timer-class.R

timer <- R6::R6Class(
    classname = "timer",
    public = list(
        initialize = function(started.at = Sys.time()) {
            private$started.at <- started.at
        },
        elapsed = function() {
            if (!private$suspended)
                secs <- as.double(difftime(Sys.time(), private$started.at, units = "secs"))
            else
                secs <- as.double(difftime(private$suspended.at[length(private$suspended.at)], private$started.at, units = "secs"))
            secs - private$suspend_time()
        },
        suspend = function() {
            if (!private$suspended) {
                private$suspended.at <- .POSIXct(c(private$suspended.at, Sys.time()))
                private$suspended <- TRUE
            }
        },
        resume = function() {
            if (private$suspended) {
                private$resumed.at <- .POSIXct(c(private$resumed.at, Sys.time()))
                private$suspended <- FALSE
            }
        },
        status = function() {
            ifelse(private$suspended, "inactive", "active")
        },
        watch = function(interval = 0.01) {
            while (TRUE) {
                cat("\r", self$elapsed(), sep = "")
                Sys.sleep(interval)
            }
        },
        reset = function() {
            private$started.at <- Sys.time()
            private$suspended <- FALSE
            private$suspended.at <- NULL
            private$resumed.at <- NULL
        },
        print = function() {
            cat("Timer:\n")
            cat(sprintf("  Started at: %s\n", format(private$started.at)))
            cat(sprintf("  Status: %s\n", self$status()))
            cat(sprintf(ngettext(private$suspend_time(),
                                 "  Suspend time: %1.3f sec\n",
                                 "  Suspend time: %1.3f secs\n"), private$suspend_time()))
            cat(sprintf("  Elapsed time: %s\n", private$pretty_time()))
            invisible(self)
        }
    ),
    private = list(
        started.at = NULL,
        suspended = FALSE,
        suspended.at = NULL,
        resumed.at = NULL,
        suspend_time = function() {
            if (is.null(private$resumed.at))
                res <- 0
            if (!is.null(private$resumed.at)) {
                if (!private$suspended)
                    res <- sum(difftime(private$resumed.at, private$suspended.at, units = "secs"))
                else
                    res <- sum(difftime(private$resumed.at, private$suspended.at[-length(private$suspended.at)], units = "secs"))
            }
            as.double(res)
        },
        pretty_time = function() {
            secs <- self$elapsed()
            mins <- secs %/% 60
            hrs <- mins %/% 60
            days <- hrs %/% 24
            mins = mins - hrs * 60
            hrs = hrs - 24 * days
            if (secs < 60L)
                res <- sprintf(ngettext(secs, "%1.3f sec", "%1.3f secs"), secs)
            else
                res <- sprintf("%02.0f:%02.0f:%02.0f", hrs, mins, secs %% 60)
            if (days >= 1L)
                res <- sprintf("%d %s %s", as.integer(days), ngettext(as.integer(days), "day", "days"), res)
            return(res)
        }
    )
)

timer-shiny.R

timerApp <- shiny::shinyApp(
    ui = list(
        titlePanel("Название приложения"),
        sidebarLayout(
            sidebarPanel( "sidebar panel"),
            mainPanel("main panel")
        )
    ),
    server = function(input, output, session) {
        timer <- timer$new()
        shiny::observeEvent(input$suspend, {
            timer$suspend()
        })
        shiny::observeEvent(input$resume, {
            timer$resume()
        })
        shiny::observeEvent(input$reset, {
            timer$reset()
        })
        output$timer <- shiny::renderPrint({
            shiny::invalidateLater(1000, session)
            timer$print()
        })
    }
)