From 6a34fa1b1dae07fe032352bea0644ab7a6f9c3f9 Mon Sep 17 00:00:00 2001
From: Yury Shkoda <shkoda.yuri@gmail.com>
Date: Thu, 14 Oct 2021 07:32:16 +0000
Subject: [PATCH] feat(session): add SessionController

---
 src/controllers/Session.ts | 127 +++++++++++++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100644 src/controllers/Session.ts

diff --git a/src/controllers/Session.ts b/src/controllers/Session.ts
new file mode 100644
index 0000000..3e9af19
--- /dev/null
+++ b/src/controllers/Session.ts
@@ -0,0 +1,127 @@
+import { Session } from '../types'
+import { getTmpSessionsFolderPath, generateUniqueFileName } from '../utils'
+import {
+  deleteFolder,
+  createFile,
+  fileExists,
+  deleteFile,
+  generateTimestamp
+} from '@sasjs/utils'
+import path from 'path'
+import { ExecutionController } from './Execution'
+
+export class SessionController {
+  private sessions: Session[] = []
+  private executionController: ExecutionController
+
+  constructor() {
+    this.executionController = new ExecutionController()
+  }
+
+  public async getSession() {
+    const readySessions = this.sessions.filter((sess: Session) => sess.ready)
+
+    const session = readySessions.length
+      ? readySessions[0]
+      : await this.createSession()
+
+    if (readySessions.length < 2) this.createSession()
+
+    return session
+  }
+
+  private async createSession() {
+    const sessionId = generateUniqueFileName(generateTimestamp())
+    const sessionFolder = path.join(await getTmpSessionsFolderPath(), sessionId)
+
+    const autoExecContent = `data _null_;
+    /* remove the dummy SYSIN */
+    length fname $8;
+    rc=filename(fname,getoption('SYSIN') );
+    if rc = 0 and fexist(fname) then rc=fdelete(fname);
+    rc=filename(fname);
+    /* now wait for the real SYSIN */
+    slept=0;
+    do until ( fileexist(getoption('SYSIN')) or slept>(60*15) );
+      slept=slept+sleep(0.01,1);
+    end;
+  run;
+  EOL`
+
+    const autoExec = path.join(sessionFolder, 'autoexec.sas')
+    await createFile(autoExec, autoExecContent)
+
+    await createFile(path.join(sessionFolder, 'code.sas'), '')
+
+    const creationTimeStamp = sessionId.split('-').pop() as string
+
+    const session: Session = {
+      id: sessionId,
+      ready: false,
+      creationTimeStamp: creationTimeStamp,
+      deathTimeStamp: (
+        parseInt(creationTimeStamp) +
+        15 * 60 * 1000 -
+        1000
+      ).toString(),
+      path: sessionFolder,
+      inUse: false
+    }
+
+    this.scheduleSessionDestroy(session)
+
+    this.executionController.execute('', autoExec, session).catch(() => {})
+
+    this.sessions.push(session)
+
+    await this.waitForSession(session)
+
+    return session
+  }
+
+  public async waitForSession(session: Session) {
+    if (await fileExists(path.join(session.path, 'code.sas'))) {
+      while (await fileExists(path.join(session.path, 'code.sas'))) {}
+
+      await deleteFile(path.join(session.path, 'log.log'))
+
+      session.ready = true
+
+      return Promise.resolve(session)
+    } else {
+      session.ready = true
+
+      return Promise.resolve(session)
+    }
+  }
+
+  public async deleteSession(session: Session) {
+    await deleteFolder(session.path)
+
+    if (session.ready) {
+      this.sessions = this.sessions.filter(
+        (sess: Session) => sess.id !== session.id
+      )
+    }
+  }
+
+  private scheduleSessionDestroy(session: Session) {
+    setTimeout(async () => {
+      if (session.inUse) {
+        session.deathTimeStamp = session.deathTimeStamp + 1000 * 10
+
+        this.scheduleSessionDestroy(session)
+      } else {
+        await this.deleteSession(session)
+      }
+    }, parseInt(session.deathTimeStamp) - new Date().getTime() - 100)
+  }
+}
+
+export const getSessionController = () => {
+  if (process.sessionController) return process.sessionController
+
+  process.sessionController = new SessionController()
+
+  return process.sessionController
+}