#!/usr/bin/env bash
#**************************************************************************
#*                                                                        *
#*                                 OCaml                                  *
#*                                                                        *
#*                David Allsopp, MetaStack Solutions Ltd.                 *
#*                                                                        *
#*   Copyright 2017 MetaStack Solutions Ltd.                              *
#*                                                                        *
#*   All rights reserved.  This file is distributed under the terms of    *
#*   the GNU Lesser General Public License version 2.1, with the          *
#*   special exception on linking described in the file LICENSE.          *
#*                                                                        *
#**************************************************************************

# Bump this on any changes. It's vital that HOOK_VERSION followed by equals
# appears nowhere else in these sources!
HOOK_VERSION=4

# For what it's worth, allow for empty trees!
if git rev-parse --verify HEAD >/dev/null 2>&1
then
  against=HEAD
else
  # Initial commit: diff against an empty tree object
  against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi

# Redirect output to stderr.
exec 1>&2

# Check to see if the script's been updated
if git ls-files --error-unmatch tools/pre-commit-githook >/dev/null 2>&1 ; then
  THEIR_VERSION=$(git cat-file --textconv HEAD:tools/pre-commit-githook \
                    | sed -ne 's/^HOOK_VERSION=//p')
  if [[ -n $THEIR_VERSION && $THEIR_VERSION -gt $HOOK_VERSION ]] ; then
    echo "Note: tools/pre-commit-githook is newer than .git/hooks/pre-commit"
    echo "      You may wish to update your local githook"
  fi
fi

# Git's built-in mechanism for whitespace is neater than ours, so do it first.
# The strange construction below creates a list of files which have either
# white-at-eol or white-at-eof included in ocaml-typo in .gitattributes and by
# prefixing the names with :! causes git diff-index to skip over them.
if [[ -n $(git diff-index --cached --name-only $against) ]] ; then
  FILES=$(git diff-index --cached --name-only $against \
          | xargs git check-attr --cached ocaml-typo \
          | sed -ne 's/\(.*\): ocaml-typo:.*[ ,]white-at-eo[fl]\(,\|$\)/:!\1/p')
  if ! git diff-index --check --cached $against -- $FILES ; then
    exit 1
  fi
else
  exit 0
fi

# Test to see if any part of the directory name has been marked prune
not_pruned () {
  DIR=$(dirname "$1")
  if [ "$DIR" = "." ] ; then
    return 0
  else
    case ",$(git check-attr typo.prune "$DIR" | sed -e 's/.*: //')," in
      ,set,)
      return 1
      ;;
      *)

      not_pruned "$DIR"
      return $?
    esac
  fi
}

# Now run check-typo over all the files in the index
ERRORS=0
export OCAML_CT_PREFIX=:
export OCAML_CT_CAT="git cat-file --textconv"
export OCAML_CT_CA_FLAG=--cached
git diff --diff-filter=d --staged --name-only | (while IFS= read -r path
do
  if not_pruned "$path" && ! tools/check-typo "./$path" ; then
    ERRORS=1
  fi
done; exit $ERRORS)