#!/usr/bin/env bash

function error_handler() {
  >&2 echo "Exited with BAD EXIT CODE '${2}' in ${0} script at line: ${1}."
  exit "$2"
}
trap 'error_handler ${LINENO} $?' ERR
set -o errtrace -o errexit -o nounset

# HELP: remove all unused functions from python files

if ! command -v dead >/dev/null 2>&1; then
  echo "dead is not installed. installing..."
  echo "pip install dead"
fi

list_of_unused_things="$(dead | grep -E '^[a-z].*is never read')"

filename_patterns_to_ignore="(codemod|migrations/versions|conftest.py|noxfile.py)"

while read -r line; do
  function_name="$(echo "$line" | awk '{print $1}')"
  echo "possible function_name: ${function_name}"
  file_name_and_line_number="$(echo "$line" | perl -p -e "s/.*is never read, defined in //g")"
  file_name="$(echo "$file_name_and_line_number" | awk -F ':' '{print $1}')"
  if ! grep "def $function_name" "$file_name" >/dev/null 2>&1; then
    echo "skipping $function_name in ${file_name} because it's not a function"
    continue
  fi
  if grep -E "$filename_patterns_to_ignore" <<< "$file_name" >/dev/null 2>&1; then
    echo "skipping ${file_name} because it's in the list of files to ignore (probably because it is a false positive and actually used)"
    continue
  fi
  echo "trying to remove $function_name from: ${file_name}"

  if python bin/codemod/update_file_to_remove_function.py "$file_name" "$function_name"; then
    # TODO: run exhaustive tests, and if they pass, report success
    echo "function ${function_name} removed from ${file_name}. yay!"
    exit 0
  fi
done <<< "$list_of_unused_things"