1 files changed, 68 insertions, 3 deletions

diff --git a/app/src/main/kotlin/com/pitchedapps/frost/injectors/JsInjector.kt b/app/src/main/kotlin/com/pitchedapps/frost/injectors/JsInjector.kt
index 2d1659cc..c7b4eaf8 100644
--- a/app/src/main/kotlin/com/pitchedapps/frost/injectors/JsInjector.kt
+++ b/app/src/main/kotlin/com/pitchedapps/frost/injectors/JsInjector.kt
@@ -5,8 +5,73 @@ import android.webkit.WebView
 /**
  * Created by Allan Wang on 2017-05-31.
  */
-object JsInjector {
-    fun inject(webView: WebView) {
+enum class JsActions(val function: String) {
+    HIDE("style.display='none'"),
+    REMOVE("remove()")
+}
 
+class VariableGenerator {
+
+    var count = 0
+
+    val next: String
+        get() {
+            var key = count
+            count++
+            if (key == 0) return "a"
+            val name = StringBuilder()
+            while (key > 0) {
+                name.append(((key % 26) + 'a'.toInt()).toChar())
+                key /= 26
+            }
+            return name.toString()
+        }
+
+    fun reset() {
+        count = 0
+    }
+}
+
+class JsBuilder {
+
+    private val map: MutableMap<String, MutableSet<JsActions>> = mutableMapOf()
+    private val v = VariableGenerator()
+    private val css: StringBuilder by lazy { StringBuilder() }
+
+    fun append(action: JsActions, vararg ids: String): JsBuilder {
+        ids.forEach { id -> map[id]?.add(action) ?: map.put(id, mutableSetOf(action)) }
+        return this
+    }
+
+    fun css(css: String): JsBuilder {
+        this.css.append(css.trim())
+        return this
+    }
+
+    fun build() = JsInjector(toString())
+
+    override fun toString(): String {
+        v.reset()
+        val builder = StringBuilder().append("!function(){")
+        map.forEach { id, actions ->
+            if (actions.size == 1) {
+                builder.append("document.getElementById('$id').${actions.first().function};")
+            } else {
+                val name = v.next
+                builder.append("var $name=document.getElementById('$id');")
+                actions.forEach { a -> builder.append("$name.${a.function};") }
+            }
+        }
+        if (css.isNotBlank()) {
+            val name = v.next
+            builder.append("var $name=document.createElement('style');$name.innerHTML='$css';document.head.appendChild($name);")
+        }
+        return builder.append("}()").toString()
+    }
+}
+
+class JsInjector(val function: String) {
+    fun inject(webView: WebView, callback: ((String) -> Unit)? = null) {
+        webView.evaluateJavascript(function, { value -> callback?.invoke(value) })
     }
-}
\ No newline at end of file
+}