From d52bb7acc7d94fe2d660a3a4ac136cd77cd0d980 Mon Sep 17 00:00:00 2001
From: Maxim Filonov <53992153+sl1depengwyn@users.noreply.github.com>
Date: Mon, 10 Jul 2023 14:52:06 +0300
Subject: [PATCH] API v2: Add sorting to tokens page

---
 CHANGELOG.md                                  |   1 +
 .../lib/block_scout_web/chain.ex              |  38 ++-
 .../controllers/api/v2/token_controller.ex    |   3 +-
 .../controllers/tokens/tokens_controller.ex   |   1 -
 .../lib/block_scout_web/paging_helper.ex      |  34 ++-
 .../api/v2/token_controller_test.exs          | 240 +++++++++++++++++-
 apps/explorer/lib/explorer/chain.ex           |  89 +------
 apps/explorer/lib/explorer/chain/token.ex     | 175 +++++++++++++
 8 files changed, 469 insertions(+), 112 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0ae959948d..c7300ba061 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@
 - [#7836](https://github.com/blockscout/blockscout/pull/7836) - Improve unverified email flow
 - [#7784](https://github.com/blockscout/blockscout/pull/7784) - Search improvements: Add new fields, light refactoring
 - [#7811](https://github.com/blockscout/blockscout/pull/7811) - Filter addresses before insertion
+- [#7895](https://github.com/blockscout/blockscout/pull/7895) - API v2: Add sorting to tokens page
 
 ### Fixes
 
diff --git a/apps/block_scout_web/lib/block_scout_web/chain.ex b/apps/block_scout_web/lib/block_scout_web/chain.ex
index 488f14279b..6409cc2053 100644
--- a/apps/block_scout_web/lib/block_scout_web/chain.ex
+++ b/apps/block_scout_web/lib/block_scout_web/chain.ex
@@ -150,16 +150,24 @@ defmodule BlockScoutWeb.Chain do
     ]
   end
 
-  def paging_options(%{
-        "market_cap" => market_cap,
-        "holder_count" => holder_count_str,
-        "name" => name,
-        "contract_address_hash" => contract_address_hash_str,
-        "is_name_null" => is_name_null
-      }) do
+  def paging_options(
+        %{
+          "market_cap" => market_cap,
+          "holder_count" => holder_count_str,
+          "name" => name,
+          "contract_address_hash" => contract_address_hash_str,
+          "is_name_null" => is_name_null
+        } = params
+      ) do
     market_cap_decimal =
       case Decimal.parse(market_cap) do
-        {decimal, ""} -> Decimal.round(decimal, 16)
+        {decimal, ""} -> decimal
+        _ -> nil
+      end
+
+    fiat_value_decimal =
+      case Decimal.parse(params["fiat_value"]) do
+        {decimal, ""} -> decimal
         _ -> nil
       end
 
@@ -171,7 +179,13 @@ defmodule BlockScoutWeb.Chain do
         [
           paging_options: %{
             @default_paging_options
-            | key: {market_cap_decimal, holder_count, token_name, contract_address_hash}
+            | key: %{
+                fiat_value: fiat_value_decimal,
+                circulating_market_cap: market_cap_decimal,
+                holder_count: holder_count,
+                name: token_name,
+                contract_address_hash: contract_address_hash
+              }
           }
         ]
 
@@ -403,14 +417,16 @@ defmodule BlockScoutWeb.Chain do
          contract_address_hash: contract_address_hash,
          circulating_market_cap: circulating_market_cap,
          holder_count: holder_count,
-         name: token_name
+         name: token_name,
+         fiat_value: fiat_value
        }) do
     %{
       "market_cap" => circulating_market_cap,
       "holder_count" => holder_count,
       "contract_address_hash" => contract_address_hash,
       "name" => token_name,
-      "is_name_null" => is_nil(token_name)
+      "is_name_null" => is_nil(token_name),
+      "fiat_value" => fiat_value
     }
   end
 
diff --git a/apps/block_scout_web/lib/block_scout_web/controllers/api/v2/token_controller.ex b/apps/block_scout_web/lib/block_scout_web/controllers/api/v2/token_controller.ex
index fdde35d0bd..647e38ab62 100644
--- a/apps/block_scout_web/lib/block_scout_web/controllers/api/v2/token_controller.ex
+++ b/apps/block_scout_web/lib/block_scout_web/controllers/api/v2/token_controller.ex
@@ -17,7 +17,7 @@ defmodule BlockScoutWeb.API.V2.TokenController do
     ]
 
   import BlockScoutWeb.PagingHelper,
-    only: [delete_parameters_from_next_page_params: 1, token_transfers_types_options: 1]
+    only: [delete_parameters_from_next_page_params: 1, token_transfers_types_options: 1, tokens_sorting: 1]
 
   action_fallback(BlockScoutWeb.API.V2.FallbackController)
 
@@ -208,6 +208,7 @@ defmodule BlockScoutWeb.API.V2.TokenController do
       params
       |> paging_options()
       |> Keyword.merge(token_transfers_types_options(params))
+      |> Keyword.merge(tokens_sorting(params))
       |> Keyword.merge(@api_true)
 
     {tokens, next_page} = filter |> Chain.list_top_tokens(options) |> split_list_by_page()
diff --git a/apps/block_scout_web/lib/block_scout_web/controllers/tokens/tokens_controller.ex b/apps/block_scout_web/lib/block_scout_web/controllers/tokens/tokens_controller.ex
index 4e4f289fcf..a0bae11f5e 100644
--- a/apps/block_scout_web/lib/block_scout_web/controllers/tokens/tokens_controller.ex
+++ b/apps/block_scout_web/lib/block_scout_web/controllers/tokens/tokens_controller.ex
@@ -2,7 +2,6 @@ defmodule BlockScoutWeb.TokensController do
   use BlockScoutWeb, :controller
 
   import BlockScoutWeb.Chain, only: [paging_options: 1, next_page_params: 3, split_list_by_page: 1]
-
   alias BlockScoutWeb.{Controller, TokensView}
   alias Explorer.Chain
   alias Phoenix.View
diff --git a/apps/block_scout_web/lib/block_scout_web/paging_helper.ex b/apps/block_scout_web/lib/block_scout_web/paging_helper.ex
index 98fd11f72d..bcbbc9b0a2 100644
--- a/apps/block_scout_web/lib/block_scout_web/paging_helper.ex
+++ b/apps/block_scout_web/lib/block_scout_web/paging_helper.ex
@@ -127,14 +127,18 @@ defmodule BlockScoutWeb.PagingHelper do
 
   def delete_parameters_from_next_page_params(params) when is_map(params) do
     params
-    |> Map.delete("block_hash_or_number")
-    |> Map.delete("transaction_hash")
-    |> Map.delete("address_hash")
-    |> Map.delete("type")
-    |> Map.delete("method")
-    |> Map.delete("filter")
-    |> Map.delete("token_address_hash")
-    |> Map.delete("q")
+    |> Map.drop([
+      "block_hash_or_number",
+      "transaction_hash",
+      "address_hash",
+      "type",
+      "method",
+      "filter",
+      "token_address_hash",
+      "q",
+      "sort",
+      "order"
+    ])
   end
 
   def delete_parameters_from_next_page_params(_), do: nil
@@ -166,4 +170,18 @@ defmodule BlockScoutWeb.PagingHelper do
   end
 
   def search_query(_), do: []
+
+  def tokens_sorting(%{"sort" => sort_field, "order" => order}) do
+    [sorting: do_tokens_sorting(sort_field, order)]
+  end
+
+  def tokens_sorting(_), do: []
+
+  defp do_tokens_sorting("fiat_value", "asc"), do: [asc_nulls_first: :fiat_value]
+  defp do_tokens_sorting("fiat_value", "desc"), do: [desc_nulls_last: :fiat_value]
+  defp do_tokens_sorting("holder_count", "asc"), do: [asc_nulls_first: :holder_count]
+  defp do_tokens_sorting("holder_count", "desc"), do: [desc_nulls_last: :holder_count]
+  defp do_tokens_sorting("circulating_market_cap", "asc"), do: [asc_nulls_first: :circulating_market_cap]
+  defp do_tokens_sorting("circulating_market_cap", "desc"), do: [desc_nulls_last: :circulating_market_cap]
+  defp do_tokens_sorting(_, _), do: []
 end
diff --git a/apps/block_scout_web/test/block_scout_web/controllers/api/v2/token_controller_test.exs b/apps/block_scout_web/test/block_scout_web/controllers/api/v2/token_controller_test.exs
index f46da387f7..fbed9880a6 100644
--- a/apps/block_scout_web/test/block_scout_web/controllers/api/v2/token_controller_test.exs
+++ b/apps/block_scout_web/test/block_scout_web/controllers/api/v2/token_controller_test.exs
@@ -393,12 +393,174 @@ defmodule BlockScoutWeb.API.V2.TokenControllerTest do
   end
 
   describe "/tokens" do
-    defp check_tokens_pagination(tokens, conn) do
-      request = get(conn, "/api/v2/tokens")
+    defp check_tokens_pagination(tokens, conn, additional_params \\ %{}) do
+      request = get(conn, "/api/v2/tokens", additional_params)
       assert response = json_response(request, 200)
-      request_2nd_page = get(conn, "/api/v2/tokens", response["next_page_params"])
+      request_2nd_page = get(conn, "/api/v2/tokens", additional_params |> Map.merge(response["next_page_params"]))
       assert response_2nd_page = json_response(request_2nd_page, 200)
       check_paginated_response(response, response_2nd_page, tokens)
+
+      # by fiat_value
+      tokens_ordered_by_fiat_value = Enum.sort(tokens, &(Decimal.compare(&1.fiat_value, &2.fiat_value) in [:eq, :lt]))
+
+      request_ordered_by_fiat_value =
+        get(conn, "/api/v2/tokens", additional_params |> Map.merge(%{"sort" => "fiat_value", "order" => "desc"}))
+
+      assert response_ordered_by_fiat_value = json_response(request_ordered_by_fiat_value, 200)
+
+      request_ordered_by_fiat_value_2nd_page =
+        get(
+          conn,
+          "/api/v2/tokens",
+          additional_params
+          |> Map.merge(%{"sort" => "fiat_value", "order" => "desc"})
+          |> Map.merge(response_ordered_by_fiat_value["next_page_params"])
+        )
+
+      assert response_ordered_by_fiat_value_2nd_page = json_response(request_ordered_by_fiat_value_2nd_page, 200)
+
+      check_paginated_response(
+        response_ordered_by_fiat_value,
+        response_ordered_by_fiat_value_2nd_page,
+        tokens_ordered_by_fiat_value
+      )
+
+      tokens_ordered_by_fiat_value_asc =
+        Enum.sort(tokens, &(Decimal.compare(&1.fiat_value, &2.fiat_value) in [:eq, :gt]))
+
+      request_ordered_by_fiat_value_asc =
+        get(conn, "/api/v2/tokens", additional_params |> Map.merge(%{"sort" => "fiat_value", "order" => "asc"}))
+
+      assert response_ordered_by_fiat_value_asc = json_response(request_ordered_by_fiat_value_asc, 200)
+
+      request_ordered_by_fiat_value_asc_2nd_page =
+        get(
+          conn,
+          "/api/v2/tokens",
+          additional_params
+          |> Map.merge(%{"sort" => "fiat_value", "order" => "asc"})
+          |> Map.merge(response_ordered_by_fiat_value_asc["next_page_params"])
+        )
+
+      assert response_ordered_by_fiat_value_asc_2nd_page =
+               json_response(request_ordered_by_fiat_value_asc_2nd_page, 200)
+
+      check_paginated_response(
+        response_ordered_by_fiat_value_asc,
+        response_ordered_by_fiat_value_asc_2nd_page,
+        tokens_ordered_by_fiat_value_asc
+      )
+
+      # by holders
+      tokens_ordered_by_holders = Enum.sort(tokens, &(&1.holder_count <= &2.holder_count))
+
+      request_ordered_by_holders =
+        get(conn, "/api/v2/tokens", additional_params |> Map.merge(%{"sort" => "holder_count", "order" => "desc"}))
+
+      assert response_ordered_by_holders = json_response(request_ordered_by_holders, 200)
+
+      request_ordered_by_holders_2nd_page =
+        get(
+          conn,
+          "/api/v2/tokens",
+          additional_params
+          |> Map.merge(%{"sort" => "holder_count", "order" => "desc"})
+          |> Map.merge(response_ordered_by_holders["next_page_params"])
+        )
+
+      assert response_ordered_by_holders_2nd_page = json_response(request_ordered_by_holders_2nd_page, 200)
+
+      check_paginated_response(
+        response_ordered_by_holders,
+        response_ordered_by_holders_2nd_page,
+        tokens_ordered_by_holders
+      )
+
+      tokens_ordered_by_holders_asc = Enum.sort(tokens, &(&1.holder_count >= &2.holder_count))
+
+      request_ordered_by_holders_asc =
+        get(conn, "/api/v2/tokens", additional_params |> Map.merge(%{"sort" => "holder_count", "order" => "asc"}))
+
+      assert response_ordered_by_holders_asc = json_response(request_ordered_by_holders_asc, 200)
+
+      request_ordered_by_holders_asc_2nd_page =
+        get(
+          conn,
+          "/api/v2/tokens",
+          additional_params
+          |> Map.merge(%{"sort" => "holder_count", "order" => "asc"})
+          |> Map.merge(response_ordered_by_holders_asc["next_page_params"])
+        )
+
+      assert response_ordered_by_holders_asc_2nd_page = json_response(request_ordered_by_holders_asc_2nd_page, 200)
+
+      check_paginated_response(
+        response_ordered_by_holders_asc,
+        response_ordered_by_holders_asc_2nd_page,
+        tokens_ordered_by_holders_asc
+      )
+
+      # by circulating_market_cap
+      tokens_ordered_by_circulating_market_cap =
+        Enum.sort(tokens, &(&1.circulating_market_cap <= &2.circulating_market_cap))
+
+      request_ordered_by_circulating_market_cap =
+        get(
+          conn,
+          "/api/v2/tokens",
+          additional_params |> Map.merge(%{"sort" => "circulating_market_cap", "order" => "desc"})
+        )
+
+      assert response_ordered_by_circulating_market_cap = json_response(request_ordered_by_circulating_market_cap, 200)
+
+      request_ordered_by_circulating_market_cap_2nd_page =
+        get(
+          conn,
+          "/api/v2/tokens",
+          additional_params
+          |> Map.merge(%{"sort" => "circulating_market_cap", "order" => "desc"})
+          |> Map.merge(response_ordered_by_circulating_market_cap["next_page_params"])
+        )
+
+      assert response_ordered_by_circulating_market_cap_2nd_page =
+               json_response(request_ordered_by_circulating_market_cap_2nd_page, 200)
+
+      check_paginated_response(
+        response_ordered_by_circulating_market_cap,
+        response_ordered_by_circulating_market_cap_2nd_page,
+        tokens_ordered_by_circulating_market_cap
+      )
+
+      tokens_ordered_by_circulating_market_cap_asc =
+        Enum.sort(tokens, &(&1.circulating_market_cap >= &2.circulating_market_cap))
+
+      request_ordered_by_circulating_market_cap_asc =
+        get(
+          conn,
+          "/api/v2/tokens",
+          additional_params |> Map.merge(%{"sort" => "circulating_market_cap", "order" => "asc"})
+        )
+
+      assert response_ordered_by_circulating_market_cap_asc =
+               json_response(request_ordered_by_circulating_market_cap_asc, 200)
+
+      request_ordered_by_circulating_market_cap_asc_2nd_page =
+        get(
+          conn,
+          "/api/v2/tokens",
+          additional_params
+          |> Map.merge(%{"sort" => "circulating_market_cap", "order" => "asc"})
+          |> Map.merge(response_ordered_by_circulating_market_cap_asc["next_page_params"])
+        )
+
+      assert response_ordered_by_circulating_market_cap_asc_2nd_page =
+               json_response(request_ordered_by_circulating_market_cap_asc_2nd_page, 200)
+
+      check_paginated_response(
+        response_ordered_by_circulating_market_cap_asc,
+        response_ordered_by_circulating_market_cap_asc_2nd_page,
+        tokens_ordered_by_circulating_market_cap_asc
+      )
     end
 
     test "get empty list", %{conn: conn} do
@@ -407,6 +569,70 @@ defmodule BlockScoutWeb.API.V2.TokenControllerTest do
       assert %{"items" => [], "next_page_params" => nil} = json_response(request, 200)
     end
 
+    test "tokens are filtered by single type", %{conn: conn} do
+      erc_20_tokens =
+        for i <- 0..50 do
+          insert(:token, fiat_value: i)
+        end
+
+      erc_721_tokens =
+        for _i <- 0..50 do
+          insert(:token, type: "ERC-721")
+        end
+
+      erc_1155_tokens =
+        for _i <- 0..50 do
+          insert(:token, type: "ERC-1155")
+        end
+
+      check_tokens_pagination(erc_20_tokens |> Enum.reverse(), conn, %{"type" => "ERC-20"})
+      check_tokens_pagination(erc_721_tokens |> Enum.reverse(), conn, %{"type" => "ERC-721"})
+      check_tokens_pagination(erc_1155_tokens |> Enum.reverse(), conn, %{"type" => "ERC-1155"})
+    end
+
+    test "tokens are filtered by multiple type", %{conn: conn} do
+      erc_20_tokens =
+        for i <- 0..25 do
+          insert(:token, fiat_value: i)
+        end
+
+      erc_721_tokens =
+        for _i <- 0..25 do
+          insert(:token, type: "ERC-721")
+        end
+
+      erc_1155_tokens =
+        for _i <- 0..24 do
+          insert(:token, type: "ERC-1155")
+        end
+
+      check_tokens_pagination(
+        erc_721_tokens |> Kernel.++(erc_1155_tokens) |> Enum.reverse(),
+        conn,
+        %{
+          "type" => "ERC-1155,ERC-721"
+        }
+      )
+
+      check_tokens_pagination(
+        erc_20_tokens |> Kernel.++(erc_1155_tokens) |> Enum.reverse(),
+        conn,
+        %{
+          "type" => "[erc-20,ERC-1155]"
+        }
+      )
+    end
+
+    test "sorting by fiat_value", %{conn: conn} do
+      tokens =
+        for i <- 0..50 do
+          insert(:token, fiat_value: i)
+        end
+        |> Enum.reverse()
+
+      check_tokens_pagination(tokens, conn)
+    end
+
     # these tests that tokens paginates by each parameter separately and by any combination of them
     test "pagination by address", %{conn: conn} do
       tokens =
@@ -419,14 +645,14 @@ defmodule BlockScoutWeb.API.V2.TokenControllerTest do
     end
 
     test "pagination by name", %{conn: conn} do
+      named_token = insert(:token, holder_count: 0)
+      empty_named_token = insert(:token, name: "", holder_count: 0)
+
       tokens =
-        for i <- 0..48 do
+        for i <- 1..49 do
           insert(:token, holder_count: i)
         end
 
-      empty_named_token = insert(:token, name: "")
-      named_token = insert(:token)
-
       tokens = [named_token, empty_named_token | tokens]
 
       check_tokens_pagination(tokens, conn)
diff --git a/apps/explorer/lib/explorer/chain.ex b/apps/explorer/lib/explorer/chain.ex
index f2d2e5f023..c9484c673e 100644
--- a/apps/explorer/lib/explorer/chain.ex
+++ b/apps/explorer/lib/explorer/chain.ex
@@ -2471,16 +2471,17 @@ defmodule Explorer.Chain do
   def list_top_tokens(filter, options \\ []) do
     paging_options = Keyword.get(options, :paging_options, @default_paging_options)
     token_type = Keyword.get(options, :token_type, nil)
+    sorting = Keyword.get(options, :sorting, [])
 
-    fetch_top_tokens(filter, paging_options, token_type, options)
+    fetch_top_tokens(filter, paging_options, token_type, sorting, options)
   end
 
-  defp fetch_top_tokens(filter, paging_options, token_type, options) do
-    base_query = base_token_query(token_type)
+  defp fetch_top_tokens(filter, paging_options, token_type, sorting, options) do
+    base_query = Token.base_token_query(token_type, sorting)
 
     base_query_with_paging =
       base_query
-      |> page_tokens(paging_options)
+      |> Token.page_tokens(paging_options, sorting)
       |> limit(^paging_options.page_size)
 
     query =
@@ -2501,31 +2502,6 @@ defmodule Explorer.Chain do
     |> select_repo(options).all()
   end
 
-  defp base_token_query(empty_type) when empty_type in [nil, []] do
-    from(t in Token,
-      order_by: [
-        desc_nulls_last: t.circulating_market_cap,
-        desc_nulls_last: t.holder_count,
-        asc: t.name,
-        asc: t.contract_address_hash
-      ],
-      preload: [:contract_address]
-    )
-  end
-
-  defp base_token_query(token_types) when is_list(token_types) do
-    from(t in Token,
-      where: t.type in ^token_types,
-      order_by: [
-        desc_nulls_last: t.circulating_market_cap,
-        desc_nulls_last: t.holder_count,
-        asc: t.name,
-        asc: t.contract_address_hash
-      ],
-      preload: [:contract_address]
-    )
-  end
-
   @doc """
   Calls `reducer` on a stream of `t:Explorer.Chain.Block.t/0` without `t:Explorer.Chain.Block.Reward.t/0`.
   """
@@ -4645,61 +4621,6 @@ defmodule Explorer.Chain do
     )
   end
 
-  defp page_tokens(query, %PagingOptions{key: nil}), do: query
-
-  defp page_tokens(query, %PagingOptions{key: {circulating_market_cap, holder_count, name, contract_address_hash}}) do
-    from(token in query,
-      where: ^page_tokens_circulating_market_cap(circulating_market_cap, holder_count, name, contract_address_hash)
-    )
-  end
-
-  defp page_tokens_circulating_market_cap(nil, holder_count, name, contract_address_hash) do
-    dynamic(
-      [t],
-      is_nil(t.circulating_market_cap) and ^page_tokens_holder_count(holder_count, name, contract_address_hash)
-    )
-  end
-
-  defp page_tokens_circulating_market_cap(circulating_market_cap, holder_count, name, contract_address_hash) do
-    dynamic(
-      [t],
-      is_nil(t.circulating_market_cap) or t.circulating_market_cap < ^circulating_market_cap or
-        (t.circulating_market_cap == ^circulating_market_cap and
-           ^page_tokens_holder_count(holder_count, name, contract_address_hash))
-    )
-  end
-
-  defp page_tokens_holder_count(nil, name, contract_address_hash) do
-    dynamic(
-      [t],
-      is_nil(t.holder_count) and ^page_tokens_name(name, contract_address_hash)
-    )
-  end
-
-  defp page_tokens_holder_count(holder_count, name, contract_address_hash) do
-    dynamic(
-      [t],
-      is_nil(t.holder_count) or t.holder_count < ^holder_count or
-        (t.holder_count == ^holder_count and ^page_tokens_name(name, contract_address_hash))
-    )
-  end
-
-  defp page_tokens_name(nil, contract_address_hash) do
-    dynamic([t], is_nil(t.name) and ^page_tokens_contract_address_hash(contract_address_hash))
-  end
-
-  defp page_tokens_name(name, contract_address_hash) do
-    dynamic(
-      [t],
-      is_nil(t.name) or
-        (t.name > ^name or (t.name == ^name and ^page_tokens_contract_address_hash(contract_address_hash)))
-    )
-  end
-
-  defp page_tokens_contract_address_hash(contract_address_hash) do
-    dynamic([t], t.contract_address_hash > ^contract_address_hash)
-  end
-
   defp page_blocks(query, %PagingOptions{key: nil}), do: query
 
   defp page_blocks(query, %PagingOptions{key: {block_number}}) do
diff --git a/apps/explorer/lib/explorer/chain/token.ex b/apps/explorer/lib/explorer/chain/token.ex
index 4701f109c2..b59f6ef2de 100644
--- a/apps/explorer/lib/explorer/chain/token.ex
+++ b/apps/explorer/lib/explorer/chain/token.ex
@@ -24,6 +24,7 @@ defmodule Explorer.Chain.Token do
 
   alias Ecto.Changeset
   alias Explorer.Chain.{Address, Hash, Token}
+  alias Explorer.PagingOptions
   alias Explorer.SmartContract.Helper
 
   @typedoc """
@@ -156,4 +157,178 @@ defmodule Explorer.Chain.Token do
   def tokens_by_contract_address_hashes(contract_address_hashes) do
     from(token in __MODULE__, where: token.contract_address_hash in ^contract_address_hashes)
   end
+
+  def base_token_query(type, sorting) do
+    query = from(t in Token, preload: [:contract_address])
+
+    query |> apply_filter(type) |> apply_sorting(sorting)
+  end
+
+  defp apply_filter(query, empty_type) when empty_type in [nil, []], do: query
+
+  defp apply_filter(query, token_types) when is_list(token_types) do
+    from(t in query, where: t.type in ^token_types)
+  end
+
+  @default_sorting [
+    desc_nulls_last: :circulating_market_cap,
+    desc_nulls_last: :holder_count,
+    asc: :name,
+    asc: :contract_address_hash
+  ]
+
+  defp apply_sorting(query, sorting) when is_list(sorting) do
+    from(t in query, order_by: ^sorting_with_defaults(sorting))
+  end
+
+  defp sorting_with_defaults(sorting) when is_list(sorting) do
+    (sorting ++ @default_sorting)
+    |> Enum.uniq_by(fn {_, field} -> field end)
+  end
+
+  def page_tokens(query, paging_options, sorting \\ [])
+  def page_tokens(query, %PagingOptions{key: nil}, _sorting), do: query
+
+  def page_tokens(
+        query,
+        %PagingOptions{
+          key: %{} = key
+        },
+        sorting
+      ) do
+    dynamic_where = sorting |> sorting_with_defaults() |> do_page_tokens()
+
+    from(token in query,
+      where: ^dynamic_where.(key)
+    )
+  end
+
+  defp do_page_tokens([{order, column} | rest]) do
+    fn key -> page_tokens_by_column(key, column, order, do_page_tokens(rest)) end
+  end
+
+  defp do_page_tokens([]), do: nil
+
+  defp page_tokens_by_column(%{fiat_value: nil} = key, :fiat_value, :desc_nulls_last, next_column) do
+    dynamic(
+      [t],
+      is_nil(t.fiat_value) and ^next_column.(key)
+    )
+  end
+
+  defp page_tokens_by_column(%{fiat_value: nil} = key, :fiat_value, :asc_nulls_first, next_column) do
+    next_column.(key)
+  end
+
+  defp page_tokens_by_column(%{fiat_value: fiat_value} = key, :fiat_value, :desc_nulls_last, next_column) do
+    dynamic(
+      [t],
+      is_nil(t.fiat_value) or t.fiat_value < ^fiat_value or
+        (t.fiat_value == ^fiat_value and ^next_column.(key))
+    )
+  end
+
+  defp page_tokens_by_column(%{fiat_value: fiat_value} = key, :fiat_value, :asc_nulls_first, next_column) do
+    dynamic(
+      [t],
+      not is_nil(t.fiat_value) and
+        (t.fiat_value > ^fiat_value or
+           (t.fiat_value == ^fiat_value and ^next_column.(key)))
+    )
+  end
+
+  defp page_tokens_by_column(
+         %{circulating_market_cap: nil} = key,
+         :circulating_market_cap,
+         :desc_nulls_last,
+         next_column
+       ) do
+    dynamic(
+      [t],
+      is_nil(t.circulating_market_cap) and ^next_column.(key)
+    )
+  end
+
+  defp page_tokens_by_column(
+         %{circulating_market_cap: nil} = key,
+         :circulating_market_cap,
+         :asc_nulls_first,
+         next_column
+       ) do
+    next_column.(key)
+  end
+
+  defp page_tokens_by_column(
+         %{circulating_market_cap: circulating_market_cap} = key,
+         :circulating_market_cap,
+         :desc_nulls_last,
+         next_column
+       ) do
+    dynamic(
+      [t],
+      is_nil(t.circulating_market_cap) or t.circulating_market_cap < ^circulating_market_cap or
+        (t.circulating_market_cap == ^circulating_market_cap and ^next_column.(key))
+    )
+  end
+
+  defp page_tokens_by_column(
+         %{circulating_market_cap: circulating_market_cap} = key,
+         :circulating_market_cap,
+         :asc_nulls_first,
+         next_column
+       ) do
+    dynamic(
+      [t],
+      not is_nil(t.circulating_market_cap) and
+        (t.circulating_market_cap > ^circulating_market_cap or
+           (t.circulating_market_cap == ^circulating_market_cap and ^next_column.(key)))
+    )
+  end
+
+  defp page_tokens_by_column(%{holder_count: nil} = key, :holder_count, :desc_nulls_last, next_column) do
+    dynamic(
+      [t],
+      is_nil(t.holder_count) and ^next_column.(key)
+    )
+  end
+
+  defp page_tokens_by_column(%{holder_count: nil} = key, :holder_count, :asc_nulls_first, next_column) do
+    next_column.(key)
+  end
+
+  defp page_tokens_by_column(%{holder_count: holder_count} = key, :holder_count, :desc_nulls_last, next_column) do
+    dynamic(
+      [t],
+      is_nil(t.holder_count) or t.holder_count < ^holder_count or
+        (t.holder_count == ^holder_count and ^next_column.(key))
+    )
+  end
+
+  defp page_tokens_by_column(%{holder_count: holder_count} = key, :holder_count, :asc_nulls_first, next_column) do
+    dynamic(
+      [t],
+      not is_nil(t.holder_count) and
+        (t.holder_count > ^holder_count or
+           (t.holder_count == ^holder_count and ^next_column.(key)))
+    )
+  end
+
+  defp page_tokens_by_column(%{name: nil} = key, :name, :asc, next_column) do
+    dynamic(
+      [t],
+      is_nil(t.name) and ^next_column.(key)
+    )
+  end
+
+  defp page_tokens_by_column(%{name: name} = key, :name, :asc, next_column) do
+    dynamic(
+      [t],
+      is_nil(t.name) or
+        (t.name > ^name or (t.name == ^name and ^next_column.(key)))
+    )
+  end
+
+  defp page_tokens_by_column(%{contract_address_hash: contract_address_hash}, :contract_address_hash, :asc, nil) do
+    dynamic([t], t.contract_address_hash > ^contract_address_hash)
+  end
 end