feat: update book transfer form (#289)

apps/app/lib/app/accounts/user.ex

@@ -4,9 +4,8 @@ defmodule App.Accounts.User do
   """
 
   use Ecto.Schema
-  import Ecto.Changeset
 
-  alias App.Balance.BalanceConfig
+  import Ecto.Changeset
 
   @type id :: integer()
   @type t :: %__MODULE__{
@@ -15,8 +14,6 @@ defmodule App.Accounts.User do
           password: String.t(),
           hashed_password: String.t(),
           confirmed_at: NaiveDateTime.t(),
-          balance_config: BalanceConfig.t(),
-          balance_config_id: BalanceConfig.id(),
           inserted_at: NaiveDateTime.t(),
           updated_at: NaiveDateTime.t()
         }
@@ -28,9 +25,6 @@ defmodule App.Accounts.User do
     field :hashed_password, :string, redact: true
     field :confirmed_at, :naive_datetime
 
-    # the current balance configuration of the user
-    belongs_to :balance_config, BalanceConfig
-
     timestamps()
   end
 
@@ -175,19 +169,4 @@ defmodule App.Accounts.User do
       add_error(changeset, :current_password, "is not valid")
     end
   end
-
-  @doc """
-  A user changeset for changing the user balance config.
-  """
-  @spec balance_config_changeset(t(), map()) :: Ecto.Changeset.t()
-  def balance_config_changeset(struct, attrs) do
-    struct
-    |> cast(attrs, [:balance_config_id])
-    |> validate_balance_config_id()
-  end
-
-  defp validate_balance_config_id(changeset) do
-    changeset
-    |> foreign_key_constraint(:balance_config_id)
-  end
 end

apps/app/lib/app/transfers.ex

@@ -26,8 +26,8 @@ defmodule App.Transfers do
 
   Raises `Ecto.NoResultsError` if the Money transfer does not exist.
   """
-  def get_money_transfer_of_book!(id, book_id),
-    do: Repo.get_by!(MoneyTransfer, id: id, book_id: book_id)
+  def get_money_transfer_of_book!(id, %Book{} = book),
+    do: Repo.get_by!(MoneyTransfer, id: id, book_id: book.id)
 
   @doc """
   Find all money transfers of a book.
@@ -201,39 +201,32 @@ defmodule App.Transfers do
   @doc """
   Creates a money_transfer.
   """
-  @spec create_money_transfer(Book.t(), map()) ::
+  @spec create_money_transfer(Book.t(), MoneyTransfer.type(), map()) ::
           {:ok, MoneyTransfer.t()} | {:error, Ecto.Changeset.t()}
-  def create_money_transfer(%Book{} = book, attrs \\ %{}) do
-    %MoneyTransfer{book_id: book.id}
-    |> MoneyTransfer.changeset(attrs)
-    |> MoneyTransfer.with_peers(&Peer.create_money_transfer_changeset/2)
-    |> link_balance_config_to_peers_changeset()
-    |> Repo.insert()
-  end
+  def create_money_transfer(%Book{} = book, type, attrs)
+      when is_map(attrs) and type in [:payment, :income] do
+    changeset =
+      %MoneyTransfer{book_id: book.id, type: type}
+      |> MoneyTransfer.changeset(attrs)
+
+    result =
+      Ecto.Multi.new()
+      |> Ecto.Multi.insert(:money_transfer, changeset)
+      |> Ecto.Multi.update_all(
+        :update_peers_balance_config,
+        fn %{money_transfer: money_transfer} ->
+          from [peer: peer] in Peer.transfer_query(money_transfer),
+            join: member in BookMember,
+            on: peer.member_id == member.id,
+            update: [set: [balance_config_id: member.balance_config_id]]
+        end,
+        []
+      )
+      |> Repo.transaction()
 
-  defp link_balance_config_to_peers_changeset(changeset) do
-    case Ecto.Changeset.fetch_change(changeset, :peers) do
-      {:ok, peers_changeset} ->
-        peers =
-          changeset
-          |> Ecto.Changeset.fetch_field!(:peers)
-          # Members are required to fetch their balance config id
-          |> Repo.preload(member: from(BookMember, select: [:balance_config_id]))
-
-        balance_config_id_by_member_id =
-          Map.new(peers, fn peer -> {peer.member_id, peer.member.balance_config_id} end)
-
-        peers_changeset_with_balance_config =
-          Enum.map(peers_changeset, fn peer_changeset ->
-            member_id = Ecto.Changeset.fetch_field!(peer_changeset, :member_id)
-            balance_config_id = balance_config_id_by_member_id[member_id]
-            Ecto.Changeset.put_change(peer_changeset, :balance_config_id, balance_config_id)
-          end)
-
-        Ecto.Changeset.put_assoc(changeset, :peers, peers_changeset_with_balance_config)
-
-      _ ->
-        changeset
+    case result do
+      {:ok, %{money_transfer: money_transfer}} -> {:ok, money_transfer}
+      {:error, :money_transfer, changeset, _changes} -> {:error, changeset}
     end
   end
 
@@ -244,10 +237,7 @@ defmodule App.Transfers do
           {:ok, MoneyTransfer.t()} | {:error, Ecto.Changeset.t()}
   def update_money_transfer(%MoneyTransfer{} = money_transfer, attrs) do
     money_transfer
-    # peers can be updated by the changeset
-    |> Repo.preload(:peers)
     |> MoneyTransfer.changeset(attrs)
-    |> MoneyTransfer.with_peers(&Peer.update_money_transfer_changeset/2)
     |> Repo.update()
   end
 
@@ -264,9 +254,7 @@ defmodule App.Transfers do
   Returns an `%Ecto.Changeset{}` for tracking money_transfer changes.
   """
   def change_money_transfer(%MoneyTransfer{} = money_transfer, attrs \\ %{}) do
-    money_transfer
-    |> MoneyTransfer.changeset(attrs)
-    |> MoneyTransfer.with_peers(&Peer.update_money_transfer_changeset/2)
+    MoneyTransfer.changeset(money_transfer, attrs)
   end
 
   ## Reimbursements

apps/app/lib/app/transfers/money_transfer.ex

@@ -65,18 +65,12 @@ defmodule App.Transfers.MoneyTransfer do
 
   def changeset(struct, attrs) do
     struct
-    |> cast(attrs, [:label, :amount, :type, :date, :tenant_id, :balance_params])
+    |> cast(attrs, [:label, :date, :balance_params, :tenant_id, :amount])
     |> validate_label()
-    |> validate_amount()
-    |> validate_type()
-    |> validate_tenant_id()
-    |> validate_book_id()
     |> validate_balance_params()
-  end
-
-  def with_peers(changeset, with_changeset) do
-    changeset
-    |> cast_assoc(:peers, with: with_changeset)
+    |> validate_tenant_id()
+    |> validate_amount()
+    |> cast_assoc(:peers, with: &Ecto.Changeset.cast(&1, &2, [:member_id, :weight]))
   end
 
   @doc """
@@ -87,7 +81,7 @@ defmodule App.Transfers.MoneyTransfer do
     |> cast(attrs, [:label, :amount, :date, :tenant_id])
     |> validate_label()
     |> validate_amount()
-    |> cast_assoc(:peers, with: &Peer.update_money_transfer_changeset/2)
+    |> cast_assoc(:peers, with: &Ecto.Changeset.cast(&1, &2, [:member_id]))
     |> validate_reimbursement_peers()
   end
 
@@ -102,24 +96,12 @@ defmodule App.Transfers.MoneyTransfer do
     |> validate_required(:amount)
   end
 
-  defp validate_type(changeset) do
-    changeset
-    |> validate_required(:type)
-    |> validate_inclusion(:type, [:payment, :income])
-  end
-
   defp validate_tenant_id(changeset) do
     changeset
     |> validate_required(:tenant_id)
     |> foreign_key_constraint(:tenant_id)
   end
 
-  defp validate_book_id(changeset) do
-    changeset
-    |> validate_required(:book_id)
-    |> foreign_key_constraint(:book_id)
-  end
-
   defp validate_balance_params(changeset) do
     changeset
     |> validate_required(:balance_params)

apps/app/lib/app/transfers/peer.ex

@@ -1,10 +1,10 @@
 defmodule App.Transfers.Peer do
   @moduledoc """
-  Entity linking money transfers to users.
+  The entity linking money transfers to book members.
   """
 
   use Ecto.Schema
-  import Ecto.Changeset
+
   import Ecto.Query
 
   alias App.Balance.BalanceConfig
@@ -33,59 +33,6 @@ defmodule App.Transfers.Peer do
     field :total_weight, :decimal, virtual: true
   end
 
-  def create_money_transfer_changeset(struct, attrs) do
-    struct
-    |> cast(attrs, [:member_id, :weight])
-    |> validate_member_id()
-    |> validate_unique_by_transfer_and_member()
-  end
-
-  def update_money_transfer_changeset(struct, attrs)
-
-  # new peer built, must set a `member_id`
-  def update_money_transfer_changeset(%{id: nil} = struct, attrs) do
-    struct
-    |> cast(attrs, [:member_id, :weight])
-    |> validate_member_id()
-    |> validate_unique_by_transfer_and_member()
-  end
-
-  # updating an existing peer, cannot change `member_id`
-  def update_money_transfer_changeset(struct, attrs) do
-    struct
-    |> cast(attrs, [:weight])
-    |> validate_unique_by_transfer_and_member()
-  end
-
-  defp validate_member_id(changeset) do
-    changeset
-    |> validate_required(:member_id)
-    |> foreign_key_constraint(:member_id)
-  end
-
-  defp validate_unique_by_transfer_and_member(changeset) do
-    changeset
-    |> unique_constraint([:transfer_id, :member_id],
-      message: "member is already a peer of this money transfer",
-      error_key: :member_id
-    )
-  end
-
-  @doc """
-  Changeset for updating the balance config of a book member.
-  """
-  @spec balance_config_changeset(t(), map()) :: Ecto.Changeset.t()
-  def balance_config_changeset(struct, attrs) do
-    struct
-    |> cast(attrs, [:balance_config_id])
-    |> validate_balance_config_id()
-  end
-
-  defp validate_balance_config_id(changeset) do
-    changeset
-    |> foreign_key_constraint(:balance_config_id)
-  end
-
   ## Queries
 
   @doc """
@@ -95,4 +42,13 @@ defmodule App.Transfers.Peer do
   def base_query do
     from peer in __MODULE__, as: :peer
   end
+
+  @doc """
+  Returns an `%Ecto.Query{}` fetching all peers of a given money transfer.
+  """
+  @spec transfer_query(Ecto.Queryable.t(), MoneyTransfer.t()) :: Ecto.Query.t()
+  def transfer_query(query \\ base_query(), %MoneyTransfer{} = transfer) do
+    from [peer: peer] in query,
+      where: peer.transfer_id == ^transfer.id
+  end
 end

apps/app/priv/repo/migrations/20241003194737_drop_users_balance_config_id.exs

@@ -0,0 +1,9 @@
+defmodule App.Repo.Migrations.DropUsersBalanceConfigId do
+  use Ecto.Migration
+
+  def change do
+    alter table(:users) do
+      remove :balance_config_id, references(:balance_configs, on_delete: :restrict)
+    end
+  end
+end