#
# Common errors
# -------------
# 400 Bad Request
# 403 Forbidden (e.g. Nature website)
# 404 Not Found
# 501 Not Implemented
# 999 LinkedIn being defensive
#
library(httr)
library(stringr)

f <- "check.log"

if (!file.exists(f)) {

  u <- str_c(
    "https://raw.githubusercontent.com/",
    "briatte/awesome-network-analysis/",
    "master/README.md"
  )

  cat("Source:", u, "\n")

  u <- GET(u) %>%
    content("text") %>%
    str_split("\\n") %>% # so as to find [foo]: bar links
    unlist()

  # remove links that have been commented out
  u <- str_remove_all(u, "<!--.*?-->")

  # total number of links (made to match web.archive.org links only once)
  t <- sum(str_count(u, "(?<!/)http"))

  cat(t, "URLs, ")

  l <- c(
    # [foo](bar)
    str_extract_all(u, "\\(http(.*?)\\)") %>%
      lapply(str_replace_all, "^\\(|\\)$", "") %>%
      unlist(),
    # [foo]: bar
    str_extract_all(u, "^\\[(.*)\\]: (.*)") %>%
      unlist() %>%
      str_replace("^\\[(.*)\\]: (.*)", "\\2")
  )

  stopifnot(length(l) == t)

} else {

  cat("Source:", f, "\n")

  l <- str_subset(stringi::stri_read_lines(f), "^http")

  cat(length(l), "URLs, ")

}

l <- str_squish(sort(unique(l)))

cat(length(l), "unique\n")

cat("Ignoring", sum(str_detect(l, "^https://doi.org/")), "DOIs\n")
l <- str_subset(l, "^https://doi.org/", negate = TRUE)

sink(f, append = FALSE)
cat(as.character(Sys.time()), ": checking", length(l), "URLs\n\n")
sink()

for (i in l) {

  x <- try(status_code(GET(i)), silent = TRUE)

  if (!"try-error" %in% class(x) && x != 200) {

    cat("X")

    sink(f, append = TRUE)
    cat(i, "\nStatus code:", x, "\n\n")
    sink()

  } else if ("try-error" %in% class(x)) {

    cat("?")

    sink(f, append = TRUE)
    cat(i, "\nFailed to access\n\n")
    sink()

  } else {

    cat(".")

  }

  if (!which(l == i) %% 50) {

    cat("", length(l) - which(l == i), "left\n")

  }

}

sink(f, append = TRUE)
f <- sum(str_count(stringi::stri_read_lines(f), "^http"))
cat(as.character(Sys.time()), ": done,", f, "errors.\n")
sink()

cat("\n", f, "errors\n")