Add filter that shortens a number of parts

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

diff --git a/src/main/kotlin/net/pterodactylus/sone/template/ShortenFilter.kt b/src/main/kotlin/net/pterodactylus/sone/template/ShortenFilter.kt
new file mode 100644 (file)
index 0000000..de7a930
--- /dev/null
+++ b/src/main/kotlin/net/pterodactylus/sone/template/ShortenFilter.kt
@@ -0,0 +1,54 @@
+package net.pterodactylus.sone.template
+
+import net.pterodactylus.sone.text.LinkPart
+import net.pterodactylus.sone.text.Part
+import net.pterodactylus.sone.text.PlainTextPart
+import net.pterodactylus.util.template.Filter
+import net.pterodactylus.util.template.TemplateContext
+import java.util.*
+
+/**
+ * [Filter] that shortens a number of [Part]s in order to restrict the maximum visible text length.
+ */
+class ShortenFilter : Filter {
+
+       override fun format(templateContext: TemplateContext?, data: Any?, parameters: Map<String, Any?>?): Any? {
+               @Suppress("UNCHECKED_CAST")
+               val parts = data as? Iterable<Part> ?: return null
+               val length = parameters?.parseInt("length") ?: -1
+               val cutOffLength = parameters?.parseInt("cut-off-length") ?: length
+               if (length > -1) {
+                       var allPartsLength = 0
+                       val shortenedParts = ArrayList<Part>()
+                       for (part in parts) {
+                               if (part is PlainTextPart) {
+                                       val longText = part.text
+                                       if (allPartsLength < cutOffLength) {
+                                               if (allPartsLength + longText.length > cutOffLength) {
+                                                       shortenedParts.add(PlainTextPart(longText.substring(0, cutOffLength - allPartsLength) + "…"))
+                                               } else {
+                                                       shortenedParts.add(part)
+                                               }
+                                       }
+                                       allPartsLength += longText.length
+                               } else if (part is LinkPart) {
+                                       if (allPartsLength < cutOffLength) {
+                                               shortenedParts.add(part)
+                                       }
+                                       allPartsLength += part.text.length
+                               } else {
+                                       if (allPartsLength < cutOffLength) {
+                                               shortenedParts.add(part)
+                                       }
+                               }
+                       }
+                       if (allPartsLength > length) {
+                               return shortenedParts
+                       }
+               }
+               return parts
+       }
+
+       private fun Map<String, Any?>.parseInt(key: String) = this[key]?.toString()?.toInt()
+
+}