#!/bin/bash

if [ $# -lt 2 ]; then
   echo "Usage: $0 <company> <domain>">&2
   echo "This script updates copyright lines for <company> for files modified">&2
   echo "this year by authors whose email addresses are at <domain>.">&2
   echo "Usage example: $0 \"Red Hat\" redhat.com">&2
   exit 1
fi

company=$1
domain=$2

# Switch to root directory of repo
rootdir=$(git rev-parse --show-toplevel)
if [ $? -ne 0 ]; then
   exit 1
fi
cd $rootdir

# This script has the potential to create a massive diff, so to help going back
# for some reason, enforce a clean working directory.
git diff --exit-code --quiet
if [ $? -ne 0 ]; then
   echo "Working directory should be clean">&2
   echo "Please stash or commit changes">&2
fi

set -e

year=$(date +%Y)
lastyear=$(expr $year - 1)

echo -n "Fetching in-tree copyrighted files... "

# Collect all the files in the tree with copyrights older than this year
old_copyrighted_files=
for file in $(git ls-tree --full-tree --name-only -r HEAD); do

   # Exclude po dir
   if [ ! -d $file ] && \
      [[ $file != po/* ]] && \
      grep -q -E 'Copyright \(C\) .*[0-9]{4}\s+'"$company" $file; then

      # Add to the list if it's not copyrighted for this year
      if ! grep -q "Copyright (C) .*$year.*$company" $file; then
         old_copyrighted_files="$old_copyrighted_files $file"
      fi
   fi
done

echo "done"
echo -n "Checking year of last modification... "

# For each of those files, do a git log to determine if it has been modified by
# an author at domain this year
needs_updating=
for file in $old_copyrighted_files; do
   authors_this_year=$(git log --format='%ae' --after="$lastyear-12-31" -- "$file")
   for author in $authors_this_year; do
      if [[ $author == *@$domain ]]; then
         needs_updating="$needs_updating $file"
         break
      fi
   done
done

echo "done"
echo -n "Updating copyright years... "

# Update all the copyright lines to the current year
n=0
for file in $needs_updating; do

   # Modify the XXXX copyright line to XXXX-YYYY
   sed -i -r 's/(.*Copyright \(C\).* )([0-9]{4})\s+('"$company"'.*)/\1\2-'$year' \3/' $file
   # Modify the XXXX-YYYY copyright line
   sed -i -r 's/(.*Copyright \(C\).*-)([0-9]{4})\s+('"$company"'.*)/\1'$year' \3/' $file

   # If it wasn't modified, output warning
   git diff --exit-code --quiet $file && \
      echo "File $file could not be updated. Continuing...">&2 || \
      n=$(expr $n + 1)
done

echo "done ($n files)"

if [ $n -gt 0 ]; then
   echo "Please carefully review modifications"
fi