From 20c287378ad93f08b3f2aef63719e3986e5c488a Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Fri, 22 Nov 2024 17:43:33 +0000
Subject: [PATCH] extract function for drag finish

---
 frontend/src/Main.elm | 64 +++++++++++++++++++++++--------------------
 1 file changed, 34 insertions(+), 30 deletions(-)

diff --git a/frontend/src/Main.elm b/frontend/src/Main.elm
index 257e4cc..d66ae73 100644
--- a/frontend/src/Main.elm
+++ b/frontend/src/Main.elm
@@ -138,7 +138,7 @@ dragDelta target d =
             else (0, 0)
         _ -> (0, 0)
 
-subTuple (fx,fy) (tx,ty) = (fx-tx, fy-ty)
+subtractTuple (fx,fy) (tx,ty) = (fx-tx, fy-ty)
 
 
 type TrackState = Empty | Loading | Failure String | Present (List Point)
@@ -197,6 +197,37 @@ update : Msg -> Model -> (Model, Cmd Msg)
 
 update msg model = (updateModel msg model, Cmd.none)
 
+secondsFromPixels model seconds =
+    (toFloat seconds) * model.duration / portalWidth
+
+handleDragFinish model target (x, y) =
+    case target of
+        Map ->
+            { model |
+                  centre = translatePixels model.centre (toZoom model.zoom) (x, y)
+            }
+        Graph ->
+            { model |
+                  startTime =
+                  model.startTime + secondsFromPixels model x
+            }
+        StartMark ->
+            { model |
+                  markedTime =
+                  let deltat = secondsFromPixels model x
+                      (s, d) = model.markedTime
+                  in (s - deltat, d + deltat)
+            }
+        EndMark ->
+            { model |
+                  markedTime =
+                  let deltat = secondsFromPixels model x
+                      (s, d) = model.markedTime
+                  in (s, d - deltat)
+            }
+        NoTarget -> model
+
+
 updateModel msg model =
     case msg of
         MapScale y ->
@@ -210,35 +241,8 @@ updateModel msg model =
 
         DragFinish (x,y) ->
             case model.drag of
-                Dragging Map start end ->
-                    { model |
-                          drag = None,
-                          centre = translatePixels model.centre (toZoom model.zoom) (subTuple start end) }
-                Dragging Graph start end ->
-                    { model |
-                          drag = None,
-                          startTime =
-                          let (delta, _) = subTuple start end
-                          in model.startTime + toFloat delta * model.duration / portalWidth
-                    }
-                Dragging StartMark start end ->
-                    { model |
-                          drag = None,
-                          markedTime =
-                          let delta = Tuple.first (subTuple start end)
-                              deltat = toFloat delta * model.duration / portalWidth
-                              (s, d) = model.markedTime
-                          in (s - deltat, d + deltat)
-                    }
-                Dragging EndMark start end ->
-                    { model |
-                          drag = None,
-                          markedTime =
-                          let delta = Tuple.first (subTuple start end)
-                              deltat = toFloat delta * model.duration / portalWidth
-                              (s, d) = model.markedTime
-                          in (s, d - deltat)
-                    }
+                Dragging target start end ->
+                    handleDragFinish { model | drag = None } target (subtractTuple start end)
 
                 _ -> model
         TimeScale factor ->