Add sending messages (#232)

app/build.gradle

@@ -72,8 +72,7 @@ play {
 
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
-    implementation "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
+    implementation('com.github.wulkanowy:api:46f09bdf34') { exclude module: "threetenbp" }
-    implementation('com.github.wulkanowy:api:0a4317f651') { exclude module: "threetenbp" }
 
     implementation "androidx.legacy:legacy-support-v4:1.0.0"
     implementation "androidx.appcompat:appcompat:1.0.2"
@@ -125,6 +124,8 @@ dependencies {
     androidTestImplementation 'androidx.test.ext:junit:1.1.0'
     androidTestImplementation 'org.mockito:mockito-android:2.23.4'
     androidTestImplementation "org.jetbrains.kotlin:kotlin-test:$kotlin_version"
+
+    implementation "com.hootsuite.android:nachos:1.1.1"
 }
 
 apply plugin: 'com.google.gms.google-services'

app/src/androidTest/java/io/github/wulkanowy/data/repositories/local/AttendanceLocalTest.kt

@@ -41,7 +41,7 @@ class AttendanceLocalTest {
         ))
 
         val attendance = attendanceLocal
-                .getAttendance(Semester(1, 2, "", 1, 3, true),
+            .getAttendance(Semester(1, 2, "", 1, 3, true, 1, 1),
                         LocalDate.of(2018, 9, 10),
                         LocalDate.of(2018, 9, 14)
                 )

app/src/androidTest/java/io/github/wulkanowy/data/repositories/local/CompletedLessonsLocalTest.kt

@@ -42,7 +42,7 @@ class CompletedLessonsLocalTest {
         ))
 
         val completed = completedLessonsLocal
-            .getCompletedLessons(Semester(1, 2, "", 1, 3, true),
+            .getCompletedLessons(Semester(1, 2, "", 1, 3, true, 1, 1),
                 LocalDate.of(2018, 9, 10),
                 LocalDate.of(2018, 9, 14)
             )

app/src/androidTest/java/io/github/wulkanowy/data/repositories/local/ExamLocalTest.kt

@@ -41,7 +41,7 @@ class ExamLocalTest {
         ))
 
         val exams = examLocal
-                .getExams(Semester(1, 2, "", 1, 3, true),
+            .getExams(Semester(1, 2, "", 1, 3, true, 1, 1),
                         LocalDate.of(2018, 9, 10),
                         LocalDate.of(2018, 9, 14)
                 )

app/src/androidTest/java/io/github/wulkanowy/data/repositories/local/LuckyNumberLocalTest.kt

@@ -37,7 +37,7 @@ class LuckyNumberLocalTest {
     fun saveAndReadTest() {
         luckyNumberLocal.saveLuckyNumber(LuckyNumber(1, LocalDate.of(2019, 1, 20), 14))
 
-        val luckyNumber = luckyNumberLocal.getLuckyNumber(Semester(1, 1, "", 1, 3, true),
+        val luckyNumber = luckyNumberLocal.getLuckyNumber(Semester(1, 1, "", 1, 3, true, 1, 1),
             LocalDate.of(2019, 1, 20)
         ).blockingGet()
 

app/src/androidTest/java/io/github/wulkanowy/data/repositories/local/RecipientLocalTest.kt

@@ -0,0 +1,61 @@
+package io.github.wulkanowy.data.repositories.local
+
+import androidx.room.Room
+import androidx.test.core.app.ApplicationProvider
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import io.github.wulkanowy.data.db.AppDatabase
+import io.github.wulkanowy.data.db.entities.Recipient
+import io.github.wulkanowy.data.db.entities.ReportingUnit
+import io.github.wulkanowy.data.db.entities.Student
+import io.github.wulkanowy.data.repositories.recipient.RecipientLocal
+import org.junit.After
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.threeten.bp.LocalDateTime
+import kotlin.test.assertEquals
+
+@RunWith(AndroidJUnit4::class)
+class RecipientLocalTest {
+
+    private lateinit var recipientLocal: RecipientLocal
+
+    private lateinit var testDb: AppDatabase
+
+    @Before
+    fun createDb() {
+        testDb = Room.inMemoryDatabaseBuilder(ApplicationProvider.getApplicationContext(), AppDatabase::class.java)
+            .build()
+        recipientLocal = RecipientLocal(testDb.recipientDao)
+    }
+
+    @After
+    fun closeDb() {
+        testDb.close()
+    }
+
+    @Test
+    fun saveAndReadTest() {
+        recipientLocal.saveRecipients(listOf(
+            Recipient(1, "2rPracownik", "Kowalski Jan", "Kowalski Jan [KJ] - Pracownik (Fake123456)", 3, 4, 2, "hash"),
+            Recipient(1, "3rPracownik", "Kowalska Karolina", "Kowalska Karolina [KK] - Pracownik (Fake123456)", 4, 4, 2, "hash"),
+            Recipient(1, "4rPracownik", "Krupa Stanisław", "Krupa Stanisław [KS] - Uczeń (Fake123456)", 5, 4, 1, "hash")
+        ))
+
+        val recipients = recipientLocal.getRecipients(
+            Student("fakelog.cf", "AUTO", "", "", "", 1, "", "", "", true, LocalDateTime.now()),
+            2,
+            ReportingUnit(1, 4, "", 0, "", emptyList())
+        ).blockingGet()
+
+        assertEquals(2, recipients.size)
+        assertEquals(1, recipients[0].studentId)
+        assertEquals("3rPracownik", recipients[1].realId)
+        assertEquals("Kowalski Jan", recipients[0].name)
+        assertEquals("Kowalska Karolina [KK] - Pracownik (Fake123456)", recipients[1].realName)
+        assertEquals(3, recipients[0].loginId)
+        assertEquals(4, recipients[1].unitId)
+        assertEquals(2, recipients[0].role)
+        assertEquals("hash", recipients[1].hash)
+    }
+}

app/src/androidTest/java/io/github/wulkanowy/data/repositories/local/TimetableLocalTest.kt

@@ -45,7 +45,7 @@ class TimetableLocalTest {
         ))
 
         val exams = timetableDb.getTimetable(
-                Semester(1, 2, "", 1, 1, true),
+            Semester(1, 2, "", 1, 1, true, 1, 1),
                 LocalDate.of(2018, 9, 10),
                 LocalDate.of(2018, 9, 14)
         ).blockingGet()

app/src/main/java/io/github/wulkanowy/data/RepositoryModule.kt

@@ -121,4 +121,12 @@ internal class RepositoryModule {
     @Singleton
     @Provides
     fun provideCompletedLessonsDao(database: AppDatabase) = database.completedLessonsDao
+
+    @Singleton
+    @Provides
+    fun provideReportingUnitDao(database: AppDatabase) = database.reportingUnitDao
+
+    @Singleton
+    @Provides
+    fun provideRecipientDao(database: AppDatabase) = database.recipientDao
 }

app/src/main/java/io/github/wulkanowy/data/db/AppDatabase.kt

@@ -16,6 +16,8 @@ import io.github.wulkanowy.data.db.dao.HomeworkDao
 import io.github.wulkanowy.data.db.dao.LuckyNumberDao
 import io.github.wulkanowy.data.db.dao.MessagesDao
 import io.github.wulkanowy.data.db.dao.NoteDao
+import io.github.wulkanowy.data.db.dao.RecipientDao
+import io.github.wulkanowy.data.db.dao.ReportingUnitDao
 import io.github.wulkanowy.data.db.dao.SemesterDao
 import io.github.wulkanowy.data.db.dao.StudentDao
 import io.github.wulkanowy.data.db.dao.SubjectDao
@@ -30,6 +32,8 @@ import io.github.wulkanowy.data.db.entities.Homework
 import io.github.wulkanowy.data.db.entities.LuckyNumber
 import io.github.wulkanowy.data.db.entities.Message
 import io.github.wulkanowy.data.db.entities.Note
+import io.github.wulkanowy.data.db.entities.Recipient
+import io.github.wulkanowy.data.db.entities.ReportingUnit
 import io.github.wulkanowy.data.db.entities.Semester
 import io.github.wulkanowy.data.db.entities.Student
 import io.github.wulkanowy.data.db.entities.Subject
@@ -38,6 +42,7 @@ import io.github.wulkanowy.data.db.migrations.Migration2
 import io.github.wulkanowy.data.db.migrations.Migration3
 import io.github.wulkanowy.data.db.migrations.Migration4
 import io.github.wulkanowy.data.db.migrations.Migration5
+import io.github.wulkanowy.data.db.migrations.Migration6
 import javax.inject.Singleton
 
 @Singleton
@@ -56,7 +61,9 @@ import javax.inject.Singleton
         Homework::class,
         Subject::class,
         LuckyNumber::class,
-        CompletedLesson::class
+        CompletedLesson::class,
+        ReportingUnit::class,
+        Recipient::class
     ],
     version = AppDatabase.VERSION_SCHEMA,
     exportSchema = false
@@ -65,7 +72,7 @@ import javax.inject.Singleton
 abstract class AppDatabase : RoomDatabase() {
 
     companion object {
-        const val VERSION_SCHEMA = 5
+        const val VERSION_SCHEMA = 6
 
         fun newInstance(context: Context): AppDatabase {
             return Room.databaseBuilder(context, AppDatabase::class.java, "wulkanowy_database")
@@ -76,7 +83,8 @@ abstract class AppDatabase : RoomDatabase() {
                     Migration2(),
                     Migration3(),
                     Migration4(),
-                    Migration5()
+                    Migration5(),
+                    Migration6()
                 )
                 .build()
         }
@@ -109,4 +117,8 @@ abstract class AppDatabase : RoomDatabase() {
     abstract val luckyNumberDao: LuckyNumberDao
 
     abstract val completedLessonsDao: CompletedLessonsDao
+
+    abstract val reportingUnitDao: ReportingUnitDao
+
+    abstract val recipientDao: RecipientDao
 }

app/src/main/java/io/github/wulkanowy/data/db/Converters.kt

@@ -8,6 +8,8 @@ import org.threeten.bp.LocalDateTime
 import org.threeten.bp.Month
 import org.threeten.bp.ZoneOffset
 import java.util.Date
+import com.google.gson.Gson
+import com.google.gson.reflect.TypeToken
 
 class Converters {
 
@@ -36,4 +38,14 @@ class Converters {
 
     @TypeConverter
     fun intToMonth(value: Int?) = value?.let { Month.of(it) }
+
+    @TypeConverter
+    fun intListToGson(list: List<Int>): String {
+        return Gson().toJson(list)
+    }
+
+    @TypeConverter
+    fun gsonToIntList(value: String): List<Int> {
+        return Gson().fromJson(value, object : TypeToken<List<Int>>() {}.type)
+    }
 }

app/src/main/java/io/github/wulkanowy/data/db/dao/RecipientDao.kt

@@ -0,0 +1,23 @@
+package io.github.wulkanowy.data.db.dao
+
+import androidx.room.Dao
+import androidx.room.Delete
+import androidx.room.Insert
+import androidx.room.Query
+import io.github.wulkanowy.data.db.entities.Recipient
+import io.reactivex.Maybe
+import javax.inject.Singleton
+
+@Singleton
+@Dao
+interface RecipientDao {
+
+    @Insert
+    fun insertAll(messages: List<Recipient>)
+
+    @Delete
+    fun deleteAll(messages: List<Recipient>)
+
+    @Query("SELECT * FROM Recipients WHERE student_id = :studentId AND role = :role AND unit_id = :unitId")
+    fun load(studentId: Int, role: Int, unitId: Int): Maybe<List<Recipient>>
+}

app/src/main/java/io/github/wulkanowy/data/db/dao/ReportingUnitDao.kt

@@ -0,0 +1,26 @@
+package io.github.wulkanowy.data.db.dao
+
+import androidx.room.Dao
+import androidx.room.Delete
+import androidx.room.Insert
+import androidx.room.Query
+import io.github.wulkanowy.data.db.entities.ReportingUnit
+import io.reactivex.Maybe
+import javax.inject.Singleton
+
+@Singleton
+@Dao
+interface ReportingUnitDao {
+
+    @Insert
+    fun insertAll(reportingUnits: List<ReportingUnit>)
+
+    @Delete
+    fun deleteAll(reportingUnits: List<ReportingUnit>)
+
+    @Query("SELECT * FROM ReportingUnits WHERE student_id = :studentId")
+    fun load(studentId: Int): Maybe<List<ReportingUnit>>
+
+    @Query("SELECT * FROM ReportingUnits WHERE student_id = :studentId AND real_id = :unitId")
+    fun loadOne(studentId: Int, unitId: Int): Maybe<ReportingUnit>
+}

app/src/main/java/io/github/wulkanowy/data/db/entities/Recipient.kt

@@ -0,0 +1,38 @@
+package io.github.wulkanowy.data.db.entities
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+import java.io.Serializable
+
+@Entity(tableName = "Recipients")
+data class Recipient(
+
+    @ColumnInfo(name = "student_id")
+    val studentId: Int,
+
+    @ColumnInfo(name = "real_id")
+    val realId: String,
+
+    val name: String,
+
+    @ColumnInfo(name = "real_name")
+    val realName: String,
+
+    @ColumnInfo(name = "login_id")
+    val loginId: Int,
+
+    @ColumnInfo(name = "unit_id")
+    val unitId: Int,
+
+    val role: Int,
+
+    val hash: String
+
+) : Serializable {
+
+    @PrimaryKey(autoGenerate = true)
+    var id: Long = 0
+
+    override fun toString() = name
+}

app/src/main/java/io/github/wulkanowy/data/db/entities/ReportingUnit.kt

@@ -0,0 +1,32 @@
+package io.github.wulkanowy.data.db.entities
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+import java.io.Serializable
+
+@Entity(tableName = "ReportingUnits")
+data class ReportingUnit(
+
+    @ColumnInfo(name = "student_id")
+    val studentId: Int,
+
+    @ColumnInfo(name = "real_id")
+    val realId: Int,
+
+    @ColumnInfo(name = "short")
+    val shortName: String,
+
+    @ColumnInfo(name = "sender_id")
+    val senderId: Int,
+
+    @ColumnInfo(name = "sender_name")
+    val senderName: String,
+
+    val roles: List<Int>
+
+) : Serializable {
+
+    @PrimaryKey(autoGenerate = true)
+    var id: Long = 0
+}

app/src/main/java/io/github/wulkanowy/data/db/entities/Semester.kt

@@ -24,7 +24,13 @@ data class Semester(
     val semesterName: Int,
 
     @ColumnInfo(name = "is_current")
-    val isCurrent: Boolean
+    val isCurrent: Boolean,
+
+    @ColumnInfo(name = "class_id")
+    val classId: Int,
+
+    @ColumnInfo(name = "unit_id")
+    val unitId: Int
 ) {
 
     @PrimaryKey(autoGenerate = true)

app/src/main/java/io/github/wulkanowy/data/db/migrations/Migration6.kt

@@ -0,0 +1,33 @@
+package io.github.wulkanowy.data.db.migrations
+
+import androidx.room.migration.Migration
+import androidx.sqlite.db.SupportSQLiteDatabase
+
+class Migration6 : Migration(5, 6) {
+
+    override fun migrate(database: SupportSQLiteDatabase) {
+        database.execSQL("CREATE TABLE ReportingUnits (" +
+            "id INTEGER NOT NULL PRIMARY KEY," +
+            "student_id INTEGER NOT NULL," +
+            "real_id INTEGER NOT NULL," +
+            "short TEXT NOT NULL," +
+            "sender_id INTEGER NOT NULL," +
+            "sender_name TEXT NOT NULL," +
+            "roles TEXT NOT NULL)")
+
+        database.execSQL("CREATE TABLE Recipients (" +
+            "id INTEGER NOT NULL PRIMARY KEY," +
+            "student_id INTEGER NOT NULL," +
+            "real_id TEXT NOT NULL," +
+            "name TEXT NOT NULL," +
+            "real_name TEXT NOT NULL," +
+            "login_id INTEGER NOT NULL," +
+            "unit_id INTEGER NOT NULL," +
+            "role INTEGER NOT NULL," +
+            "hash TEXT NOT NULL)")
+
+        database.execSQL("DELETE FROM Semesters WHERE 1")
+        database.execSQL("ALTER TABLE Semesters ADD COLUMN class_id INTEGER DEFAULT 0 NOT NULL")
+        database.execSQL("ALTER TABLE Semesters ADD COLUMN unit_id INTEGER DEFAULT 0 NOT NULL")
+    }
+}

app/src/main/java/io/github/wulkanowy/data/repositories/message/MessageRemote.kt

@@ -2,13 +2,16 @@ package io.github.wulkanowy.data.repositories.message
 
 import io.github.wulkanowy.api.Api
 import io.github.wulkanowy.api.messages.Folder
+import io.github.wulkanowy.api.messages.SentMessage
 import io.github.wulkanowy.data.db.entities.Message
+import io.github.wulkanowy.data.db.entities.Recipient
 import io.github.wulkanowy.utils.toLocalDateTime
 import io.reactivex.Single
 import org.threeten.bp.LocalDateTime.now
 import javax.inject.Inject
 import javax.inject.Singleton
 import io.github.wulkanowy.api.messages.Message as ApiMessage
+import io.github.wulkanowy.api.messages.Recipient as ApiRecipient
 
 @Singleton
 class MessageRemote @Inject constructor(private val api: Api) {
@@ -39,4 +42,21 @@ class MessageRemote @Inject constructor(private val api: Api) {
     fun getMessagesContent(message: Message, markAsRead: Boolean = false): Single<String> {
         return api.getMessageContent(message.messageId, message.folderId, markAsRead, message.realId)
     }
+
+    fun sendMessage(subject: String, content: String, recipients: List<Recipient>): Single<SentMessage> {
+        return api.sendMessage(
+            subject = subject,
+            content = content,
+            recipients = recipients.map {
+                ApiRecipient(
+                    id = it.realId,
+                    realName = it.realName,
+                    loginId = it.loginId,
+                    reportingUnitId = it.unitId,
+                    role = it.role,
+                    hash = it.hash
+                )
+            }
+        )
+    }
 }

app/src/main/java/io/github/wulkanowy/data/repositories/message/MessageRepository.kt

@@ -2,8 +2,10 @@ package io.github.wulkanowy.data.repositories.message
 
 import com.github.pwittchen.reactivenetwork.library.rx2.ReactiveNetwork
 import com.github.pwittchen.reactivenetwork.library.rx2.internet.observing.InternetObservingSettings
+import io.github.wulkanowy.api.messages.SentMessage
 import io.github.wulkanowy.data.ApiHelper
 import io.github.wulkanowy.data.db.entities.Message
+import io.github.wulkanowy.data.db.entities.Recipient
 import io.github.wulkanowy.data.db.entities.Student
 import io.reactivex.Completable
 import io.reactivex.Single
@@ -82,4 +84,8 @@ class MessageRepository @Inject constructor(
     fun updateMessages(messages: List<Message>): Completable {
         return Completable.fromCallable { local.updateMessages(messages) }
     }
+
+    fun sendMessage(subject: String, content: String, recipients: List<Recipient>): Single<SentMessage> {
+        return remote.sendMessage(subject, content, recipients)
+    }
 }

app/src/main/java/io/github/wulkanowy/data/repositories/recipient/RecipientLocal.kt

@@ -0,0 +1,25 @@
+package io.github.wulkanowy.data.repositories.recipient
+
+import io.github.wulkanowy.data.db.dao.RecipientDao
+import io.github.wulkanowy.data.db.entities.Recipient
+import io.github.wulkanowy.data.db.entities.ReportingUnit
+import io.github.wulkanowy.data.db.entities.Student
+import io.reactivex.Maybe
+import javax.inject.Inject
+import javax.inject.Singleton
+
+@Singleton
+class RecipientLocal @Inject constructor(private val recipientDb: RecipientDao) {
+
+    fun getRecipients(student: Student, role: Int, unit: ReportingUnit): Maybe<List<Recipient>> {
+        return recipientDb.load(student.studentId, role, unit.realId).filter { !it.isEmpty() }
+    }
+
+    fun saveRecipients(recipients: List<Recipient>) {
+        return recipientDb.insertAll(recipients)
+    }
+
+    fun deleteRecipients(recipients: List<Recipient>) {
+        recipientDb.deleteAll(recipients)
+    }
+}

app/src/main/java/io/github/wulkanowy/data/repositories/recipient/RecipientRemote.kt

@@ -0,0 +1,30 @@
+package io.github.wulkanowy.data.repositories.recipient
+
+import io.github.wulkanowy.api.Api
+import io.github.wulkanowy.data.db.entities.Recipient
+import io.github.wulkanowy.data.db.entities.ReportingUnit
+import io.reactivex.Single
+import javax.inject.Inject
+import javax.inject.Singleton
+
+@Singleton
+class RecipientRemote @Inject constructor(private val api: Api) {
+
+    fun getRecipients(role: Int, unit: ReportingUnit): Single<List<Recipient>> {
+        return api.getRecipients(role, unit.realId)
+            .map { recipients ->
+                recipients.map {
+                    Recipient(
+                        studentId = api.studentId,
+                        name = it.name,
+                        realName = it.realName,
+                        realId = it.id,
+                        hash = it.hash,
+                        loginId = it.loginId,
+                        role = it.role,
+                        unitId = it.reportingUnitId
+                    )
+                }
+            }
+    }
+}

app/src/main/java/io/github/wulkanowy/data/repositories/recipient/RecipientRepository.kt

@@ -0,0 +1,42 @@
+package io.github.wulkanowy.data.repositories.recipient
+
+import com.github.pwittchen.reactivenetwork.library.rx2.ReactiveNetwork
+import com.github.pwittchen.reactivenetwork.library.rx2.internet.observing.InternetObservingSettings
+import io.github.wulkanowy.data.ApiHelper
+import io.github.wulkanowy.data.db.entities.Recipient
+import io.github.wulkanowy.data.db.entities.ReportingUnit
+import io.github.wulkanowy.data.db.entities.Student
+import io.reactivex.Single
+import java.net.UnknownHostException
+import javax.inject.Inject
+import javax.inject.Singleton
+
+@Singleton
+class RecipientRepository @Inject constructor(
+    private val settings: InternetObservingSettings,
+    private val local: RecipientLocal,
+    private val remote: RecipientRemote,
+    private val apiHelper: ApiHelper
+) {
+
+    fun getRecipients(student: Student, role: Int, unit: ReportingUnit, forceRefresh: Boolean = false): Single<List<Recipient>> {
+        return Single.just(apiHelper.initApi(student))
+            .flatMap { _ ->
+                local.getRecipients(student, role, unit).filter { !forceRefresh }
+                    .switchIfEmpty(ReactiveNetwork.checkInternetConnectivity(settings)
+                        .flatMap {
+                            if (it) remote.getRecipients(role, unit)
+                            else Single.error(UnknownHostException())
+                        }.flatMap { new ->
+                            local.getRecipients(student, role, unit).toSingle(emptyList())
+                                .doOnSuccess { old ->
+                                    local.deleteRecipients(old - new)
+                                    local.saveRecipients(new - old)
+                                }
+                        }.flatMap {
+                            local.getRecipients(student, role, unit).toSingle(emptyList())
+                        }
+                    )
+            }
+    }
+}

app/src/main/java/io/github/wulkanowy/data/repositories/reportingunit/ReportingUnitLocal.kt

@@ -0,0 +1,28 @@
+package io.github.wulkanowy.data.repositories.reportingunit
+
+import io.github.wulkanowy.data.db.dao.ReportingUnitDao
+import io.github.wulkanowy.data.db.entities.ReportingUnit
+import io.github.wulkanowy.data.db.entities.Student
+import io.reactivex.Maybe
+import javax.inject.Inject
+import javax.inject.Singleton
+
+@Singleton
+class ReportingUnitLocal @Inject constructor(private val reportingUnitDb: ReportingUnitDao) {
+
+    fun getReportingUnits(student: Student): Maybe<List<ReportingUnit>> {
+        return reportingUnitDb.load(student.studentId).filter { !it.isEmpty() }
+    }
+
+    fun getReportingUnit(student: Student, unitId: Int): Maybe<ReportingUnit> {
+        return reportingUnitDb.loadOne(student.studentId, unitId)
+    }
+
+    fun saveReportingUnits(reportingUnits: List<ReportingUnit>) {
+        return reportingUnitDb.insertAll(reportingUnits)
+    }
+
+    fun deleteReportingUnits(reportingUnits: List<ReportingUnit>) {
+        reportingUnitDb.deleteAll(reportingUnits)
+    }
+}

app/src/main/java/io/github/wulkanowy/data/repositories/reportingunit/ReportingUnitRemote.kt

@@ -0,0 +1,26 @@
+package io.github.wulkanowy.data.repositories.reportingunit
+
+import io.github.wulkanowy.api.Api
+import io.github.wulkanowy.data.db.entities.ReportingUnit
+import io.reactivex.Single
+import javax.inject.Inject
+import javax.inject.Singleton
+
+@Singleton
+class ReportingUnitRemote @Inject constructor(private val api: Api) {
+
+    fun getReportingUnits(): Single<List<ReportingUnit>> {
+        return api.getReportingUnits().map {
+            it.map { unit ->
+                ReportingUnit(
+                    studentId = api.studentId,
+                    realId = unit.id,
+                    roles = unit.roles,
+                    senderId = unit.senderId,
+                    senderName = unit.senderName,
+                    shortName = unit.short
+                )
+            }
+        }
+    }
+}

app/src/main/java/io/github/wulkanowy/data/repositories/reportingunit/ReportingUnitRepository.kt

@@ -0,0 +1,55 @@
+package io.github.wulkanowy.data.repositories.reportingunit
+
+import com.github.pwittchen.reactivenetwork.library.rx2.ReactiveNetwork
+import com.github.pwittchen.reactivenetwork.library.rx2.internet.observing.InternetObservingSettings
+import io.github.wulkanowy.data.ApiHelper
+import io.github.wulkanowy.data.db.entities.ReportingUnit
+import io.github.wulkanowy.data.db.entities.Student
+import io.reactivex.Maybe
+import io.reactivex.Single
+import java.net.UnknownHostException
+import javax.inject.Inject
+import javax.inject.Singleton
+
+@Singleton
+class ReportingUnitRepository @Inject constructor(
+    private val settings: InternetObservingSettings,
+    private val local: ReportingUnitLocal,
+    private val remote: ReportingUnitRemote,
+    private val apiHelper: ApiHelper
+) {
+
+    fun getReportingUnits(student: Student, forceRefresh: Boolean = false): Single<List<ReportingUnit>> {
+        return Single.just(apiHelper.initApi(student))
+            .flatMap { _ ->
+                local.getReportingUnits(student).filter { !forceRefresh }
+                    .switchIfEmpty(ReactiveNetwork.checkInternetConnectivity(settings)
+                        .flatMap {
+                            if (it) remote.getReportingUnits()
+                            else Single.error(UnknownHostException())
+                        }.flatMap { new ->
+                            local.getReportingUnits(student).toSingle(emptyList())
+                                .doOnSuccess { old ->
+                                    local.deleteReportingUnits(old - new)
+                                    local.saveReportingUnits(new - old)
+                                }
+                        }.flatMap { local.getReportingUnits(student).toSingle(emptyList()) }
+                    )
+            }
+    }
+
+    fun getReportingUnit(student: Student, unitId: Int): Maybe<ReportingUnit> {
+        return Maybe.just(apiHelper.initApi(student))
+            .flatMap { _ ->
+                local.getReportingUnit(student, unitId)
+                    .switchIfEmpty(ReactiveNetwork.checkInternetConnectivity(settings)
+                        .flatMap {
+                            if (it) getReportingUnits(student, true)
+                            else Single.error(UnknownHostException())
+                        }.flatMapMaybe {
+                            local.getReportingUnit(student, unitId)
+                        }
+                    )
+            }
+    }
+}

app/src/main/java/io/github/wulkanowy/data/repositories/semester/SemesterRemote.kt

@@ -19,7 +19,9 @@ class SemesterRemote @Inject constructor(private val api: Api) {
                     diaryName = semester.diaryName,
                     semesterId = semester.semesterId,
                     semesterName = semester.semesterNumber,
-                    isCurrent = semester.current
+                    isCurrent = semester.current,
+                    classId = semester.classId,
+                    unitId = semester.unitId
                 )
             }
 

app/src/main/java/io/github/wulkanowy/services/job/SyncWorker.kt

@@ -14,6 +14,8 @@ import io.github.wulkanowy.data.repositories.message.MessageRepository
 import io.github.wulkanowy.data.repositories.message.MessageRepository.MessageFolder.RECEIVED
 import io.github.wulkanowy.data.repositories.note.NoteRepository
 import io.github.wulkanowy.data.repositories.preferences.PreferencesRepository
+import io.github.wulkanowy.data.repositories.recipient.RecipientRepository
+import io.github.wulkanowy.data.repositories.reportingunit.ReportingUnitRepository
 import io.github.wulkanowy.data.repositories.semester.SemesterRepository
 import io.github.wulkanowy.data.repositories.student.StudentRepository
 import io.github.wulkanowy.data.repositories.timetable.TimetableRepository
@@ -26,6 +28,7 @@ import io.github.wulkanowy.utils.isHolidays
 import io.github.wulkanowy.utils.monday
 import io.reactivex.Completable
 import io.reactivex.Maybe
+import io.reactivex.Single
 import io.reactivex.disposables.CompositeDisposable
 import org.threeten.bp.LocalDate
 import timber.log.Timber
@@ -69,6 +72,12 @@ class SyncWorker : SimpleJobService() {
     @Inject
     lateinit var completedLessons: CompletedLessonsRepository
 
+    @Inject
+    lateinit var reportingUnitRepository: ReportingUnitRepository
+
+    @Inject
+    lateinit var recipientRepository: RecipientRepository
+
     @Inject
     lateinit var prefRepository: PreferencesRepository
 
@@ -98,21 +107,24 @@ class SyncWorker : SimpleJobService() {
         disposable.add(student.isStudentSaved()
             .flatMapMaybe { if (it) student.getCurrentStudent().toMaybe() else Maybe.empty() }
             .flatMap { semester.getCurrentSemester(it, true).map { semester -> semester to it }.toMaybe() }
-            .flatMapCompletable {
+            .flatMapCompletable { c ->
                 Completable.merge(
                     listOf(
-                        gradesDetails.getGrades(it.second, it.first, true, notify).ignoreElement(),
+                        gradesDetails.getGrades(c.second, c.first, true, notify).ignoreElement(),
-                        gradesSummary.getGradesSummary(it.first, true).ignoreElement(),
+                        gradesSummary.getGradesSummary(c.first, true).ignoreElement(),
-                        attendance.getAttendance(it.first, start, end, true).ignoreElement(),
+                        attendance.getAttendance(c.first, start, end, true).ignoreElement(),
-                        exam.getExams(it.first, start, end, true).ignoreElement(),
+                        exam.getExams(c.first, start, end, true).ignoreElement(),
-                        timetable.getTimetable(it.first, start, end, true).ignoreElement(),
+                        timetable.getTimetable(c.first, start, end, true).ignoreElement(),
-                        message.getMessages(it.second, RECEIVED, true, notify).ignoreElement(),
+                        message.getMessages(c.second, RECEIVED, true, notify).ignoreElement(),
-                        note.getNotes(it.second, it.first, true, notify).ignoreElement(),
+                        note.getNotes(c.second, c.first, true, notify).ignoreElement(),
-                        homework.getHomework(it.first, LocalDate.now(), true).ignoreElement(),
+                        homework.getHomework(c.first, LocalDate.now(), true).ignoreElement(),
-                        homework.getHomework(it.first, LocalDate.now().plusDays(1), true).ignoreElement(),
+                        homework.getHomework(c.first, LocalDate.now().plusDays(1), true).ignoreElement(),
-                        luckyNumber.getLuckyNumber(it.first, true, notify).ignoreElement(),
+                        luckyNumber.getLuckyNumber(c.first, true, notify).ignoreElement(),
-                        completedLessons.getCompletedLessons(it.first, start, end, true).ignoreElement()
+                        completedLessons.getCompletedLessons(c.first, start, end, true).ignoreElement()
-                    )
+                    ) + reportingUnitRepository.getReportingUnits(c.second, true)
+                        .flatMapPublisher { reportingUnits ->
+                            Single.merge(reportingUnits.map { recipientRepository.getRecipients(c.second, 2, it, true) })
+                        }.ignoreElements()
                 )
             }
             .subscribe({}, { error = it }))

app/src/main/java/io/github/wulkanowy/ui/modules/main/MainModule.kt

@@ -20,6 +20,7 @@ import io.github.wulkanowy.ui.modules.luckynumber.LuckyNumberFragment
 import io.github.wulkanowy.ui.modules.message.MessageFragment
 import io.github.wulkanowy.ui.modules.message.MessageModule
 import io.github.wulkanowy.ui.modules.message.preview.MessagePreviewFragment
+import io.github.wulkanowy.ui.modules.message.send.SendMessageFragment
 import io.github.wulkanowy.ui.modules.more.MoreFragment
 import io.github.wulkanowy.ui.modules.note.NoteFragment
 import io.github.wulkanowy.ui.modules.settings.SettingsFragment
@@ -94,9 +95,13 @@ abstract class MainModule {
 
     @PerFragment
     @ContributesAndroidInjector
-    abstract fun bindAccountDialog(): AccountDialog
+    abstract fun bindCompletedLessonsFragment(): CompletedLessonsFragment
 
     @PerFragment
     @ContributesAndroidInjector
-    abstract fun bindCompletedLessonsFragment(): CompletedLessonsFragment
+    abstract fun bindSendMessageFragment(): SendMessageFragment
+
+    @PerFragment
+    @ContributesAndroidInjector
+    abstract fun bindAccountDialog(): AccountDialog
 }

app/src/main/java/io/github/wulkanowy/ui/modules/message/MessageFragment.kt

@@ -12,7 +12,9 @@ import io.github.wulkanowy.data.repositories.message.MessageRepository.MessageFo
 import io.github.wulkanowy.data.repositories.message.MessageRepository.MessageFolder.TRASHED
 import io.github.wulkanowy.ui.base.BaseFragment
 import io.github.wulkanowy.ui.base.BaseFragmentPagerAdapter
+import io.github.wulkanowy.ui.modules.main.MainActivity
 import io.github.wulkanowy.ui.modules.main.MainView
+import io.github.wulkanowy.ui.modules.message.send.SendMessageFragment
 import io.github.wulkanowy.ui.modules.message.tab.MessageTabFragment
 import io.github.wulkanowy.utils.setOnSelectPageListener
 import kotlinx.android.synthetic.main.fragment_message.*
@@ -61,6 +63,8 @@ class MessageFragment : BaseFragment(), MessageView, MainView.TitledView {
             setOnSelectPageListener { presenter.onPageSelected(it) }
         }
         messageTabLayout.setupWithViewPager(messageViewPager)
+
+        openSendMessageButton.setOnClickListener { presenter.onSendMessageButtonClicked() }
     }
 
     override fun showContent(show: Boolean) {
@@ -80,6 +84,10 @@ class MessageFragment : BaseFragment(), MessageView, MainView.TitledView {
         (pagerAdapter.getFragmentInstance(index) as? MessageView.MessageChildView)?.onParentLoadData(forceRefresh)
     }
 
+    override fun openSendMessage() {
+        (activity as? MainActivity)?.pushView(SendMessageFragment.newInstance())
+    }
+
     override fun onDestroyView() {
         presenter.onDetachView()
         super.onDestroyView()

app/src/main/java/io/github/wulkanowy/ui/modules/message/MessagePresenter.kt

@@ -42,4 +42,8 @@ class MessagePresenter @Inject constructor(
             showProgress(false)
         }
     }
+
+    fun onSendMessageButtonClicked() {
+        view?.openSendMessage()
+    }
 }

app/src/main/java/io/github/wulkanowy/ui/modules/message/MessageView.kt

@@ -14,6 +14,8 @@ interface MessageView : BaseView {
 
     fun notifyChildLoadData(index: Int, forceRefresh: Boolean)
 
+    fun openSendMessage()
+
     interface MessageChildView {
 
         fun onParentLoadData(forceRefresh: Boolean)

app/src/main/java/io/github/wulkanowy/ui/modules/message/send/SendMessageFragment.kt

@@ -0,0 +1,154 @@
+package io.github.wulkanowy.ui.modules.message.send
+
+import android.content.Context
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.Menu
+import android.view.MenuInflater
+import android.view.MenuItem
+import android.view.View
+import android.view.ViewGroup
+import android.widget.ArrayAdapter
+import android.widget.Toast
+import androidx.core.content.ContextCompat
+import com.hootsuite.nachos.ChipConfiguration
+import com.hootsuite.nachos.chip.ChipSpan
+import com.hootsuite.nachos.chip.ChipSpanChipCreator
+import com.hootsuite.nachos.tokenizer.SpanChipTokenizer
+import io.github.wulkanowy.R
+import io.github.wulkanowy.data.db.entities.Recipient
+import io.github.wulkanowy.data.db.entities.ReportingUnit
+import io.github.wulkanowy.ui.base.session.BaseSessionFragment
+import io.github.wulkanowy.ui.modules.main.MainActivity
+import io.github.wulkanowy.ui.modules.main.MainView
+import io.github.wulkanowy.utils.hideSoftInput
+import io.github.wulkanowy.utils.setOnTextChangedListener
+import kotlinx.android.synthetic.main.activity_main.*
+import kotlinx.android.synthetic.main.fragment_send_message.*
+import javax.inject.Inject
+
+class SendMessageFragment : BaseSessionFragment(), SendMessageView, MainView.TitledView {
+
+    @Inject
+    lateinit var presenter: SendMessagePresenter
+
+    private var recipients: List<Recipient> = emptyList()
+
+    private lateinit var recipientsAdapter: ArrayAdapter<Recipient>
+
+    companion object {
+        fun newInstance() = SendMessageFragment()
+    }
+
+    override val titleStringId: Int
+        get() = R.string.send_message_title
+
+    override val formRecipientsData: List<Recipient>
+        get() = sendMessageRecipientInput.allChips.map { it.data as Recipient }
+
+    override val formSubjectValue: String
+        get() = sendMessageSubjectInput.text.toString()
+
+    override val formContentValue: String
+        get() = sendMessageContentInput.text.toString()
+
+    override val messageRequiredRecipients: String
+        get() = getString(R.string.send_message_required_recipients)
+
+    override val messageContentMinLength: String
+        get() = getString(R.string.send_message_content_min_length)
+
+    override val messageSuccess: String
+        get() = getString(R.string.send_message_successful)
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setHasOptionsMenu(true)
+    }
+
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
+        return inflater.inflate(R.layout.fragment_send_message, container, false)
+    }
+
+    override fun onActivityCreated(savedInstanceState: Bundle?) {
+        super.onActivityCreated(savedInstanceState)
+        presenter.onAttachView(this)
+    }
+
+    override fun initView() {
+        context?.let {
+            sendMessageRecipientInput.chipTokenizer = SpanChipTokenizer<ChipSpan>(it, object : ChipSpanChipCreator() {
+                override fun createChip(context: Context, text: CharSequence, data: Any?): ChipSpan {
+                    return ChipSpan(context, text, ContextCompat.getDrawable(context, R.drawable.ic_all_account_24dp), data)
+                }
+
+                override fun configureChip(chip: ChipSpan, chipConfiguration: ChipConfiguration) {
+                    super.configureChip(chip, chipConfiguration)
+                    chip.setShowIconOnLeft(true)
+                }
+            }, ChipSpan::class.java)
+            recipientsAdapter = ArrayAdapter(it, android.R.layout.simple_dropdown_item_1line)
+        }
+
+        sendMessageRecipientInput.setAdapter(recipientsAdapter)
+        sendMessageRecipientInput.setOnTextChangedListener { presenter.onTypingRecipients() }
+    }
+
+    override fun onCreateOptionsMenu(menu: Menu?, inflater: MenuInflater?) {
+        inflater?.inflate(R.menu.action_menu_send_message, menu)
+    }
+
+    override fun onOptionsItemSelected(item: MenuItem?): Boolean {
+        return if (item?.itemId == R.id.sendMessageMenuSend) presenter.onSend()
+        else false
+    }
+
+    override fun setReportingUnit(unit: ReportingUnit) {
+        sendMessageFromTextView.setText(unit.senderName)
+    }
+
+    override fun setRecipients(recipients: List<Recipient>) {
+        this.recipients = recipients
+    }
+
+    override fun refreshRecipientsAdapter() {
+        recipientsAdapter.run {
+            clear()
+            addAll(recipients - sendMessageRecipientInput.allChips.map { it.data as Recipient })
+            notifyDataSetChanged()
+        }
+    }
+
+    override fun showProgress(show: Boolean) {
+        sendMessageProgress.visibility = if (show) View.VISIBLE else View.GONE
+    }
+
+    override fun showContent(show: Boolean) {
+        sendMessageContent.visibility = if (show) View.VISIBLE else View.GONE
+    }
+
+    override fun showEmpty(show: Boolean) {
+        sendMessageEmpty.visibility = if (show) View.VISIBLE else View.GONE
+    }
+
+    override fun popView() {
+        (activity as? MainActivity)?.popView()
+    }
+
+    override fun hideSoftInput() {
+        activity?.hideSoftInput()
+    }
+
+    override fun showBottomNav(show: Boolean) {
+        (activity as? MainActivity)?.mainBottomNav?.visibility = if (show) View.VISIBLE else View.GONE
+    }
+
+    override fun showMessage(text: String) {
+        Toast.makeText(context, text, Toast.LENGTH_LONG).show()
+    }
+
+    override fun onDestroyView() {
+        super.onDestroyView()
+        presenter.onDetachView()
+    }
+}

app/src/main/java/io/github/wulkanowy/ui/modules/message/send/SendMessagePresenter.kt

@@ -0,0 +1,137 @@
+package io.github.wulkanowy.ui.modules.message.send
+
+import io.github.wulkanowy.data.db.entities.Recipient
+import io.github.wulkanowy.data.db.entities.ReportingUnit
+import io.github.wulkanowy.data.repositories.message.MessageRepository
+import io.github.wulkanowy.data.repositories.recipient.RecipientRepository
+import io.github.wulkanowy.data.repositories.reportingunit.ReportingUnitRepository
+import io.github.wulkanowy.data.repositories.semester.SemesterRepository
+import io.github.wulkanowy.data.repositories.student.StudentRepository
+import io.github.wulkanowy.ui.base.session.BaseSessionPresenter
+import io.github.wulkanowy.ui.base.session.SessionErrorHandler
+import io.github.wulkanowy.utils.FirebaseAnalyticsHelper
+import io.github.wulkanowy.utils.SchedulersProvider
+import timber.log.Timber
+import javax.inject.Inject
+
+class SendMessagePresenter @Inject constructor(
+    private val errorHandler: SessionErrorHandler,
+    private val schedulers: SchedulersProvider,
+    private val studentRepository: StudentRepository,
+    private val semesterRepository: SemesterRepository,
+    private val messageRepository: MessageRepository,
+    private val reportingUnitRepository: ReportingUnitRepository,
+    private val recipientRepository: RecipientRepository,
+    private val analytics: FirebaseAnalyticsHelper
+) : BaseSessionPresenter<SendMessageView>(errorHandler) {
+
+    private lateinit var reportingUnit: ReportingUnit
+
+    override fun onAttachView(view: SendMessageView) {
+        Timber.i("Send message view is attached")
+        super.onAttachView(view)
+        view.run {
+            initView()
+            showBottomNav(false)
+        }
+        loadRecipients()
+    }
+
+    private fun loadRecipients() {
+        Timber.i("Loading recipients started")
+        disposable.add(studentRepository.getCurrentStudent()
+            .flatMapMaybe { student ->
+                semesterRepository.getCurrentSemester(student)
+                    .flatMapMaybe { reportingUnitRepository.getReportingUnit(student, it.unitId) }
+                    .doOnSuccess { reportingUnit = it }
+                    .flatMap { recipientRepository.getRecipients(student, 2, it).toMaybe() }
+            }
+            .subscribeOn(schedulers.backgroundThread)
+            .observeOn(schedulers.mainThread)
+            .doOnSubscribe {
+                view?.run {
+                    showProgress(true)
+                    showContent(false)
+                }
+            }
+            .doFinally {
+                view?.run {
+                    showProgress(false)
+                }
+            }
+            .subscribe({
+                view?.apply {
+                    setReportingUnit(reportingUnit)
+                    setRecipients(it)
+                    refreshRecipientsAdapter()
+                    showContent(true)
+                }
+                Timber.i("Loading recipients result: Success, fetched %s recipients", it.size.toString())
+            }, {
+                Timber.i("Loading recipients result: An exception occurred")
+                view?.showContent(true)
+                errorHandler.dispatch(it)
+            }, {
+                Timber.i("Loading recipients result: Can't find the reporting unit")
+                view?.showEmpty(true)
+            })
+        )
+    }
+
+    private fun sendMessage(subject: String, content: String, recipients: List<Recipient>) {
+        Timber.i("Sending message started")
+        disposable.add(messageRepository.sendMessage(subject, content, recipients)
+            .subscribeOn(schedulers.backgroundThread)
+            .observeOn(schedulers.mainThread)
+            .doOnSubscribe {
+                view?.run {
+                    hideSoftInput()
+                    showContent(false)
+                    showProgress(true)
+                }
+            }
+            .doFinally {
+                view?.showProgress(false)
+            }
+            .subscribe({
+                Timber.i("Sending message result: Success")
+                analytics.logEvent("send_message", "recipients" to recipients.size)
+                view?.run {
+                    showMessage(messageSuccess)
+                    popView()
+                }
+            }, {
+                Timber.i("Sending message result: An exception occurred")
+                view?.showContent(true)
+                errorHandler.dispatch(it)
+            })
+        )
+    }
+
+    fun onTypingRecipients() {
+        view?.refreshRecipientsAdapter()
+    }
+
+    fun onSend(): Boolean {
+        view?.run {
+            when {
+                formRecipientsData.isEmpty() -> showMessage(messageRequiredRecipients)
+                formContentValue.length < 3 -> showMessage(messageContentMinLength)
+                else -> {
+                    sendMessage(
+                        subject = formSubjectValue,
+                        content = formContentValue,
+                        recipients = formRecipientsData
+                    )
+                    return true
+                }
+            }
+        }
+        return false
+    }
+
+    override fun onDetachView() {
+        view?.showBottomNav(true)
+        super.onDetachView()
+    }
+}

app/src/main/java/io/github/wulkanowy/ui/modules/message/send/SendMessageView.kt

@@ -0,0 +1,40 @@
+package io.github.wulkanowy.ui.modules.message.send
+
+import io.github.wulkanowy.data.db.entities.Recipient
+import io.github.wulkanowy.data.db.entities.ReportingUnit
+import io.github.wulkanowy.ui.base.session.BaseSessionView
+
+interface SendMessageView : BaseSessionView {
+
+    val formRecipientsData: List<Recipient>
+
+    val formSubjectValue: String
+
+    val formContentValue: String
+
+    val messageRequiredRecipients: String
+
+    val messageContentMinLength: String
+
+    val messageSuccess: String
+
+    fun initView()
+
+    fun setReportingUnit(unit: ReportingUnit)
+
+    fun setRecipients(recipients: List<Recipient>)
+
+    fun refreshRecipientsAdapter()
+
+    fun showProgress(show: Boolean)
+
+    fun showContent(show: Boolean)
+
+    fun showEmpty(show: Boolean)
+
+    fun popView()
+
+    fun hideSoftInput()
+
+    fun showBottomNav(show: Boolean)
+}

app/src/main/res/drawable/ic_menu_send_message_24dp.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:tint="#FFFFFF"
+    android:viewportWidth="24.0"
+    android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M2.01,21L23,12 2.01,3 2,10l15,2 -15,2z" />
+</vector>

app/src/main/res/drawable/ic_send_message_24dp.xml

@@ -0,0 +1,9 @@
+<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="#FF000000"
+        android:pathData="M20.71,7.04C21.1,6.65 21.1,6 20.71,5.63L18.37,3.29C18,2.9 17.35,2.9 16.96,3.29L15.12,5.12L18.87,8.87M3,17.25V21H6.75L17.81,9.93L14.06,6.18L3,17.25Z" />
+</vector>

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

@@ -24,10 +24,22 @@
         android:layout_marginTop="48dp"
         android:visibility="invisible" />
 
+    <com.google.android.material.floatingactionbutton.FloatingActionButton
+        android:id="@+id/openSendMessageButton"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="bottom|end"
+        android:layout_margin="16dp"
+        android:clickable="true"
+        android:focusable="true"
+        android:tint="#FFFFFF"
+        app:srcCompat="@drawable/ic_send_message_24dp" />
+
     <ProgressBar
         android:id="@+id/messageProgress"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_gravity="center"
         android:indeterminate="true" />
+
 </androidx.coordinatorlayout.widget.CoordinatorLayout>

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

@@ -0,0 +1,145 @@
+<?xml version="1.0" encoding="utf-8"?>
+<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <LinearLayout
+        android:id="@+id/sendMessageContent"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:orientation="vertical">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:padding="14dp">
+
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginEnd="10dp"
+                android:layout_marginRight="10dp"
+                android:text="@string/send_message_from"
+                android:textColor="@android:color/darker_gray"
+                android:textSize="18sp" />
+
+            <androidx.appcompat.widget.AppCompatEditText
+                android:id="@+id/sendMessageFromTextView"
+                android:layout_width="match_parent"
+                android:layout_height="38dp"
+                android:background="@android:color/transparent"
+                android:enabled="false"
+                android:textColor="?android:attr/textColorPrimaryNoDisable"
+                tools:text="Jan Kowalski" />
+        </LinearLayout>
+
+        <View
+            android:layout_width="match_parent"
+            android:layout_height="1dp"
+            android:background="?attr/dividerColor" />
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:paddingStart="14dp"
+            android:paddingLeft="14dp"
+            android:paddingTop="14dp"
+            android:paddingEnd="0dp"
+            android:paddingRight="0dp"
+            android:paddingBottom="14dp">
+
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginEnd="10dp"
+                android:layout_marginRight="10dp"
+                android:text="@string/send_message_to"
+                android:textColor="@android:color/darker_gray"
+                android:textSize="18sp" />
+
+            <com.hootsuite.nachos.NachoTextView
+                android:id="@+id/sendMessageRecipientInput"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:background="@android:color/transparent"
+                android:inputType="text"
+                android:maxLines="1"
+                android:textColor="?attr/chipTextColor"
+                app:chipBackground="?attr/chipBackgroundColor" />
+        </LinearLayout>
+
+        <View
+            android:layout_width="match_parent"
+            android:layout_height="1dp"
+            android:background="?attr/dividerColor" />
+
+        <androidx.appcompat.widget.AppCompatEditText
+            android:id="@+id/sendMessageSubjectInput"
+            android:layout_width="match_parent"
+            android:layout_height="66dp"
+            android:background="@android:color/transparent"
+            android:hint="@string/send_message_subject"
+            android:inputType="text"
+            android:maxLines="1"
+            android:padding="14dp" />
+
+        <View
+            android:layout_width="match_parent"
+            android:layout_height="1dp"
+            android:background="?attr/dividerColor" />
+
+        <androidx.appcompat.widget.AppCompatEditText
+            android:id="@+id/sendMessageContentInput"
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:background="@android:color/transparent"
+            android:gravity="top|start"
+            android:hint="@string/send_message_content"
+            android:inputType="textMultiLine"
+            android:paddingStart="14dp"
+            android:paddingLeft="14dp"
+            android:paddingTop="18dp"
+            android:paddingEnd="14dp"
+            android:paddingRight="14dp"
+            android:singleLine="false" />
+    </LinearLayout>
+
+    <androidx.coordinatorlayout.widget.CoordinatorLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent">
+
+        <LinearLayout
+            android:id="@+id/sendMessageEmpty"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center"
+            android:orientation="vertical"
+            android:visibility="gone">
+
+            <androidx.appcompat.widget.AppCompatImageView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_gravity="center"
+                android:minWidth="100dp"
+                android:minHeight="100dp"
+                app:srcCompat="@drawable/ic_more_messages_24dp" />
+
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_gravity="center"
+                android:text="@string/error_unknown"
+                android:textSize="20sp" />
+        </LinearLayout>
+
+        <ProgressBar
+            android:id="@+id/sendMessageProgress"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center"
+            android:visibility="gone" />
+    </androidx.coordinatorlayout.widget.CoordinatorLayout>
+</RelativeLayout>

app/src/main/res/menu/action_menu_send_message.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+    <item
+        android:id="@+id/sendMessageMenuSend"
+        android:icon="@drawable/ic_menu_send_message_24dp"
+        android:orderInCategory="1"
+        android:title="@string/send_message_title"
+        app:showAsAction="ifRoom" />
+</menu>

app/src/main/res/values-night/styles.xml

@@ -7,6 +7,9 @@
         <item name="preferenceTheme">@style/PreferenceThemeOverlay.v14.Material</item>
         <item name="bottomNavBackground">@color/bottom_nav_background</item>
         <item name="android:navigationBarColor" tools:targetApi="21">@color/bottom_nav_background</item>
+        <item name="chipBackgroundColor">@color/chip_material_background_inverse</item>
+        <item name="chipTextColor">@color/chip_default_text_color_inverse</item>
+        <item name="dividerColor">@color/divider_inverse</item>
 
         <!--AboutLibraries specific values-->
         <item name="about_libraries_window_background">@color/about_libraries_window_background_dark</item>

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

@@ -168,6 +168,16 @@
         <item quantity="many">Dostałeś %1$d wiadomości</item>
     </plurals>
 
+    <!--Send message-->
+    <string name="send_message_title">Wyślij</string>
+    <string name="send_message_from">Od:</string>
+    <string name="send_message_to">Do:</string>
+    <string name="send_message_subject">Temat</string>
+    <string name="send_message_content">Treść</string>
+    <string name="send_message_successful">Wiadomość wysłana pomyślnie</string>
+    <string name="send_message_required_recipients">Musisz wybrać co najmniej 1 adresata</string>
+    <string name="send_message_content_min_length">Treść wiadomości musi zawierać co najmniej 3 znaki</string>
+
     <!--About-->
     <string name="about_source_code">Kod źródłowy</string>
     <string name="about_feedback">Zgłoś błąd</string>

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

@@ -1,4 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <attr name="bottomNavBackground" format="reference" />
+    <attr name="dividerColor" format="reference" />
 </resources>

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

@@ -16,4 +16,10 @@
 
     <color name="bottom_nav_background">#303030</color>
     <color name="bottom_nav_background_inverse">#ffffff</color>
+
+    <color name="chip_material_background_inverse">#595959</color>
+    <color name="chip_default_text_color_inverse">#fefefe</color>
+
+    <color name="divider">#cccccc</color>
+    <color name="divider_inverse">#777777</color>
 </resources>

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

@@ -155,6 +155,16 @@
         <item quantity="other">You received %1$d messages</item>
     </plurals>
 
+    <!--Send message-->
+    <string name="send_message_title">Send</string>
+    <string name="send_message_from">From:</string>
+    <string name="send_message_to">To:</string>
+    <string name="send_message_subject">Subject</string>
+    <string name="send_message_content">Content</string>
+    <string name="send_message_successful">Message sent successfully</string>
+    <string name="send_message_required_recipients">You need to choose at least 1 recipient</string>
+    <string name="send_message_content_min_length">The message content must be at least 3 characters</string>
+
     <!--About-->
     <string name="about_source_code">Source code</string>
     <string name="about_feedback">Report a bug</string>

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

@@ -14,6 +14,9 @@
         <item name="subtitleTextColor">@android:color/primary_text_dark</item>
         <item name="android:colorBackground">@android:color/white</item>
         <item name="bottomNavBackground">@color/bottom_nav_background_inverse</item>
+        <item name="chipBackgroundColor">@color/chip_material_background</item>
+        <item name="chipTextColor">@color/chip_default_text_color</item>
+        <item name="dividerColor">@color/divider</item>
 
         <!-- AboutLibraries specific values -->
         <item name="about_libraries_window_background">@color/about_libraries_window_background</item>