feat: Implement user data saving and updating functionality

app/src/main/java/cz/eman/android/interview/MainActivity.kt

@@ -3,21 +3,31 @@ package cz.eman.android.interview
 import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.WindowInsets
 import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.navigationBars
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.windowInsetsPadding
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.material3.Button
+import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
+import androidx.compose.material3.TextField
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.text.style.TextAlign
 import androidx.core.view.WindowCompat
 import androidx.room.Room
 import cz.eman.android.interview.database.AppDatabase
+import cz.eman.android.interview.repository.Repository
 
 class MainActivity : ComponentActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -44,16 +54,57 @@ class MainActivity : ComponentActivity() {
                                 .fillMaxSize()
                                 .padding(paddingValues)
                         ) {
-                            Text(
-                                modifier = Modifier.fillMaxSize(),
-                                textAlign = TextAlign.Center,
-                                color = Color.Blue,
-                                text = "Hello eMan candidate",
-                            )
+                            content(MainViewModel(Repository(db))) // DI will be done in next MR
                         }
                     }
                 )
             }
         }
     }
 }
+
+@Composable
+private fun content(
+    viewModel: MainViewModel,
+) {
+    Column {
+        Text(
+            modifier = Modifier.fillMaxWidth(),
+            textAlign = TextAlign.Center,
+            color = Color.Blue,
+            text = "Hello eMan candidate",
+        )
+
+        var jmeno: String = ""
+        var prijmeni: String = ""
+
+        Row {
+            Column {
+                Text("Jmeno")
+                TextField(jmeno, onValueChange = {
+                    jmeno = it
+                })
+            }
+            Column {
+                Text("Prijmeni")
+                TextField("", onValueChange = {
+                    prijmeni = it
+                })
+            }
+        }
+
+
+        Button(
+            onClick = {
+                viewModel.onClick(
+                    jmeno = jmeno,
+                    prijmeni = prijmeni,
+                )
+            }
+        ) {
+            Text(text = "Ulozit")
+        }
+
+
+    }
+}

app/src/main/java/cz/eman/android/interview/MainState.kt

@@ -0,0 +1,27 @@
+package cz.eman.android.interview
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import cz.eman.android.interview.repository.Repository
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.runBlocking
+
+class MainViewModel(
+    private val repository: Repository
+): ViewModel() {
+
+    fun onClick(
+        jmeno: String,
+        prijmeni: String
+    ): Boolean {
+        viewModelScope.launch {
+            runBlocking(Dispatchers.IO) {
+                repository.saveName(jmeno, prijmeni)
+            }
+            return@launch
+        }
+        return false
+    }
+}

app/src/main/java/cz/eman/android/interview/database/User/UserDao.kt

@@ -4,6 +4,7 @@ import androidx.room.Dao
 import androidx.room.Delete
 import androidx.room.Insert
 import androidx.room.Query
+import androidx.room.Update
 
 @Dao
 interface UserDao {
@@ -18,7 +19,10 @@ interface UserDao {
     fun findByName(first: String, last: String): User
 
     @Insert
-    fun insertAll(vararg users: User)
+    suspend fun insertAll(vararg users: User)
+
+    @Update
+    suspend fun update(users: User)
 
     @Delete
     fun delete(user: User)

app/src/main/java/cz/eman/android/interview/repository/Repository.kt

@@ -0,0 +1,22 @@
+package cz.eman.android.interview.repository
+
+import cz.eman.android.interview.database.AppDatabase
+import cz.eman.android.interview.database.User.User
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.runBlocking
+
+class Repository(
+    private val database: AppDatabase
+) {
+
+    val names = runBlocking(Dispatchers.IO) {  database.userDao().getAll() }
+
+    suspend fun saveName(jmeno: String, prijmeni: String) {
+        if (names.any { it.lastName == prijmeni }) {
+            database.userDao().update(
+                User(database.userDao().findByName(jmeno, prijmeni).uid, jmeno, prijmeni))
+        } else {
+            database.userDao().insertAll(User(0, jmeno, prijmeni))
+        }
+    }
+}