#!/bin/bash

# Relational pipes

# Copyright © 2020 František Kučera (Frantovo.cz, GlobalCode.info)

#

# 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, version 3 of the License.

#

# 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/>.

# This streamlet computes hashes of given files.

# Default algorithm is sha256.

#

# Any supported hash algorithm can be specified by e.g. --option "attribute" "sha512"

# The hash command is derived from the algorithm name by adding "sum" suffix and must be available at $PATH.

#

# Multiple algorithms can be specified (just repeat the --option).

# But single streamlet instance will run them sequentially.

# When parallell processing is needed (usually faster) then multiple scriptlet instances should be used:

#   --scriptlet hash --option "sha1" --as "sha1" --scriptlet hash --option "sha256" --as "sha256"

# instead of:

#   --scriptlet hash --option "sha1" --as "sha1" --option "sha256" --as "sha256"

. "$(dirname $0)/streamlet-common.sh"

processMessage_WAITING_FOR_OUTPUT_ATTRIBUTES_METADATA() {

	hashTypes=()

	hashCommands=()

	for (( i=0; i<${#optionNames[@]}; i++)); do

		if [[ "x${optionNames[$i]}" == "xattribute" ]]; then

			if type "${optionValues[$i]}sum" > /dev/null; then

				hashTypes+=("${optionValues[$i]}");

				hashCommands+=("${optionValues[$i]}sum");

			else

				echo "Unsupported attribute: ${optionValues[$i]}" >&2

			fi

		else

			echo "Unsupported option: ${optionNames[$i]}" >&2

		fi

	done

	if [[ -z "$hashTypes" ]]; then

		hashTypes=("sha256")

		hashCommands=("sha256sum")

	fi

	for (( i=0; i<${#hashTypes[@]}; i++)); do

		send OUTPUT_ATTRIBUTE_METADATA "${outputAttributeAliases[$i]-${hashTypes[$i]}}"    "string"

	done

	send WAITING_FOR_INPUT_ATTRIBUTES

}

processMessage_WAITING_FOR_OUTPUT_ATTRIBUTES() {

	for (( i=0; i<${#hashTypes[@]}; i++)); do

		value=$("${hashCommands[$i]}" "$currentFile" | cut -d" " -f1) 2>/dev/null;

		if [[ -z "$value" ]]; then isNull="true"; else isNull="false"; fi

		send OUTPUT_ATTRIBUTE "$value"    "$isNull";

	done

	send WAITING_FOR_INPUT_ATTRIBUTES;

}

initialize

processMessages