#!/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 provides a single attribute: OCR recognized texf of given image file. It calls the tool tesseract.
# Languages can be specified by: --option "language" "eng" --option "language" "ces"


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

processMessage_WAITING_FOR_OUTPUT_ATTRIBUTES_METADATA() {
	tesseractLanguage="";
	for (( i=0; i<${#optionNames[@]}; i++)); do
		if [[ "x${optionNames[$i]}" == "xlanguage" ]]; then
			tesseractLanguage+="+${optionValues[$i]}";
		else
			echo "Unsupported option: ${optionNames[$i]}" >&2
		fi
	done

	send OUTPUT_ATTRIBUTE_METADATA "${outputAttributeAliases[0]-tesseract}"    "string"
	send WAITING_FOR_INPUT_ATTRIBUTES
}

processMessage_WAITING_FOR_OUTPUT_ATTRIBUTES() {
	value="$(cat "$currentFile" | tesseract stdin stdout "${tesseractLanguage:+-l}" "${tesseractLanguage}")";
	if   [[ "x$?" == "x0" ]]; then isNull="false"; else value=""; isNull="true"; fi
	value="$(echo "$value" | tr -d \\f)"
	send OUTPUT_ATTRIBUTE "$value"    "$isNull";
	send WAITING_FOR_INPUT_ATTRIBUTES;
}

initialize
processMessages