worldfootballr_helpers.R

#' Get fbref League URLs
#'
#' Returns the URLs for season leagues of a selected country
#'
#' @param country the three character country code
#' @param gender gender of competition, either "M" or "F"
#' @param season_end_year the year the season(s) concludes (defaults to all available seasons)
#' @param tier the tier of the league, ie '1st' for the EPL or '2nd' for the Championship and so on
#'
#' @return returns a character vector of all fbref league URLs for selected country, season, gender and tier
#'
#' @importFrom magrittr %>%
#' @importFrom rlang .data
#'
#' @export
#'
#' @examples
#' \dontrun{
#' try({
#' fb_league_urls(country = "ENG", gender = "M", season_end_year = 2021, tier = '1st')
#' })
#' }
fb_league_urls <- function(country, gender, season_end_year, tier = "1st") {

  # .pkg_message("Getting league URLs")

  main_url <- "https://fbref.com"

  country_abbr <- country
  gender_M_F <- gender
  season_end_year_num <- season_end_year
  comp_tier <- tier

  seasons <- read.csv("https://raw.githubusercontent.com/JaseZiv/worldfootballR_data/master/raw-data/all_leages_and_cups/all_competitions.csv", stringsAsFactors = F)

  league_seasons_urls <- seasons %>%
    dplyr::filter(.data[["country"]] %in% country_abbr,
           .data[["gender"]] %in% gender_M_F,
           .data[["season_end_year"]] %in% season_end_year_num,
           .data[["tier"]] %in% comp_tier) %>%
    dplyr::pull(.data[["seasons_urls"]]) %>% unique()

  return(league_seasons_urls)

}


#' Get fbref Team URLs
#'
#' Returns the URLs for all teams for a given league
#'
#' @param league_url the league URL (can be from fb_league_urls())
#' @param time_pause the wait time (in seconds) between page loads
#'
#' @return returns a character vector of all fbref team URLs for a selected league
#'
#' @importFrom magrittr %>%
#' @importFrom rlang .data
#'
#' @export
#'
#' @examples
#' \dontrun{
#' try({
#' fb_teams_urls("https://fbref.com/en/comps/9/Premier-League-Stats")
#' })
#' }
fb_teams_urls <- function(league_url, time_pause=3) {

  # .pkg_message("Scraping team URLs")

  # put sleep in as per new user agreement on FBref
  Sys.sleep(time_pause)

  league_season_page <- .load_page(league_url)

  main_url <- "https://fbref.com"

  urls <- league_season_page %>%
    rvest::html_elements(".stats_table") %>%
    rvest::html_nodes("img+ a") %>%
    rvest::html_attr("href") %>%
    unique() %>% paste0(main_url, .)

  return(urls)
}


#' Get fbref Player URLs
#'
#' Returns the URLs for all players for a given team
#'
#' @param team_url the player's team URL (can be from fb_team_urls())
#' @param time_pause the wait time (in seconds) between page loads
#'
#' @return returns a character vector of all fbref player URLs for a selected team
#'
#' @importFrom magrittr %>%
#' @importFrom rlang .data
#'
#' @export
#'
#' @examples
#' \dontrun{
#' try({
#' fb_player_urls("https://fbref.com/en/squads/fd962109/Fulham-Stats")
#' })
#' }
fb_player_urls <- function(team_url, time_pause=3) {

  # .pkg_message("Scraping Player URLs")

  main_url <- "https://fbref.com"

  # put sleep in as per new user agreement on FBref
  Sys.sleep(time_pause)

  player_page <- .load_page(team_url)

  player_urls <- player_page %>%
    rvest::html_nodes("#all_stats_standard th a") %>%
    rvest::html_attr("href") %>%
    paste0(main_url, .)

  return(player_urls)
}


#' Get transfermarkt Team URLs
#'
#' Returns the URLs for all teams for a given league season
#'
#' @param country_name the country of the league's players
#' @param start_year the start year of the season (2020 for the 20/21 season)
#' @param league_url league url from transfermarkt.com. To be used when country_name not available in main function
#'
#' @return returns a character vector of all transfermarkt team URLs for a selected league
#'
#' @importFrom magrittr %>%
#' @importFrom rlang .data
#' @importFrom utils read.csv
#'
#' @export
tm_league_team_urls <- function(country_name, start_year, league_url = NA) {
  main_url <- "https://www.transfermarkt.com"

  if(is.na(league_url)) {
    meta_df <- read.csv(url("https://raw.githubusercontent.com/JaseZiv/worldfootballR_data/master/raw-data/transfermarkt_leagues/main_comp_seasons.csv"),
                        stringsAsFactors = F)

    tryCatch({meta_df_seasons <- meta_df %>%
      dplyr::filter(.data[["country"]] %in% country_name, .data[["season_start_year"]] %in% start_year)}, error = function(e) {meta_df_seasons <- data.frame()})

    if(nrow(meta_df_seasons) == 0) {
      stop(glue::glue("Country {country_name} or season {start_year} not found. Check that the country and season exists at https://github.com/JaseZiv/worldfootballR_data/blob/master/raw-data/transfermarkt_leagues/main_comp_seasons.csv"))
    }

    season_url <- meta_df_seasons$season_urls

  } else {
    tryCatch({league_page <- xml2::read_html(league_url)}, error = function(e) {league_page <- c()})

    tryCatch({country_name <- league_page %>%
      rvest::html_nodes(".profilheader") %>%
      rvest::html_node("img") %>%
      rvest::html_attr("alt") %>% .[!is.na(.)]}, error = function(e) {country_name <- NA_character_})

    if(length(league_page) == 0) {
      stop(glue::glue("League URL(s) {league_url} not found. Please check transfermarkt.com for the correct league URL"))
    }

    season_url <- paste0(league_url, "?saison_id=", start_year)

  }

  season_page <- xml2::read_html(season_url)

  team_urls <- season_page %>%
    rvest::html_nodes("#yw1 .hauptlink a") %>% rvest::html_attr("href") %>%
    # rvest::html_elements("tm-tooltip a") %>% rvest::html_attr("href") %>%
    unique() %>% paste0(main_url, .)
  # there now appears to be an errorneous URL so will remove that manually:
  if(any(grepl("com#", team_urls))) {
    team_urls <- team_urls[-grep(".com#", team_urls)]
  }

  return(team_urls)
}


#' Get transfermarkt Player URLs
#'
#' Returns the transfermarkt URLs for all players for a given team
#'
#' @param team_url the player's team URL (can be from tm_league_team_urls())
#'
#' @return returns a character vector of all transfermarkt player URLs for a selected team
#'
#' @importFrom magrittr %>%
#' @importFrom rlang .data
#'
#' @export
#'
tm_team_player_urls <- function(team_url) {

  main_url <- "https://www.transfermarkt.com"

  tryCatch({team_page <- xml2::read_html(team_url)}, error = function(e) {team_page <- c()})

  player_urls <- team_page %>%
    rvest::html_nodes("#yw1 td.posrela .hauptlink a") %>% rvest::html_attr("href") %>%
    unique() %>%
    paste0(main_url, .)

  return(player_urls)
}

#' Get transfermarkt Club Staff URLs
#'
#' Returns the transfermarkt URLs for all staff of selected roles for a given team
#'
#' @param team_urls the staff member's team URL (can be from tm_league_team_urls())
#' @param staff_role role of the staff member URLs required for with options including:
#'
#' \emph{"Manager"}, \emph{"Assistant Manager"}, \emph{"Goalkeeping Coach"},
#' \emph{"Fitness Coach"}, \emph{"Conditioning Coach"}
#'
#' @return returns a character vector of all transfermarkt staff URLs for a selected team(s)
#'
#' @importFrom magrittr %>%
#' @importFrom rlang .data
#'
#' @export
tm_team_staff_urls <- function(team_urls, staff_role) {

  if(!staff_role %in% c("Manager", "Assistant Manager", "Goalkeeping Coach", "Fitness Coach", "Conditioning Coach")) stop("Check that staff role is one of:\n'Manager', 'Assistant Manager', 'Goalkeeping Coach', 'Fitness Coach' or 'Conditioning Coach'")

  get_each_team <- function(team_url) {
    pb$tick()
    main_url <- "https://www.transfermarkt.com"

    manager_history_url <- gsub("startseite", "mitarbeiter", team_url) %>% gsub("/saison_id.*", "", .)

    history_pg <- xml2::read_html(manager_history_url)


    coaching <- history_pg %>% rvest::html_nodes(".large-8") %>% rvest::html_nodes(".box") %>% .[1]

    name <- coaching %>% rvest::html_nodes(".hauptlink a") %>% rvest::html_text()
    url <- coaching %>% rvest::html_nodes(".hauptlink a") %>% rvest::html_attr("href") %>% paste0(main_url, .)
    position <- coaching %>% rvest::html_nodes(".inline-table tr+ tr td") %>% rvest::html_text()
    coaching_df <- data.frame(name, url, position)

    if(staff_role == "Manager") {
      url <- coaching_df %>% dplyr::filter(position %in% c("Manager", "Caretaker Manager")) %>% dplyr::pull(.data[["url"]])
    } else {
      url <- coaching_df %>% dplyr::filter(position == staff_role) %>% dplyr::pull(.data[["url"]])
    }

    return(url)
  }

  # create the progress bar with a progress function.
  pb <- progress::progress_bar$new(total = length(team_urls))

  f_possibly <- purrr::possibly(get_each_team, otherwise = NA_character_, quiet = FALSE)
  purrr::map(
    team_urls,
    f_possibly
  ) %>% unlist()

}


#' Get Understat available teams
#'
#' Returns all available team names for the selected leagues
#'
#' @param leagues the available leagues in Understat as outlined below
#'#'
#' The leagues currently available for Understat are:
#' \emph{"EPL"}, \emph{"La liga}", \emph{"Bundesliga"},
#' \emph{"Serie A"}, \emph{"Ligue 1"}, \emph{"RFPL"}
#'
#' #' @return a character vector teams names
#'
#' @export
#' @examples
##' \dontrun{
#' try({
#' understat_available_teams(leagues = c('EPL', 'La liga'))
#' })
#' }
understat_available_teams <- function(leagues){
  correct_leagues <- c("EPL", "La liga", "Bundesliga", "Serie A", "Ligue 1", "RFPL")

  teams_list <- list()

  for(lg in leagues){
    if(!lg %in% correct_leagues){warning(glue::glue("League {lg} not found. Please check understats.com for the correct league name")); next}
    match_url <- switch (lg,
                         'EPL' = 'https://understat.com/team/Arsenal',
                         'La liga' = 'https://understat.com/team/Barcelona',
                         'Bundesliga' = 'https://understat.com/team/Bayern_Munich',
                         'Serie A' = 'https://understat.com/team/AC_Milan',
                         'Ligue 1' = 'https://understat.com/team/Paris_Saint_Germain',
                         'RFPL' = 'https://understat.com/team/Spartak_Moscow'
    )
    team_page <- tryCatch(.load_page(match_url), error = function(e) NA)
    teams_list[[lg]] <- team_page %>% rvest::html_nodes(".header-wrapper") %>% html_text() %>% gsub("([\n\t])|(\\d{4}/\\d{4})", "", .) %>% gsub('(?<!\\s)([[:upper:]])', '(&&)\\1', ., perl = TRUE) %>%
      strsplit(., "\\(&&\\)", perl = TRUE) %>% unlist(.) %>% .[2:length(.)] %>%  unlist(.)
  }
  if(length(leagues) == 1){
    return(unlist(teams_list, use.names = FALSE))
  }

  return(teams_list)
}

#' Get Understat team info
#'
#' Retrieve Understat team metadata, including team URLs. Similar to `understatr::get_team_meta`.
#'
#' @param team_names a vector of team names (can be just 1)
#'
#' @return a data.frame
#'
#' @export
#' @examples
##' \dontrun{
#' try({
#' understat_team_meta(team_name = c("Liverpool", "Manchester City"))
#' })
#' }
understat_team_meta <- function(team_names) {
  f_possibly <- purrr::possibly(.understat_team_meta, otherwise = data.frame(), quiet = FALSE)
  purrr::map_dfr(team_names, f_possibly)
}

#' @importFrom stringr str_replace_all
#' @importFrom rvest read_html html_nodes html_attr html_text
.understat_team_meta <- function(team_name) {
  # .pkg_message("Scraping {team_name} metadata. Please acknowledge understat.com as the data source")

  main_url <- "https://understat.com"

  team_name <- stringr::str_replace_all(team_name, " ", "_")
  team_url <- paste(main_url, "team", team_name, sep = "/")

  team_page <- xml2::read_html(team_url)
  year_link <- rvest::html_nodes(team_page, "#header :nth-child(2)")
  year_options <- rvest::html_nodes(year_link[2], "option")

  team_df <- data.frame(
    team_name = team_name,
    year = as.numeric(rvest::html_attr(year_options, "value")),
    season = rvest::html_text(year_options),
    stringsAsFactors = FALSE
  )

  team_df$url <- paste(team_url, team_df$year, sep = "/")

  return(team_df)

}