chore: Converted classes to Kotlin (#2405)

* converted classes to kotlin

* fixed code according to codestyle

android/app/src/main/java/org/fossasia/openevent/common/api/JWTUtils.kt

@@ -0,0 +1,101 @@
+package org.fossasia.openevent.common.api
+
+import android.support.v4.util.SparseArrayCompat
+
+import org.json.JSONException
+import org.json.JSONObject
+
+object JWTUtils {
+
+    private fun decode(token: String): SparseArrayCompat<String> {
+        val decoded = SparseArrayCompat<String>(2)
+
+        val split = token.split("\\.".toRegex()).dropLastWhile { it.isEmpty() }.toTypedArray()
+        decoded.append(0, getJson(split[0]))
+        decoded.append(1, getJson(split[1]))
+
+        return decoded
+    }
+
+    @Throws(JSONException::class)
+    private fun getExpiry(token: String): Long {
+        val decoded = decode(token)
+
+        // We are using JSONObject instead of GSON as it takes about 5 ms instead of 150 ms taken by GSON
+        return JSONObject(decoded.get(1)).get("exp").toString().toLong()
+    }
+
+    @Throws(JSONException::class)
+    @JvmStatic
+    fun getIdentity(token: String): Int {
+        val decoded = decode(token)
+
+        return JSONObject(decoded.get(1)).get("identity").toString().toInt()
+    }
+
+    @JvmStatic
+    fun isExpired(token: String): Boolean {
+        val expiry: Long
+
+        try {
+            expiry = getExpiry(token)
+        } catch (jse: JSONException) {
+            return true
+        }
+
+        return System.currentTimeMillis() / 1000 >= expiry
+    }
+
+    private fun getJson(strEncoded: String): String {
+        val decodedBytes = Base64Utils.decode(strEncoded)
+        return String(decodedBytes)
+    }
+
+    /**
+     * Base64 class because we can't test Android class and this is faster
+     */
+    private object Base64Utils {
+
+        private val ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray()
+
+        private val toInt = IntArray(128)
+
+        init {
+            for (i in ALPHABET.indices) {
+                toInt[ALPHABET[i].toInt()] = i
+            }
+        }
+
+        /**
+         * Translates the specified Base64 string into a byte array.
+         *
+         * @param s the Base64 string (not null)
+         * @return the byte array (not null)
+         */
+        fun decode(s: String): ByteArray {
+            val delta = if (s.endsWith("==")) 2 else if (s.endsWith("=")) 1 else 0
+            val buffer = ByteArray(s.length * 3 / 4 - delta)
+            val mask = 0xFF
+            var index = 0
+            var i = 0
+            while (i < s.length) {
+                val c0 = toInt[s[i].toInt()]
+                val c1 = toInt[s[i + 1].toInt()]
+                buffer[index++] = (c0 shl 2 or (c1 shr 4) and mask).toByte()
+                if (index >= buffer.size) {
+                    return buffer
+                }
+                val c2 = toInt[s[i + 2].toInt()]
+                buffer[index++] = (c1 shl 4 or (c2 shr 2) and mask).toByte()
+                if (index >= buffer.size) {
+                    return buffer
+                }
+                val c3 = toInt[s[i + 3].toInt()]
+                buffer[index++] = (c2 shl 6 or c3 and mask).toByte()
+                i += 4
+            }
+            return buffer
+        }
+
+    }
+}

android/app/src/main/java/org/fossasia/openevent/common/api/Urls.kt

@@ -0,0 +1,85 @@
+package org.fossasia.openevent.common.api
+
+import android.webkit.URLUtil
+
+import org.fossasia.openevent.common.utils.Utils
+
+object Urls {
+
+    const val API_VERSION = "v1"
+
+    /**
+     * Change EVENT Id Here *
+     */
+    const val EVENT_ID = 1
+
+    const val WEB_APP_URL_BASIC = "http://fossasia.github.io/open-event-webapp/#/"
+
+    const val EVENT = "event"
+
+    const val SPEAKERS = "speakers"
+
+    const val TRACKS = "tracks"
+
+    const val SESSIONS = "sessions"
+
+    const val SPONSORS = "sponsors"
+
+    const val BOOKMARKS = "bookmarks"
+
+    const val MICROLOCATIONS = "microlocations"
+
+    const val SESSION_TYPES = "session_types"
+
+    const val MAP = "map"
+
+    @JvmField
+    var BASE_URL = "https://eventyay.com/api/v1/events/6"
+
+    const val FACEBOOK_BASE_URL = "https://graph.facebook.com"
+
+    const val LOKLAK_BASE_URL = "https://api.loklak.org"
+
+    @JvmField
+    val BASE_GET_URL = "$BASE_URL/api/$API_VERSION"
+
+    const val BASE_GET_URL_ALT = "https://raw.githubusercontent.com/fossasia/open-event/master/testapi/"
+
+    // Replace the template in getAppLink() if changing it
+    private const val APP_LINK = "https://app_link_goes_here.com"
+
+    const val INVALID_LINK = "http://abc//"
+
+    const val EMPTY_LINK = "http://xyz//"
+
+    private const val GOOGLE_PLAY_HOME = "https://play.google.com/store"
+
+    var baseUrl: String
+        @JvmStatic
+        get() = BASE_URL
+        @JvmStatic
+        set(baseUrl) = if (URLUtil.isValidUrl(baseUrl)) {
+            BASE_URL = if (!baseUrl.endsWith("/")) {
+                "$baseUrl/"
+            } else {
+                baseUrl
+            }
+        } else {
+            BASE_URL = if (!Utils.isEmpty(baseUrl)) {
+                INVALID_LINK
+            } else {
+                EMPTY_LINK
+            }
+        }
+
+    /**
+     * Checks if the app link is replaced by the generator, if not
+     * returns null which is to be checked by caller to make decision
+     * accordingly.
+     * @return String
+     */
+    val appLink: String
+        @JvmStatic
+        get() = if (APP_LINK == "https://app_link_goes_here.com") GOOGLE_PLAY_HOME else APP_LINK
+
+}

android/app/src/main/java/org/fossasia/openevent/common/utils/Utils.kt

@@ -29,7 +29,7 @@ object Utils {
 
         @JvmStatic
         val isBaseUrlEmpty: Boolean
-            get() = Urls.getBaseUrl() == Urls.EMPTY_LINK
+            get() = Urls.baseUrl == Urls.EMPTY_LINK
 
         @JvmStatic
         fun isEmpty(string: String?): Boolean {
@@ -85,15 +85,15 @@ object Utils {
             if (isBaseUrlEmpty) {
                 swipeRefreshLayout.isEnabled = false
             } else {
-                StrategyRegistry.instance.eventBusStrategy!!.eventBus.register(`object`)
+                StrategyRegistry.instance.eventBusStrategy?.eventBus?.register(`object`)
                 swipeRefreshLayout.setOnRefreshListener(onRefreshListener)
             }
         }
 
         @JvmStatic
         fun unregisterIfUrlValid(`object`: Any) {
             if (!isBaseUrlEmpty) {
-                StrategyRegistry.instance.eventBusStrategy!!.eventBus.unregister(`object`)
+                StrategyRegistry.instance.eventBusStrategy?.eventBus?.unregister(`object`)
             }
         }