diff --git a/app/src/main/java/com/pixelized/biblib/database/factory/AuthorDboFactory.kt b/app/src/main/java/com/pixelized/biblib/database/factory/AuthorDboFactory.kt
new file mode 100644
index 0000000..a0bcd02
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/factory/AuthorDboFactory.kt
@@ -0,0 +1,16 @@
+package com.pixelized.biblib.database.factory
+
+import com.pixelized.biblib.database.data.AuthorDbo
+import com.pixelized.biblib.model.book.Author
+
+fun AuthorDbo.toAuthor() = Author(
+    id = id,
+    name = name,
+    sort = sort,
+)
+
+fun Author.toDbo() = AuthorDbo(
+    id = id,
+    name = name,
+    sort = sort,
+)
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/factory/BookDboFactory.kt b/app/src/main/java/com/pixelized/biblib/database/factory/BookDboFactory.kt
new file mode 100644
index 0000000..ccb7d6f
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/factory/BookDboFactory.kt
@@ -0,0 +1,36 @@
+package com.pixelized.biblib.database.factory
+
+import com.pixelized.biblib.database.data.BookDbo
+import com.pixelized.biblib.database.relation.BookRelation
+import com.pixelized.biblib.model.book.Book
+
+fun BookRelation.toBook(): Book = Book(
+    id = book.id,
+    title = book.title,
+    sort = book.sort,
+    author = authors.map { it.toAuthor() },
+    haveCover = book.haveCover,
+    releaseDate = book.releaseDate,
+    language = language?.toLanguage(),
+    rating = book.rating,
+    genre = genres?.map { it.toGenre() },
+    series = series?.toSeries(),
+    seriesIndex = book.seriesIndex,
+    synopsis = book.synopsis,
+    isNew = book.isNew,
+)
+
+fun Book.toDbo() = BookDbo(
+    id = id,
+    title = title,
+    sort = sort,
+    haveCover = haveCover,
+    releaseDate = releaseDate,
+    language = language?.id,
+    rating = rating,
+    series = series?.id,
+    seriesIndex = seriesIndex,
+    synopsis = synopsis,
+    isNew = isNew,
+    newOrder = newOrder,
+)
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/factory/GenreDboFactory.kt b/app/src/main/java/com/pixelized/biblib/database/factory/GenreDboFactory.kt
new file mode 100644
index 0000000..8b5e206
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/factory/GenreDboFactory.kt
@@ -0,0 +1,14 @@
+package com.pixelized.biblib.database.factory
+
+import com.pixelized.biblib.database.data.GenreDbo
+import com.pixelized.biblib.model.book.Genre
+
+fun GenreDbo.toGenre() = Genre(
+    id = id,
+    name = name,
+)
+
+fun Genre.toDbo() = GenreDbo(
+    id = id,
+    name = name,
+)
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/factory/LanguageDboFactory.kt b/app/src/main/java/com/pixelized/biblib/database/factory/LanguageDboFactory.kt
new file mode 100644
index 0000000..002755d
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/factory/LanguageDboFactory.kt
@@ -0,0 +1,14 @@
+package com.pixelized.biblib.database.factory
+
+import com.pixelized.biblib.database.data.LanguageDbo
+import com.pixelized.biblib.model.book.Language
+
+fun LanguageDbo.toLanguage() = Language(
+    id = id,
+    code = code,
+)
+
+fun Language.toDbo() = LanguageDbo(
+    id = id,
+    code = code
+)
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/factory/SeriesDboFactory.kt b/app/src/main/java/com/pixelized/biblib/database/factory/SeriesDboFactory.kt
new file mode 100644
index 0000000..e5415c6
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/factory/SeriesDboFactory.kt
@@ -0,0 +1,16 @@
+package com.pixelized.biblib.database.factory
+
+import com.pixelized.biblib.database.data.SeriesDbo
+import com.pixelized.biblib.model.book.Series
+
+fun SeriesDbo.toSeries() = Series(
+    id = id,
+    name = name,
+    sort = sort,
+)
+
+fun Series.toDbo(id: Int) = SeriesDbo(
+    id = id,
+    name = name,
+    sort = sort,
+)
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/module/NetworkModule.kt b/app/src/main/java/com/pixelized/biblib/module/NetworkModule.kt
index 5d4bfeb..159925a 100644
--- a/app/src/main/java/com/pixelized/biblib/module/NetworkModule.kt
+++ b/app/src/main/java/com/pixelized/biblib/module/NetworkModule.kt
@@ -6,6 +6,7 @@ import com.google.gson.GsonBuilder
 import com.pixelized.biblib.network.client.BibLibClient
 import com.pixelized.biblib.network.client.IBibLibClient
 import com.pixelized.biblib.repository.connectivity.ConnectivityRepository
+import com.pixelized.biblib.repository.connectivity.IConnectivityRepository
 import dagger.Module
 import dagger.Provides
 import dagger.hilt.InstallIn
@@ -37,7 +38,7 @@ class NetworkModule {
     @Singleton
     fun provideConnectivityRepository(
         @ApplicationContext context: Context,
-    ): ConnectivityRepository {
+    ): IConnectivityRepository {
         return ConnectivityRepository(context)
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/repository/book/BookRepository.kt b/app/src/main/java/com/pixelized/biblib/repository/book/BookRepository.kt
index 55143d2..9a10ec4 100644
--- a/app/src/main/java/com/pixelized/biblib/repository/book/BookRepository.kt
+++ b/app/src/main/java/com/pixelized/biblib/repository/book/BookRepository.kt
@@ -6,8 +6,8 @@ import com.pixelized.biblib.database.BibLibDatabase
 import com.pixelized.biblib.database.crossref.BookAuthorCrossRef
 import com.pixelized.biblib.database.crossref.BookGenreCrossRef
 import com.pixelized.biblib.database.data.*
-import com.pixelized.biblib.database.relation.BookRelation
 import com.pixelized.biblib.model.book.*
+import com.pixelized.biblib.database.factory.*
 import javax.inject.Inject
 
 class BookRepository @Inject constructor(
@@ -75,79 +75,4 @@ class BookRepository @Inject constructor(
         database.crossRefDao().insert(*bookAuthorCrossRef.toTypedArray())
         database.crossRefDao().insert(*bookGenreCrossRef.toTypedArray())
     }
-
-    private fun Author.toDbo() = AuthorDbo(
-        id = id,
-        name = name,
-        sort = sort,
-    )
-
-    private fun Genre.toDbo() = GenreDbo(
-        id = id,
-        name = name,
-    )
-
-    private fun Series.toDbo(id: Int) = SeriesDbo(
-        id = id,
-        name = name,
-        sort = sort,
-    )
-
-    private fun Language.toDbo() = LanguageDbo(
-        id = id,
-        code = code
-    )
-
-    private fun Book.toDbo() = BookDbo(
-        id = id,
-        title = title,
-        sort = sort,
-        haveCover = haveCover,
-        releaseDate = releaseDate,
-        language = language?.id,
-        rating = rating,
-        series = series?.id,
-        seriesIndex = seriesIndex,
-        synopsis = synopsis,
-        isNew = isNew,
-        newOrder = newOrder,
-    )
-
-    private fun BookRelation.toBook(): Book = Book(
-        id = book.id,
-        title = book.title,
-        sort = book.sort,
-        author = authors.map { it.toAuthor() },
-        haveCover = book.haveCover,
-        releaseDate = book.releaseDate,
-        language = language?.toLanguage(),
-        rating = book.rating,
-        genre = genres?.map { it.toGenre() },
-        series = series?.toSeries(),
-        seriesIndex = book.seriesIndex,
-        synopsis = book.synopsis,
-        isNew = book.isNew,
-    )
-
-    private fun AuthorDbo.toAuthor() = Author(
-        id = id,
-        name = name,
-        sort = sort,
-    )
-
-    private fun LanguageDbo.toLanguage() = Language(
-        id = id,
-        code = code,
-    )
-
-    private fun GenreDbo.toGenre() = Genre(
-        id = id,
-        name = name,
-    )
-
-    private fun SeriesDbo.toSeries() = Series(
-        id = id,
-        name = name,
-        sort = sort,
-    )
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/repository/connectivity/ConnectivityRepository.kt b/app/src/main/java/com/pixelized/biblib/repository/connectivity/ConnectivityRepository.kt
index 3e68d30..f12e020 100644
--- a/app/src/main/java/com/pixelized/biblib/repository/connectivity/ConnectivityRepository.kt
+++ b/app/src/main/java/com/pixelized/biblib/repository/connectivity/ConnectivityRepository.kt
@@ -16,12 +16,11 @@ import kotlinx.coroutines.flow.MutableStateFlow
  */
 class ConnectivityRepository constructor(
     @ApplicationContext context: Context,
-) {
-
+) : IConnectivityRepository {
     private val _networkAvailabilityFlow = MutableStateFlow(true)
 
-    val networkAvailabilityFlow: Flow<Boolean> get() = _networkAvailabilityFlow
-    val isNetworkAvailable: Boolean get() = _networkAvailabilityFlow.value
+    override val networkAvailabilityFlow: Flow<Boolean> get() = _networkAvailabilityFlow
+    override val isNetworkAvailable: Boolean get() = _networkAvailabilityFlow.value
 
     init {
         context.getSystemService<ConnectivityManager>()?.let { connectivityManager ->
diff --git a/app/src/main/java/com/pixelized/biblib/repository/connectivity/IConnectivityRepository.kt b/app/src/main/java/com/pixelized/biblib/repository/connectivity/IConnectivityRepository.kt
new file mode 100644
index 0000000..59aeea2
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/repository/connectivity/IConnectivityRepository.kt
@@ -0,0 +1,14 @@
+package com.pixelized.biblib.repository.connectivity
+
+import kotlinx.coroutines.flow.Flow
+
+/**
+ * This class is responsible to check for internet availability.
+ * https://developer.android.com/training/monitoring-device-state/connectivity-status-type
+ */
+interface IConnectivityRepository {
+
+    val networkAvailabilityFlow: Flow<Boolean>
+
+    val isNetworkAvailable: Boolean
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/repository/search/SearchRepository.kt b/app/src/main/java/com/pixelized/biblib/repository/search/SearchRepository.kt
index 939ef06..66f60a3 100644
--- a/app/src/main/java/com/pixelized/biblib/repository/search/SearchRepository.kt
+++ b/app/src/main/java/com/pixelized/biblib/repository/search/SearchRepository.kt
@@ -5,9 +5,9 @@ import com.pixelized.biblib.database.BibLibDatabase
 import com.pixelized.biblib.database.crossref.BookAuthorCrossRef
 import com.pixelized.biblib.database.crossref.BookGenreCrossRef
 import com.pixelized.biblib.database.data.*
-import com.pixelized.biblib.database.relation.BookRelation
 import com.pixelized.biblib.model.book.*
 import com.pixelized.biblib.model.search.SortType
+import com.pixelized.biblib.database.factory.*
 import javax.inject.Inject
 
 class SearchRepository @Inject constructor(
@@ -20,7 +20,7 @@ class SearchRepository @Inject constructor(
         seriesId: Int?,
         genreId: Int?,
         languageId: Int?,
-        sortBy : SortType,
+        sortBy: SortType,
         limit: Int,
         offset: Int
     ): List<Book> {
@@ -132,44 +132,4 @@ private fun MutableList<Any>.where(
     } else {
         ""
     }
-}
-
-// TODO Duplicate
-
-private fun BookRelation.toBook(): Book = Book(
-    id = book.id,
-    title = book.title,
-    sort = book.sort,
-    author = authors.map { it.toAuthor() },
-    haveCover = book.haveCover,
-    releaseDate = book.releaseDate,
-    language = language?.toLanguage(),
-    rating = book.rating,
-    genre = genres?.map { it.toGenre() },
-    series = series?.toSeries(),
-    seriesIndex = book.seriesIndex,
-    synopsis = book.synopsis,
-    isNew = book.isNew,
-)
-
-private fun AuthorDbo.toAuthor() = Author(
-    id = id,
-    name = name,
-    sort = sort,
-)
-
-private fun LanguageDbo.toLanguage() = Language(
-    id = id,
-    code = code,
-)
-
-private fun GenreDbo.toGenre() = Genre(
-    id = id,
-    name = name,
-)
-
-private fun SeriesDbo.toSeries() = Series(
-    id = id,
-    name = name,
-    sort = sort,
-)
\ No newline at end of file
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/ui/screen/home/common/connectivity/ConnectivityViewModel.kt b/app/src/main/java/com/pixelized/biblib/ui/screen/home/common/connectivity/ConnectivityViewModel.kt
index c76b024..8ea55ef 100644
--- a/app/src/main/java/com/pixelized/biblib/ui/screen/home/common/connectivity/ConnectivityViewModel.kt
+++ b/app/src/main/java/com/pixelized/biblib/ui/screen/home/common/connectivity/ConnectivityViewModel.kt
@@ -4,14 +4,14 @@ import androidx.compose.runtime.State
 import androidx.compose.runtime.mutableStateOf
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
-import com.pixelized.biblib.repository.connectivity.ConnectivityRepository
+import com.pixelized.biblib.repository.connectivity.IConnectivityRepository
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.launch
 import javax.inject.Inject
 
 @HiltViewModel
 class ConnectivityViewModel @Inject constructor(
-    private val connectivityRepository: ConnectivityRepository,
+    private val connectivityRepository: IConnectivityRepository,
 ) : ViewModel() {
 
     private val _isNetworkAvailable = mutableStateOf(connectivityRepository.isNetworkAvailable)