1 files changed, 76 insertions, 0 deletions
diff --git a/src/main/kotlin/de/romjaki/pluggabledino/api/PluginLoader.kt b/src/main/kotlin/de/romjaki/pluggabledino/api/PluginLoader.kt
new file mode 100644
index 0000000..7ce8649
--- /dev/null
+++ b/src/main/kotlin/de/romjaki/pluggabledino/api/PluginLoader.kt
@@ -0,0 +1,76 @@
+package de.romjaki.pluggabledino.api
+
+import com.beust.klaxon.Klaxon
+import java.io.File
+import java.net.URL
+import java.net.URLClassLoader
+import java.util.*
+
+
+object PluginLoader {
+    private val _plugins: MutableMap<String, IPlugin> = mutableMapOf()
+    private val klaxon = Klaxon()
+    private const val pluginFolder = "plugins"
+
+    val plugins
+        get() = _plugins.toMap()
+
+
+    fun loadPlugin(url: URL): IPlugin? {
+        val cl = URLClassLoader(arrayOf(url))
+        val pluginInfo = klaxon.parse<PluginMeta>(
+                Scanner(
+                        cl.getResourceAsStream("plugin.json"))
+                        .useDelimiter("\\A")
+                        .next())!!
+        val pluginClass = cl.loadClass(pluginInfo.clazz)
+        if (!IPlugin::class.java.isAssignableFrom(pluginClass)) {
+            return null
+        }
+        val plugin = pluginClass.newInstance() as IPlugin
+        plugin.meta = pluginInfo
+        _plugins[pluginInfo.name] = plugin
+        return plugin
+    }
+
+    private fun checkDependencies() {
+        for ((name, instance) in _plugins) {
+            for (dep in instance.meta!!.dependencies) {
+                if (!_plugins.containsKey(dep.dependencyName)) {
+                    throw DependencyMissing(name, dep.dependencyName, dep.dependencyVersion)
+                }
+                val dependency = _plugins[dep.dependencyName]!!
+                if (dep.dependencyVersion.matches(dependency.meta!!.name.toRegex())) {
+                    throw DependencyMissing(name, dep.dependencyName, dep.dependencyVersion)
+                }
+            }
+        }
+    }
+
+    fun loadPlugins() = loadPlugins(File(pluginFolder))
+    fun loadPlugins(folder: File) {
+        if (!folder.isDirectory) {
+            throw PluginFolderNotFound(folder.absolutePath)
+        }
+        folder.listFiles { _, filename -> filename.endsWith(".jar") }
+                .map {
+                    it.toURI().toURL()
+                }.forEach { loadPlugin(it) }
+        checkDependencies()
+        injectDependencies()
+    }
+
+
+    private fun injectDependencies() {
+        for ((name, instance) in _plugins) {
+            for (field in instance.javaClass.fields) {
+                val inject = field.getAnnotation(Inject::class.java) as Inject
+                if (_plugins.containsKey(inject.what)) {
+                    field.set(instance, _plugins[inject.what])
+                } else {
+                    throw InjectException(name, inject.what)
+                }
+            }
+        }
+    }
+}
+\ No newline at end of file