#!/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 EXIF metadata. It calls the tool exiv2.

# With no options it returns "Image size", "Copyright" and "Exif comment" attributes.

# Specific attributes can be selected using options – e.g. --option 'attribute' 'Image size'

# List of available attributes can be obtained by directly calling the exiv2 command on a image file.

# Two additional attributes are provided by this streamlet: "Image height" and "Image width" (they are extracted from "Image size").

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

processMessage_WAITING_FOR_OUTPUT_ATTRIBUTES_METADATA() {

	streamletFields=()

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

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

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

		elif [[ "x${optionNames[$i]}" == "xprefix" ]]; then

			pdfPrefix="${optionValues[$i]}";

		else

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

		fi

	done

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

		streamletFields=( "Image size" "Copyright" "Exif comment" );

	fi

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

		if [[ "x${streamletFields[$i]}" == "xImage height" ]] ||[[ "x${streamletFields[$i]}" == "xImage width" ]]; then local type="integer"; else local type="string"; fi

		send OUTPUT_ATTRIBUTE_METADATA "${outputAttributeAliases[$i]-$pdfPrefix${streamletFields[$i]}}"    "$type"

	done

	send WAITING_FOR_INPUT_ATTRIBUTES

}

processMessage_WAITING_FOR_OUTPUT_ATTRIBUTES() {

	local streamletInfo streamletValid value isNull;

	[[ -d "$currentFile" ]] || streamletInfo="$(exiv2 "$currentFile")";

	streamletValid="$?";

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

		value="$(echo "$streamletInfo" | grep -P "^\Q${streamletFields[$i]}\E\s*:" | sed -E 's/[^:]+:\s+(.*)/\1/g' | tr -d '\n';)"; # the field name must not contain "\E"

		if   [[ -z "$value" ]] && [[ "x${streamletFields[$i]}" == "xImage width"  ]]; then value="$(echo "$streamletInfo" | grep -E 'Image size\s*:\s*[0-9]+ x [0-9]+' | sed -E 's/Image size\s*:\s*([0-9]+) x ([0-9]+)/\1/g')";

		elif [[ -z "$value" ]] && [[ "x${streamletFields[$i]}" == "xImage height" ]]; then value="$(echo "$streamletInfo" | grep -E 'Image size\s*:\s*[0-9]+ x [0-9]+' | sed -E 's/Image size\s*:\s*([0-9]+) x ([0-9]+)/\2/g')";

		fi

		# n.b. if file has no exif data, exiv2 exits with error „No Exif data found in the file“ and thus $streamletValid != 0, but there still might be some value like „Image size“

		if   [[ ! "x$streamletValid" == "x0" ]] && [[ "x$value" == "x" ]]; then value="";  isNull="true";

		else                                                                               isNull="false";

		fi

		send OUTPUT_ATTRIBUTE "$value"    "$isNull";

	done

	send WAITING_FOR_INPUT_ATTRIBUTES;

}

initialize

processMessages