#!/bin/bash

# related documentation:
# https://wiki.lineageos.org/extracting_blobs_from_zips

set -e
#set -x

BOLD=$(tput bold)
RST=$(tput sgr0)
RED=$(tput setaf 1)
GREEN=$(tput setaf 2)
YELLOW=$(tput setaf 3)
CYAN=$(tput setaf 6)

PROGNAME="$0"

echoinfo() {
	>&2 echo "${CYAN}$@${RST}"
}

echoerr() {
	>&2 echo "${RED}${BOLD}error:${RST}${RED} $@${RST}"
}

echowarn() {
	>&2 echo "${YELLOW}${BOLD}warning:${RST}${YELLOW} $@${RST}"
}

die() {
    echoerr "$@"
    exit 1
}

usage() {
	cat <<-_EOF 
	usage: $PROGNAME OPTIONS

	Options:
	    -i|--input FILE  Path to installable zip
	    -o|--output DIR  Directory to extract to
	    --skip-unzipping
	    --los-device-directory DIR

	_EOF
	exit 1
}

installed() {
	command -v "$1" > /dev/null
	return $?
}

block_ota() {
	[ -d system ] && die "system: directory already exists!"
	[ -f super.transfer.list ] && die "super.transfer.list: not supported"

	local f= file=
	for f in system vendor; do
		if [ ! -f "${f}.new.dat.br" ]; then continue; fi
		echoinfo "extracting $f..."
		brotli --decompress --output="${f}.new.dat" "${f}.new.dat.br"
		sdat2img.py "${f}.transfer.list" "${f}.new.dat" "${f}.img"
	done

	mkdir system
	[ -f vendor.img ] && mkdir system/vendor

	echoinfo "mounting system..."
	sudo mount system.img system/

	if [ -f vendor.img ]; then
		echoinfo "mounting vendor..."
		sudo mount vendor.img system/vendor/
	fi

	local workdir="$(pwd)"
	pushd "$LOS_DEVICE_DIR"
	echoinfo "launching extract-files.sh..."
	./extract-files.sh "$workdir"
	popd

	if [ -f vendor.img ]; then
		echoinfo "unmounting vendor..."
		sudo umount system/vendor/
	fi

	echoinfo "unmounting system..."
	sudo umount system/
}

payload_ota() {
	die "payload_ota: not implemented"
}

filebased_ota() {
	die "filebased_ota: not implemented"
}

[[ $# -lt 1 ]] && usage
for prog in brotli sdat2img.py; do
	if ! installed $prog; then
		die "$prog: command not found"
	fi
done

INPUT=
OUTPUT=
SKIP_UNZIP=
LOS_DEVICE_DIR=

while [[ $# -gt 0 ]]; do
	case $1 in
		-i|--input)
			INPUT="$2"
			shift
			;;

		-o|--output)
			OUTPUT="$2"
			shift
			;;

		--los-device-directory)
			LOS_DEVICE_DIR="$2"
			shift
			;;
			
		--skip-unzipping)
			SKIP_UNZIP=1
			;;

		*)
			die "unrecognized option $1"
			exit 1
			;;
	esac
	shift
done

[ -z "$INPUT" ] && die "no input file specified"
[ -z "$OUTPUT" ] && die "no output directory specified"
[ -z "$LOS_DEVICE_DIR" ] && die "no lineageos device directory specified"
[ -d "$LOS_DEVICE_DIR" ] || die "$LOS_DEVICE_DIR: no such directory"
[ -f "$INPUT" ] || die "$INPUT: no such file"
[ -z "$SKIP_UNZIP" ] && [ -d "$OUTPUT" ] && die "$OUTPUT: directory already exists"

if [ -z "$SKIP_UNZIP" ]; then
	unzip -d "$OUTPUT" "$INPUT"
elif [ ! -d "$OUTPUT" ]; then
	die "$OUTPUT: no such directory"
fi

pushd "$OUTPUT"
if [ -f payload.bin ]; then
	payload_ota
elif [ -f system.transfer.list ]; then
	block_ota
else
	filebased_ota
fi
popd