#!/bin/bash
#
# Moves a branch to or from the current git tree to or from
# another git tree
#
# usage:   git-branchmove get|put REMOTE BRANCH

set -e
set -o posix

fail () { echo >&2 "git-branchmove: $*"; exit 16; }
badusage () { fail "bad usage: $*"; }

case "$#.$1" in
3.get)
	op=get
	remote="$2"
	branch="$3"
	;;
3.put)
	op=put
	branch="$3"
	;;
*)
	badusage "wrong number of arguments or wrong operation"
	;;
esac

# Plan of attack:
#  determine execute-sh runes for src and dst trees
#  check that source branch is not checked out
#  list affected branches on source
#  list affected branches on destination and moan if any nonequal overlap
#  transfer src->dst refs/heads/BRANCH:refs/heads/BRANCH
#  transfer and merge reflog(s) xxx todo
#  delete src refs

case "$remote" in
*:*)	remoteurl="$remote" ;;
*)	remoteurl="$(
		git config remote."$remote".pushurl ||
		git config remote."$remote".url ||
		fail "no pushurl or url defined for remote $remote"
		)"
esac

remote_spec="$(perl -e '
    $_ = $ARGV[0];
    if (m#^ssh://([^:/]+)(?:\:(\w+))?#) {
	print "$'\''|ssh ";
	print " -p $3" if $2;
        print "$1\n";
    } elsif (m#^([-+_.0-9a-zA-Z\@]+):(?!//)#) {
        print "$'\''|ssh $1\n";
    } else {
        die "git-branchmove: unsupported remote url \`$_'\''\n";
    }
' "$remoteurl")"

remote_path="${remote_spec%%|*}"
remote_rune="${remote_spec#*|}"

case $op in
get)
	src_rune="$remote_rune"
	src_path="$remote_path"
	dst_rune="sh -c"
	dst_path=.
	;;
put)
	dst_rune="$remote_rune"
	dst_path="$remote_path"
	src_rune="sh -c"
	src_path=.
	;;
esac