1 files changed, 61 insertions, 0 deletions
diff --git a/src/State.ml b/src/State.ml
new file mode 100644
index 0000000..cc20b16
--- /dev/null
+++ b/src/State.ml
@@ -0,0 +1,61 @@
+type marker_state =
+  { pos : Leaflet.lat_lng
+  ; name : string
+  ; color : string
+  ; icon : string
+  }
+
+let remove state pos =
+  Js.Array.filter (fun m -> m.pos != pos) state
+
+let update state previousPos marker =
+  Js.Array.concat [| marker |] (remove state previousPos)
+
+let last_added state =
+  if Js.Array.length state > 0 then
+    Some state.(0)
+  else
+    None
+
+(* Serialization *)
+
+let sep = "|"
+
+let marker_to_string marker =
+  [| String.format_float 6 marker.pos.lat
+  ;  String.format_float 6 marker.pos.lng
+  ;  marker.name
+  ;  marker.color
+  ;  marker.icon
+  |]
+    |> Js.Array.joinWith sep
+
+let to_string state =
+  state
+    |> Js.Array.map marker_to_string
+    |> Js.Array.joinWith sep
+    |> String.encode
+
+let from_string str =
+  let (_, _, res) = Js.Array.reduce
+    (fun (acc_str, acc_marker, acc_state) c ->
+      let length = Js.Array.length acc_marker in
+      if c != sep then
+        (acc_str ^ c, acc_marker, acc_state)
+      else if c == sep && length < 4 then
+        ("", Js.Array.concat [| acc_str |] acc_marker, acc_state)
+      else
+        let marker =
+          { pos =
+              { lat = Js.Float.fromString acc_marker.(0)
+              ; lng = Js.Float.fromString acc_marker.(1)
+              }
+          ; name = acc_marker.(2)
+          ; color = acc_marker.(3)
+          ; icon = acc_str
+          }
+        in ("", [| |], Js.Array.concat acc_state [| marker |])
+    )
+    ("", [| |], [| |])
+    (Js.Array.from (Js.String.castToArrayLike ((String.decode str) ^ sep)))
+  in res