#!/bin/bash
# arcs - Automatic Revision Control System - version 2

set -eu

arcs_d=$(dirname "$(readlink -f "$0")")

net=1 qv=-q quiet= net=1 fork=

m() { if [ -z "$quiet" ]; then echo >&2 "$@"; fi }
die() { if [ $# -gt 0 ]; then echo >&2 "$@"; fi; exit 1; }
v() { m "$@"; "$@"; }
qe() { "$@" 2>/dev/null; }

prog=`basename $0`

usage() {
	echo "usage: $prog [opts] [dir ...]"
	echo "  -i      init"
	echo "  -c url  clone"
	echo "  [-s]    sync"
	echo "  -q      quiet"
	echo "  -v      verbose"
	echo "  -n      no action"
	echo "  -N      no net"
	echo "  -f      fork"
}

init() {
	cd "$1"
	m "$PWD"
	git init $qv --shared
	git config receive.denyCurrentBranch refuse
	cp -a "$arcs_d/git-info-exclude" .git/info/exclude
	if [ -e .arcs/peers ]; then
		git config --unset-all arcs.peers || true
		cat .arcs/peers |
		while read peer; do
			git config --add arcs.peers "$peer"
		done
	fi
	git config --replace-all arcs.init 1
	if [ -z "$quiet" ]; then
		if ! git config --get-all arcs.peers; then
			m "You can add some peers with:"
			m "  git config --add arcs.peers user@host.net:path/to/mod"
		fi
	fi
}

check() {
	cd "$1"
	go_to_git_root
	v git add -A -n
}

sync() {
	cd "$1"
	go_to_git_root
	peers=
	if [ -n "$net" ]; then
		peers=`git config --get-all arcs.peers || true`
	fi
	v git add -A
	v git commit $qv -m . || true
	for peer in $peers; do
		v sshc "$peer" sh -c "git init $qv --shared; git config receive.denyCurrentBranch refuse; git add -A; git commit $qv -m . || true"
		v git pull $qv --no-edit "$peer" master
	done
	for peer in $peers; do
		v git push $qv "$peer" master:in
		v sshc "$peer" sh -c "git merge $qv in; if [ x$quiet != x1 ]; then git log --format=format:%H%n -n1; fi; \`git config --get arcs.make || true\`"
	done
	if [ -z "$quiet" ]; then v git log --format=format:%H%n -n1 | cat; fi
	`git config --get arcs.make || true`
}

go_to_git_root() {
	m "$PWD"
	root=$(qe git rev-parse --show-toplevel || die "can't find .git")
	cd "$root"
	if ! git config --get-all arcs.init >/dev/null; then
		if git config --get-all arcs.peers >/dev/null; then
			git config --replace-all arcs.init 1
		else
			die "first run: $prog -i"
		fi
	fi
	m "$PWD"
}

clone() {
	from=$clone_url
	dir=$1
	if [ -z "$dir" -o "$dir" = . ]; then
		dir=${from##*/} dir=${dir##*:}
	fi
	v git clone $qv "$from" "$dir"
	cd "$dir"
	v git config --add arcs.peers "$from"
	init .
}

loop() {
	op=$1 ; shift
	if [ $# = 0 ]; then
		("$op" .)
		m
		return
	fi
	for arg; do
		if [ -n "$fork" ]; then
			("$op" "$arg") &
		else
			("$op" "$arg")
			m
		fi
	done
	wait
	return
}

main() {
	while [ $# -gt 0 ]; do
		opt=$1
		case "$opt" in
		-*) shift ;;
		*) break ;;
		esac
		case "$opt" in
		-h|-help|--help) usage ; exit ;;
		-i)	loop init "$@" ; exit ;;
		-c)	clone_url=$1 ; shift ; loop clone "$@" ; exit ;;
		-s)	break ;;
		-n)	loop check "$@" ; exit ;;
		-N)	net= ;;
		-q)	quiet=1 ;;
		-v)	qv= ;;
		-f)	fork=1 ;;
		--)	break ;;
		esac
	done

	loop sync "$@"
}

main "$@"

# TODO auto-exclude ELF and other executables at each sync
# TODO commit message, use $task instead of . and put $task in shell prompt and/or screen window name