#!/bin/sh

[ "$VCSH_DEBUG" -gt 0 ] && set -x

SELF=$(basename $0)

[ -z "$XDG_CONFIG_HOME" ] && XDG_CONFIG_HOME="$HOME/.config"
for check_directory in $XDG_CONFIG_HOME $XDG_CONFIG_HOME/vcsh $XDG_CONFIG_HOME/vcsh/repo.d
do
	if [ ! -d "$check_directory" ]; then
		if [ -e "$check_directory" ]; then
			echo "$SELF: error: $check_directory exists but is not a directory" >&2
			exit 2
		else
			mkdir $check_directory || (echo "$SELF: error: could not create $check_directory" >&2; exit 2)
		fi
	fi
done

VCSH_BASE="$XDG_CONFIG_HOME/vcsh/repo.d"

debug() {
	[ -n "$VCSH_DEBUG" ] && echo "$SELF: debug: $1"
}

verbose() {
	if [ -n "$VCSH_DEBUG" ] || [ -n "$VCSH_VERBOSE" ]; then echo "$SELF: verbose: $1"; fi
}

help() {
	echo "usage: $SELF <args>

   help           Display this help

   list           List all repos

   use <repo>     Use this repository
   run <repo>
       <command>  Use this repository

   init           Initialize a new repository
   clone <remote>
         [<repo>] Clone from an existing repository

   exit           Exit vcsh mode" >&2
}

use() {
	verbose "use() start"
	REPO_NAME="$1"
	GIT_DIR="$VCSH_BASE/$REPO_NAME.git"

	if [ ! -d "$GIT_DIR" ]; then
		echo E: no repository found for "$REPO_NAME" >&2
		return 2
	fi

	export GIT_DIR
	export GIT_WORK_TREE="$(git config --get core.worktree)"
	export VCSH_DIRECTORY="$REPO_NAME"
	verbose "use() stop"
}

init() {
	verbose "init() start"
	[ -e "$GIT_DIR" ] &&
		echo "$SELF: fatal: $GIT_DIR exists" &&
		return 21
	export GIT_WORK_TREE="$HOME"
	mkdir -p $GIT_WORK_TREE
	cd $GIT_WORK_TREE ||
		(echo "$SELF: fatal: could not enter $GIT_WORK_TREE" &&
		 exit 20) || exit 20
	cd $GIT_WORK_TREE
	git init
	git config core.worktree $GIT_WORK_TREE
	verbose "init() stop"
}

leave() {
	unset GIT_DIR
	unset GIT_WORK_TREE
	unset VCSH_DIRECTORY
}

if [ "$1" = 'help' ] || [ "$#" -eq 0 ]; then
	help
	[ "$1" = 'help' ]
	exit $?

elif [ "$1" = 'list' ]; then
	verbose "list start"
	for i in $VCSH_BASE/*.git; do
		echo $(basename $i .git)
	done
	verbose "list stop"
	exit 0

elif [ "$1" = 'run' ]; then
	verbose "run start"
	use $2
	shift 2
	"$@"
	leave
	verbose "run start"
	exit 0

elif [ "$1" = 'use' ]; then
	verbose "use start"
	if [ -n "$ZSH_VERSION" ]; then
		if [ -o NO_IGNORE_EOF ]; then
			export VCSH_NO_IGNORE_EOF=1
			setopt IGNORE_EOF
		fi
		vcsh_exit() {
			vcsh exit;
			zle reset-prompt;
		}
		zle -N vcsh_exit
		bindkey '^d' 'vcsh_exit'
	fi
	use $2
	[ -n "$ZSH_VERSION" ] && [ "$USER" = richih ] && buildPS1
	verbose "use stop"
	exit 0

elif [ "$1" = 'clone' ]; then
	verbose "clone start"
	GIT_REMOTE="$2"
	REPO_NAME="$3"
	[ -z "$REPO_NAME" ] && REPO_NAME=$(basename $GIT_REMOTE .git)
	export REPO_NAME
	export GIT_DIR="$VCSH_BASE/$REPO_NAME.git"
	init

	git remote add origin $GIT_REMOTE
	git config branch.master.remote origin
	git config branch.master.merge  refs/heads/master
	git fetch
	for object in $(git ls-tree -r origin/master | awk '{print $4}'); do
		[ -e "$object" ] &&
			echo "$SELF: error: $object exists." &&
			VCSH_CONFLICT=1;
	done
	[ -n "$VCSH_CONFLICT" ] &&
		echo "$SELF: fatal: will stop after fetching and not try to merge!\n" &&
		exit 3
	git merge origin/master
	vcsh use $REPO_NAME
	verbose "clone end"

elif [ "$1" = 'init' ]; then
	verbose "init start"
	export REPO_NAME="$2"
	export GIT_DIR="$VCSH_BASE/$REPO_NAME.git"
	init
	vcsh use $REPO_NAME
	verbose "init stop"

elif [ "$1" = 'exit' ]; then
	verbose "exit start"
	if [ -n "$ZSH_VERSION" ] && [ -n "$VCSH_NO_IGNORE_EOF" ]; then
		unset VCSH_NO_IGNORE_EOF
		setopt NO_IGNORE_EOF
	fi
	leave
	[ -n "$ZSH_VERSION" ] && [ "$USER" = richih ] && buildPS1
	verbose "exit stop"
	exit 0

else
	verbose "defaulting to calling help()"
	help
	exit 3

fi