app.R

library(sparklyr)
library(shiny)
library(leaflet)
library(readr)
library(ggplot2)

spark <- 0 

if(spark){
  
  Sys.setenv(SPARK_HOME = "/home/sean/.cache/spark/spark-1.6.2-bin-hadoop2.6")
  sc <- spark_connect(master = "local", version = "1.6.2")
  spark_read_csv(sc, "nyc_taxi_sample", path = "../../nathan/sol-eng-nyc-taxi-data/csv/trips/nyc_taxi_trips_2015-11.csv")

  nyc_data <- tbl(sc, "nyc_taxi_sample")

  m <- nyc_data %>%
    filter(fare_amount > 0,
           pickup_latitude > 0,
           pickup_longitude < 0,
           dropoff_latitude > 0,
           dropoff_longitude < 0) %>%
    ml_linear_regression(fare_amount ~ pickup_latitude + pickup_longitude + dropoff_latitude + dropoff_longitude)
  
}else {
  nyc_data <- read_csv("testdata.csv")
  m <- lm(data=nyc_data, fare_amount ~ pickup_latitude + pickup_longitude + dropoff_latitude + dropoff_longitude)
}


# Define UI for application that draws a histogram
ui <- fluidPage(
   
   
   fluidRow(
      leafletOutput("map"),    
      p("Click on Location First and Desired Destination Second"),
      actionButton("go", "Predict Cost"),
      textOutput("result")
      
   )
   
)


server <- function(input, output) {
  
  new_points <- data.frame(lat=c(), lng=c())
  
   output$map <- renderLeaflet({
     leaflet() %>% 
       fitBounds(lng1 = -73.97, lng2 = -73.85, lat1 = 40.68, lat2 = 40.77) %>% # NYC
       addProviderTiles("Stamen.Toner")
   })
   
   observeEvent(input$map_click, {
     proxy <- leafletProxy("map")
     data <- input$map_click
     proxy %>% 
       addMarkers(lng = data$lng, lat = data$lat)
     
     new_points <<- rbind(new_points, data)
   })
   

   prediction <- eventReactive(input$go, {
     new_data <- data.frame(pickup_latitude = new_points$lat[1],
                   pickup_longitude = new_points$lng[1],
                   dropoff_latitude = new_points$lat[2],
                   dropoff_longitude = new_points$lng[2])
     print(new_data)
     predict(m, new_data)
   })
   
   output$result <- renderText({
     num_trips <- nyc_data %>% count()
     result <- paste("Your estimated trip fare is: $", round(prediction(),2), " based on", num_trips, "trips.")
     result
   })
   
   observeEvent(input$go, {
     proxy <- leafletProxy("map")
     proxy %>% 
       addCircles(lng = nyc_data$pickup_longitude, lat = nyc_data$pickup_latitude, col = "orange") %>% 
       addCircles(lng = nyc_data$dropoff_longitude, lat = nyc_data$dropoff_latitude, col = "green")
   })
   
   
}

# Run the application 
shinyApp(ui = ui, server = server)