day 10 part 2

lib/day10.ex

@@ -3,15 +3,19 @@ import Integer, only: [mod: 2]
 defmodule Day10 do
   @behaviour Solution
 
-  def init_state(_) do
+  def init_state(p) when p == :part1 do
-    %{ vm: VirtualMachine.new(), acc: 0 }
+    %{ vm: VirtualMachine.new(), acc: 0, p: p }
+  end
+
+  def init_state(p) when p == :part2 do
+    %{ vm: VirtualMachine.new(), crt: "", p: p}
   end
 
   def execute(line, state) when line == "" do
     state
   end
 
-  def execute(line, state) do
+  def execute(line, state) when state.p == :part1 do
     VirtualMachine.plan_execute(line) |>
     Enum.reduce(
       state,
@@ -21,12 +25,42 @@ defmodule Day10 do
         vm = tock.(vm)
         %{ vm: vm, acc: acc}
       end
-    )
+    ) |> Map.put(:p, state.p)
   end
 
-  def get_answer(state) do
+  def execute(line, state) when state.p == :part2 do
+    VirtualMachine.plan_execute(line) |>
+    Enum.reduce(
+      state,
+      fn (tock, %{vm: vm, crt: crt}) ->
+        next_tick = vm.tick + 1
+
+        char = case mod(vm.tick, 40) do
+          x when x >= (vm.x - 1) and x <= (vm.x + 1) -> "#"
+          _ -> "."
+        end
+
+        crt = crt <> char
+
+        crt = crt <> if mod(next_tick, 40) == 0 do
+          "\n"
+        else ""
+        end
+
+        vm = tock.(vm)
+
+        %{ vm: vm, crt: crt}
+      end
+    ) |> Map.put(:p, state.p)
+  end
+
+  def get_answer(state) when state.p == :part1 do
     state.acc
   end
+
+  def get_answer(state) when state.p == :part2 do
+    state.crt
+  end
 end
 
 defmodule VirtualMachine do

main.exs

@@ -1 +1 @@
-AOCRunner.run(Day10, :part1)
+AOCRunner.run(Day10, :part2)