#!/usr/bin/env bash

#############################################################################
#                                                                           #
# Open Source License                                                       #
# Copyright (c) 2022 Nomadic Labs <contact@nomadic-labs.com>                #
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#############################################################################

# This script is a wrapper for git-gas-diff. See the README.md for more
# information about the tool.

# The script accepts zero, one or two commit hash arguments.
# If no commit is provided, the script will use git-gas-diff between the
# last merge commit and HEAD.
# If one commit is provided, the script will use git-gas-diff between this
# commit and HEAD.
# If two commits are provided, the script will use git-gas-diff between the
# first and the second.

# The script saves the git diff between the two commits to a temporary file
# that will be applied to git-gas-diff.
# The diff is restricted to regression test output files, does not consider
# added and deleted files (option `--diff-filter=ad`), and does not carry the
# context around modified lines (option `U0`).

case "$#" in
0)
  OLD=$(git log --pretty=format:"%H" --merges -n 1)
  NEW='HEAD'
  ;;

1)
  OLD=$1
  NEW='HEAD'
  ;;

2)
  OLD=$1
  NEW=$2
  ;;

*)
  echo "** Error: wrong number of arguments (0, 1 or 2 expected, found $#)."
  echo 'Usage: ./git-gas-diff.sh to use git-gas-diff between the last merge commit and HEAD;'
  echo '       ./git-gas-diff.sh [commit] to use git-gas-diff between [commit] and HEAD;'
  echo '       ./git-gas-diff.sh [commit1] [commit2] to use git-gas-diff between [commit1] and [commit2].'
  exit 1
  ;;

esac

DIFF_FILE=$(mktemp)

MSG="-- LINE NUMBERS REFER TO TEMPORARY FILE ${DIFF_FILE}. --"

echo -e "$MSG\n"

git diff --no-ext-diff --diff-filter=ad -U0 --output="$DIFF_FILE" "$OLD" "$NEW" \
  ../../tezt/tests/expected/
dune exec git-gas-diff "$DIFF_FILE"

echo -e "\n$MSG"