#!/usr/bin/env bash

# [start-readme]
# The script is run once per day via a scheduled GitHub Action to check all links in the site. It automatically opens an issue if it finds broken links.
# To exclude a URL from the link check, add it to `lib/excluded-links.js`.
#
# For checking internal links, see `script/check-internal-links`.
# [end-readme]

internal=""
while getopts "h?i" opt; do
  case "${opt}" in
    h|\?) echo "Usage:"
          echo "    script/check-external-links [OPTIONS] [two-letter language code]"
          echo ""
          echo "    script/check-external-links -i              Check internal links. Without this flag, check all links."
          echo "    script/check-external-links -h              Display this help message."
          exit 0
          ;;
    i) internal=" --internalOnly"
       ;;
  esac
done
shift $((OPTIND -1))

if [ -z "${1}" ]
then
  echo "error: must provide two-letter language code"
  exit 1
fi

languageCode=${1}

# Pass options to script to construct blc command
blcCommand="$(./script/get-blc-command.js ${internal} --language ${languageCode})"

# Exit if script returned an error
if test $? -eq 1
then
	exit 1
fi

# Determine logfile name based on options
logfile=""
if [ -z "${internal}" ]
then
  logfile="blc_output.log"
else
  logfile="blc_output_internal.log"
fi

# Kill any server running in the background, then start the server
killall node >/dev/null 2>&1
node server.js >/dev/null &
sleep 5

host="http://localhost:4000"

# Check whether localhost is accessible
hostStatus=$(curl -I --silent "${host}" | head -1)
isHostOK=$(echo "${hostStatus}" | grep "[2|3][0-9][0-9]")
if [ -z "${isHostOK}" ]
then
  echo "Can't connect to ${host}!"
  echo ${hostStatus}
  echo ${isHostOK}
  exit 1
fi

# Execute blc and save output
${blcCommand[@]} > ${logfile}

# We're done with the server now, so end the process
# killall node will also terminate this script, so find and kill the specific pid
pid=$(ps aux | grep "node server.js" | grep -v "grep" | awk '{ print $2 }'); kill -INT $pid >/dev/null 2>&1

# Recheck "403 Forbidden" results due to a bug
# https://github.com/stevenvachon/broken-link-checker/issues/58
# Also recheck "429" GitHub results
urlsToRecheck=$(egrep "HTTP_4(03|29)" ${logfile} | grep -o "http.* ")

if [ ! -z "${urlsToRecheck}" ]
then
  for url in ${urlsToRecheck}
  do
    # Curl each URL and grep for 4xx or 5xx in status code response
    status=$(curl -I --silent "${url}" | head -1 | grep "[4|5][0-9][0-9]")
    if [ -z "${status}" ]
    then
      # If no 4/5xx found, the link is NOT really broken, so remove it from the list
      # This command needs to work in all implementations of sed (Mac/GNU/etc)
      sed -i'.bak' -e "s|^.*$url.*$||" ${logfile}
      # Remove backup file
      find . -name "${logfile}.bak" | xargs rm
    fi
  done
fi

# Count number of broken links in output
# Ignore "308 Permanent Redirect" results, which are not actually broken
numberOfBrokenLinks=$(grep "BROKEN" ${logfile} | grep -vc HTTP_308)
brokenLinks=$(grep "BROKEN" ${logfile} | grep -v HTTP_308)

# If broken links are found, exit with status 1 so the check run fails
if [ ${numberOfBrokenLinks} -gt 0 ]
then
  # Print "links" or "link" in message depending on the number found
  if [ ${numberOfBrokenLinks} -gt 1 ]
  then
    linkOrLinks="links"
  else
    linkOrLinks="link"
  fi
  echo -e "\n${numberOfBrokenLinks} broken ${linkOrLinks} found on help.github.com\n"
  echo -e "Note: links that start with 'http://localhost:4000/' are internal links.\n"

  # List broken links
  echo "${brokenLinks}"

  # Update final number of broken links
  echo -e "\n$(tail -2 ${logfile})" | sed "s|. [0-9]* broken.|. ${numberOfBrokenLinks} broken.|"

  # Exit without failure when checking all links so script/open-broken-links-issue can run
  if [ -z "${internal}" ]
  then
    exit 0
  else
    exit 1
  fi
else
  echo "All links are good!"
  echo -e "\n$(tail -2 ${logfile})"
  exit 0
fi