/**
 * Relational pipes
 * Copyright © 2023 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/>.
 */
#pragma once

#include <cstdlib>
#include <iostream>
#include <string>
#include <sstream>
#include <vector>
#include <algorithm>
#include <exception>
#include <regex>

#include <libxml++-2.6/libxml++/libxml++.h>

#include <relpipe/writer/typedefs.h>

namespace relpipe {
namespace in {
namespace ods {

using namespace relpipe::writer;

class ODSCommand {
private:
	std::wstring_convert<codecvt_utf8<wchar_t>> convertor;

	xmlpp::Node::PrefixNsMap ns;
	std::shared_ptr<RelationalWriter> writer;

	string_t xpath(xmlpp::Node* node, std::string xpath) {
		return convertor.from_bytes(node->eval_to_string(xpath, ns));
	}

	void processCell(xmlpp::Node* c, AttributeMetadata& am) {
		string_t value = xpath(c, "@o:value");
		if (value.size()) writer->writeAttribute(value);
		else writer->writeAttribute(xpath(c, "tx:p"));
		// TODO: be aware of the current data types
	}

	void processRow(xmlpp::Node* r, std::vector<AttributeMetadata>& am) {
		for (int i = 0; i < am.size(); i++) {
			auto xpe = std::string("t:table-cell[")
					+ std::to_string(i + 1)
					+ "]";
			auto cells = r->find(xpe, ns);
			if (cells.size() == 1) {
				processCell(cells[0], am[i]);
			} else {
				writer->writeAttribute(L"");
				// TODO: support also other data types
			}
		}

		// FIXME: support sparse data / missing values:
		// <table:table-row  table:number-rows-repeated="2">
		// <table:table-cell table:number-columns-repeated="3"/>

	}

	void processTable(xmlpp::Node* t) {
		auto relation = xpath(t, "@t:name");
		std::vector<AttributeMetadata> metadata;

		for (xmlpp::Node* c : t->find("t:table-row[1]/t:table-cell", ns)) {
			auto name = xpath(c, "tx:p");
			if (name.size()) {
				metadata.push_back({name, TypeId::STRING});
				// TODO: detect and support other data types
			}
		}

		writer->startRelation(relation, metadata, true);

		int i = 0;
		for (xmlpp::Node* r : t->find("t:table-row", ns)) {
			i++;
			if (i == 1) continue; // skip header row
			processRow(r, metadata);
		}
	}

public:

	ODSCommand(std::shared_ptr<RelationalWriter> writer) : writer(writer) {
		ns["o"] = "urn:oasis:names:tc:opendocument:xmlns:office:1.0";
		ns["t"] = "urn:oasis:names:tc:opendocument:xmlns:table:1.0";
		ns["tx"] = "urn:oasis:names:tc:opendocument:xmlns:text:1.0";
	}

	void process(std::istream & input) {
		xmlpp::DomParser parser;
		parser.parse_stream(input);

		xmlpp::Element* root = parser.get_document()->get_root_node();
		auto spreadsheets = root->find("/o:document/o:body/o:spreadsheet", ns);

		if (spreadsheets.size() == 1) {
			for (xmlpp::Node* table : spreadsheets[0]->find("t:table", ns)) {
				processTable(table);
			}
		} else {
			throw RelpipeWriterException(L"Invalid XML structure. "
					"Expecting OpenDocument spreadsheet.");
		}


	}
};

}
}
}