From 233d539a006c7575db809d0fe3d12f565b3b1589 Mon Sep 17 00:00:00 2001
From: Felipe Renan <felipe.renan@plataformatec.com.br>
Date: Fri, 26 Oct 2018 18:20:20 -0300
Subject: [PATCH] Add AddressCurrentTokenBalance schema

---
 .../chain/address/current_token_balance.ex    | 60 +++++++++++++++++++
 ..._create_address_current_token_balances.exs | 32 ++++++++++
 apps/explorer/test/support/factory.ex         | 11 ++++
 3 files changed, 103 insertions(+)
 create mode 100644 apps/explorer/lib/explorer/chain/address/current_token_balance.ex
 create mode 100644 apps/explorer/priv/repo/migrations/20181026180921_create_address_current_token_balances.exs

diff --git a/apps/explorer/lib/explorer/chain/address/current_token_balance.ex b/apps/explorer/lib/explorer/chain/address/current_token_balance.ex
new file mode 100644
index 0000000000..448ae7da34
--- /dev/null
+++ b/apps/explorer/lib/explorer/chain/address/current_token_balance.ex
@@ -0,0 +1,60 @@
+defmodule Explorer.Chain.Address.CurrentTokenBalance do
+  @moduledoc """
+  Represents the current token balance from addresses according to the last block.
+  """
+
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  alias Explorer.Chain.{Address, Block, Hash, Token}
+
+  @typedoc """
+   *  `address` - The `t:Explorer.Chain.Address.t/0` that is the balance's owner.
+   *  `address_hash` - The address hash foreign key.
+   *  `token` - The `t:Explorer.Chain.Token/0` so that the address has the balance.
+   *  `token_contract_address_hash` - The contract address hash foreign key.
+   *  `block_number` - The block's number that the transfer took place.
+   *  `value` - The value that's represents the balance.
+  """
+  @type t :: %__MODULE__{
+          address: %Ecto.Association.NotLoaded{} | Address.t(),
+          address_hash: Hash.Address.t(),
+          token: %Ecto.Association.NotLoaded{} | Token.t(),
+          token_contract_address_hash: Hash.Address,
+          block_number: Block.block_number(),
+          inserted_at: DateTime.t(),
+          updated_at: DateTime.t(),
+          value: Decimal.t() | nil
+        }
+
+  schema "address_current_token_balances" do
+    field(:value, :decimal)
+    field(:block_number, :integer)
+    field(:value_fetched_at, :utc_datetime)
+
+    belongs_to(:address, Address, foreign_key: :address_hash, references: :hash, type: Hash.Address)
+
+    belongs_to(
+      :token,
+      Token,
+      foreign_key: :token_contract_address_hash,
+      references: :contract_address_hash,
+      type: Hash.Address
+    )
+
+    timestamps()
+  end
+
+  @optional_fields ~w(value value_fetched_at)a
+  @required_fields ~w(address_hash block_number token_contract_address_hash)a
+  @allowed_fields @optional_fields ++ @required_fields
+
+  @doc false
+  def changeset(%__MODULE__{} = token_balance, attrs) do
+    token_balance
+    |> cast(attrs, @allowed_fields)
+    |> validate_required(@required_fields)
+    |> foreign_key_constraint(:address_hash)
+    |> foreign_key_constraint(:token_contract_address_hash)
+  end
+end
diff --git a/apps/explorer/priv/repo/migrations/20181026180921_create_address_current_token_balances.exs b/apps/explorer/priv/repo/migrations/20181026180921_create_address_current_token_balances.exs
new file mode 100644
index 0000000000..d497d1feda
--- /dev/null
+++ b/apps/explorer/priv/repo/migrations/20181026180921_create_address_current_token_balances.exs
@@ -0,0 +1,32 @@
+defmodule Explorer.Repo.Migrations.CreateAddressCurrentTokenBalances do
+  use Ecto.Migration
+
+  def change do
+    create table(:address_current_token_balances) do
+      add(:address_hash, references(:addresses, column: :hash, type: :bytea), null: false)
+      add(:block_number, :bigint, null: false)
+
+      add(
+        :token_contract_address_hash,
+        references(:tokens, column: :contract_address_hash, type: :bytea),
+        null: false
+      )
+
+      add(:value, :decimal, null: true)
+      add(:value_fetched_at, :utc_datetime, default: fragment("NULL"), null: true)
+
+      timestamps(null: false, type: :utc_datetime)
+    end
+
+    create(unique_index(:address_current_token_balances, ~w(address_hash token_contract_address_hash)a))
+
+    create(
+      index(
+        :address_current_token_balances,
+        [:value],
+        name: :address_current_token_balances_value,
+        where: "value IS NOT NULL"
+      )
+    )
+  end
+end
diff --git a/apps/explorer/test/support/factory.ex b/apps/explorer/test/support/factory.ex
index f168091195..54f99731a8 100644
--- a/apps/explorer/test/support/factory.ex
+++ b/apps/explorer/test/support/factory.ex
@@ -13,6 +13,7 @@ defmodule Explorer.Factory do
 
   alias Explorer.Chain.{
     Address,
+    Address.CurrentTokenBalance,
     Address.TokenBalance,
     Address.CoinBalance,
     Block,
@@ -480,6 +481,16 @@ defmodule Explorer.Factory do
     }
   end
 
+  def address_current_token_balance_factory() do
+    %CurrentTokenBalance{
+      address: build(:address),
+      token_contract_address_hash: insert(:token).contract_address_hash,
+      block_number: block_number(),
+      value: Enum.random(1..100_000),
+      value_fetched_at: DateTime.utc_now()
+    }
+  end
+
   defmacrop left + right do
     quote do
       fragment("? + ?", unquote(left), unquote(right))