Code to make my graph is interactive in shiny - r

Question

I am trying to show the top ten highest temps from each year but the way I coded it, it will not change and just stays the same.
server.R
library(shiny)
library(dplyr)
library(ggplot2)
library(plotly)
library(readr)
library(tidyverse)
temp_df <-read_csv("~/Environment_Temperature_change_E_All_Data_NOFLAG.csv")
year_df <- temp_df[,8:66] #for the widget
info_df <- temp_df %>%
select(Area, Months, Element)
combine_df <- mutate(info_df, year_df)
combine_df <- na.omit(temp_df) # Get rid of NA rows
combine_df <- temp_df[!grepl("Standard Deviation",temp_df$Element), ] # Get rid of SD rows
top_ten_df <-top_n(combine_df, 10)
# Define server
server <-shinyServer(function(input, output) {
observe({
output$selected_var <- renderText({
paste("You have selected", input$year)
})
output$scatter <- renderPlot({
ggplot(data = top_ten_df, aes(x= Months, y = `Area`)) +
geom_point(aes(col=`Area`))
})
output$data <- renderTable({
final_df <-top_ten_df%>%
select(Area, Months, Element, input$year)
brushedPoints(final_df, input$plot_brush)
})
output$plotlyscatter <- renderPlotly({
plot_ly(data = top_ten_df, x = ~Area, y = ~Months, color=~Area, type = "scatter")
})
})
})
ui.R
library(shiny)
library(dplyr)
library(ggplot2)
library(plotly)
library(readr)
library(tidyverse)
temp_df <-read_csv("~/Environment_Temperature_change_E_All_Data_NOFLAG.csv")
year_df <- temp_df[,8:66] #for the widget
info_df <- temp_df %>%
select(Area, Months, Element)
combine_df <- mutate(info_df, year_df)
# Define UI
ui <- shinyUI(navbarPage(inverse = T, "Rising Temperatures",
tabPanel( "Top Ten Highest Tempratures",
sidebarLayout(
sidebarPanel(
h5("Selection"),
selectInput(inputId = "year",
label = "Select the year:",
choices = names(year_df),
),
textOutput("selected_var"),
),
mainPanel(
plotOutput(outputId = "scatter", brush = "plot_brush"),
tableOutput(outputId = "data"),
plotlyOutput(outputId = "plotlyscatter")
)
)
)
)
)
Also, I do not know where to use the app.R in this situation, sorry I am a bit new to all of this. I would like this to be an interactive scatter plot that when you pick an input from the widget.