library(tidyverse)
library(lubridate)
library(glue)
library(rvest)
libray(janitor)

scrape_nfl_table <- function(url, page) {
  

  glue("{url}&d-447263-p={page}") %>% 
    read_html() %>% 
    html_nodes("#result") %>% 
    html_table() %>%
    flatten_df() %>% 
    mutate_at(c(1, 5:8, 10:15, 17:19), as.numeric) %>% 
    mutate_at(9, as.character) %>%
    clean_names() %>%
    mutate_at("yds", parse_number)
  
}

pull_nfl_statistics <- function(archive, conference, statisticCategory, season, seasonType) {
  
  Sys.sleep(5)
  
  if (season != 2018) {
    archive <- "true"
  } else {
    archive <- "false"
  }
  
  url <- glue("http://www.nfl.com/stats/categorystats?archive={archive}&conference={conference}&statisticCategory={statisticCategory}&season={season}&seasonType={seasonType}&experience=&tabSeq=0&qualified=true&Submit=Go")

    pages <- read_html(url) %>% 
    html_nodes("#main-content > div.c > div.grid > div.col.span-12 > form > span:nth-child(4)") %>% 
    html_text() %>% 
    str_extract_all("\\d", simplify = TRUE) 
  
  map_dfr(pages, ~scrape_nfl_table(url, .x))
    
}



scaffold <- tibble(archive = "true",
                   conference = "null",
                   statisticCategory = "PASSING",
                   season = 2018,
                   seasonType = "REG")

output <- pmap(scaffold, pull_nfl_statistics)