/**

 * 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/>.

 */

#include <unistd.h>

#include <Magick++.h>

#include <zbar.h>

#include <relpipe/xmlwriter/XMLWriter.h>

#include "streamlet-common.h"

/**

 * This streamlet extracts QR codes from image files.

 * 

 * It provides two attributes:

 *  - qr: first QR code found (if any)

 *  - qr_xml: XML containing all QR cpdes found an additional metadata

 *	

 */

class QRStreamlet : public Streamlet {

private:

	const wstring XMLNS = L"tag:globalcode.info,2018:qr:FIXME:final-xmlns"; // FIXME: correct xmlns URI

	class Symbol {

	public:

		int id;

		std::wstring value;

		std::wstring type;

		int x;

		int y;

		int width;

		int height;

	};

	std::vector<Symbol> findSymbols(std::wstring fileName) {

		std::vector<Symbol> result;

		Magick::Image magick(toBytes(fileName));

		int width = magick.columns();

		int height = magick.rows();

		Magick::Blob blob;

		magick.modifyImage();

		magick.write(&blob, "GRAY", 8);

		const void *raw = blob.data();

		zbar::Image image(width, height, "Y800", raw, width * height);

		zbar::ImageScanner scanner;

		scanner.scan(image);

		int id = 0;

		for (zbar::Image::SymbolIterator symbol = image.symbol_begin(); symbol != image.symbol_end(); ++symbol, id++) {

			Symbol s;

			s.id = id;

			s.type = fromBytes(symbol->get_type_name());

			s.value = fromBytes(symbol->get_data());

			int minX = 0;

			int minY = 0;

			int maxX = 0;

			int maxY = 0;

			// TODO: return original polygon in XML

			for (int i = 0, locationSize = symbol->get_location_size(); i < locationSize; i++) {

				int x = symbol->get_location_x(i);

				int y = symbol->get_location_y(i);

				minX = minX ? std::min(minX, x) : x;

				minY = minY ? std::min(minY, y) : y;

				maxX = std::max(maxX, x);

				maxY = std::max(maxY, y);

			}

			s.x = minX;

			s.y = minY;

			s.width = maxX - minX;

			s.height = maxY - minY;

			result.push_back(s);

		}

		return result;

	}

protected:

	std::vector<AttributeMetadata> getOutputAttributesMetadata() override {

		std::vector<AttributeMetadata> oam;

		int i = 0;

		oam.push_back({getAlias(i++, L"qr"), STRING});

		oam.push_back({getAlias(i++, L"qr_xml"), STRING});

		return oam;

	}

	std::vector<OutputAttribute> getOutputAttributes() override {

		bool validInput = false;

		bool hasSymbols = false;

		std::wstring first;

		std::stringstream xml;

		std::vector<Symbol> symbols;

		try {

			symbols = findSymbols(getCurrentFile());

			validInput = true;

		} catch (...) {

			// just ignore the errors;

			// the file is probably not an image or we do not have read permissions

			validInput = false;

		}

		for (Symbol s : symbols) {

			// TODO: match against pattern (if any)

			first = s.value;

			hasSymbols = true;

			break;

		}

		relpipe::xmlwriter::XMLWriter xmlWriter(xml);

		xmlWriter.writeStartElement(L"qr",{L"xmlns", XMLNS});

		// TODO: common metadata

		// xmlWriter.writeStartElement(L"source");

		// xmlWriter.writeTextElement(L"height",{}, std::to_wstring(...));

		// xmlWriter.writeTextElement(L"width",{}, std::to_wstring(...));

		// xmlWriter.writeEndElement();

		for (Symbol s : symbols) {

			xmlWriter.writeStartElement(L"symbol");

			xmlWriter.writeTextElement(L"value",{}, s.value);

			xmlWriter.writeTextElement(L"x",{}, std::to_wstring(s.x));

			xmlWriter.writeTextElement(L"y",{}, std::to_wstring(s.y));

			xmlWriter.writeTextElement(L"height",{}, std::to_wstring(s.height));

			xmlWriter.writeTextElement(L"width",{}, std::to_wstring(s.width));

			// TODO: polygon

			xmlWriter.writeEndElement();

		}

		xmlWriter.writeEndElement();

		std::vector<OutputAttribute> oa;

		// TODO: report also validInput (distinguish it from hasSymbols)

		oa.push_back({first, !hasSymbols});

		oa.push_back({fromBytes(xml.str()), false});

		return oa;

	}

};

STREAMLET_RUN(QRStreamlet)