Add file attachment functionality with permission handling

app/build.gradle

@@ -9,7 +9,7 @@ android {
 
     defaultConfig {
         applicationId "com.duckai.app"
-        minSdk 31
+        minSdk 33
         targetSdk 34
         versionCode 1
         versionName "1.0"
@@ -35,5 +35,6 @@ android {
 dependencies {
     implementation 'androidx.core:core-ktx:1.12.0'
     implementation 'androidx.appcompat:appcompat:1.6.1'
+    implementation 'androidx.activity:activity-ktx:1.8.2'
     implementation 'com.google.android.material:material:1.11.0'
 }

app/src/main/java/com/duckai/app/web/MainActivity.kt

@@ -1,31 +1,67 @@
 package com.duckai.app.web
 
+import android.Manifest
 import android.content.Context
 import android.content.Intent
+import android.content.pm.PackageManager
 import android.net.Uri
+import android.os.Build
 import android.os.Bundle
+import android.view.View
 import android.view.inputmethod.InputMethodManager
 import android.webkit.CookieManager
+import android.webkit.ValueCallback
+import android.webkit.WebChromeClient
 import android.webkit.WebView
 import android.webkit.WebViewClient
+import android.widget.Toast
+import androidx.activity.result.contract.ActivityResultContracts
 import androidx.appcompat.app.AppCompatActivity
+import androidx.core.content.ContextCompat
 import com.duckai.app.R
 
 class MainActivity : AppCompatActivity() {
 
     private lateinit var webView: WebView
+    private lateinit var attachButton: View
+    private var filePathCallback: ValueCallback<Array<Uri>>? = null
     
     companion object {
         private const val BASE_URL = "https://duck.ai"
     }
 
+    private val filePickerLauncher = registerForActivityResult(
+        ActivityResultContracts.OpenMultipleDocuments()
+    ) { uris ->
+        if (uris.isNotEmpty()) {
+            filePathCallback?.onReceiveValue(uris.toTypedArray())
+            Toast.makeText(this, getString(R.string.file_attached), Toast.LENGTH_SHORT).show()
+        } else {
+            filePathCallback?.onReceiveValue(null)
+        }
+        filePathCallback = null
+    }
+
+    private val permissionLauncher = registerForActivityResult(
+        ActivityResultContracts.RequestMultiplePermissions()
+    ) { permissions ->
+        val allGranted = permissions.values.all { it }
+        if (allGranted) {
+            openFilePicker()
+        } else {
+            Toast.makeText(this, getString(R.string.permission_required), Toast.LENGTH_SHORT).show()
+        }
+    }
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
 
         webView = findViewById(R.id.webView)
+        attachButton = findViewById(R.id.attachButton)
         
         setupWebView()
+        setupAttachButton()
         loadUrlFromIntent()
     }
 
@@ -45,12 +81,24 @@ class MainActivity : AppCompatActivity() {
         CookieManager.getInstance().setAcceptCookie(true)
         CookieManager.getInstance().setAcceptThirdPartyCookies(webView, true)
 
+        webView.webChromeClient = object : WebChromeClient() {
+            override fun onShowFileChooser(
+                webView: WebView?,
+                filePathCallback: ValueCallback<Array<Uri>>?,
+                fileChooserParams: FileChooserParams?
+            ): Boolean {
+                this@MainActivity.filePathCallback = filePathCallback
+                checkPermissionAndPickFile()
+                return true
+            }
+        }
+        
         webView.webViewClient = object : WebViewClient() {
             override fun onPageFinished(view: WebView?, url: String?) {
                 view?.postDelayed({
                     view.evaluateJavascript(
                         "setTimeout(() => {" +
-                        "  const input = document.querySelector('input[type=\"text\"], textarea[id*=\"message\"], [role=\"combobox\"]');" +
+                        "  const input = document.querySelector('input[type=\"text\"], textarea[id*=\"message\"], [role=\"combobox\"], input[type=\"file\"]');" +
                         "  if(input) { input.focus(); input.click(); }" +
                         "}, 100);"
                     ) { _ -> }
@@ -59,6 +107,41 @@ class MainActivity : AppCompatActivity() {
         }
     }
 
+    private fun setupAttachButton() {
+        attachButton.setOnClickListener {
+            checkPermissionAndPickFile()
+        }
+    }
+
+    private fun checkPermissionAndPickFile() {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+            val permissions = arrayOf(
+                Manifest.permission.READ_MEDIA_IMAGES,
+                Manifest.permission.READ_MEDIA_VIDEO,
+                Manifest.permission.READ_MEDIA_AUDIO
+            )
+            val notGranted = permissions.filter { 
+                ContextCompat.checkSelfPermission(this, it) != PackageManager.PERMISSION_GRANTED
+            }
+            if (notGranted.isEmpty()) {
+                openFilePicker()
+            } else {
+                permissionLauncher.launch(notGranted.toTypedArray())
+            }
+        } else {
+            if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE) 
+                == PackageManager.PERMISSION_GRANTED) {
+                openFilePicker()
+            } else {
+                permissionLauncher.launch(arrayOf(Manifest.permission.READ_EXTERNAL_STORAGE))
+            }
+        }
+    }
+
+    private fun openFilePicker() {
+        filePickerLauncher.launch(arrayOf("image/*", "video/*", "audio/*", "application/pdf"))
+    }
+
     private fun loadUrlFromIntent() {
         val query = intent?.data?.getQueryParameter("q")
         val url = if (query != null) {

app/src/main/res/drawable/ic_attach.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="#000000"
+        android:pathData="M16.5,6v11.5c0,2.21 -1.79,4 -4,4s-4,-1.79 -4,-4V5c0,-1.38 1.12,-2.5 2.5,-2.5s2.5,1.12 2.5,2.5v10.5c0,0.55 -0.45,1 -1,1s-1,-0.45 -1,-1V6H10v9.5c0,1.38 1.12,2.5 2.5,2.5s2.5,-1.12 2.5,-2.5V5c0,-2.21 -1.79,-4 -4,-4S7,2.79 7,5v12.5c0,3.04 2.46,5.5 5.5,5.5s5.5,-2.46 5.5,-5.5V6h-1.5z"/>
+</vector>

app/src/main/res/layout/activity_main.xml

@@ -12,4 +12,17 @@
         android:layout_width="match_parent"
         android:layout_height="match_parent" />
 
+    <com.google.android.material.floatingactionbutton.FloatingActionButton
+        android:id="@+id/attachButton"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="bottom|end"
+        android:layout_margin="16dp"
+        android:layout_marginBottom="80dp"
+        android:contentDescription="@string/attach_file"
+        android:src="@drawable/ic_attach"
+        app:fabSize="mini"
+        app:tint="?attr/colorOnPrimaryContainer"
+        app:backgroundTint="?attr/colorPrimaryContainer" />
+
 </androidx.coordinatorlayout.widget.CoordinatorLayout>

app/src/main/res/values/strings.xml

@@ -9,4 +9,8 @@
     <string name="yes">Yes</string>
     <string name="no">No</string>
     <string name="history_cleared">Chat history cleared</string>
+    <string name="attach_file">Attach file</string>
+    <string name="file_attached">File attached</string>
+    <string name="no_app_for_file">No app found to open this file</string>
+    <string name="permission_required">Storage permission required</string>
 </resources>