Show loading animation while loading elements

[Sone.git] / src / main / kotlin / net / pterodactylus / sone / template / LinkedElementRenderFilter.kt

diff --git a/src/main/kotlin/net/pterodactylus/sone/template/LinkedElementRenderFilter.kt b/src/main/kotlin/net/pterodactylus/sone/template/LinkedElementRenderFilter.kt
new file mode 100644 (file)
index 0000000..6255f9d
--- /dev/null
+++ b/src/main/kotlin/net/pterodactylus/sone/template/LinkedElementRenderFilter.kt
@@ -0,0 +1,47 @@
+package net.pterodactylus.sone.template
+
+import net.pterodactylus.sone.core.LinkedElement
+import net.pterodactylus.sone.core.LinkedImage
+import net.pterodactylus.util.template.Filter
+import net.pterodactylus.util.template.TemplateContext
+import net.pterodactylus.util.template.TemplateContextFactory
+import net.pterodactylus.util.template.TemplateParser
+import java.io.StringReader
+import java.io.StringWriter
+
+/**
+ * Renders all kinds of [LinkedElement]s.
+ */
+class LinkedElementRenderFilter(private val templateContextFactory: TemplateContextFactory) : Filter {
+
+       companion object {
+               private val loadedImageTemplate = """<a href="/<% link|html>"><span class="linked-element" title="<% link|html>" style="background-image: url('/<% link|html>')"></span></a>""".parse()
+               private val notLoadedImageTemplate = """<span class="linked-element" title="<% link|html>" style="background-image: url('images/loading-animation.gif')"></span>""".parse()
+
+               private fun String.parse() = StringReader(this).use { TemplateParser.parse(it) }
+       }
+
+       override fun format(templateContext: TemplateContext?, data: Any?, parameters: Map<String, Any?>?) =
+                       when {
+                               data is LinkedElement && data.loading -> renderNotLoadedLinkedElement(data)
+                               data is LinkedImage -> renderLinkedImage(data)
+                               else -> null
+                       }
+
+       private fun renderLinkedImage(linkedImage: LinkedImage) =
+                       StringWriter().use {
+                               val templateContext = templateContextFactory.createTemplateContext()
+                               templateContext["link"] = linkedImage.link
+                               loadedImageTemplate.render(templateContext, it)
+                               it
+                       }.toString()
+
+       private fun renderNotLoadedLinkedElement(linkedElement: LinkedElement) =
+                       StringWriter().use {
+                               val templateContext = templateContextFactory.createTemplateContext()
+                               templateContext["link"] = linkedElement.link
+                               notLoadedImageTemplate.render(templateContext, it)
+                               it
+                       }.toString()
+
+}