# This hook downloads the distfiles specified in a template by
# the $distfiles variable and then verifies its sha256 checksum comparing
# its value with the one stored in the $checksum variable.

# Get the checksum for $curfile at index $dfcount
get_cksum() {
	local curfile="$1" dfcount="$2" ckcount cksum i

	ckcount=0
	cksum=0
	for i in ${checksum}; do
		if [ $dfcount -eq $ckcount -a -n "$i" ]; then
			cksum=$i
		fi
		ckcount=$((ckcount + 1))
	done
	if [ -z "$cksum" ]; then
		msg_error "$pkgver: cannot find checksum for $curfile.\n"
	fi
	echo "$cksum"
}

# Return the checksum of the contents of a tarball
contents_cksum() {
	local curfile="$1" cursufx cksum

	case $curfile in
	*.tar.lzma)   cursufx="txz";;
	*.tar.lz)     cursufx="tlz";;
	*.tlz)        cursufx="tlz";;
	*.tar.xz)     cursufx="txz";;
	*.txz)        cursufx="txz";;
	*.tar.bz2)    cursufx="tbz";;
	*.tbz)        cursufx="tbz";;
	*.tar.gz)     cursufx="tgz";;
	*.tgz)        cursufx="tgz";;
	*.gz)         cursufx="gz";;
	*.bz2)        cursufx="bz2";;
	*.tar)        cursufx="tar";;
	*.zip)        cursufx="zip";;
	*.rpm)        cursufx="rpm";;
	*.patch)      cursufx="txt";;
	*.diff)       cursufx="txt";;
	*.txt)        cursufx="txt";;
	*.7z)	      cursufx="7z";;
	*.gem)	      cursufx="gem";;
	*.crate)      cursufx="crate";;
	*) msg_error "$pkgver: unknown distfile suffix for $curfile.\n";;
	esac

	case ${cursufx} in
	tar|txz|tbz|tlz|tgz|crate)
		cksum=$(tar xf "$curfile" --to-stdout | sha256sum | awk '{print $1}')
		if [ $? -ne 0 ]; then
			msg_error "$pkgver: extracting $curfile to pipe.\n"
		fi
		;;
	gz)
		cksum=$(gunzip -c "$curfile" | sha256sum | awk '{print $1}')
		;;
	bz2)
		cksum=$(bunzip2 -c "$curfile" | sha256sum | awk '{print $1}')
		;;
	zip)
		if command -v unzip &>/dev/null; then
			cksum=$(unzip -p "$curfile" | sha256sum | awk '{print $1}')
			if [ $? -ne 0 ]; then
				msg_error "$pkgver: extracting $curfile to pipe.\n"
			fi
		else
			msg_error "$pkgver: cannot find unzip bin for extraction.\n"
		fi
		;;
	rpm)
		if command -v rpmextract &>/dev/null; then
			cksum=$(rpm2cpio "$curfile" | bsdtar xf - --to-stdout | sha256sum | awk '{print $1}')
			if [ $? -ne 0 ]; then
				msg_error "$pkgver: extracting $curfile to pipe.\n"
			fi
		else
			msg_error "$pkgver: cannot find rpmextract for extraction.\n"
		fi
		;;
	txt)
		cksum=$(cat "$curfile" | sha256sum | awk '{print $1}')
		;;
	7z)
		if command -v 7z &>/dev/null; then
			cksum=$(7z x -o "$curfile" | sha256sum | awk '{print $1}')
			if [ $? -ne 0 ]; then
				msg_error "$pkgver: extracting $curfile to pipe.\n"
			fi
		else
			msg_error "$pkgver: cannot find 7z bin for extraction.\n"
		fi
		;;
	gem)
		cksum=$(tar -xf "$curfile" data.tar.gz --to-stdout | tar -xzO | sha256sum | awk '{print $1}')
		;;
	*)
		msg_error "$pkgver: cannot guess $curfile extract suffix. ($cursufx)\n"
		;;
	esac

	if [ -z "$cksum" ]; then
		msg_error "$pkgver: cannot find contents checksum for $curfile.\n"
	fi
	echo "$cksum"
}

# Verify the checksum for $curfile stored at $distfile and index $dfcount
verify_cksum() {
	local curfile="$1" distfile="$2" dfcount="$3" filesum cksum

	cksum=$(get_cksum $curfile $dfcount)

	# If the checksum starts with an commercial at (@) it is the contents checksum
	if [ "${cksum:0:1}" = "@" ]; then
		cksum=${cksum:1}
		msg_normal "$pkgver: verifying contents checksum for distfile '$curfile'... "
		filesum=$(contents_cksum "$curfile")
		if [ "${cksum}" != "$filesum" ]; then
			echo
			msg_red "SHA256 mismatch for '$curfile:'\n@$filesum\n"
			errors=$((errors + 1))
		else
			msg_normal_append "OK.\n"
		fi
	else
		msg_normal "$pkgver: verifying checksum for distfile '$curfile'... "
		filesum=$(${XBPS_DIGEST_CMD} "$distfile")
		if [ "$cksum" != "$filesum" ]; then
			echo
			msg_red "SHA256 mismatch for '$curfile:'\n$filesum\n"
			errors=$((errors + 1))
		else
			if [ ! -f "$XBPS_SRCDISTDIR/by_sha256/${cksum}_${curfile}" ]; then
				mkdir -p "$XBPS_SRCDISTDIR/by_sha256"
				ln -f "$distfile" "$XBPS_SRCDISTDIR/by_sha256/${cksum}_${curfile}"
			fi
			msg_normal_append "OK.\n"
		fi
	fi
}

# Link an existing cksum $distfile for $curfile at index $dfcount
link_cksum() {
	local curfile="$1" distfile="$2" dfcount="$3" filesum cksum

	cksum=$(get_cksum $curfile $dfcount)

	if [ -n "$cksum" -a -f "$XBPS_SRCDISTDIR/by_sha256/${cksum}_${curfile}" ]; then
		ln -f "$XBPS_SRCDISTDIR/by_sha256/${cksum}_${curfile}" "$distfile"
		msg_normal "$pkgver: using known distfile $curfile.\n"
	fi
}

try_mirrors() {
	local curfile="$1" distfile="$2" dfcount="$3" subdir="$4" f="$5"
	local filesum cksum basefile mirror path scheme
	[ -z "$XBPS_DISTFILES_MIRROR" ] && return
	basefile="${f##*/}"
	cksum=$(get_cksum $curfile $dfcount)
	for mirror in $XBPS_DISTFILES_MIRROR; do
		scheme="file"
		if [[ $mirror == *://* ]]; then
			scheme="${mirror%%:/*}"
			path="${mirror#${scheme}://}"
		else
			path="$mirror"
		fi
		if [ "$scheme" == "file" ]; then
			# Skip file:// mirror locations (/some/where or file:///some/where)
			# where the specified directory does not exist
			if [ ! -d "$path" ]; then
				msg_warn "$pkgver: mount point $path does not exist...\n"
				continue
			fi
		fi
		if [[ "$mirror" == *voidlinux* ]]; then
			# For distfiles.voidlinux.* append the subdirectory
			mirror="$mirror/$subdir"
		fi
		msg_normal "$pkgver: fetching distfile '$curfile' from '$mirror'...\n"
		$fetch_cmd "$mirror/$curfile"
		# If basefile was not found, but a curfile file may exist, try to fetch it
		if [ ! -f "$distfile" -a "$basefile" != "$curfile" ]; then
			$fetch_cmd "$mirror/$basefile"
		fi
		[ ! -f "$distfile" ] && continue
		flock -n ${distfile}.part rm -f ${distfile}.part
		filesum=$(${XBPS_DIGEST_CMD} "$distfile")
		[ "$cksum" == "$filesum" ] && break
		msg_normal "$pkgver: checksum failed - removing '$curfile'...\n"
		rm -f ${distfile}
	done
}

hook() {
	local srcdir="$XBPS_SRCDISTDIR/$pkgname-$version"
	local dfcount=0 dfgood=0 errors=0

	if [ ! -d "$srcdir" ]; then
		mkdir -p -m775 "$srcdir"
		chgrp $(id -g) "$srcdir"
	fi

	cd $srcdir || msg_error "$pkgver: cannot change dir to $srcdir!\n"

	# Disable trap on ERR; the code is smart enough to report errors and abort.
	trap - ERR

	# Detect distfiles with obsolete checksum and purge them from the cache
	for f in ${distfiles}; do
		curfile=$(basename "${f#*>}")
		distfile="$srcdir/$curfile"
		if [ -f "$distfile" ]; then
			cksum=$(get_cksum $curfile $dfcount)
			if [ "${cksum:0:1}" = "@" ]; then
				cksum=${cksum:1}
				filesum=$(contents_cksum "$distfile")
			else
				filesum=$(${XBPS_DIGEST_CMD} "$distfile")
			fi
			if [ "$cksum" = "$filesum" ]; then
				dfgood=$((dfgood + 1))
			else
				inode=$(stat "$distfile" --printf "%i")
				msg_warn "$pkgver: wrong checksum found for ${curfile} - purging\n"
				find ${XBPS_SRCDISTDIR} -inum ${inode} -delete -print
			fi
		fi
		dfcount=$((dfcount + 1))
	done

	# We're done, if all distfiles were found and had good checksums
	[ $dfcount -eq $dfgood ] && return

	# Download missing distfiles and verify their checksums
	dfcount=0
	for f in ${distfiles}; do
		curfile=$(basename "${f#*>}")
		distfile="$srcdir/$curfile"

		# If file lock cannot be acquired wait until it's available.
		while true; do
			flock -w 1 ${distfile}.part true
			[ $? -eq 0 ] && break
			msg_warn "$pkgver: ${curfile} is being already downloaded, waiting for 1s ...\n"
		done
		# If distfile does not exist, try to link to it.
		if [ ! -f "$distfile" ]; then
			link_cksum $curfile $distfile $dfcount
		fi
		# If distfile does not exist, download it from a mirror location.
		if [ ! -f "$distfile" ]; then
			try_mirrors $curfile $distfile $dfcount $pkgname-$version $f
		fi
		# If distfile does not exist, download it from the original location.
		if [ ! -f "$distfile" ]; then
			msg_normal "$pkgver: fetching distfile '$curfile'...\n"
			flock "${distfile}.part" $fetch_cmd "$f"
		fi
		if [ ! -f "$distfile" ]; then
			msg_error "$pkgver: failed to fetch $curfile.\n"
		fi
		# distfile downloaded, verify sha256 hash.
		flock -n ${distfile}.part rm -f ${distfile}.part
		verify_cksum $curfile $distfile $dfcount
		dfcount=$((dfcount + 1))
	done

	if [ $errors -gt 0 ]; then
		msg_error "$pkgver: couldn't verify distfiles, exiting...\n"
	fi
}