From 234422293089f42355504e7d3f58776212a4b27b Mon Sep 17 00:00:00 2001
From: Paul Tsupikoff <goodsoft@goodsoft.lv>
Date: Thu, 22 Aug 2019 17:34:50 +0200
Subject: [PATCH] Fetch unremovable staking and disallow staking to empty pool
 (#2608)

is_unremovable field is added to staking pools and filled using contract
getter unremovableValidator.
If such validator hasn't staked to itself yet, Stake button is disabled.
Also, Remove My Pool button is disabled for such validator.

Also, fetching is_validator field is optimized, and is now performed using
one getValidators call instead of one isValidator call per pool.
---
 .../block_scout_web/controllers/stakes_controller.ex | 10 +++++++++-
 .../templates/stakes/_stakes_modal_move.html.eex     |  4 +++-
 .../templates/stakes/_stakes_top.html.eex            |  4 +++-
 .../explorer/chain/import/runner/staking_pools.ex    |  1 +
 apps/explorer/lib/explorer/chain/staking_pool.ex     |  5 ++++-
 .../explorer/lib/explorer/staking/contract_reader.ex |  4 ++--
 apps/explorer/lib/explorer/staking/contract_state.ex | 12 ++++++++----
 ...190820212841_add_unremovable_to_staking_pools.exs |  9 +++++++++
 .../test/explorer/staking/contract_state_test.exs    | 11 ++++-------
 9 files changed, 43 insertions(+), 17 deletions(-)
 create mode 100644 apps/explorer/priv/repo/migrations/20190820212841_add_unremovable_to_staking_pools.exs

diff --git a/apps/block_scout_web/lib/block_scout_web/controllers/stakes_controller.ex b/apps/block_scout_web/lib/block_scout_web/controllers/stakes_controller.ex
index 4371f19a2f..0a3a51c282 100644
--- a/apps/block_scout_web/lib/block_scout_web/controllers/stakes_controller.ex
+++ b/apps/block_scout_web/lib/block_scout_web/controllers/stakes_controller.ex
@@ -92,7 +92,7 @@ defmodule BlockScoutWeb.StakesController do
           average_block_time: average_block_time,
           pools_type: filter,
           buttons: %{
-            stake: true,
+            stake: stake_allowed?(pool, delegator),
             move: move_allowed?(delegator),
             withdraw: withdraw_allowed?(delegator, epoch_number)
           }
@@ -130,6 +130,14 @@ defmodule BlockScoutWeb.StakesController do
     inactive_pools_path(conn, :index, params)
   end
 
+  defp stake_allowed?(pool, nil) do
+    Decimal.positive?(pool.self_staked_amount)
+  end
+
+  defp stake_allowed?(pool, delegator) do
+    Decimal.positive?(pool.self_staked_amount) or delegator.delegator_address_hash == pool.staking_address_hash
+  end
+
   defp move_allowed?(nil), do: false
 
   defp move_allowed?(delegator) do
diff --git a/apps/block_scout_web/lib/block_scout_web/templates/stakes/_stakes_modal_move.html.eex b/apps/block_scout_web/lib/block_scout_web/templates/stakes/_stakes_modal_move.html.eex
index e140654e95..e2e620a725 100644
--- a/apps/block_scout_web/lib/block_scout_web/templates/stakes/_stakes_modal_move.html.eex
+++ b/apps/block_scout_web/lib/block_scout_web/templates/stakes/_stakes_modal_move.html.eex
@@ -26,7 +26,9 @@
               <div class="input-group form-group">
                 <select pool-select class="form-control">
                   <option disabled <%= unless @pool_to do "selected" end %>><%= gettext("Choose Pool") %></option>
-                  <%= for %{pool: pool} <- @pools, pool.staking_address_hash != @pool_from.staking_address_hash do %>
+                  <%= for %{pool: pool} <- @pools,
+                        pool.staking_address_hash != @pool_from.staking_address_hash,
+                        Decimal.positive?(pool.self_staked_amount) or pool.staking_address_hash == @delegator.delegator_address_hash do %>
                     <option
                       value="<%= pool.staking_address_hash %>"
                       <%= if @pool_to && pool.staking_address_hash == @pool_to.staking_address_hash do "selected" end %>
diff --git a/apps/block_scout_web/lib/block_scout_web/templates/stakes/_stakes_top.html.eex b/apps/block_scout_web/lib/block_scout_web/templates/stakes/_stakes_top.html.eex
index 7889b19aa7..75fab761b6 100644
--- a/apps/block_scout_web/lib/block_scout_web/templates/stakes/_stakes_top.html.eex
+++ b/apps/block_scout_web/lib/block_scout_web/templates/stakes/_stakes_top.html.eex
@@ -8,7 +8,9 @@
       <!-- Buttons -->
       <div class="stakes-top-buttons">
         <%= if @account[:pool] && @account.pool.is_active do %>
-          <%= render BlockScoutWeb.StakesView, "_stakes_btn_remove_pool.html", text: gettext("Remove My Pool"), extra_class: "js-remove-pool" %>
+          <%= unless @account.pool.is_unremovable do %>
+            <%= render BlockScoutWeb.StakesView, "_stakes_btn_remove_pool.html", text: gettext("Remove My Pool"), extra_class: "js-remove-pool" %>
+          <% end %>
         <% else %>
           <%= render BlockScoutWeb.CommonComponentsView, "_btn_add_full.html", text: gettext("Become a Candidate"), extra_class: "js-become-candidate" %>
         <% end %>
diff --git a/apps/explorer/lib/explorer/chain/import/runner/staking_pools.ex b/apps/explorer/lib/explorer/chain/import/runner/staking_pools.ex
index 030f240d8d..0666aab2fb 100644
--- a/apps/explorer/lib/explorer/chain/import/runner/staking_pools.ex
+++ b/apps/explorer/lib/explorer/chain/import/runner/staking_pools.ex
@@ -127,6 +127,7 @@ defmodule Explorer.Chain.Import.Runner.StakingPools do
           is_active: fragment("EXCLUDED.is_active"),
           is_banned: fragment("EXCLUDED.is_banned"),
           is_validator: fragment("EXCLUDED.is_validator"),
+          is_unremovable: fragment("EXCLUDED.is_unremovable"),
           likelihood: fragment("EXCLUDED.likelihood"),
           block_reward_ratio: fragment("EXCLUDED.block_reward_ratio"),
           staked_ratio: fragment("EXCLUDED.staked_ratio"),
diff --git a/apps/explorer/lib/explorer/chain/staking_pool.ex b/apps/explorer/lib/explorer/chain/staking_pool.ex
index d35ea83e39..f3ceefe424 100644
--- a/apps/explorer/lib/explorer/chain/staking_pool.ex
+++ b/apps/explorer/lib/explorer/chain/staking_pool.ex
@@ -20,6 +20,7 @@ defmodule Explorer.Chain.StakingPool do
           is_active: boolean,
           is_banned: boolean,
           is_validator: boolean,
+          is_unremovable: boolean,
           likelihood: Decimal.t(),
           block_reward_ratio: Decimal.t(),
           staked_ratio: Decimal.t(),
@@ -34,11 +35,12 @@ defmodule Explorer.Chain.StakingPool do
     is_active delegators_count staked_amount self_staked_amount is_validator
     was_validator_count is_banned was_banned_count banned_until likelihood
     staked_ratio staking_address_hash mining_address_hash block_reward_ratio
+    is_unremovable
   )a
   @req_attrs ~w(
     is_active delegators_count staked_amount self_staked_amount is_validator
     was_validator_count is_banned was_banned_count banned_until
-    staking_address_hash mining_address_hash
+    staking_address_hash mining_address_hash is_unremovable
   )a
 
   schema "staking_pools" do
@@ -47,6 +49,7 @@ defmodule Explorer.Chain.StakingPool do
     field(:is_active, :boolean, default: false)
     field(:is_banned, :boolean, default: false)
     field(:is_validator, :boolean, default: false)
+    field(:is_unremovable, :boolean, default: false)
     field(:likelihood, :decimal)
     field(:block_reward_ratio, :decimal)
     field(:staked_ratio, :decimal)
diff --git a/apps/explorer/lib/explorer/staking/contract_reader.ex b/apps/explorer/lib/explorer/staking/contract_reader.ex
index 236fc93676..33d954a5bb 100644
--- a/apps/explorer/lib/explorer/staking/contract_reader.ex
+++ b/apps/explorer/lib/explorer/staking/contract_reader.ex
@@ -17,7 +17,8 @@ defmodule Explorer.Staking.ContractReader do
       inactive_pools: {:staking, "getPoolsInactive", []},
       pools_likely: {:staking, "getPoolsToBeElected", []},
       pools_likelihood: {:staking, "getPoolsLikelihood", []},
-      validators: {:validator_set, "getValidators", []}
+      validators: {:validator_set, "getValidators", []},
+      unremovable_validator: {:validator_set, "unremovableValidator", []}
     ]
   end
 
@@ -37,7 +38,6 @@ defmodule Explorer.Staking.ContractReader do
 
   def pool_mining_requests(mining_address) do
     [
-      is_validator: {:validator_set, "isValidator", [mining_address]},
       was_validator_count: {:validator_set, "validatorCounter", [mining_address]},
       is_banned: {:validator_set, "isValidatorBanned", [mining_address]},
       banned_until: {:validator_set, "bannedUntil", [mining_address]},
diff --git a/apps/explorer/lib/explorer/staking/contract_state.ex b/apps/explorer/lib/explorer/staking/contract_state.ex
index 6ebb46b143..f713801f12 100644
--- a/apps/explorer/lib/explorer/staking/contract_state.ex
+++ b/apps/explorer/lib/explorer/staking/contract_state.ex
@@ -128,6 +128,8 @@ defmodule Explorer.Staking.ContractState do
     :ets.insert(@table_name, settings)
 
     pools = global_responses.active_pools ++ global_responses.inactive_pools
+    is_validator = Enum.into(global_responses.validators, %{}, &{hash_to_string(&1), true})
+    unremovable_validator = global_responses.unremovable_validator
 
     pool_staking_responses =
       pools
@@ -179,7 +181,9 @@ defmodule Explorer.Staking.ContractState do
             end,
           likelihood: ratio(likelihood[staking_address] || 0, total_likelihood),
           block_reward_ratio: staking_response.block_reward / 10_000,
-          is_deleted: false
+          is_deleted: false,
+          is_validator: is_validator[staking_response.mining_address_hash] || false,
+          is_unremovable: hash_to_string(staking_address) == unremovable_validator
         }
         |> Map.merge(
           Map.take(staking_response, [
@@ -191,7 +195,6 @@ defmodule Explorer.Staking.ContractState do
         )
         |> Map.merge(
           Map.take(mining_response, [
-            :is_validator,
             :was_validator_count,
             :is_banned,
             :banned_until,
@@ -203,10 +206,9 @@ defmodule Explorer.Staking.ContractState do
     delegator_entries =
       Enum.map(delegator_responses, fn {{pool_address, delegator_address, is_active}, response} ->
         staking_response = pool_staking_responses[pool_address]
-        mining_response = pool_mining_responses[pool_address]
 
         reward_ratio =
-          if mining_response.is_validator do
+          if is_validator[staking_response.mining_address_hash] do
             reward_ratio = delegator_rewards[pool_address][delegator_address]
 
             if reward_ratio do
@@ -304,6 +306,8 @@ defmodule Explorer.Staking.ContractState do
   defp ratio(_numerator, 0), do: 0
   defp ratio(numerator, denominator), do: numerator / denominator * 100
 
+  defp hash_to_string(hash), do: "0x" <> Base.encode16(hash, case: :lower)
+
   # sobelow_skip ["Traversal"]
   defp abi(file_name) do
     :explorer
diff --git a/apps/explorer/priv/repo/migrations/20190820212841_add_unremovable_to_staking_pools.exs b/apps/explorer/priv/repo/migrations/20190820212841_add_unremovable_to_staking_pools.exs
new file mode 100644
index 0000000000..a7d82d31b6
--- /dev/null
+++ b/apps/explorer/priv/repo/migrations/20190820212841_add_unremovable_to_staking_pools.exs
@@ -0,0 +1,9 @@
+defmodule Explorer.Repo.Migrations.AddUnremovableToStakingPools do
+  use Ecto.Migration
+
+  def change do
+    alter table(:staking_pools) do
+      add(:is_unremovable, :boolean, default: false, null: false)
+    end
+  end
+end
diff --git a/apps/explorer/test/explorer/staking/contract_state_test.exs b/apps/explorer/test/explorer/staking/contract_state_test.exs
index 38614c9110..96c0cf2070 100644
--- a/apps/explorer/test/explorer/staking/contract_state_test.exs
+++ b/apps/explorer/test/explorer/staking/contract_state_test.exs
@@ -76,7 +76,7 @@ defmodule Explorer.Staking.ContractStateTest do
       EthereumJSONRPC.Mox,
       :json_rpc,
       fn requests, _opts ->
-        assert length(requests) == 11
+        assert length(requests) == 12
 
         {:ok,
          format_responses([
@@ -90,7 +90,8 @@ defmodule Explorer.Staking.ContractStateTest do
            "0x00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000001000000000000000000000000b6695f5c2e3f5eff8036b5f5f3a9d83a5310e51e",
            "0x00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000002000000000000000000000000b916e7e1f4bcb13549602ed042d36746fd0d96c9000000000000000000000000db9cb2478d917719c53862008672166808258577",
            "0x00000000000000000000000000000000000000000000000000000000000000400000000000000000000000000000000000000000000000000000000000000514000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000c8000000000000000000000000000000000000000000000000000000000000044c",
-           "0x00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000003000000000000000000000000bbcaa8d48289bb1ffcf9808d9aa4b1d215054c78000000000000000000000000f67cc5231c5858ad6cc87b105217426e17b824bb000000000000000000000000be69eb0968226a1808975e1a1f2127667f2bffb3"
+           "0x00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000003000000000000000000000000bbcaa8d48289bb1ffcf9808d9aa4b1d215054c78000000000000000000000000f67cc5231c5858ad6cc87b105217426e17b824bb000000000000000000000000be69eb0968226a1808975e1a1f2127667f2bffb3",
+           "0x0000000000000000000000000b2f5e2f3cbd864eaa2c642e3769c1582361caf6"
          ])}
       end
     )
@@ -147,26 +148,22 @@ defmodule Explorer.Staking.ContractStateTest do
       EthereumJSONRPC.Mox,
       :json_rpc,
       fn requests, _opts ->
-        assert length(requests) == 20
+        assert length(requests) == 16
 
         {:ok,
          format_responses([
-           "0x0000000000000000000000000000000000000000000000000000000000000001",
            "0x000000000000000000000000000000000000000000000000000000000000004b",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
-           "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000002",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
-           "0x0000000000000000000000000000000000000000000000000000000000000001",
            "0x000000000000000000000000000000000000000000000000000000000000004a",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
-           "0x0000000000000000000000000000000000000000000000000000000000000001",
            "0x000000000000000000000000000000000000000000000000000000000000004a",
            "0x0000000000000000000000000000000000000000000000000000000000000000",
            "0x0000000000000000000000000000000000000000000000000000000000000000",