#!/bin/bash
# wslu - Windows 10 linux Subsystem Utility
# Component of Windows 10 linux Subsystem Utility
# <https://github.com/wslutilities/wslu>
# Copyright (C) 2019 Patrick Wu
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# Version
wslu_version=2.3.6

# Speed up script by not using unicode.
LC_ALL=C
LANG=C

# force bash to not showing code manually.
set +x

# checking interopability
grep enabled /proc/sys/fs/binfmt_misc/WSLInterop >/dev/null || (echo "WSL Interopability is disabled. Please enable it before using WSL."; exit 1)

# variables
## color
black=$(echo -e '\e[30m')
red=$(echo -e '\e[31m')
green=$(echo -e '\e[32m')
brown=$(echo -e '\e[33m')
blue=$(echo -e '\e[34m')
purple=$(echo -e '\e[35m')
cyan=$(echo -e '\e[36m')
yellow=$(echo -e '\e[1;33m')
white=$(echo -e '\e[1;37m')
dark_gray=$(echo -e '\e[1;30m')
light_red=$(echo -e '\e[1;31m')
light_green=$(echo -e '\e[1;32m')
light_blue=$(echo -e '\e[1;34m')
light_purple=$(echo -e '\e[1;35m')
light_cyan=$(echo -e '\e[1;36m')
light_gray=$(echo -e '\e[37m')
orange=$(echo -e '\e[38;5;202m')
light_orange=$(echo -e '\e[38;5;214m')
bold=$(echo -e '\033[1m')
reset=$(echo -e '\033(B\033[m')

## indicator
info="${green}[info]${reset}"
input_info="${cyan}[input]${reset}"
error="${red}[error]${reset}"
warn="${orange}[warn]${reset}"
debug="${orange}${bold}[debug]${reset}"

## Windows build number constant
readonly BN_SPR_CREATORS=15063		#1703, Redstone 2, Creators Update
readonly BN_FAL_CREATORS=16299		#1709, Redstone 3, Fall Creators Update
readonly BN_APR_EIGHTEEN=17134		#1803, Redstone 4, April 2018 Update
readonly BN_OCT_EIGHTEEN=17763		#1809, Redstone 5, October 2018 Update
readonly BN_MAY_NINETEEN=18362		#1903, 19H1, May 2019 Update

# functions

function help {
	app_name=$(basename "$1")
	echo -e "$app_name - Part of wslu, a collection of utilities for Windows 10 Windows Subsystem for Linux
Usage: $2

For more help for $app_name, visit the following site: https://github.com/wslutilities/wslu/wiki/$app_name"
}

function double_dash_p {
	echo "${@//\\/\\\\}"
}

function interop_prefix {
	if [ -f /etc/wsl.conf ]; then
		tmp=$(awk -F '=' '/root/ {print $2}' /etc/wsl.conf | awk '{$1=$1;print}')
		if [ "$tmp" == "" ]; then
			echo "/mnt/"
		else
			echo "$tmp"
		fi
	else
		echo "/mnt/"
	fi
}

function chcp_com {
	"$(interop_prefix)"c/Windows/System32/chcp.com "$@" >/dev/null
}

function winps_exec {
	chcp_com $(cat ~/.config/wslu/oemcp)
	"$(interop_prefix)"c/Windows/System32/WindowsPowerShell/v1.0/powershell.exe -NoProfile -NonInteractive -Command "$@"
	chcp_com 65001
}

function baseexec_gen {
	wslutmpbuild=$(reg.exe query "HKLM\\Software\\Microsoft\\Windows NT\\CurrentVersion" /v CurrentBuild | tail -n 2 | head -n 1 | sed -e 's|\r||g')
	wslutmpbuild=${wslutmpbuild##* }
	wslutmpbuild="$(( $wslutmpbuild + 0 ))"
	if [ $wslutmpbuild -ge $BN_MAY_NINETEEN ]; then
		# The environment variable only available in 19H1 or later.
		wslu_distro_regpath=$("$(interop_prefix)"c/Windows/System32/reg.exe query "HKCU\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Lxss" /s /f DistributionName 2>&1 | grep -B1 -e "$WSL_DISTRO_NAME" | head -n1 | sed -e 's|\r||g')
		if $(interop_prefix)c/Windows/System32/reg.exe query "$wslu_distro_regpath" /v PackageFamilyName &>/dev/null; then
			# if it is a store distro
			wslu_distro_packagename=$($(interop_prefix)c/Windows/System32/reg.exe query "$wslu_distro_regpath" /v PackageFamilyName | tail -n 2 | head -n 1 | sed -e 's|\r||g')
			wslu_distro_packagename=${wslu_distro_packagename##* }
			wslu_base_exec_folder_path="$(wslpath "$(double_dash_p $(winps_exec "Write-Output \$Env:LOCALAPPDATA" | tr -d "\r"))\\Microsoft\\WindowsApps\\$wslu_distro_packagename")"
			wslpath -w "$(find "$wslu_base_exec_folder_path" -name "*.exe")" > ~/.config/wslu/baseexec
		else
			# fallback if it is imported repository or other type
			echo "C:\\Windows\\System32\\wsl.exe" > ~/.config/wslu/baseexec
		fi
	else
		# older version fallback.
		echo "C:\\Windows\\System32\\wsl.exe" > ~/.config/wslu/baseexec
	fi
}

# first run, saving some information
if [ ! -d ~/.config/wslu ]; then
	mkdir -p ~/.config/wslu
fi

# generate oem codepage
if [ ! -f ~/.config/wslu/oemcp ]; then
	"$(interop_prefix)"c/Windows/System32/reg.exe query "HKLM\\SYSTEM\\CurrentControlSet\\Control\\Nls\\CodePage" /v OEMCP 2>&1 | sed -n 3p | sed -e 's|\r||g' | grep -o '[[:digit:]]*' > ~/.config/wslu/oemcp
fi

# generate base exe locaiton
if [ ! -f ~/.config/wslu/baseexec ]; then
	# if it is not generated
	baseexec_gen
elif grep -q "/" ~/.config/wslu/baseexec; then
	# if baseexec is using the old linux style, regenerate
	baseexec_gen
elif ! which "$(cat ~/.config/wslu/baseexec)" &>/dev/null; then
	# if baseexec cannnot be executed, regenerate
	rm ~/.config/wslu/baseexec
	baseexec_gen
fi

# when --debug, debug.
if [ "$1" == "--debug" ]; then
	echo "${debug}Debug Mode Enabled."
	shift
	set -x
fi

# basic distro detection
distro="$(head -n1 /etc/os-release | sed -e 's/NAME=\"//g')"
case $distro in
	*Pengwin*) distro="pengwin";;
	*WLinux*) distro="wlinux";;
	Ubuntu*) distro="ubuntu";;
	*Debian*) distro="debian";;
	*Kali*) distro="kali";;
	openSUSE*) distro="opensuse";;
	SLES*) distro="sles";;
	Alpine*) distro="alpine";;
	Arch*) distro="archlinux";;
	*Oracle*) distro="oracle";;
	Scientific*) distro="scilinux";;
	*Fedora*) distro="fedora";;
	*Generic*) [ "fedora" == "$(grep -e "LIKE=" /etc/os-release | sed -e 's/ID_LIKE=//g')" ] && distro="oldfedora" || distro="unknown";;
	*) distro="unknown";;
esac
