---
title: "Logging Test"
author: "Russell Almond"
date: "June 3, 2020"
output: html_document
runtime: shiny
---

The logging function appends a line to the `mess` object each time it is called.  This is rendered in the log table output.

```{r setup}
knitr::opts_chunk$set(echo = TRUE)

## Don't really need to check for this demo.
checkPassword <- function (uid, pwd) TRUE
```
```{r}
status <- reactiveVal("Ready.")
nclicks <- reactiveVal(0)
logstatus <- reactiveValues()
logstatus$logfile <- character()
logstatus$log <- data.frame(Messages="No log file yet.")
logtimer <- reactiveTimer(1000)
  readlog <- reactive({
    logtimer()
    if (status()=="Working..." &&
        length(logstatus$logfile) >0L  &&
        file.exists(logstatus$logfile)) {
      cat("Checking log file:",logstatus$logfile,".\n")
      if (!file.exists("/tmp/signal")) status("Done.")
      lf <- file(logstatus$logfile)
      mess <- readLines(lf)
      close(lf)
      cat("Found ",length(mess),"messages.\n")
      logstatus$log <- data.frame(Messages=mess)
    }
  })
  observeEvent(input$go, {
    showNotification(
        ifelse(checkPassword(input$adminid,input$adminpwd),
               sprintf("Logged into application %s.", input$branch),
               "Authentication Error."))
    if (nclicks() > 0L) {
      showNotification("Already running model builder.")
      return (NULL)
    }
    logstatus$logfile <- "/tmp/Logging.log"
    if (file.exists(logstatus$logfile)) unlink(logstatus$logfile)
    status("Working...")

    system2("/home/ralmond/Projects/rgroup-shiny/Proc4/Trivial",wait=FALSE)

    return(NULL)
  })

output$status <- renderText(status())
output$log <- renderTable({readlog();logstatus$log},colnames=FALSE)

```



## Login 

Press Go to test the logging mechanism.

```{r login, echo=FALSE}
tags$head(tags$script(src = "message-handler.js"))
inputPanel(
  textInput("adminid", label = "Username:",
              width = 500),
  passwordInput("adminpwd", label = "Password:",
              width = 500),
  textInput("branch", label = "Vesion Branch:",
            value="PP-main",width = 500),
  actionButton("go","Go"),
  actionButton("log","Show Log.")
)
```
## Results
```{r}
p("Model Builder is ",textOutput("status"))
p(tableOutput("log"))

```