From 60fde9c3ce51640e4907b3fb71a4dd3f2e9c46c5 Mon Sep 17 00:00:00 2001
From: Jordan Bracco <href@random.sh>
Date: Mon, 15 Jun 2020 13:57:39 +0200
Subject: [PATCH] Unified API: `GenMagic.perform/2,3`

---
 README.md               | 18 +++++++++---------
 lib/gen_magic.ex        | 33 +++++++++++++++++++++++++++++++++
 lib/gen_magic/server.ex |  6 ++++--
 3 files changed, 46 insertions(+), 11 deletions(-)

diff --git a/README.md b/README.md
index a182566..7d1d402 100644
--- a/README.md
+++ b/README.md
@@ -27,7 +27,7 @@ Depending on the use case, you may utilise a single (one-off) GenMagic process w
 To use GenMagic directly, you can use `GenMagic.Helpers.perform_once/1`:
 
 ```elixir
-iex(1)> GenMagic.Helpers.perform_once "."
+iex(1)> GenMagic.perform(".", once: true)
 {:ok,
  %GenMagic.Result{
    content: "directory",
@@ -40,7 +40,7 @@ To use the GenMagic server as a daemon, you can start it first, keep a reference
 
 ```elixir
 {:ok, pid} = GenMagic.Server.start_link([])
-{:ok, result} = GenMagic.Server.perform(pid, path)
+{:ok, result} = GenMagic.perform(path, server: pid)
 ```
 
 See `GenMagic.Server.start_link/1` and `t:GenMagic.Server.option/0` for more information on startup parameters.
@@ -67,7 +67,7 @@ See `t:GenMagic.Server.option/0` for details.
 For ad-hoc requests, you can use the helper method `GenMagic.Helpers.perform_once/2`:
 
 ```elixir
-iex(1)> GenMagic.Helpers.perform_once(Path.join(File.cwd!(), "Makefile"))
+iex(1)> GenMagic.perform(Path.join(File.cwd!(), "Makefile"), once: true)
 {:ok,
  %GenMagic.Result{
    content: "makefile script, ASCII text",
@@ -90,8 +90,8 @@ iex(1)> {:ok, pid} = Supervisor.start_link([{GenMagic.Server, name: :gen_magic}]
 Now we can ask it to inspect a file:
 
 ```elixir
-iex(2)> GenMagic.Server.perform(:gen_magic, Path.expand("~/.bash_history"))
-{:ok, [mime_type: "text/plain", encoding: "us-ascii", content: "ASCII text"]}
+iex(2)> GenMagic.perform(Path.expand("~/.bash_history"), server: :gen_magic)
+{:ok, %GenMagic.Result{mime_type: "text/plain", encoding: "us-ascii", content: "ASCII text"}}
 ```
 
 Note that in this case we have opted to use a named process.
@@ -114,11 +114,11 @@ You can add a pool in your application supervisor by adding it as a child:
     Supervisor.start_link(children, opts)
 ```
 
-And then you can use it with `GenMagic.Pool.perform/2`:
+And then you can use it with `GenMagic.perform/2` with `pool: YourApp.GenMagicPool` option:
 
 ```
-iex(1)> GenMagic.Pool.perform(YourApp.GenMagicPool, Path.expand("~/.bash_history"))
-{:ok, [mime_type: "text/plain", encoding: "us-ascii", content: "ASCII text"]}
+iex(1)> GenMagic.perform(Path.expand("~/.bash_history"), pool: YourApp.GenMagicPool)
+{:ok, %GenMagic.Result{mime_type: "text/plain", encoding: "us-ascii", content: "ASCII text"}}
 ```
 
 ### Check Uploaded Files
@@ -127,7 +127,7 @@ If you use Phoenix, you can inspect the file from your controller:
 
 ```elixir
 def upload(conn, %{"upload" => %{path: path}}) do,
-  {:ok, result} = GenMagic.Helpers.perform_once(:gen_magic, path)
+  {:ok, result} = GenMagic.perform(path, server: :gen_magic)
   text(conn, "Received your file containing #{result.content}")
 end
 ```
diff --git a/lib/gen_magic.ex b/lib/gen_magic.ex
index f598521..292dfe8 100644
--- a/lib/gen_magic.ex
+++ b/lib/gen_magic.ex
@@ -4,4 +4,37 @@ defmodule GenMagic do
 
   See `GenMagic.Server` or the README for usage.
   """
+
+  @doc """
+  Perform on `path`.
+
+  An option of `server: ServerName`, `pool: PoolName` or `once: true` must be passed.
+  """
+  @type option :: name
+    when name: {:pool, atom()} | {:server, GenMagic.Server.t()} | {:once, true}
+
+  @spec perform(GenMagic.Server.target(), [option()]) :: GenMagic.Server.result()
+  def perform(path, opts, timeout \\ 5000) do
+    mod = cond do
+      Keyword.has_key?(opts, :pool) -> {GenMagic.Pool, Keyword.get(opts, :pool)}
+      Keyword.has_key?(opts, :server) -> {GenMagic.Server, Keyword.get(opts, :server)}
+      Keyword.has_key?(opts, :once) -> {GenMagic.Helpers, nil}
+      true -> nil
+    end
+
+    if mod do
+      do_perform(mod, path, timeout)
+    else
+      {:error, :no_method}
+    end
+  end
+
+  defp do_perform({GenMagic.Helpers, _}, path, timeout) do
+    GenMagic.Helpers.perform_once(path, timeout)
+  end
+
+  defp do_perform({mod, name}, path, timeout) do
+    mod.perform(name, path, tiemout)
+  end
+
 end
diff --git a/lib/gen_magic/server.ex b/lib/gen_magic/server.ex
index fc686b2..0e34586 100644
--- a/lib/gen_magic/server.ex
+++ b/lib/gen_magic/server.ex
@@ -55,6 +55,9 @@ defmodule GenMagic.Server do
           | {:recycle_threshold, non_neg_integer() | :infinity}
           | {:database_patterns, nonempty_list(:default | Path.t())}
 
+  @type target :: Path.t() | {:bytes, binary()}
+  @type result :: {:ok, Result.t()} | {:error, term() | String.t()}
+
   @typedoc """
   Current state of the Server:
 
@@ -81,8 +84,7 @@ defmodule GenMagic.Server do
 
   @spec child_spec([option()]) :: Supervisor.child_spec()
   @spec start_link([option()]) :: :gen_statem.start_ret()
-  @spec perform(t(), Path.t() | {:bytes, binary()}, timeout()) ::
-          {:ok, Result.t()} | {:error, term() | String.t()}
+  @spec perform(t(), target(), timeout()) :: result()
   @spec status(t(), timeout()) :: {:ok, Status.t()} | {:error, term()}
   @spec stop(t(), term(), timeout()) :: :ok