[LONGITUDINAL]
input = {ka, Tk0, V, k}

EQUATION:
  D  = 100

if t>Tk0
f0=D/(V*Tk0*k)*(1-exp(-k*Tk0))*exp(-k*(t-Tk0))
else
  f0=D/(V*Tk0*k)*(1-exp(-k*t))
end

f1 = f0
f2 = D*ka/(V*(ka-k))*(exp(-k*t) - exp(-ka*t))

ui <- shinyUI(fluidPage(
navbarPage(" ",
tabPanel("Plot",
fluidRow(
column(2,
sliderInput("ka", label="ka",value=0.5,min=0.1,max=1,step=0.1),
numericInput("Tk0", label="Tk0",value=2),
selectInput("k", label="k", choices=c(0.05,0.2,0.4),selected=0.2),
br()
),
column(2,
br(),
checkboxGroupInput("out1", label="plot", choices=c('f1','f2'), selected=c('f1','f2')),hr(),
strong("add"),
checkboxInput("legend", label="legend", value=TRUE),

fluidRow(
column(5,checkboxInput("boxref", label="ref.")),
column(4,actionButton("butref", label = "Reset"))
),
hr(),

br()
),
column(8,br(),            
plotOutput("plot")
)
)
),
tabPanel("Mlxtran", pre(includeText("model.txt"))),
tabPanel("ui.R", pre(includeText("ui.R"))),
tabPanel("server.R", pre(includeText("server.R")))
)
))

#source("../../initMlxR.R")
library("mlxR")
library("reshape")
library("gridExtra")
source("shinymlxTools.R")

f <- list(name=c('f1','f2'), time=seq(0,20,by=0.1))
f <- list(f)
nf <- length(f)
info <- info_res(f)

server <- function(input, output) {
  ref <- reactive({
    input$butref
    p <- list(name  = c('ka', 'Tk0', 'V', 'k'),
              value = isolate(c(input$ka, input$Tk0, 2, as.numeric(input$k))))

    r <- simulx( model     = 'model.txt',
                 parameter = p,
                 output    = f)

    ref <- merge_res(r,f)
    return(ref)
  })
  
  res <- reactive({
    p <- list(name  = c('ka', 'Tk0', 'V', 'k'),
              value = c(input$ka, input$Tk0, 2, as.numeric(input$k)))
                     
    r <- simulx( model     = 'model.txt',
                 parameter = p,
                 output    = f)
                     
    res <- merge_res(r,f)
    return(res)
  })  
  
  output$plot <- renderPlot({
    res=res()
   ref=ref()    
    gr.txt <- "grid.arrange("
    for (j in (1:length(f))){
      xj <- "time"
      fj <- f[[j]]
      name.fj <- fj$name

   eval(parse(text=paste0("inputyj=input$out",j)))  
  i.plot=FALSE
  if (!is.null(inputyj)){
    ij <- which(name.fj %in% inputyj)
    if (length(ij>0)){
      eval(parse(text=paste0("inputxj=input$x",j)))
      if (!is.null(inputxj))
        xj <- inputxj
    }
    i.plot=TRUE
  }
  else if (is.null(inputyj) & length(f)==1){
    ij=1
    i.plot=TRUE
  }
  if (i.plot){
    pl <- ggplotmlx()
    nfj <- length(name.fj)
    for (k in (1:nfj)){
      if (k %in% ij){
           if (input$boxref==TRUE){
      pj <- paste0('pl <- pl + geom_path(data=ref[[j]], aes(x=time,y=',name.fj[k],'),colour="grey",size=0.75)')
      eval(parse(text=pj))
    }
       pj <- paste0('pl <- pl + geom_path(data=res[[j]], aes(x=time,y=',name.fj[k],',colour="',info[[j]]$colour[k],'"),size=0.75)')
       eval(parse(text=pj))
      }  
    }
    pl <- pl + scale_colour_manual(values=info[[j]]$values, labels=info[[j]]$labels)
    if (length(ij)>1){
      if (!is.null(input$legend) && input$legend==FALSE)
        pl <- pl + theme(legend.position="none")
      else
        pl <- pl + guides(colour=guide_legend(title=NULL)) + theme(legend.position=c(.9, .8))
      pl <- pl + ylab("")
    }else{
      pl <- pl + theme(legend.position="none")
    }
  
  
    eval(parse(text=paste0("pl",j," <- pl")))
    gr.txt <- paste0(gr.txt,"pl",j,",")
  }
    }
    gr.txt <- paste0(gr.txt,"ncol=1)")
    eval(parse(text=gr.txt))
  }, height = 500)
}