Add SessionGenerator

Author: samedson

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/SessionGenerator.kt

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2023 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.firebase.sessions
+
+import java.util.UUID
+
+/**
+ * [SessionInfo] is a data class responsible for storing information about the
+ * current Session.
+ *
+ * @hide
+ */
+internal data class SessionInfo(
+  val sessionId: String,
+  val firstSessionId: String,
+  val shouldDispatchEvents: Boolean,
+  val sessionIndex: Int,
+)
+
+/**
+ * The [SessionGenerator] is responsible for generating the Session ID, and keeping the
+ * [SessionInfo] up to date with the latest values.
+ *
+ * @hide
+ */
+internal class SessionGenerator(collectEvents: Boolean) {
+  private var thisSession: SessionInfo = SessionInfo("", "", collectEvents, -1)
+
+  private var firstSessionId = ""
+  private var sessionIndex: Int = -1
+  private var collectEvents = collectEvents
+
+  // Generates a new Session ID. If there was already a generated Session ID
+  // from the last session during the app's lifecycle, it will also set the last Session ID
+  fun generateNewSession() {
+    // val newSessionId = UUID().uuidString.replacingOccurrences(of: "-", with: "").lowercased()
+    val newSessionId = UUID.randomUUID().toString().replace("-", "").lowercase()
+
+    // If firstSessionId is set, use it. Otherwise set it to the
+    // first generated Session ID
+    firstSessionId = if (firstSessionId.isEmpty()) newSessionId else firstSessionId
+
+    sessionIndex += 1
+
+    thisSession = SessionInfo(newSessionId,
+                                 firstSessionId,
+                                 collectEvents,
+                                 sessionIndex)
+  }
+
+  val currentSession: SessionInfo get() = thisSession
+}