#!/bin/sh
#
# Copyright (c) 2005 Linus Torvalds
#
# Resolve two trees.
#
. git-sh-setup-script || die "Not a git archive"

usage () {
	die "git-resolve-script <head> <remote> <merge-message>"
}

dropheads() {
	rm -f -- "$GIT_DIR/MERGE_HEAD" \
		"$GIT_DIR/LAST_MERGE" || exit 1
}

head=$(git-rev-parse --verify "$1"^0) &&
merge=$(git-rev-parse --verify "$2"^0) &&
merge_msg="$3" || usage

#
# The remote name is just used for the message,
# but we do want it.
#
if [ -z "$head" -o -z "$merge" -o -z "$merge_msg" ]; then
	usage
fi

dropheads
echo $head > "$GIT_DIR"/ORIG_HEAD
echo $merge > "$GIT_DIR"/LAST_MERGE

common=$(git-merge-base $head $merge)
if [ -z "$common" ]; then
	die "Unable to find common commit between" $merge $head
fi

if [ "$common" == "$merge" ]; then
	echo "Already up-to-date. Yeeah!"
	dropheads
	exit 0
fi
if [ "$common" == "$head" ]; then
	echo "Updating from $head to $merge."
	git-read-tree -u -m $head $merge || exit 1
	echo $merge > "$GIT_DIR"/HEAD
	git-diff-tree -p $head $merge | git-apply --stat
	dropheads
	exit 0
fi
echo "Trying to merge $merge into $head"
git-read-tree -u -m $common $head $merge || exit 1
result_tree=$(git-write-tree  2> /dev/null)
if [ $? -ne 0 ]; then
	echo "Simple merge failed, trying Automatic merge"
	git-merge-cache -o git-merge-one-file-script -a
	if [ $? -ne 0 ]; then
		echo $merge > "$GIT_DIR"/MERGE_HEAD
		die "Automatic merge failed, fix up by hand"
	fi
	result_tree=$(git-write-tree) || exit 1
fi
result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree -p $head -p $merge)
echo "Committed merge $result_commit"
echo $result_commit > "$GIT_DIR"/HEAD
git-diff-tree -p $head $result_commit | git-apply --stat
dropheads