From 7463e87a9c56b801268ff1f403230dc9ff1404a5 Mon Sep 17 00:00:00 2001
From: Sridhar Ratnakumar <srid@srid.ca>
Date: Mon, 19 Apr 2021 15:22:41 -0400
Subject: [PATCH] Have the browser refresh on ghcid restart

---
 README.md          | 12 ++++++++----
 ema.cabal          |  1 -
 src/Ema/App.hs     | 11 ++++++++++-
 src/Ema/Example.hs |  8 ++++----
 4 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/README.md b/README.md
index a872f0d..b7c6365 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # ema
 
-ema is a **WIP** next-gen Haskell static site generator that is *change-aware*. In addition to static site generation, it provides a live server that hot-reload's on code *or* data change. 
+ema is a **WIP** next-gen Haskell static site generator that is *change-aware*. In addition to static site generation, it provides a live server that hot-reload's on code *or* data change[^1]. 
 
 The ultimate goal of ema is to make it possible to easily implement your own [neuron](https://neuron.zettel.page/), or just about any app that creates a browser view of arbitrarily changing data (on disk, database, or whatever). ema is designed to facilitate creation of apps whose data is normally *edited* via traditional mechanisms (eg: text editor) but *rendered* as a delightful web page - so as to provide an economical read-only view, of your data, on desktop & mobile.
 
@@ -14,6 +14,8 @@ main = do
     encodeUtf8 $ "<b>Hello,</b> " <> name
 ```
 
+[^1]: At the moment, only data change triggers a true hot reload; but code change triggers reload via a full page refresh in the browser, which creates a subtle flicker. Ideally this should be improved somehow, possibly by persisting the server and websocket across ghci(d) restarts (cf. [ghci-websockets](https://github.com/j-mueller/ghci-websockets)).
+
 ## Hacking
 
 Open in VSCode, and run the build task.
@@ -23,13 +25,15 @@ Open in VSCode, and run the build task.
 - [x] MVP
 - [ ] Implement hot reload, and ditch browser-sync
   - [x] server to client refresh
-  - [ ] client to server reconnect (on ghcid reload, or accidental client disconnect)
-    - [ ] or, investigate https://hackage.haskell.org/package/ghci-websockets
+  - [x] client to server reconnect (on ghcid reload, or accidental client disconnect)
+    - [x] or, investigate https://hackage.haskell.org/package/ghci-websockets
 - [ ] Example: filesystem watcher
+- [ ] position re: hakyll
 
-public,
+pre-announce,
 - [ ] refactor and simplify
 - [ ] examples
+- [ ] documentation ([howto](https://documentation.divio.com/))
 
 doc notes,
 - use async:race to avoid ghcid ghosts
diff --git a/ema.cabal b/ema.cabal
index e0fdb4f..8c94db4 100644
--- a/ema.cabal
+++ b/ema.cabal
@@ -49,7 +49,6 @@ library
     , warp
     , websockets
 
-  -- record-hasfield is included due to https://github.com/commercialhaskell/stackage/issues/4449
   mixins:
     base hiding (Prelude),
     relude (Relude as Prelude, Relude.Container.One),
diff --git a/src/Ema/App.hs b/src/Ema/App.hs
index b16d961..08754f2 100644
--- a/src/Ema/App.hs
+++ b/src/Ema/App.hs
@@ -122,6 +122,14 @@ runEma ema = do
           });
         }
 
+        function refreshPage() {
+          // The setTimeout is necessary, otherwise reload will hang forever (at
+          // least on Brave browser)
+          setTimeout(function() {
+            window.location.reload();
+          }, 100);
+        };
+
         window.onpageshow = () => {
           console.log("ema: Opening ws conn");
           var ws = new WebSocket("ws://" + window.location.host);
@@ -130,7 +138,8 @@ runEma ema = do
             ws.send(document.location.pathname);
           };
           ws.onclose = () => {
-            console.log("ema: closed");
+            console.log("ema: closed; reloading..");
+            refreshPage();
           };
           ws.onmessage = evt => {
             // console.log(evt.data);
diff --git a/src/Ema/Example.hs b/src/Ema/Example.hs
index 0cc1dbe..9e8c6e1 100644
--- a/src/Ema/Example.hs
+++ b/src/Ema/Example.hs
@@ -62,15 +62,16 @@ timeC = do
 runSimpleSitePure :: IO ()
 runSimpleSitePure = do
   (model, runTimeC) <- timeC
-  race_ runTimeC $
-    runEma $
+  race_ runTimeC (runEma $ ema model)
+  where
+    ema model =
       Ema model $ \now r ->
         Layout.tailwindSite (H.title "Simple Site") $
           H.div ! A.class_ "container mx-auto" $ do
             H.header ! A.class_ "text-4xl font-bold border-b-1" $ "Simple Site!"
             case r of
               PR_Index -> do
-                H.p ! A.style "color: red;" $ "Checkout some profiles:"
+                H.p ! A.style "color: red; text-3xl" $ "Checkout some profiles:"
                 forM_ ["Srid Ratna", "ema", "Great India"] $ \person ->
                   H.li $
                     routeElem (PR_Person person) $
@@ -86,7 +87,6 @@ runSimpleSitePure = do
                     color = colors !! mod epoch (length colors)
                     cls = "text-" <> color <> "-500"
                 H.span ! A.class_ cls $ H.toMarkup $ formatTime defaultTimeLocale "%Y/%m/%d %H:%M:%S" now
-  where
     routeElem r w =
       H.a ! A.class_ "text-xl text-purple-500 hover:underline" ! routeHref r $ w
     routeHref r =