WIP: Rewrite project in Kotlin - core classes and utilities (#34)

* WIP: Rewrite project in Kotlin - core classes and utilities

- Add Kotlin plugin to build.gradle files
- Convert core app classes: ProxyDroidApplication, Profile, ProxyedApp
- Convert services: ProxyDroidService, ProxyDroidVpnService
- Convert receivers: ProxyDroidReceiver, ConnectivityBroadcastReceiver
- Convert widget: ProxyDroidWidgetProvider
- Convert JNI interfaces: Exec, Tun2SocksHelper
- Convert utility classes: Utils, Constraints, Option, ImageLoader,
  ImageLoaderFactory, RegexValidator, LocalProxyServer
- Convert helper: InnerSocketBuilder

This is work in progress - remaining files to convert:
- UI activities (ProxyDroid, AppManager, BypassListActivity, FileChooser)
- PAC selector classes
- Adapters and validators
- Test files

https://claude.ai/code/session_01A8JRXuv4RL3LWQCZq4QDr9

* Complete Kotlin rewrite of ProxyDroid project

This commit completes the full conversion of the ProxyDroid Android
project from Java to Kotlin.

Changes include:
- Updated build.gradle files with Kotlin plugin and dependencies
- Converted all 36 Java source files to Kotlin
- Converted all test files to Kotlin
- Removed all original Java files

Converted files by package:

org.proxydroid:
- ProxyDroid, ProxyDroidApplication, Profile, ProxyedApp
- ProxyDroidService, ProxyDroidVpnService
- AppManager, BypassListActivity, FileChooser, FileArrayAdapter
- ConnectivityBroadcastReceiver, ProxyDroidReceiver
- ProxyDroidWidgetProvider
- Exec, InnerSocketBuilder, DomainValidator

org.proxydroid.utils:
- Utils, Constraints, Option, Base64
- ImageLoader, ImageLoaderFactory
- LocalProxyServer, Tun2SocksHelper, RegexValidator

com.btr.proxy.selector.pac:
- PacProxySelector, PacScriptParser, PacScriptSource
- RhinoPacScriptParser, UrlPacScriptSource
- PacScriptMethods, ScriptMethods
- Proxy, ProxyException, ProxyEvaluationException

com.ksmaze.android.preference:
- ListPreferenceMultiSelect

Test files:
- ExampleUnitTest, ExampleInstrumentedTest
- LocalHttpProxyTest

https://claude.ai/code/session_01A8JRXuv4RL3LWQCZq4QDr9

* Fix Kotlin compilation errors

- Add missing Base64.kt utility class that wraps android.util.Base64
- Fix duplicate companion object in AppManager.kt (merged into one)
- Add missing vpn_running string resource

https://claude.ai/code/session_01A8JRXuv4RL3LWQCZq4QDr9

* Add missing init() method to Profile class

The ProxyDroid activity calls mProfile.init() to reset profile values,
but this method was missing after the Kotlin conversion.

https://claude.ai/code/session_01A8JRXuv4RL3LWQCZq4QDr9

* Fix Kotlin compilation errors

- Change androidx.preference.PreferenceManager to android.preference.PreferenceManager
  (androidx.preference requires additional dependency)
- Add explicit type parameter to emptyList<String>() in ConnectivityBroadcastReceiver

https://claude.ai/code/session_01A8JRXuv4RL3LWQCZq4QDr9

* Fix ProxyedApp and AppManager compilation errors

- Add missing isProxyed and isEnabled properties to ProxyedApp
- Make username, procname, name nullable in ProxyedApp
- Fix OnScrollListener reference to use AbsListView.OnScrollListener
- Add null check before Arrays.binarySearch for nullable username

https://claude.ai/code/session_01A8JRXuv4RL3LWQCZq4QDr9

* Fix Kotlin compilation error in ImageLoader.kt

Cast lock object to Object before calling notifyAll() since Kotlin's Any
type doesn't have the notifyAll() method. This is consistent with the
existing wait() call pattern on line 121.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Max Lv <mlv@MaxdeMac-mini.local>

Author: 3 people

app/build.gradle

@@ -1,5 +1,6 @@
 plugins {
     id 'com.android.application'
+    id 'org.jetbrains.kotlin.android'
 }
 
 android {
@@ -35,6 +36,10 @@ android {
         targetCompatibility JavaVersion.VERSION_11
     }
 
+    kotlinOptions {
+        jvmTarget = '11'
+    }
+
     externalNativeBuild {
         cmake {
             version '3.22.1'
@@ -51,6 +56,8 @@ dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
     implementation 'androidx.appcompat:appcompat:1.6.1'
     implementation 'com.google.android.material:material:1.9.0'
+    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+    implementation 'androidx.core:core-ktx:1.10.1'
     // Exclude JUnit from json-simple (it pulls junit as compile dependency)
     implementation('com.googlecode.json-simple:json-simple:1.1.1') {
         exclude group: 'junit', module: 'junit'

app/src/androidTest/java/org/proxydroid/ExampleInstrumentedTest.java

@@ -0,0 +1,16 @@
+package org.proxydroid
+
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.platform.app.InstrumentationRegistry
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.Assert.*
+
+@RunWith(AndroidJUnit4::class)
+class ExampleInstrumentedTest {
+    @Test
+    fun useAppContext() {
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("org.proxydroid", appContext.packageName)
+    }
+}

app/src/androidTest/java/org/proxydroid/ExampleInstrumentedTest.kt

@@ -0,0 +1,89 @@
+package com.btr.proxy.selector.pac
+
+import android.util.Log
+import java.net.URI
+
+class PacProxySelector(pacSource: PacScriptSource) {
+
+    companion object {
+        private const val PAC_SOCKS = "SOCKS"
+        private const val PAC_DIRECT = "DIRECT"
+        private const val PAC_HTTPS = "HTTPS"
+        private const val TAG = "ProxyDroid.PAC"
+    }
+
+    private var pacScriptParser: PacScriptParser? = null
+
+    init {
+        selectEngine(pacSource)
+    }
+
+    private fun selectEngine(pacSource: PacScriptSource) {
+        try {
+            pacScriptParser = RhinoPacScriptParser(pacSource)
+        } catch (e: Exception) {
+            Log.e(TAG, "PAC parser error.", e)
+        }
+    }
+
+    fun select(uri: URI): List<Proxy>? {
+        if (uri.host == null) {
+            throw IllegalArgumentException("URI must not be null.")
+        }
+
+        val scriptSource = pacScriptParser?.getScriptSource()
+        if (scriptSource.toString().contains(uri.host)) {
+            return null
+        }
+
+        return findProxy(uri)
+    }
+
+    private fun findProxy(uri: URI): List<Proxy>? {
+        return try {
+            val proxies = mutableListOf<Proxy>()
+            val parseResult = pacScriptParser?.evaluate(uri.toString(), uri.host) ?: return null
+            val proxyDefinitions = parseResult.split(";")
+
+            for (proxyDef in proxyDefinitions) {
+                if (proxyDef.trim().isNotEmpty()) {
+                    proxies.add(buildProxyFromPacResult(proxyDef))
+                }
+            }
+            proxies
+        } catch (e: ProxyEvaluationException) {
+            Log.e(TAG, "PAC resolving error.", e)
+            null
+        }
+    }
+
+    private fun buildProxyFromPacResult(pacResult: String?): Proxy {
+        if (pacResult == null || pacResult.trim().length < 6) {
+            return Proxy.NO_PROXY
+        }
+
+        val proxyDef = pacResult.trim()
+        if (proxyDef.uppercase().startsWith(PAC_DIRECT)) {
+            return Proxy.NO_PROXY
+        }
+
+        var type = Proxy.TYPE_HTTP
+        if (proxyDef.uppercase().startsWith(PAC_SOCKS)) {
+            type = Proxy.TYPE_SOCKS5
+        }
+        if (proxyDef.uppercase().startsWith(PAC_HTTPS)) {
+            type = Proxy.TYPE_HTTPS
+        }
+
+        var host = proxyDef.substring(6)
+        var port = if (type == Proxy.TYPE_HTTPS) 443 else 80
+
+        val indexOfPort = host.indexOf(':')
+        if (indexOfPort != -1) {
+            port = host.substring(indexOfPort + 1).trim().toInt()
+            host = host.substring(0, indexOfPort).trim()
+        }
+
+        return Proxy(host, port, type)
+    }
+}