#!/bin/sh
# In a git/autoconf/automake-enabled project with a NEWS file and a version-
# controlled .prev-version file, automate the procedure by which we record
# the date, release-type and version string in the NEWS file.  That commit
# will serve to identify the release, so apply a signed tag to it as well.
VERSION=2018-03-07.03 # UTC

# Note: this is a bash script (could be zsh or dash)

# Copyright (C) 2009-2018 Free Software Foundation, Inc.

# 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 <https://www.gnu.org/licenses/>.

# Written by Jim Meyering

ME=$(basename "$0")
warn() { printf '%s: %s\n' "$ME" "$*" >&2; }
die() { warn "$*"; exit 1; }

help()
{
  cat <<EOF
Usage: $ME [OPTION...] VERSION RELEASE_TYPE

Run this script from top_srcdir to perform the final pre-release NEWS
update in which the date, release-type and version string are
recorded.  Commit that result with a log entry marking the release,
and apply a signed tag.  Run it from your project's top-level
directory.

Requirements:
- you use git for version-control
- a version-controlled .prev-version file
- a NEWS file, with line 3 identical to this:
$noteworthy_stub

Options:
  --branch=BRANCH     set release branch (default: $branch)
  -C, --builddir=DIR  location of (configured) Makefile (default: $builddir)
  --help              print this help, then exit
  --version           print version number, then exit

EXAMPLE:
To update NEWS and tag the beta 8.1 release of coreutils, I would run this:

  $ME 8.1 beta

Report bugs and patches to <bug-gnulib@gnu.org>.
EOF
  exit
}

version()
{
  year=$(echo "$VERSION" | sed 's/[^0-9].*//')
  cat <<EOF
$ME $VERSION
Copyright (C) $year Free Software Foundation, Inc,
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
EOF
  exit
}

## ------ ##
## Main.  ##
## ------ ##

# Constants.
noteworthy='* Noteworthy changes in release'
noteworthy_stub="$noteworthy ?.? (????-??-??) [?]"

# Variables.
branch=$(git branch | sed -ne '/^\* /{s///;p;q;}')
builddir=.

while test $# != 0
do
  # Handle --option=value by splitting apart and putting back on argv.
  case $1 in
    --*=*)
      opt=$(echo "$1" | sed -e 's/=.*//')
      val=$(echo "$1" | sed -e 's/[^=]*=//')
      shift
      set dummy "$opt" "$val" "$@"; shift
      ;;
  esac

  case $1 in
    --help|--version) ${1#--};;
    --branch) shift; branch=$1; shift ;;
    -C|--builddir) shift; builddir=$1; shift ;;
    --*) die "unrecognized option: $1";;
    *) break;;
  esac
done

test $# = 2 \
  || die "Usage: $ME [OPTION...] VERSION TYPE"

ver=$1
type=$2


## ---------------------- ##
## First, sanity checks.  ##
## ---------------------- ##

# Verify that $ver looks like a version number, and...
echo "$ver"|grep -E '^[0-9][0-9.]*[0-9]$' > /dev/null \
  || die "invalid version: $ver"
prev_ver=$(cat .prev-version) \
  || die 'failed to determine previous version number from .prev-version'

# Verify that $ver is sensible (> .prev-version).
case $(printf "$prev_ver\n$ver\n"|sort -V -u|tr '\n' ':') in
  "$prev_ver:$ver:") ;;
  *) die "invalid version: $ver (<= $prev_ver)";;
esac

case $type in
  alpha|beta|stable) ;;
  *) die "invalid release type: $type";;
esac

# No local modifications allowed.
case $(git diff-index --name-only HEAD) in
  '') ;;
  *) die 'this tree is dirty; commit your changes first';;
esac

# Ensure the current branch name is correct:
curr_br=$(git rev-parse --symbolic-full-name HEAD)
test "$curr_br" = "refs/heads/$branch" || die not on branch $branch

# Extract package name from Makefile.
Makefile=$builddir/Makefile
pkg=$(sed -n 's/^PACKAGE = \(.*\)/\1/p' "$Makefile") \
  || die "failed to determine package name from $Makefile"

# Check that line 3 of NEWS is the stub line about to be replaced.
test "$(sed -n 3p NEWS)" = "$noteworthy_stub" \
  || die "line 3 of NEWS must be exactly '$noteworthy_stub'"

## --------------- ##
## Then, changes.  ##
## --------------- ##

# Update NEWS to have today's date, plus desired version number and $type.
perl -MPOSIX -ni -e 'my $today = strftime "%F", localtime time;' \
 -e 'my ($type, $ver) = qw('"$type $ver"');' \
 -e 'my $pfx = "'"$noteworthy"'";' \
 -e 'print $.==3 ? "$pfx $ver ($today) [$type]\n" : $_' \
     NEWS || die 'failed to update NEWS'

printf "version $ver\n\n* NEWS: Record release date.\n" \
    | git commit -F -  -a || die 'git commit failed'
git tag -s -m "$pkg $ver" v$ver HEAD || die 'git tag failed'

# Local variables:
# indent-tabs-mode: nil
# eval: (add-hook 'before-save-hook 'time-stamp)
# time-stamp-start: "VERSION="
# time-stamp-format: "%:y-%02m-%02d.%02H"
# time-stamp-time-zone: "UTC0"
# time-stamp-end: " # UTC"
# End: