app.R

library(shiny)
library(shinythemes)

# Define UI for application that draws a histogram
ui <- fluidPage(theme = shinytheme("sandstone"),
                navbarPage(
                  "Analyzing the Classics",
                  tabPanel("Counts and Feels",
                           sidebarLayout(
                             sidebarPanel(
                               selectizeInput("book",
                                              "Select the name of a book to analyze:",
                                              choices = NULL),
                               actionButton("gotime", "Go!")
                             ),
                             mainPanel(tabsetPanel(
                               id = "analyses",
                               tabPanel("Top 10",
                                        p("The top 10 Words for the selected document appear 
                                          here."),
                                        plotOutput("plt")),
                               tabPanel("Sentiments",
                                        p("The sentiment scores for the selected document 
                                          appear here."),
                                        plotOutput("sent"))
                             ))
                           )),
                  tabPanel("Topics",
                           sidebarLayout(
                             sidebarPanel(
                               selectizeInput("book1",
                                              "Enter the name of the first book to compare:",
                                              choices = NULL),
                               selectizeInput("book2",
                                              "Enter the name of the second book to compare:",
                                              choices = NULL),
                               sliderInput("topic_slider", "Number of Topics to Find in Books:",
                                           min = 1, max = 10, value = 5),
                               numericInput("top_tops", "N Top Words to Display:",
                                            min = 1, value = 10),
                               selectInput("algorithm", "Select the algorithm to use:",
                                           choices = c("LDA", "Pachinko"),
                                           selected = "LDA"),
                               actionButton("topics", "Get Topics")
                             ),
                             mainPanel(tabsetPanel(
                               id = "topic_analyses",
                               tabPanel("Topic Probabilities",
                                        p("This tab lets you view the probabilities of words 
                                          being generated from certain topics. The 'beta' value 
                                          for a word is the probability of that word being 
                                          generated from that topic."),
                                        plotOutput("betas")),
                               tabPanel("Document Probabilities",
                                        p("This tab lets you view the probability that the words 
                                          for a topic came from a given document. The gamma 
                                          value is the probability that the words for the topic 
                                          in the topic column came from that document."),
                                        tableOutput("doc_probs"))
                             ))
                           ))
                ))

server <- function(input, output, session) {
  source("analyze.R")
  source("topics.R")
  
  # Keep a list of titles to select from
  book_choices <- gutenberg_metadata$title
  
  # Update the select fields with titles
  updateSelectizeInput(session, "book",
                       choices = book_choices,
                       server = TRUE,
                       options = list(maxOptions = 10,
                                      placeholder = "Select a Document"))
  updateSelectizeInput(session, "book1",
                       choices = book_choices,
                       server = TRUE,
                       options = list(maxOptions = 10,
                                      placeholder = "Select a Document"))
  updateSelectizeInput(session, "book2",
                       choices = book_choices,
                       server = TRUE,
                       options = list(maxOptions = 10,
                                      placeholder = "Select a Document"))
  
  # Generate analyses for "counts and feels"
  observeEvent(input$gotime, {
    txt <- get_book(input$book)
    tidy_book <- process_text(txt)
    output$plt <- renderPlot({
      word_counts(tidy_book)
    })
    output$sent <- renderPlot({
      sentiment_counts(tidy_book)
    })
  })
  
  # Generate analysis for "topics"
  observeEvent(input$topics, {
    pbooks <- process_books(c(input$book1, input$book2))
    
    # Figure out how to selectively work out the models here
    topic_model <- get_books_lda(pbooks, input$topic_slider)

    output$betas <- renderPlot({
      topic_beta_graphs(topic_model, input$top_tops)
    })
    output$doc_probs <- renderTable({
      topic_gamma_info(topic_model)
    })
  })
}

shinyApp(ui = ui, server = server)