
    end

    allowed_keys = [:from_opts_full_ops, :boundary_ops_user_asserted]

    case Keyword.keys(opts) -- allowed_keys do
      [] ->
        :ok

      unknown ->
        raise ArgumentError,
              "use QueryBuilder.Extension got unknown options #{inspect(unknown)}; " <>
                "supported options: #{inspect(allowed_keys)}"
    end

    validate_extension_ops_list!(opts, :from_opts_full_ops)
    validate_extension_ops_list!(opts, :boundary_ops_user_asserted)

    opts
  end

  defp validate_extension_opts!(opts) do
    raise ArgumentError,
          "use QueryBuilder.Extension expects options to be a keyword list, got: #{inspect(opts)}"
  end

  defp validate_extension_ops_list!(opts, key) do
    case Keyword.get(opts, key, []) do
      list when is_list(list) ->
        Enum.each(list, fn
          op when is_atom(op) ->
            :ok

          other ->
            raise ArgumentError,
                  "use QueryBuilder.Extension expects #{inspect(key)} to be a list of atoms, got: #{inspect(other)} in #{inspect(list)}"
        end)

      other ->
        raise ArgumentError,
              "use QueryBuilder.Extension expects #{inspect(key)} to be a list of atoms, got: #{inspect(other)}"
    end
  end
end