Initial commit

.formatter.exs

@@ -0,0 +1,4 @@
+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]

.gitignore

@@ -0,0 +1,24 @@
+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+exledger-*.tar
+

README.md

@@ -0,0 +1,21 @@
+# Exledger
+
+**TODO: Add description**
+
+## Installation
+
+If [available in Hex](https://hex.pm/docs/publish), the package can be installed
+by adding `exledger` to your list of dependencies in `mix.exs`:
+
+```elixir
+def deps do
+  [
+    {:exledger, "~> 0.1.0"}
+  ]
+end
+```
+
+Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
+and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
+be found at [https://hexdocs.pm/exledger](https://hexdocs.pm/exledger).
+

lib/account.ex

@@ -0,0 +1,13 @@
+defmodule ExLedger.Account do
+
+  defstruct ~w[name sub_accounts]a
+
+  @type t :: %__MODULE__{
+    name: String.t(),
+    sub_accounts: [__MODULE__.t()]
+  }
+
+  def new(attrs) do
+    struct!(%__MODULE__{}, attrs)
+  end
+end

lib/amount.ex

@@ -0,0 +1,13 @@
+defmodule ExLedger.Amount do
+
+  defstruct ~w[quantity currency]a
+
+  @type t :: %__MODULE__{
+    quantity: integer(),
+    currency: tuple() | String.t()
+  }
+
+  def new(attrs) do
+    struct!(%__MODULE__{}, attrs)
+  end
+end

lib/entry.ex

@@ -0,0 +1,23 @@
+defmodule ExLedger.Entry do
+
+  defstruct [:date, :status, :description, transactions: []]
+
+  alias ExLedger.Transaction
+
+  @type t :: %__MODULE__{
+    date: DateTime.t(),
+    status: bool(),
+    description: String.t(),
+    transactions: [Transaction.t()]
+  }
+
+  def new(attrs) do
+    struct!(%__MODULE__{}, attrs)
+  end
+
+  def transactions(entries) do
+    entries
+    |> Enum.map(&(&1.transactions))
+    |> List.flatten()
+  end
+end

lib/exledger.ex

@@ -0,0 +1,4 @@
+defmodule Exledger do
+
+
+end

lib/ledger.ex

@@ -0,0 +1,27 @@
+defmodule ExLedger.Ledger do
+
+  defstruct entries: []
+
+  alias ExLedger.Entry
+
+  @type t :: %__MODULE__{
+    entries: [Entry.t()],
+  }
+
+  def new(attrs) do
+    struct!(%__MODULE__{}, attrs)
+  end
+
+  @spec balance(__MODULE__.t()) :: integer()
+  def balance(%{entries: entries} = _ledger) do
+    entries
+    |> Entry.transactions()
+    |> sum()
+  end
+
+  def sum(transactions) do
+    transactions
+    |> Enum.map(&(&1.amount.quantity))
+    |> Enum.sum()
+  end
+end

lib/transaction.ex

@@ -0,0 +1,15 @@
+defmodule ExLedger.Transaction do
+
+  defstruct ~w[account amount]a
+
+  alias ExLedger.{Account, Amount}
+
+  @type t :: %__MODULE__{
+    account: Account.t(),
+    amount: Amount.t(),
+  }
+
+  def new(attrs) do
+    struct!(%__MODULE__{}, attrs)
+  end
+end

mix.exs

@@ -0,0 +1,28 @@
+defmodule Exledger.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :exledger,
+      version: "0.1.0",
+      elixir: "~> 1.10",
+      start_permanent: Mix.env() == :prod,
+      deps: deps()
+    ]
+  end
+
+  # Run "mix help compile.app" to learn about applications.
+  def application do
+    [
+      extra_applications: [:logger]
+    ]
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      # {:dep_from_hexpm, "~> 0.3.0"},
+      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
+    ]
+  end
+end

test/exledger_test.exs

@@ -0,0 +1,22 @@
+defmodule ExledgerTest do
+  use ExUnit.Case
+
+  alias ExLedger.{Ledger, Entry, Transaction, Account, Amount}
+
+  test "Ledger.balance/1" do
+    account = Account.new(name: "assets")
+    amount = Amount.new(quantity: 1, currency: :USD)
+    txn1 = Transaction.new(account: account, amount: amount)
+
+    account2 = Account.new(name: "expenses")
+    amount2 = Amount.new(quantity: -1, currency: :USD)
+    txn2 = Transaction.new(account: account2, amount: amount2)
+
+    entry = Entry.new(date: DateTime.utc_now(), transactions: [txn1, txn2])
+
+    ledger = Ledger.new(entries: [entry])
+
+    # IO.inspect(ledger)
+    assert Ledger.balance(ledger) == 0
+  end
+end

test/test_helper.exs

@@ -0,0 +1 @@
+ExUnit.start()