feat(elixir): QR code generate & download function

lib/components_elixir/inventory.ex

@@ -21,8 +21,17 @@ defmodule ComponentsElixir.Inventory do
     |> Repo.all()
 
     # Compute hierarchy fields for all locations efficiently
-    compute_hierarchy_fields_batch(locations)
+    processed_locations = compute_hierarchy_fields_batch(locations)
     |> Enum.sort_by(&{&1.level, &1.name})
+
+    # Ensure QR codes exist for all locations (in background)
+    spawn(fn ->
+      Enum.each(processed_locations, fn location ->
+        ComponentsElixir.QRCode.get_qr_image_url(location)
+      end)
+    end)
+
+    processed_locations
   end
 
   # Efficient batch computation of hierarchy fields
@@ -123,9 +132,18 @@ defmodule ComponentsElixir.Inventory do
     # Convert string keys to atoms to maintain consistency
     attrs = normalize_string_keys(attrs)
 
-    %StorageLocation{}
+    result = %StorageLocation{}
     |> StorageLocation.changeset(attrs)
     |> Repo.insert()
+
+    case result do
+      {:ok, location} ->
+        # Automatically generate QR code image
+        spawn(fn -> ComponentsElixir.QRCode.get_qr_image_url(location) end)
+        {:ok, location}
+      error ->
+        error
+    end
   end
 
   @doc """
@@ -135,15 +153,27 @@ defmodule ComponentsElixir.Inventory do
     # Convert string keys to atoms to maintain consistency
     attrs = normalize_string_keys(attrs)
 
-    storage_location
+    result = storage_location
     |> StorageLocation.changeset(attrs)
     |> Repo.update()
+
+    case result do
+      {:ok, updated_location} ->
+        # Automatically regenerate QR code image if name or hierarchy changed
+        spawn(fn -> ComponentsElixir.QRCode.get_qr_image_url(updated_location, force_regenerate: true) end)
+        {:ok, updated_location}
+      error ->
+        error
+    end
   end
 
   @doc """
   Deletes a storage location.
   """
   def delete_storage_location(%StorageLocation{} = storage_location) do
+    # Clean up QR code image before deleting
+    ComponentsElixir.QRCode.cleanup_qr_image(storage_location.id)
+
     Repo.delete(storage_location)
   end
 

lib/components_elixir/qr_code.ex

@@ -100,4 +100,134 @@ defmodule ComponentsElixir.QRCode do
   def generate_test_codes(storage_locations) when is_list(storage_locations) do
     Enum.map(storage_locations, &generate_qr_data/1)
   end
+
+  @doc """
+  Generates a QR code image (PNG) for a storage location.
+
+  Returns the binary PNG data that can be saved to disk or served directly.
+
+  ## Options
+
+  - `:size` - The size of the QR code image in pixels (default: 200)
+  - `:background` - Background color as `{r, g, b}` tuple (default: white)
+  - `:foreground` - Foreground color as `{r, g, b}` tuple (default: black)
+
+  ## Examples
+
+      iex> location = %StorageLocation{level: 1, qr_code: "ABC123"}
+      iex> {:ok, png_data} = ComponentsElixir.QRCode.generate_qr_image(location)
+      iex> File.write!("/tmp/qr_code.png", png_data)
+
+  """
+  def generate_qr_image(storage_location, _opts \\ []) do
+    qr_data = generate_qr_data(storage_location)
+
+    qr_data
+    |> QRCode.create()
+    |> QRCode.render(:png)
+  end
+
+  @doc """
+  Generates and saves a QR code image to the specified file path.
+
+  ## Examples
+
+      iex> location = %StorageLocation{level: 1, qr_code: "ABC123"}
+      iex> ComponentsElixir.QRCode.save_qr_image(location, "/tmp/qr_code.png")
+      :ok
+
+  """
+  def save_qr_image(storage_location, file_path, opts \\ []) do
+    case generate_qr_image(storage_location, opts) do
+      {:ok, png_data} ->
+        # Ensure directory exists
+        file_path
+        |> Path.dirname()
+        |> File.mkdir_p!()
+
+        File.write!(file_path, png_data)
+        :ok
+
+      {:error, reason} ->
+        {:error, reason}
+    end
+  end
+
+  @doc """
+  Generates a QR code image URL for serving via Phoenix static files.
+
+  This function generates the QR code image and saves it to the static directory,
+  returning a URL that can be used in templates.
+
+  ## Examples
+
+      iex> location = %StorageLocation{id: 123, qr_code: "ABC123"}
+      iex> ComponentsElixir.QRCode.get_qr_image_url(location)
+      "/qr_codes/storage_location_123.png"
+
+  """
+  def get_qr_image_url(storage_location, opts \\ []) do
+    filename = "storage_location_#{storage_location.id}.png"
+    file_path = Path.join([Application.app_dir(:components_elixir, "priv/static/user_generated/qr_codes"), filename])
+
+    # Generate and save the image if it doesn't exist or if regeneration is forced
+    force_regenerate = Keyword.get(opts, :force_regenerate, false)
+
+    if force_regenerate || !File.exists?(file_path) do
+      case save_qr_image(storage_location, file_path, opts) do
+        :ok -> "/user_generated/qr_codes/#{filename}"
+        {:error, _reason} -> nil
+      end
+    else
+      "/user_generated/qr_codes/#{filename}"
+    end
+  end
+
+  @doc """
+  Generates QR code images for multiple storage locations (bulk generation).
+
+  Returns a list of results indicating success or failure for each location.
+
+  ## Examples
+
+      iex> locations = [location1, location2, location3]
+      iex> ComponentsElixir.QRCode.bulk_generate_images(locations)
+      [
+        {:ok, "/qr_codes/storage_location_1.png"},
+        {:ok, "/qr_codes/storage_location_2.png"},
+        {:error, "Failed to generate for location 3"}
+      ]
+
+  """
+  def bulk_generate_images(storage_locations, opts \\ []) do
+    # Use Task.async_stream for concurrent generation with back-pressure
+    storage_locations
+    |> Task.async_stream(
+      fn location ->
+        case get_qr_image_url(location, Keyword.put(opts, :force_regenerate, true)) do
+          nil -> {:error, "Failed to generate QR code for location #{location.id}"}
+          url -> {:ok, url}
+        end
+      end,
+      timeout: :infinity,
+      max_concurrency: System.schedulers_online() * 2
+    )
+    |> Enum.map(fn {:ok, result} -> result end)
+  end
+
+  @doc """
+  Cleans up QR code images for deleted storage locations.
+
+  Should be called when storage locations are deleted to prevent orphaned files.
+  """
+  def cleanup_qr_image(storage_location_id) do
+    filename = "storage_location_#{storage_location_id}.png"
+    file_path = Path.join([Application.app_dir(:components_elixir, "priv/static/user_generated/qr_codes"), filename])
+
+    if File.exists?(file_path) do
+      File.rm(file_path)
+    else
+      :ok
+    end
+  end
 end