some more organization

app.R

@@ -44,14 +44,14 @@ server <- function(input, output, session) {
   # Observer used at app startup time to allow using the 'Send' button once the
   # model has been loaded.
   observeEvent(loading$reload, ignoreInit = FALSE, ignoreNULL = FALSE, priority = 0, {
-
+  
     # the model is already loaded, we just make sure that we propagate this
     # by setting generating to FALSE
     if (!is.null(sess$is_loaded) && sess$is_loaded) {
       context$generating <- FALSE
       return()
     } 
-    
+
     # the model isn't loaded and no task is trying to load it, so we start a new
     # task to load it
     if (is.null(sess$is_loaded)) {
@@ -62,7 +62,7 @@ server <- function(input, output, session) {
       # the model is loading, but this is handled by another session. We should
       # come back to this observer later to enable the send button once model
       # is loaded.
-      invalidateLater(5000, session)
+      invalidateLater(100, session)
       return()
     }
     
@@ -71,6 +71,7 @@ server <- function(input, output, session) {
     m <- loading$model %>% 
       promises::then(
         onFulfilled = function(x) {
+          Sys.sleep(5)
           cat("Model has been loaded!", "\n")
           context$generating <- FALSE
           sess$is_loaded <- TRUE
@@ -146,22 +147,37 @@ server <- function(input, output, session) {
     # this controls the state of the send button.
     # if generating is TRUE we want it to be disabled, otherwise it's enabled
     # if generating is `NULL`, then the model is not yet loaded
-    btn <- if (is.null(context$generating) || context$generating == "loading") {
-      btn <- list(class = "btn-secondary disabled", label = "Loading model ...", 
-                  icon = icon("spinner", class="fa-spin"))
+    
+    # in the first startup we have to insert the send button directly, otherwise
+    # it would exist after all observers ran, including the one that loads the
+    # model
+    if (context$generating == "loading") {
+      btn <- list(
+        class = "btn-secondary disabled", 
+        label = "Loading model ...", 
+        icon = icon("spinner", class="fa-spin")
+      )
       insertUI(
-        "#sendButton", 
-        ui = actionButton(
-          "send",
-          icon =  btn$icon,
-          width = "100%", 
-          label = btn$label, 
-          class = btn$class
-        ), 
+        "#sendButton",
+        ui = ui_send(btn),
         immediate = TRUE
       )
-      btn
-    } else if (context$generating == "error") {
+      
+      msgs <- list(list(
+        role = "info", 
+        content = "Model is loading. It might take some time."
+      ))
+      insertUI(
+        "#messages", 
+        ui = ui_messages(msgs), 
+        immediate = TRUE
+      )
+      
+      return()
+    } 
+    
+    # now we can use the loop for everyone
+    btn <- if (context$generating == "error") {
       list(class = "btn-secondary disabled", label = "Generating error ...")
     } else if (context$generating) {
       list(class = "btn-secondary disabled", label = "Generating response ...", 
@@ -178,16 +194,8 @@ server <- function(input, output, session) {
   
   observeEvent(context$messages, priority = 10, {
     # this observer generates and updates the messages list
-    msg_cards <- context$messages %>% 
-      lapply(function(msg) {
-        emoji <- if (msg$role == "user") "🤗" else "🤖"
-        card(style="margin-bottom:5px;", card_body(
-          p(paste0(emoji, ":",  msg$content))
-        ))
-      })
-    
     output$messages <- renderUI({
-      rlang::exec(card_body, !!!msg_cards, gap = 5, fillable = FALSE)
+      ui_messages(context$messages)
     })
   })
   
@@ -245,4 +253,25 @@ server <- function(input, output, session) {
   })
 }
 
+ui_messages <- function(messages) {
+  emojis <- c(user = "🤗", assistant = "🤖", info = "📣", error = "😭")
+  msg_cards <- messages %>% 
+    lapply(function(msg) {
+      card(style="margin-bottom:5px;", card_body(
+        p(paste0(emojis[msg$role], ": ",  msg$content))
+      ))
+    })
+  rlang::exec(card_body, !!!msg_cards, gap = 5, fillable = FALSE)
+}
+
+ui_send <- function(btn) {
+  actionButton(
+    "send",
+    icon =  btn$icon,
+    width = "100%", 
+    label = btn$label, 
+    class = btn$class
+  )
+}
+
 shinyApp(ui, server)