improvement: make state diagrams the default chart

docs: docs improvements

documentation/tutorials/get-started-with-state-machines.md

@@ -107,13 +107,13 @@ end
 run `mix ash_state_machine.generate_flow_charts` to generate flow charts for your resources. See the task documentation for more. Here is a chart generated from the example above:
 
 ```mermaid
-flowchart TD
-pending --> |confirm| confirmed
-confirmed --> |begin_delivery| on_its_way
-on_its_way --> |package_arrived| arrived
-on_its_way --> |error| error
-confirmed --> |error| error
-pending --> |error| error
+stateDiagram-v2
+pending --> confirmed: confirm
+confirmed --> on_its_way: begin_delivery
+on_its_way --> arrived: package_arrived
+on_its_way --> error: error
+confirmed --> error: error
+pending --> error: error
 ```
 
 ## Learning more

lib/charts.ex

@@ -3,18 +3,29 @@ defmodule AshStateMachine.Charts do
   Returns a mermaid flow chart of a given state machine resource.
   """
 
+  @spec mermaid_state_diagram(Ash.Resource.t()) :: String.t()
+  def mermaid_state_diagram(resource) do
+    resource
+    |> AshStateMachine.Info.state_machine_initial_states!()
+    |> Enum.reduce({["stateDiagram-v2"], MapSet.new()}, fn state, {lines, checked} ->
+      add_to_chart(resource, state, lines ++ [], checked, :state_diagram)
+    end)
+    |> elem(0)
+    |> Enum.join("\n")
+  end
+
   @spec mermaid_flowchart(Ash.Resource.t()) :: String.t()
   def mermaid_flowchart(resource) do
     resource
     |> AshStateMachine.Info.state_machine_initial_states!()
     |> Enum.reduce({["flowchart TD"], MapSet.new()}, fn state, {lines, checked} ->
-      add_to_chart(resource, state, lines ++ [], checked)
+      add_to_chart(resource, state, lines ++ [], checked, :flow_chart)
     end)
     |> elem(0)
     |> Enum.join("\n")
   end
 
-  defp add_to_chart(resource, state, lines, checked) do
+  defp add_to_chart(resource, state, lines, checked, type) do
     if state in checked do
       {lines, checked}
     else
@@ -24,14 +35,28 @@ defmodule AshStateMachine.Charts do
       |> transitions_from(resource)
       |> Enum.reduce({lines, checked}, fn event, {lines, checked} ->
         Enum.reduce(List.wrap(event.to), {lines, checked}, fn to, {lines, checked} ->
-          name =
-            case event.action do
-              :* -> ""
-              action -> "|#{action}|"
+          lines =
+            case type do
+              :flow_chart ->
+                name =
+                  case event.action do
+                    :* -> ""
+                    action -> "|#{action}|"
+                  end
+
+                lines ++ ["#{state} --> #{name} #{to}"]
+
+              :state_diagram ->
+                name =
+                  case event.action do
+                    :* -> ""
+                    action -> ": #{action}"
+                  end
+
+                lines ++ ["#{state} --> #{to}#{name}"]
             end
 
-          lines = lines ++ ["#{state} --> #{name} #{to}"]
-          add_to_chart(resource, to, lines, checked)
+          add_to_chart(resource, to, lines, checked, type)
         end)
       end)
     end

lib/mix/generate_flow_charts.ex

@@ -11,6 +11,7 @@ defmodule Mix.Tasks.AshStateMachine.GenerateFlowCharts do
 
   ## Command line options
 
+    * `--type` - generates a given type. Valid values are `"state_diagram"` and `"flow_chart"`. Defaults to `"state_diagram"`.
     * `--only` - only generates the given Flow file
     * `--format` - Can be set to one of either:
       * `plain` - Prints just the mermaid output as text. This is the default.
@@ -30,8 +31,8 @@ defmodule Mix.Tasks.AshStateMachine.GenerateFlowCharts do
 
     {opts, _} =
       OptionParser.parse!(argv,
-        strict: [only: :keep, format: :string],
-        aliases: [o: :only, f: :format]
+        strict: [only: :keep, format: :string, type: :string],
+        aliases: [o: :only, f: :format, t: :type]
       )
 
     only =
@@ -47,11 +48,20 @@ defmodule Mix.Tasks.AshStateMachine.GenerateFlowCharts do
         source = state_machine.module_info(:compile)[:source]
 
         if is_nil(only) || Path.expand(source) in only do
+          diagram =
+            case opts[:type] || "state_diagram" do
+              "state_diagram" ->
+                AshStateMachine.Charts.mermaid_state_diagram(state_machine)
+
+              "flow_chart" ->
+                AshStateMachine.Charts.mermaid_flowchart(state_machine)
+            end
+
           Mix.Mermaid.generate_diagram(
             source,
             "mermaid-flowchart",
             format,
-            AshStateMachine.Charts.mermaid_flowchart(state_machine),
+            diagram,
             "Generated Mermaid flowchart for #{inspect(state_machine)}"
           )
         end

test/ash_state_machine_test.exs

@@ -154,7 +154,7 @@ defmodule AshStateMachineTest do
 
   describe "charts" do
     test "it generates the appropriate chart" do
-      AshStateMachine.Charts.mermaid_flowchart(Order) |> IO.puts()
+      AshStateMachine.Charts.mermaid_state_diagram(Order) |> IO.puts()
 
       assert AshStateMachine.Charts.mermaid_flowchart(ThreeStates) ==
                """