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

set -eu

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

# read default arcs.hosts from global .gitconfig in home dir
peer_hosts=`git config --global --get-all arcs.hosts 2>/dev/null || true`
if [ -z "$peer_hosts" ]; then
	peer_hosts="ucm.dev pi.ucm.dev"

	cat <<-EOF
warning: no arcs.hosts in ~/.gitconfig
defaulting to $peer_hosts
you can add peer hosts with, for example:
  git config --global --add arcs.hosts ucm.dev
  git config --global --add arcs.hosts pi.ucm.dev

EOF

fi

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 "  -p url      push to"
	echo "  [-s]        sync"
	echo "  -q          quiet"
	echo "  -v          verbose"
	echo "  -n          no action"
	echo "  -N          no net"
	echo "  -f          fork"
	echo "  -r old new  rename repo locally and remotely"
}

init() {
	cd "$1"
	m "$PWD"
	git init $qv --shared -b main
	git config --unset-all receive.denyNonFastforwards
	git config receive.denyCurrentBranch updateInstead
#	cp -a "$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 "$peer"
		done
	fi
	git config --replace-all arcs.init 1
	if git config arcs.main; then
		:
	elif [ -n "`git branch --list main`" ]; then
		git config arcs.main main
	elif [ -n "`git branch --list master`" ]; then
		git config arcs.main master
	else
		git config arcs.main main
	fi
	if [ -z "$quiet" ]; then
		if ! git config --get-all arcs.peers; then
			setup_peers
		fi
	fi
}

setup_peers() {
	origin=`git remote show origin 2>/dev/null | sed -n '/: /{s/.*: //; p; q;}'`
	m "You can add a peer with, for example:"
	WD=`pwd -P`
	if [ -n "$origin" ]; then
		m "  git config --add arcs.peers $origin"
	fi
	for host in $peer_hosts; do
		m "  git config --add arcs.peers $USER@$host:${WD#$HOME/}"
	done
	m "Do this now? [y/N]"
	if read -r -n 1 -t 10; then
		if [ "$REPLY" = y -o "$REPLY" = Y ]; then
			if [ -n "$origin" ]; then
				git config --add arcs.peers $origin
			fi
			for host in $peer_hosts; do
				git config --add arcs.peers $USER@$host:${WD#$HOME/}
			done
		fi
	fi
}

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

sync() {
	local dir=$1
	if [ ! -d "$dir" ]; then
		dir=$(dirname "$dir")
	fi
	cd "$dir"
	go_to_git_root
	peers=
	if [ -n "$net" ]; then
		peers=`git config --get-all arcs.peers || true`
	fi
	main1=`git config arcs.main || true`
	main=${main1:-`git rev-parse --abbrev-ref HEAD`}
	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 --unset-all receive.denyNonFastforwards; git config receive.denyCurrentBranch updateInstead; git add -A; git commit $qv -m . || true" &
	done
	wait
	for peer in $peers; do
		v git pull $qv --no-edit "$peer" $main || true
	done
	for peer in $peers; do
		v git push $qv "$peer" $main &
	done
	wait
	if [ -z "$quiet" ]; then v git log --format=format:%H%n -n1 | cat; fi
	`git config --get arcs.make || true`
	if [ -z "$main1" ]; then
		git config arcs.main $main
	fi
}

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 .
}

push() {
	to=$push_url
	dir=$1
	cd "$dir"
	init .
	v git config --add arcs.peers "$to"
	sync .
}

rename_repo() { (
	old_name=${1#/}
	new_name=${2#/}

	# This is for renaming only, not for moving to a different directory
	# check if / in either path, and reject if so
	if [[ $old_name == */* || $new_name == */* ]]; then
		echo "Paths must be in the current directory"
		exit 1
	fi

	# Rename locally
	mv -i -v "$old_name" "$new_name"

	cd "$new_name"

	# Get all arcs.peers
	peers=$(git config --get-all arcs.peers)

	# Rename remote repos and update arcs.peers
	for peer in $peers; do
		host=${peer%%:*}
		old_remote_path=${peer#*:}
		remote_dir=$(dirname "$old_remote_path")

		if [[ $peer == *"/$old_name" ]] || [[ $peer == *":$old_name" ]]; then
			v sshc "$host:$remote_dir" mv -i -v "$old_name" "$new_name"
			new_peer=${peer%$old_name}$new_name
			git config --add arcs.peers "$new_peer"
			git config --unset-all arcs.peers "$peer"
		else
			echo >&2 "Peer $peer does not match old path $old_name, skipping"
		fi
	done

	m "Repository renamed from $old_name to $new_name locally and on any remote hosts."
	m "Note: did not update arcs.peers config on remote hosts."
) }

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 ;;
		-p) push_url=${1-} ; shift ; loop push "$@" ; exit ;;
		-s) break ;;
		-n) loop check "$@" ; exit ;;
		-N) net= ;;
		-q) quiet=1 ;;
		-v) qv= ;;
		-f) fork=1 ;;
		-y) yes=1 ;;
		-no) no=1 ;;
		-r) rename_repo "$@"; exit ;;
		--) 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