Trigger thumbnail generation from the admin page

src/library/library.cr

@@ -221,10 +221,16 @@ class Library
   end
 
   def thumbnail_generation_progress
+    return 0 if @entries_count == 0
     @thumbnails_count / @entries_count
   end
 
   def generate_thumbnails
+    if @thumbnails_count > 0
+      Logger.debug "Thumbnail generation in progress"
+      return
+    end
+
     Logger.info "Starting thumbnail generation"
     entries = deep_titles.map(&.deep_entries).flatten.reject &.err_msg
     @entries_count = entries.size
@@ -233,10 +239,18 @@ class Library
     # Report generation progress regularly
     spawn do
       loop do
-        break if thumbnail_generation_progress.to_i == 1
-        Logger.debug "Thumbnail generation progress: " \
-                     "#{(thumbnail_generation_progress * 100).round 1}%"
-        sleep 30.seconds
+        unless @thumbnails_count == 0
+          Logger.debug "Thumbnail generation progress: " \
+                       "#{(thumbnail_generation_progress * 100).round 1}%"
+        end
+        # Generation is completed. We reset the count to 0 to allow subsequent
+        #   calls to the function, and break from the loop to stop the progress
+        #   report fiber
+        if thumbnail_generation_progress.to_i == 1
+          @thumbnails_count = 0
+          break
+        end
+        sleep 10.seconds
       end
     end
 
@@ -249,8 +263,6 @@ class Library
       end
       @thumbnails_count += 1
     end
-    Logger.info "Thumbnail generation finished. " \
-                "#{@thumbnails_count}/#{@entries_count} " \
-                "thumbnails generated"
+    Logger.info "Thumbnail generation finished"
   end
 end

src/routes/api.cr

@@ -76,6 +76,18 @@ class APIRouter < Router
       }.to_json
     end
 
+    get "/api/admin/thumbnail_progress" do |env|
+      send_json env, {
+        "progress" => Library.default.thumbnail_generation_progress,
+      }.to_json
+    end
+
+    post "/api/admin/generate_thumbnails" do |env|
+      spawn do
+        Library.default.generate_thumbnails
+      end
+    end
+
     post "/api/admin/user/delete/:username" do |env|
       begin
         username = env.params.url["username"]

src/views/admin.html.ecr

@@ -1,11 +1,17 @@
-<ul class="uk-list uk-list-large uk-list-divider">
-  <li data-url="<%= base_url %>admin/user">User Managerment</li>
-  <li onclick="if(!scanning){scan()}">
-    <span id="scan">Scan Library Files</span>
-    <span id="scan-status" class="uk-align-right">
-      <div uk-spinner hidden></div>
-      <span hidden></span>
-    </span>
+<ul class="uk-list uk-list-large uk-list-divider" id="root" x-data="{progress : 1.0, generating : false, scanTitles: 0, scanMs: -1, scanning : false}">
+  <li @click="location.href = '<%= base_url %>admin/user'">User Managerment</li>
+  <li :class="{'nopointer' : scanning}" @click="scan()">
+    <span :style="`${scanning ? 'color:grey' : ''}`">Scan Library Files</span>
+    <div class="uk-align-right">
+      <div uk-spinner x-show="scanning"></div>
+      <span x-show="!scanning && scanMs > 0" x-text="`Scan ${scanTitles} titles in ${scanMs}ms`"></span>
+    </div>
+  </li>
+  <li :class="{'nopointer' : generating}" @click="generateThumbnails()">
+    <span :style="`${generating ? 'color:grey' : ''}`">Generate Thumbnails</span>
+    <div class="uk-align-right">
+      <span x-show="generating && progress > 0" x-text="`${(progress * 100).toFixed(2)}%`"></span>
+    </div>
   </li>
   <li class="nopointer">
     <span>Theme</span>