Added room database and book entity

app/build.gradle

@@ -34,6 +34,12 @@ dependencies {
     implementation 'androidx.cardview:cardview:1.0.0'
     implementation 'com.google.android.material:material:1.0.0'
 
+    implementation 'androidx.lifecycle:lifecycle-extensions:2.0.0'
+    kapt 'androidx.lifecycle:lifecycle-compiler:2.0.0'
+
+    implementation 'androidx.room:room-runtime:2.0.0'
+    kapt 'androidx.room:room-compiler:2.0.0'
+
     implementation 'androidx.paging:paging-runtime:2.1.0'
 
     def anko_version = '0.10.8'

app/src/main/java/io/legado/app/data/entities/Book.kt

@@ -0,0 +1,33 @@
+package io.legado.app.data.entities
+
+import android.os.Parcelable
+import androidx.room.*
+import kotlinx.android.parcel.Parcelize
+import java.util.*
+
+@Parcelize
+@Entity(tableName = "books",
+    indices = [(Index(value = ["url"]))])
+data class Book(@PrimaryKey
+                var url: String = "",
+                var name: String = "",
+                var tag: String = "",
+                var author: String? = null,
+                var coverUrl: String? = null,
+                var customCoverUrl: String? = null,
+                var introduction: String? = null,
+                var charset: String? = null,
+                var type: Int = 0,   // 0: text, 1: audio
+                var latestChapterName: String? = null,
+                var lastUpdateTime: Date? = null,
+                var latestChapterTime: Date? = null,
+                var durChapterIndex: Int = 0,
+                var durChapterPage: Int = 0,
+                var totalChapterNum: Int = 0,
+                var hasNewChapter: Boolean = false,
+                var allowUpdate: Boolean = true
+                ) : Parcelable {
+
+    fun getUnreadChapterNum() = Math.max(totalChapterNum - durChapterIndex - 1, 0)
+
+}