#!/bin/sh
#
# mfh - Merge from head to a given branch
# Copyright 2013 Baptiste Daroussin
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# MAINTAINER=	portmgr@FreeBSD.org
set -eu

##########################################
# Init and Validation
#########################################
if [ $# -ne 3 ]
then
  echo "$(basename $0) requires 3 arguments: {ports|base} <branch> <revnumber> "
  echo "e.g. $0 base stable/10 r245453"
  exit 1
fi


LF=$(printf '\nX')
LF=${LF%X}
IFS="${LF}"

case ${1} in
base)
  tree=base
  branchprefix=
  ;;
ports)
  tree=ports
  branchprefix=/branches
  ;;
*)
  echo "need a tree to work in: $0 <tree> <branch> <change-to-merge>"
  echo "e.g. $0 base stable/10 r345453"
  exit 1
 ;;
esac

shift

branch=$1

# what branches do we support and how?
case "${branch}" in
 stable/[89])
    echo "only sure this works on 10 for now)"
    # maybe we could set something here to support them??
    exit 1
    ;;
  stable/1[01])
    echo "using source tree root as base of merge"
    ;;
esac


: ${svnserver:="repo.FreeBSD.org"}

if [ -n "$(type svn 2>/dev/null)" ]
then
	svn=svn
elif [ -n "$(type svnlite 2>/dev/null)" ]
then
	svn=svnlite
else
	err "Neither svn(1) nor svnlite(1) found. Please install devel/subversion."
fi

workdir=$(mktemp -d /tmp/merge.XXXXXX)
cd "${workdir}"
echo  > ${workdir}/commit.txt

trap " cd - ; rc=\$? ; rm -rf \"\${workdir}\" ; exit \$rc" EXIT

err() {
	echo "$@" >&2
	exit 1
}

clean() {
	rm -rf "${workdir}"
	exit 1
}

ask() {
	question=${1}

	answer=x
	while [ "${answer}" != "y" -a "${answer}" != "n" ] ; do
		read -p "${question} [y/n] " answer
	done

	[ "${answer}" = "y" ] && return 0
	return 1
}

#########################################################
# mergebranch branch rev
# e.g. mergebranch stable/10 243545
#
# we compile filelist though we don't use it.. 
# We COULD just check out the files we need for a super-sparse
# checkout but I have no idea if it would work so stick with
# using dirlist in the 'svn up' for now even though it checks
# out stuff we don't touch
#########################################################
mergechange() {
  filelist=""
  dirlist=""

  # svn:// is faster than svn+ssh://. Use it wherever it's possible.
  for f in $("${svn}" diff --summarize -c ${rev} svn://${svnserver}/${tree}/head); do
	case ${f} in
	*/*) ;;
	*)continue;;
	esac
	file=${f##*/${tree}/head/}
	filelist="${filelist}${LF}${file}"
	dir=${file%/*}
	dirlist="${dirlist}${LF}${dir}"
  done
  filelist=$(printf '%s\n' "${filelist}" | sort -u)
  dirlist=$(printf '%s\n' "${dirlist}" | sort -u)
  echo "MFH: r${rev}" >> ${workdir}/commit.txt
  "${svn}" log -r${rev} svn://${svnserver}/${tree}/head | sed '1,2d;$d;/^MFH:/d' \
    | sed '$d' >> ${workdir}/commit.txt
  "${svn}" up --parents $(printf '%s\n' $dirlist \
    | sed "s}^}${branch}/}")
  "${svn}" up --quiet "${branch}"
  "${svn}" merge -c r${rev} ^/head/ "${branch}"
  "${svn}" up --quiet "${branch}"
  "${svn}" status "${branch}"
  "${svn}" diff "${branch}"
}

#####################################################
#  main code
#####################################################
rev=${2##r} # remove a leading "r"
case ${rev} in
  ''|*[!0-9]*) err "revision should be a number" ;;
esac

"${svn}" co --depth=empty svn+ssh://${svnserver}/${tree}${branchprefix}/"${branch}" ${branch}
  
while :
do
  mergechange ${branch} ${rev}
  read -p "Do you want to integrate another change number? (CR for no) : " VAL JUNK
  echo "VAL=$VAL"
  rev=${VAL##r} # remove a leading "r"
  case "${rev}" in
    "")
      break
      ;;
    [1-9]*)
      rev=$(($rev)) # normalise
      if [ "${rev}" = "0" ]
      then
        echo "really?"
        break
      fi
      ;;
    *)
      break
      ;;
  esac
done

ask "Do you want to commit? (no = start a shell)" || (
    echo "Dropping you to a shell so you can investigate. Exit the shell to resume this script."
    cd "${branch}"
    pwd
    su -m $(id -un) || :
    ask "Do you want to commit now? (no = clean up and abort)" || clean
)

${EDITOR:-vi} ${workdir}/commit.txt
"${svn}" ci -F ${workdir}/commit.txt "${branch}"
rm -rf "${workdir}"
trap - 0