#!/usr/bin/env bash
#
# Portions based on cg-merge Copyright (c) Petr Baudis, 2005
# Copyright (c) 2005, Intel Corporation, James Ketrenos

. ${COGITO_LIB:-/usr/lib/cogito/}cg-Xlib

function die()
{
	ret=$1
	shift
	echo $@ >&2
	exit $ret
}

([ "$1" ] && [ "$2" ]) || 
	die 1 "usage: git-merge-heads parent-sha1 child-sha1"

git-read-tree HEAD ||
	die 8 "Failed to read tree"

parent=$1
child=$2
base=$(git-merge-base $1 $2) || 
	die 2 "Failed to obtain common base for trees"

git-read-tree -m $base $parent $child ||
	die 3 "Failed to merge trees"

if ! git-merge-cache -o ${COGITO_LIB:-/usr/lib/cogito/}cg-Xmergefile -a; then
	git-resolve-conflicts ||
		die 4 "Failed to resolve conflicts"
fi

tree=$(git-write-tree) || 
	die 5 "Failed to write merged tree."

echo "Merge succeeded as tree $tree."

while true; do
	read -p "Do you wish to commit this tree? [y]n :" reply <&1
	case $reply in
	n)	break
		;;
	y|*)
		echo "Type your COMMIT message followed by CTRL-D:"
		commit=$(git-commit-tree $tree -p $parent -p $child) ||
			die 6 "Commit failed."
		echo "Commit succeeded as commit $commit."
		echo "Moving HEAD to $commit"
		echo $commit > .git/HEAD
		break
		;;
	esac
done

git-read-tree -m HEAD

while true; do
	read -p "Do you wish to update the files on disk to reflect repository? [y]n :" reply <&1
	case $reply in
	n)	break
		;;
	y|*)
		git-read-tree -m HEAD ||
			die 9 "Failed to read tree."

		git-checkout-cache -q -u -f -a ||
			die 7 "Checkout failed."

		break
		;;
	esac
done