# Exercise 2 - solution

library(shiny)
library(gapminder)
library(dplyr)

# Note: This code creates data sets to use in each tab.
# It removes Kuwait since Kuwait distorts the gdp scale
all_data <- filter(gapminder, country != "Kuwait")
africa_data <- filter(gapminder, continent == "Africa")
americas_data <- filter(gapminder, continent == "Americas")
asia_data <- filter(gapminder, continent == "Asia", country != "Kuwait")
europe_data <- filter(gapminder, continent == "Europe")
oceania_data <- filter(gapminder, continent == "Oceania")

ui <- fluidPage(
  titlePanel("Gapminder"),
  tabsetPanel(id = "continent",
              tabPanel("All",
                       plotOutput("all_plot"),
                       sliderInput("all_year", "Select Year", value = 1952, min = 1952,
                                   max = 2007, step = 5, animate = animationOptions(interval = 500))
              ),
              tabPanel("Africa",
                       plotOutput("africa_plot"),
                       sliderInput("africa_year", "Select Year", value = 1952, min = 1952,
                                   max = 2007, step = 5, animate = animationOptions(interval = 500))
              ),
              tabPanel("Americas",
                       plotOutput("americas_plot"),
                       sliderInput("americas_year", "Select Year", value = 1952, min = 1952,
                                   max = 2007, step = 5, animate = animationOptions(interval = 500))
              ),
              tabPanel("Asia",
                       plotOutput("asia_plot"),
                       sliderInput("asia_year", "Select Year", value = 1952, min = 1952,
                                   max = 2007, step = 5, animate = animationOptions(interval = 500))
              ),
              tabPanel("Europe",
                       plotOutput("europe_plot"),
                       sliderInput("europe_year", "Select Year", value = 1952, min = 1952,
                                   max = 2007, step = 5, animate = animationOptions(interval = 500))
              ),
              tabPanel("Oceania",
                       plotOutput("oceania_plot"),
                       sliderInput("oceania_year", "Select Year", value = 1952, min = 1952,
                                   max = 2007, step = 5, animate = animationOptions(interval = 500))
              )
  )
)

server <- function(input, output) {

  # collect one year of data
  ydata_all <- reactive({
    filter(all_data, year == input$all_year)
  })

  ydata_africa <- reactive({
    filter(africa_data, year == input$africa_year)
  })

  ydata_americas <- reactive({
    filter(americas_data, year == input$americas_year)
  })

  ydata_asia <- reactive({
    filter(asia_data, year == input$asia_year)
  })

  ydata_europe <- reactive({
    filter(europe_data, year == input$europe_year)
  })

  ydata_oceania <- reactive({
    filter(oceania_data, year == input$oceania_year)
  })

  # compute plot ranges
  xrange_all <- range(all_data$gdpPercap)
  yrange_all <- range(all_data$lifeExp)

  xrange_africa <- range(africa_data$gdpPercap)
  yrange_africa <- range(africa_data$lifeExp)

  xrange_americas <- range(americas_data$gdpPercap)
  yrange_americas <- range(americas_data$lifeExp)

  xrange_asia <- range(asia_data$gdpPercap)
  yrange_asia <- range(asia_data$lifeExp)

  xrange_europe <- range(europe_data$gdpPercap)
  yrange_europe <- range(europe_data$lifeExp)

  xrange_oceania <- range(oceania_data$gdpPercap)
  yrange_oceania <- range(oceania_data$lifeExp)

  # render plots
  output$all_plot <- renderPlot({

    # draw background plot with legend
    plot(all_data$gdpPercap, all_data$lifeExp, type = "n",
         xlab = "GDP per capita", ylab = "Life Expectancy",
         panel.first = {
           grid()
           text(mean(xrange_all), mean(yrange_all), input$all_year,
                col = "grey90", cex = 5)
         }
    )

    legend("bottomright", legend = levels(all_data$continent),
           cex = 1.3, inset = 0.01, text.width = diff(xrange_all)/5,
           fill = c("#E41A1C99", "#377EB899", "#4DAF4A99", "#984EA399", "#FF7F0099")
    )

    # Determine bubble colors
    cols <- c("Africa" = "#E41A1C99",
              "Americas" = "#377EB899",
              "Asia" = "#4DAF4A99",
              "Europe" = "#984EA399",
              "Oceania" = "#FF7F0099")[ydata_all()$continent]

    # add bubbles
    symbols(ydata_all()$gdpPercap, ydata_all()$lifeExp,
            circles = sqrt(ydata_all()$pop), bg = cols, inches = 0.5, fg = "white",
            add = TRUE)
  })

  output$africa_plot <- renderPlot({

    # draw background plot with legend
    plot(africa_data$gdpPercap, africa_data$lifeExp, type = "n",
         xlab = "GDP per capita", ylab = "Life Expectancy",
         panel.first = {
           grid()
           text(mean(xrange_africa), mean(yrange_africa), input$africa_year,
                col = "grey90", cex = 5)
         }
    )

    legend("bottomright", legend = levels(africa_data$continent),
           cex = 1.3, inset = 0.01, text.width = diff(xrange_africa)/5,
           fill = c("#E41A1C99", "#377EB899", "#4DAF4A99", "#984EA399", "#FF7F0099")
    )

    # Determine bubble colors
    cols <- c("Africa" = "#E41A1C99",
              "Americas" = "#377EB899",
              "Asia" = "#4DAF4A99",
              "Europe" = "#984EA399",
              "Oceania" = "#FF7F0099")[ydata_africa()$continent]

    # add bubbles
    symbols(ydata_africa()$gdpPercap, ydata_africa()$lifeExp,
            circles = sqrt(ydata_africa()$pop), bg = cols, inches = 0.5, fg = "white",
            add = TRUE)
  })

  output$americas_plot <- renderPlot({

    # draw background plot with legend
    plot(americas_data$gdpPercap, americas_data$lifeExp, type = "n",
         xlab = "GDP per capita", ylab = "Life Expectancy",
         panel.first = {
           grid()
           text(mean(xrange_americas), mean(yrange_americas), input$americas_year,
                col = "grey90", cex = 5)
         }
    )

    legend("bottomright", legend = levels(americas_data$continent),
           cex = 1.3, inset = 0.01, text.width = diff(xrange_americas)/5,
           fill = c("#E41A1C99", "#377EB899", "#4DAF4A99", "#984EA399", "#FF7F0099")
    )

    # Determine bubble colors
    cols <- c("Africa" = "#E41A1C99",
              "Americas" = "#377EB899",
              "Asia" = "#4DAF4A99",
              "Europe" = "#984EA399",
              "Oceania" = "#FF7F0099")[ydata_americas()$continent]

    # add bubbles
    symbols(ydata_americas()$gdpPercap, ydata_americas()$lifeExp,
            circles = sqrt(ydata_americas()$pop), bg = cols, inches = 0.5, fg = "white",
            add = TRUE)
  })

  output$asia_plot <- renderPlot({

    # draw background plot with legend
    plot(asia_data$gdpPercap, asia_data$lifeExp, type = "n",
         xlab = "GDP per capita", ylab = "Life Expectancy",
         panel.first = {
           grid()
           text(mean(xrange_asia), mean(yrange_asia), input$asia_year,
                col = "grey90", cex = 5)
         }
    )

    legend("bottomright", legend = levels(asia_data$continent),
           cex = 1.3, inset = 0.01, text.width = diff(xrange_asia)/5,
           fill = c("#E41A1C99", "#377EB899", "#4DAF4A99", "#984EA399", "#FF7F0099")
    )

    # Determine bubble colors
    cols <- c("Africa" = "#E41A1C99",
              "Americas" = "#377EB899",
              "Asia" = "#4DAF4A99",
              "Europe" = "#984EA399",
              "Oceania" = "#FF7F0099")[ydata_asia()$continent]

    # add bubbles
    symbols(ydata_asia()$gdpPercap, ydata_asia()$lifeExp,
            circles = sqrt(ydata_asia()$pop), bg = cols, inches = 0.5, fg = "white",
            add = TRUE)
  })

  output$europe_plot <- renderPlot({
    stop("Error: Don't look at Europe")
    # draw background plot with legend
    plot(europe_data$gdpPercap, europe_data$lifeExp, type = "n",
         xlab = "GDP per capita", ylab = "Life Expectancy",
         panel.first = {
           grid()
           text(mean(xrange_europe), mean(yrange_europe), input$europe_year,
                col = "grey90", cex = 5)
         }
    )

    legend("bottomright", legend = levels(europe_data$continent),
           cex = 1.3, inset = 0.01, text.width = diff(xrange_europe)/5,
           fill = c("#E41A1C99", "#377EB899", "#4DAF4A99", "#984EA399", "#FF7F0099")
    )

    # Determine bubble colors
    cols <- c("Africa" = "#E41A1C99",
              "Americas" = "#377EB899",
              "Asia" = "#4DAF4A99",
              "Europe" = "#984EA399",
              "Oceania" = "#FF7F0099")[ydata_europe()$continent]

    # add bubbles
    symbols(ydata_europe()$gdpPercap, ydata_europe()$lifeExp,
            circles = sqrt(ydata_europe()$pop), bg = cols, inches = 0.5, fg = "white",
            add = TRUE)
  })

  output$oceania_plot <- renderPlot({

    # draw background plot with legend
    plot(oceania_data$gdpPercap, oceania_data$lifeExp, type = "n",
         xlab = "GDP per capita", ylab = "Life Expectancy",
         panel.first = {
           grid()
           text(mean(xrange_oceania), mean(yrange_oceania), input$oceania_year,
                col = "grey90", cex = 5)
         }
    )

    legend("bottomright", legend = levels(oceania_data$continent),
           cex = 1.3, inset = 0.01, text.width = diff(xrange_oceania)/5,
           fill = c("#E41A1C99", "#377EB899", "#4DAF4A99", "#984EA399", "#FF7F0099")
    )

    # Determine bubble colors
    cols <- c("Africa" = "#E41A1C99",
              "Americas" = "#377EB899",
              "Asia" = "#4DAF4A99",
              "Europe" = "#984EA399",
              "Oceania" = "#FF7F0099")[ydata_oceania()$continent]

    # add bubbles
    symbols(ydata_oceania()$gdpPercap, ydata_oceania()$lifeExp,
            circles = sqrt(ydata_oceania()$pop), bg = cols, inches = 0.5, fg = "white",
            add = TRUE)
  })
}

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