#!/bin/bash
# Updates copyright of various source files and commits to repository
#
#  Copyright (C) 2013, 2014 Mike Gerwitz
#
#  This file is part of GNU ease.js.
#
#  This program is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation, either version 3 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# Please note that this file will update itself. Further, it will only
# update files that state ``this file is part of ease.js''.
#
# This script will look up the modification dates from the file commits and
# update the copyright line accordingly. Since the history must not include
# the copyright update itself, this script will also perform the commit
# (feel free to amend afterward) to ensure consistency in future filtering.
#
# This should be run from the tools directory.
##

owner="${@:?Missing copyright owner}"

# refuse to run on a dirty tree
if [ -n "$( git status --short | grep -v ^?? )" ]; then
  echo 'Please stash or commit your changes.' >&2
  exit 1
fi

# safety check
wd="$(pwd)"
[ "${wd##*/}" == tools ] || {
  echo 'Please run from within tools directory' >&2
  exit 1
}

# enable extglob for !()
shopt -s extglob || {
  echo 'extglob unsupported' >&2
  exit 1
}

# we will be updating all files that contain this line
ident='This \(file\|document\) is part of \(the \)\?GNU ease.js'

ignorepath='.git|build|webroot|node_modules'
files=$( grep -rl "$ident" ../!($ignorepath) )

(
  echo 'The following files will be updated to reflect modification years:'
  echo
  echo "$files"
) | less -EX

read -p 'Are you sure you want to continue (y/N)? ' c
[[ "$c" == [yY] ]] || {
  echo 'Aborting.' >&2
  exit 1
}

copyupdate()
{
  local years="$1"
  local file="$2"

  sed -i "s/\(. \+Copyright (C) \).*\$/\\1$years $owner/" "$file"
}

getyears()
{
  grep -vF '[copyright]'$'\n''[no-copyright]' \
    | cut -d' ' -f4 \
    | sort -u \
    | tr '\n' , \
    | sed 's/,/, /g;s/, $//'
}

# have at it
for file in $files; do
  ext="${file##*/*.}"
  echo -n "updating $file..."

  # determine copyrightable years from commit log and format as year1, year2,
  # ..., yearn (TODO: join consecutive years with dash)
  years="$(
    git log --format='%aD %s' --follow -- "$file" \
      | getyears
  )"

  # no years, then no history
  if [ -z "$years" ]; then
    echo 'unknown; skipped.'
    continue
  fi

  # perform copyright update
  copyupdate "$years" "$file"
  echo "$years."
done

# general license templates will contain all copyright years
years="$(
  git log --format='%aD %s' \
    | getyears
)"
copyupdate "$years" license.tpl
copyupdate "$years" license-min.tpl

# commit
git commit -am '[copyright] Copyright update'