server.R

library(shiny)
library(ggplot2)

getColor = function(ratio){
  if(ratio <= 0.1){
    ratio = 0
  }else{
    ratio = ratio * 2
  }
  ratio = min(max(ratio, 0), 1)
  color1 = '99cc00'
  color2 = 'ff4444'
  hex = function(x) {
    hex = as.character(as.hexmode(x))
    if(nchar(hex) == 1){
      hex = paste0('0', hex)
    }
    hex
  }
  r = ceiling(as.integer(paste0('0x', substring(color1, 1, 2))) * ratio + as.integer(paste0('0x', substring(color2, 1,2))) * (1-ratio))
  g = ceiling(as.integer(paste0('0x', substring(color1, 3, 4))) * ratio + as.integer(paste0('0x', substring(color2, 3,4))) * (1-ratio))
  b = ceiling(as.integer(paste0('0x', substring(color1, 5, 6))) * ratio + as.integer(paste0('0x', substring(color2, 5,6))) * (1-ratio))
  paste0('#', hex(r), hex(g), hex(b))
}

idxToTime = function(idx){
  idx = idx
  hours = formatC(idx %/%  60, width = 2, format = "d", flag = "0") 
  minutes = formatC(idx %% 60, width = 2, format = "d", flag = "0")
  paste0(hours, ':', minutes)
}

plotPrediction = function(stationId, timeIdx){
  ratios = pmax(predictionByStationId[[stationId]]$ratios, 0)
  dataLength = 24 * 60
  chances = ratios * 100;
  data <- data.frame(x=1:length(chances),y=chances)
  color = sapply(ratios, getColor)
  interval = 150
  minIdx = max(timeIdx - interval, 1) - max(timeIdx + interval - dataLength, 0)
  maxIdx = min(timeIdx + interval, dataLength) + max(interval + 1 - timeIdx, 0)
  maxChance = max(chances[minIdx:maxIdx])
  ggplot(data=data, aes(x=x)) + 
    geom_linerange(color=color, ymax=chances, ymin=-0.1, size=1) + 
    geom_text(x=min(max(timeIdx, 10), 60 * 24 - 10), y=max(maxChance/2, 5), size=8, label=paste0(round(chances[timeIdx]), '%')) +
    xlab("Time") +
    ylab("Chance(%)") +
    scale_y_continuous(limits = c(0, max(maxChance, 10)), breaks=0:10 * 10) +
    scale_x_continuous(
      limits = c(minIdx, maxIdx), 
      breaks = (0:24) * 60,
      labels=idxToTime
    )
}

load('predictionByStationId.rda')

shinyServer(function(input, output) {  
  output$getPredictionByTimeIdx <- function(){
    pred = list()
    if(input$getPredictionByTimeIdx > 0){
      for(p in predictionByStationId){  
        pred[[as.character(p$id)]] = list(
          id=p$id,
          name=p$name,
          district=p$district,
          address=p$address,
          lat=p$lat,
          lon=p$lon,
          ratio=p$ratios[input$getPredictionByTimeIdx]
        )
      }
    }
    pred
  }
  
  output$plotPrediction <- function(){
    input$plotPrediction
  }
  
  output$plot <- renderPlot({
    if(input$plotPrediction != ''){
      plotPrediction(input$plotPrediction$stationId, input$plotPrediction$timeIdx)
    }
  })
})