Added Settings.

src/main/kotlin/de/fabianonline/telegram_backup/Database.kt

@@ -539,7 +539,27 @@ class Database private constructor(var client: TelegramClient) {
 			e.printStackTrace()
 			throw RuntimeException("Exception shown above happened.")
 		}
+	}
 	
+	fun settingsSetValue(key: String, value: String?) {
+		val ps = conn!!.prepareStatement("INSERT OR REPLACE INTO settings (key, value) VALUES (?, ?)")
+		ps.setString(1, key)
+		if (value==null) {
+			ps.setNull(2, Types.VARCHAR)
+		} else {
+			ps.setString(2, value)
+		}
+		ps.execute()
+	}
+	
+	fun settingsGetSettings(): Map<String, String?> {
+		val rs = stmt!!.executeQuery("SELECT key, value FROM settings")
+		val result = mutableMapOf<String, String?>()
+		while (rs.next()) {
+			result.set(rs.getString(1), rs.getString(2))
+		}
+		rs.close()
+		return result
 	}
 
 	fun getIdsFromQuery(query: String): LinkedList<Int> {

src/main/kotlin/de/fabianonline/telegram_backup/DatabaseUpdates.kt

@@ -32,6 +32,7 @@ class DatabaseUpdates(protected var conn: Connection, protected var db: Database
 		register(DB_Update_7(conn, db))
 		register(DB_Update_8(conn, db))
 		register(DB_Update_9(conn, db))
+		register(DB_Update_10(conn, db))
 	}
 
 	fun doUpdates() {
@@ -398,3 +399,14 @@ internal class DB_Update_9(conn: Connection, db: Database) : DatabaseUpdate(conn
 		execute("DELETE FROM messages WHERE id IN (" + messages_to_delete.joinToString() + ")")
 	}
 }
+
+internal class DB_Update_10(conn: Connection, db: Database) : DatabaseUpdate(conn, db) {
+	override val version: Int
+		get() = 10
+	
+	@Throws(SQLException::class)
+	override fun _doUpdate() {
+		val logger = LoggerFactory.getLogger(DB_Update_10::class.java)
+		execute("CREATE TABLE settings (key TEXT PRIMARY KEY, value TEXT)")
+	}
+}

src/main/kotlin/de/fabianonline/telegram_backup/Settings.kt

@@ -0,0 +1,60 @@
+package de.fabianonline.telegram_backup
+
+class Settings() {
+
+	val options = arrayOf(
+		Option("gmaps_api_key", "abc", "This contains the api key bla foo bar.")
+	)
+	
+	init {
+		var all_settings = Database.getInstance().settingsGetSettings()
+		for ((key, value) in all_settings) {
+			val opt = options.find{it.key == key}
+			if (opt==null) throw IllegalArgumentException("Setting with key ${key} is unknown.")
+			if (value!=null) opt.value = value
+		}
+	}
+	
+	fun print() {
+		val modifiedSettings = options.filter{!it.isDefaultValue()}
+		val defaultSettings = options.filter{it.isDefaultValue()}
+		
+		if (modifiedSettings.count() > 0) {
+			println("Modified settings:")
+			modifiedSettings.forEach{it.print()}
+			println("\n")
+		}
+		
+		if (defaultSettings.count() > 0) {
+			println("Settings with default value:")
+			defaultSettings.forEach{it.print()}
+			println("\n")
+		}
+	}
+	
+	inner open class HiddenOption(val key: String, val default: String) {
+		var value: String? = null
+		
+		fun save() {
+			if (isDefaultValue()) {
+				Database.getInstance().settingsSetValue(key, null)
+			} else {
+				Database.getInstance().settingsSetValue(key, value)
+			}
+		}
+		
+		open fun print() {
+			println("%-30s %-30s".format(key, value))
+		}
+		
+		fun isDefaultValue(): Boolean = (value==null || value==default)
+			
+	}
+	inner class Option(key: String, default: String, val descr: String): HiddenOption(key, default) {
+		override fun print() {
+			println("%-30s %-30s %s".format(key, value, descr))
+		}
+	}
+}
+
+