fix crash on first start, if tcor is not reachable

app/src/main/java/org/mosad/seil0/projectlaogai/controller/TCoRAPIController.kt

@@ -24,16 +24,22 @@ package org.mosad.seil0.projectlaogai.controller
 
 import android.content.Context
 import android.util.Log
-import kotlinx.coroutines.*
+import com.google.gson.GsonBuilder
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
 import org.json.JSONObject
 import org.mosad.seil0.projectlaogai.controller.PreferencesController.Companion.coursesCacheTime
 import org.mosad.seil0.projectlaogai.controller.PreferencesController.Companion.mensaCacheTime
 import org.mosad.seil0.projectlaogai.controller.PreferencesController.Companion.timetableCacheTime
+import org.mosad.seil0.projectlaogai.hsoparser.CoursesList
+import org.mosad.seil0.projectlaogai.hsoparser.MensaMenu
+import org.mosad.seil0.projectlaogai.hsoparser.TimetableCourseWeek
 import java.io.BufferedWriter
 import java.io.File
 import java.io.FileWriter
 import java.net.URL
-import kotlin.Exception
 
 class TCoRAPIController {
 
@@ -45,10 +51,10 @@ class TCoRAPIController {
          * get the json object from tcor api and write it as file (cache)
          */
         fun getCoursesList(context: Context) = GlobalScope.launch {
-            try {
-                val url = URL("$tcorBaseURL/courseList")
-                val file = File(context.filesDir, "courses.json")
+            val url = URL("$tcorBaseURL/courseList")
+            val file = File(context.filesDir, "courses.json")
 
+            try {
                 // read data from the API
                 val coursesObject = JSONObject(url.readText()) //JSONObject(inReader.readLine())
 
@@ -64,18 +70,24 @@ class TCoRAPIController {
                 PreferencesController.save(context)
             } catch (ex: Exception) {
                 Log.e(className, "failed to get /courseList", ex)
-            }
 
+                // write a empty file, since it is loaded later
+                withContext(Dispatchers.IO) {
+                    val writer = BufferedWriter(FileWriter(file))
+                    writer.write(GsonBuilder().create().toJson(CoursesList()))
+                    writer.close()
+                }
+            }
         }
 
         /**
          * get the json object from tcor api and write it as file (cache)
          */
         fun getMensa(context: Context) = GlobalScope.launch {
-            try {
-                val url = URL("$tcorBaseURL/mensamenu")
-                val file = File(context.filesDir, "mensa.json")
+            val url = URL("$tcorBaseURL/mensamenu")
+            val file = File(context.filesDir, "mensa.json")
 
+            try {
                 // read data from the API
                 val mensaObject = JSONObject(url.readText()) //JSONObject(inReader.readLine())
 
@@ -91,6 +103,13 @@ class TCoRAPIController {
                 PreferencesController.save(context)
             } catch (ex: Exception) {
                 Log.e(className, "failed to get /mensamenu", ex)
+
+                // write a empty file, since it is loaded later
+                withContext(Dispatchers.IO) {
+                    val writer = BufferedWriter(FileWriter(file))
+                    writer.write(GsonBuilder().create().toJson(MensaMenu()))
+                    writer.close()
+                }
             }
 
         }
@@ -99,10 +118,10 @@ class TCoRAPIController {
          * get the json object from tcor api and write it as file (cache)
          */
         fun getTimetable(courseName: String, week: Int, context: Context) = GlobalScope.launch {
-            try {
-                val url = URL("$tcorBaseURL/timetable?courseName=$courseName&week=$week")
-                val file = File(context.filesDir, "timetable-$courseName-$week.json")
+            val url = URL("$tcorBaseURL/timetable?courseName=$courseName&week=$week")
+            val file = File(context.filesDir, "timetable-$courseName-$week.json")
 
+            try {
                 // read data from the API
                 val timetableObject = JSONObject(url.readText()) //JSONObject(inReader.readLine())
 
@@ -118,6 +137,13 @@ class TCoRAPIController {
                 PreferencesController.save(context)
             } catch (ex: Exception) {
                 Log.e(className, "failed to get /timetable", ex)
+
+                // write a empty file, since it is loaded later
+                withContext(Dispatchers.IO) {
+                    val writer = BufferedWriter(FileWriter(file))
+                    writer.write(GsonBuilder().create().toJson(TimetableCourseWeek()))
+                    writer.close()
+                }
             }
 
         }

app/src/main/java/org/mosad/seil0/projectlaogai/hsoparser/DataTypes.kt

@@ -124,6 +124,10 @@ class NotRetardedCalendar {
 // data classes for the course part
 data class Course(val courseLink: String, val courseName: String)
 
+data class CoursesMeta(val updateTime: Long = 0, val totalCourses: Int = 0)
+
+data class CoursesList(val meta: CoursesMeta = CoursesMeta(), val courses: ArrayList<Course> = ArrayList())
+
 // data classes for the Mensa part
 data class Meal(val day: String, val heading: String, val parts: ArrayList<String>, val additives: String)