#!/bin/sh

## Ignore script if POWSCRIPT_NOPREPUSH is set

case $POWSCRIPT_NOPREPUSH in
  yes|on|ok) exit 0;;
esac

## Check if githook is up to date

if [ -f '.git/hooks/pre-push' ] && ! diff "$0" '.git/hooks/pre-push' > /dev/null; then
  echo "You're using an outdated git pre-push hook! Please update it before pushing your changes."
  echo
  exit 1
fi


## Utilities

deref() {
  eval "echo \"\$$1\""
}

append() {
  local varname="$1"
  local value="$2"
  if [ -n "$(deref $varname)" ]; then
    local arg1="$(deref $varname)"
    local arg2="$value"
    eval "$varname=\"\$(printf '%s\n%s' '$arg1' '$arg2')\""
  else
    eval "$varname='$value'"
  fi
}


## Helper functions for finding and highlighting trailing whitespace

find_trailing_whitespace() {
  local found_trailing=""
  for file in "$@"; do
    if [ -d "$file" ] && [ ! -f "$file"/.ignore_trailing_whitespace ]; then
      append found_trailing "$(find_trailing_whitespace "$file/"*)"
    elif [ -f "$file" ]; then
      if echo "$file" | grep -q -E '\.pow$'; then
        local pattern='\S\s+$'
      else
        local pattern='\s+$'
      fi
      local found_trailing_file="$(grep -n -E "$pattern" "$file")"
      if [ -n "$found_trailing_file" ]; then
        local filename_color='\033[1;34m'
        local reset='\033[0m'
        append found_trailing "${filename_color}${file}:${reset}"
        append found_trailing "$found_trailing_file"
      fi
    fi
  done
  echo "$found_trailing"
}

highlight_trailing_whitespace() {
  local text="$1"

  local arrow_color='\\033[33m'
  local whitespace_bg='\\033[41m'
  local reset='\\033[0m'

  local find_trailing='\([ \t]\+\)$'
  local found_trailing='\1'


  local highlighted="$(echo "$text" | sed -e "s/${find_trailing}/${arrow_color}>>${whitespace_bg}${found_trailing}${reset}${arrow_color}<<${reset}/")"
  local indented="$(echo "$highlighted" | sed -e 's/^\(.*\)>\(.*\)$/  \1>\2/')"
  echo "$indented"
}


## Error if trailing whitespace is found.

case "$POWSCRIPT_PREPUSH_NOWHITESPACE" in
  yes|on|ok) ;;
  *)
    FoundTrailing="$(find_trailing_whitespace *)"
    if [ -n "$FoundTrailing" ]; then
      echo "Found trailing whitespace:"
      printf '%b\n' "$(highlight_trailing_whitespace "$FoundTrailing")"
      echo "Please fix it before pushing your changes."
      exit 1
    fi
  ;;
esac

## Error if in CDEBUG mode

if [ -f .cdebug ]; then
  echo "The compiler is in debug mode! Switch it off before committing your changes."
  exit 1
fi

## Error if user forgot to compile

case "$POWSCRIPT_PREPUSH_NOCOMPILE" in
  yes|on|ok) ;;
  *)
    .tools/compile
    if [ -n "$(git --no-pager diff powscript)" ]; then
      case "$POWSCRIPT_PREPUSH_NOINTERACTIVE" in
        yes|on|ok)
          echo "Compilation created unstaged changes! Please commit them before pushing your changes."
          exit 1
        ;;
        *)
          echo "Compilation created unstaged changes! Commit message: (leave blank to cancel)"
          exec < /dev/tty
          read -r commit_message
          exec <&-
          if [ -n "$commit_message" ]; then
            [ "$PAGER" = "less" ] && { PAGER="less -K" git diff powscript || exit 1; }
            git add powscript
            git commit -m "$commit_message"
            git rebase -i HEAD~"$(($(git rev-list --count "$1"/master..)+1))"
          else
            exit 1
          fi
        ;;
      esac
    fi
  ;;
esac

## Error if tests fail

case "$POWSCRIPT_PREPUSH_NOTESTS" in
  yes|on|ok) ;;
  *) .tools/runtests || exit 1 ;;
esac

exit 0