real-time sync with websockets (untested)

app/src/main/java/org/foxarmy/barcodescannerforemployees/WebSocketClient.kt

@@ -0,0 +1,113 @@
+package org.foxarmy.barcodescannerforemployees
+
+import android.content.Context
+import android.os.Build
+import androidx.annotation.RequiresApi
+import okhttp3.*
+import org.foxarmy.barcodescannerforemployees.database.AbstractProductDAO
+import org.foxarmy.barcodescannerforemployees.database.CategoryDAO
+import org.foxarmy.barcodescannerforemployees.database.DBStorageController
+import org.foxarmy.barcodescannerforemployees.database.ProductDAO
+import org.foxarmy.barcodescannerforemployees.dataclasses.AbstractProduct
+import org.foxarmy.barcodescannerforemployees.dataclasses.Category
+import org.foxarmy.barcodescannerforemployees.dataclasses.Product
+import org.json.JSONObject
+
+class WebSocketClient(private val context: Context, private val server: String) {
+
+    private lateinit var webSocket: WebSocket
+
+    fun connect(token: String, currentGroup: String) {
+        val client = OkHttpClient()
+        val request = Request.Builder().url("ws://$server:8282").build()
+        client.newWebSocket(request, object : WebSocketListener() {
+            override fun onOpen(webSocket: WebSocket, response: Response) {
+                this@WebSocketClient.webSocket = webSocket
+                sendMessage("\"token\":\"$token\",\"currentGroup\":\"$currentGroup\"")
+            }
+
+            @RequiresApi(Build.VERSION_CODES.O)
+            override fun onMessage(webSocket: WebSocket, text: String) {
+                val payload = JSONObject(text)
+
+                val item = payload["item"] as String
+                val data = payload["data"] as JSONObject
+                val action = payload["action"] as String
+                val currentGroup = payload["groupId"] as String
+
+                val dbHelper = DBStorageController(context, currentGroup)
+                val abstractProductDAO = AbstractProductDAO(dbHelper)
+                val productDAO = ProductDAO(dbHelper)
+                val categoryDAO = CategoryDAO(dbHelper)
+
+                when (action) {
+                    "create" -> {
+                        when (item) {
+                            "abstractproduct" -> {
+                                val newAbstractProduct = AbstractProduct.createFromJSON(data)
+                                abstractProductDAO.addAbstractProduct(newAbstractProduct)
+                            }
+
+                            "product" -> {
+                                val newProduct = Product.createFromJSON(data)
+                                productDAO.insertNewProduct(newProduct)
+                            }
+
+                            "category" -> {
+                                val newCategory = Category.createFromJSON(data)
+                                categoryDAO.addCategory(newCategory)
+                            }
+                        }
+                    }
+
+                    "update" -> {
+                        when (item) {
+                            "abstractproduct" -> {
+                                val updatedAbstractProduct = AbstractProduct.createFromJSON(data)
+                                abstractProductDAO.updateAbstractProduct(updatedAbstractProduct)
+                            }
+                            "product" -> {
+                                val updatedProduct = Product.createFromJSON(data)
+                                productDAO.updateProduct(updatedProduct)
+                            }
+                            "category" -> {
+                                val updatedCategory = Category.createFromJSON(data)
+                                categoryDAO.updateCategory(updatedCategory)
+                            }
+                        }
+                    }
+
+                    "delete" -> {
+                        val id = data["local_id"] as Int
+
+                        when(item) {
+                            "abstractproduct" -> {
+                                abstractProductDAO.eraseAbstractProduct(id, context)
+                            }
+                            "product" -> {
+                                productDAO.eraseProduct(id)
+                            }
+                            "category" -> {
+                                categoryDAO.eraseCategory(id, context)
+                            }
+                        }
+                    }
+                }
+            }
+
+            override fun onClosing(webSocket: WebSocket, code: Int, reason: String) {
+            }
+
+            override fun onFailure(webSocket: WebSocket, t: Throwable, response: Response?) {
+            }
+        })
+    }
+
+    fun sendMessage(message: String) {
+        webSocket.send(message)
+    }
+
+    fun close() {
+        webSocket.close(1000, "Closing WebSocket connection")
+    }
+}

app/src/main/java/org/foxarmy/barcodescannerforemployees/activities/GroupActivity.kt

@@ -31,7 +31,6 @@ class GroupActivity : AppCompatActivity() {
         binding.createGroupButton.setOnClickListener {
             val groupName = binding.groupNameTextEdit.text.toString()
             val groupPassword = binding.groupPasswordTextEdit.text.toString()
-            // group is set to "successful"
             val net = Net()
             net.language = sharedPreferences.getString("language", "en-US")!!
             net.server = sharedPreferences.getString("server", "")!!
@@ -69,7 +68,14 @@ class GroupActivity : AppCompatActivity() {
             if (!net.serverIsAvailable(this)) {
                 noInternetConnectionAvailableNotification(this)
             } else {
-                val groupId = net.getGroupId(groupName).toInt()
+                val requestGroupIdResponse = net.getGroupId(groupName)
+                var groupId: Int
+                try {
+                   groupId = requestGroupIdResponse.toInt()
+                } catch (e: Exception) {
+                    Toast.makeText(this, requestGroupIdResponse, Toast.LENGTH_SHORT).show()
+                    return@setOnClickListener
+                }
                 val response = net.joinGroup(groupId, groupPassword)
                 val responseText = response.body!!.string()
 

app/src/main/java/org/foxarmy/barcodescannerforemployees/activities/MainActivity.kt

@@ -17,6 +17,7 @@ import androidx.security.crypto.EncryptedSharedPreferences
 import androidx.security.crypto.MasterKeys
 import androidx.viewpager.widget.ViewPager
 import com.google.android.material.navigation.NavigationView
+import okhttp3.internal.wait
 import org.foxarmy.barcodescannerforemployees.*
 import org.foxarmy.barcodescannerforemployees.database.AbstractProductDAO
 import org.foxarmy.barcodescannerforemployees.database.CategoryDAO
@@ -112,8 +113,11 @@ class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelecte
         val currentGroup = sharedPreferences.getString("currentGroup", "offline")!!
         if ( currentGroup != "offline" && !net.serverIsAvailable(this)) {
             noInternetConnectionAvailableNotification(this)
-        } else {
+        } else if (currentGroup != "offline" && net.serverIsAvailable(this)) {
             synchronize()
+            val ws = WebSocketClient(this, sharedPreferences.getString("server", "")!!)
+            val token = sharedPreferences.getString("token", "")!!
+            ws.connect(token, currentGroup)
         }
     }
 
@@ -204,15 +208,7 @@ class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelecte
 
             if (categoryInRemoteDB != null && categoryInLocalDB != null) {
                 if (categoryInRemoteDB["hash"] != categoryInLocalDB.calculateHash()) {
-
+                    val updatedData = Category.createFromJSON(categoryInRemoteDB)
-                    var updatedData: Category
-
-                    with(categoryInRemoteDB) {
-                        updatedData = Category(
-                            this["local_id"].toString().toInt(),
-                            this["name"].toString()
-                        )
-                    }
 
                     categoryDAO.updateCategory(updatedData)
                 }
@@ -251,35 +247,14 @@ class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelecte
             }
 
             if (productInLocalDB == null && remoteProduct != null) {
-                var newProduct: Product
+                val newProduct = Product.createFromJSON(remoteProduct)
-
-                with(remoteProduct) {
-                    newProduct = Product(
-                        this["local_id"].toString().toInt(),
-                        this["abstract_product_id"].toString().toInt(),
-                        this["amount"].toString().toInt(),
-                        convertToUnixEpochTimestamp(this["date_of_production"].toString()),
-                        convertToUnixEpochTimestamp(this["expiry_date"].toString())
-                    )
-                }
 
                 productDAO.insertNewProduct(newProduct)
             }
 
             if (productInRemoteDB != null && productInLocalDB != null) {
                 if (productInRemoteDB["hash"] != productInLocalDB.calculateHash()) {
-
+                    val updatedData = Product.createFromJSON(productInRemoteDB)
-                    var updatedData: Product
-
-                    with(productInRemoteDB) {
-                        updatedData = Product(
-                            this["local_id"].toString().toInt(),
-                            this["abstract_product_id"].toString().toInt(),
-                            this["amount"].toString().toInt(),
-                            convertToUnixEpochTimestamp(this["date_of_production"].toString()),
-                            convertToUnixEpochTimestamp(this["expiry_date"].toString())
-                        )
-                    }
 
                     productDAO.updateProduct(updatedData)
                 }
@@ -330,19 +305,7 @@ class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelecte
                 val url = "https://${net.server}/api/abstractproduct/getImage/${currentGroup}/${localId}"
                 net.downloadImage(url, pictureFile)
 
-                var newAbstractProduct: AbstractProduct
+                val newAbstractProduct = AbstractProduct.createFromJSON(remoteAbstractProduct)
-
-                with(remoteAbstractProduct) {
-                    newAbstractProduct = AbstractProduct(
-                        this["local_id"].toString().toInt(),
-                        this["barcode"].toString(),
-                        this["name"].toString(),
-                        this["net_weight"].toString().toDouble(),
-                        this["image_filename"].toString(),
-                        this["category"].toString().toInt(),
-                        this["unit"].toString().toInt()
-                    )
-                }
 
                 abstractProductDAO.addAbstractProduct(newAbstractProduct)
 
@@ -357,20 +320,7 @@ class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelecte
                     val url = "https://${net.server}/api/abstractproduct/getImage/${currentGroup}/${localId}"
                     net.downloadImage(url, pictureFile)
 
-                    var updatedData: AbstractProduct
+                    val updatedData = AbstractProduct.createFromJSON(abstractProductInRemoteDB)
-
-                    with(abstractProductInRemoteDB) {
-                        updatedData = AbstractProduct(
-                            this["local_id"].toString().toInt(),
-                            this["barcode"].toString(),
-                            this["name"].toString(),
-                            this["net_weight"].toString().toDouble(),
-                            this["image_filename"].toString(),
-                            this["category"].toString().toInt(),
-                            this["unit"].toString().toInt()
-                        )
-                    }
-
 
                     abstractProductDAO.updateAbstractProduct(updatedData)
                 }

app/src/main/java/org/foxarmy/barcodescannerforemployees/dataclasses/AbstractProduct.kt

@@ -3,6 +3,7 @@ package org.foxarmy.barcodescannerforemployees.dataclasses
 import android.os.Parcel
 import android.os.Parcelable
 import org.foxarmy.barcodescannerforemployees.md5
+import org.json.JSONObject
 
 class AbstractProduct() : Parcelable {
     var id: Int = 0
@@ -59,5 +60,17 @@ class AbstractProduct() : Parcelable {
         override fun newArray(size: Int): Array<AbstractProduct?> {
             return arrayOfNulls(size)
         }
+
+        fun createFromJSON(json: JSONObject): AbstractProduct {
+            return AbstractProduct(
+                json["local_id"].toString().toInt(),
+                json["barcode"].toString(),
+                json["name"].toString(),
+                json["net_weight"].toString().toDouble(),
+                json["image_filename"].toString(),
+                json["category"].toString().toInt(),
+                json["unit"].toString().toInt()
+            )
+        }
     }
 }

app/src/main/java/org/foxarmy/barcodescannerforemployees/dataclasses/Category.kt

@@ -3,6 +3,7 @@ package org.foxarmy.barcodescannerforemployees.dataclasses
 import android.os.Parcel
 import android.os.Parcelable
 import org.foxarmy.barcodescannerforemployees.md5
+import org.json.JSONObject
 
 class Category() : Parcelable {
     var id = 0
@@ -40,5 +41,12 @@ class Category() : Parcelable {
         override fun newArray(size: Int): Array<Category?> {
             return arrayOfNulls(size)
         }
+
+        fun createFromJSON(json: JSONObject): Category {
+            return Category(
+                json["local_id"].toString().toInt(),
+                json["name"].toString()
+            )
+        }
     }
 }

app/src/main/java/org/foxarmy/barcodescannerforemployees/dataclasses/Product.kt

@@ -5,7 +5,9 @@ import android.os.Parcel
 import android.os.Parcelable
 import androidx.annotation.RequiresApi
 import org.foxarmy.barcodescannerforemployees.calculateProductFreshness
+import org.foxarmy.barcodescannerforemployees.convertToUnixEpochTimestamp
 import org.foxarmy.barcodescannerforemployees.md5
+import org.json.JSONObject
 
 class Product() : Parcelable {
     var id = 0
@@ -59,5 +61,16 @@ class Product() : Parcelable {
         override fun newArray(size: Int): Array<Product?> {
             return arrayOfNulls(size)
         }
+
+        @RequiresApi(Build.VERSION_CODES.O)
+        fun createFromJSON(json: JSONObject): Product {
+            return Product(
+                json["local_id"].toString().toInt(),
+                json["abstract_product_id"].toString().toInt(),
+                json["amount"].toString().toInt(),
+                convertToUnixEpochTimestamp(json["date_of_production"].toString()),
+                convertToUnixEpochTimestamp(json["expiry_date"].toString())
+            )
+        }
     }
 }