package org.simantics.district.network.techtype.requests;

import java.io.IOException;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVParser;
import org.apache.commons.csv.CSVRecord;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.request.ResourceRead;
import org.simantics.db.exception.DatabaseException;
import org.simantics.district.network.ontology.DistrictNetworkResource;
import org.simantics.district.network.techtype.TechTypeUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class TechTypeTableData extends ResourceRead<Map<String, Map<String, String>>> {

	private final static Logger LOGGER = LoggerFactory.getLogger(TechTypeTableData.class);
	
	public TechTypeTableData(Resource table) {
		super(table);
	}

	@Override
	public Map<String, Map<String, String>> perform(ReadGraph graph) throws DatabaseException {
		Resource table = this.resource;

		String data = graph.getRelatedValue2(table,
				DistrictNetworkResource.getInstance(graph).TechType_TechTypeTable_HasData);
		if (data == null)
			return Collections.emptyMap();
		
		String keyName = TechTypeUtils.getKeyPropertyName(graph, table);
		if (keyName.startsWith("_"))
			keyName = keyName.substring(1);

		Map<String, Map<String, String>> map = new HashMap<>();
		
		long ncommas = data.chars().filter(c -> c == ',').count();
		long nsemis = data.chars().filter(c -> c == ';').count();
		char delim = nsemis > ncommas ? ';' : ',';
		StringReader reader = new StringReader(data);

		List<CSVRecord> records = new ArrayList<>();
		try {
			CSVFormat format = CSVFormat.newFormat(delim).withQuote('"');
			try (CSVParser parser = format.parse(reader)) {
				Iterator<CSVRecord> it = parser.iterator();
				while (it.hasNext()) {
					records.add(it.next());
				}
			}
		} catch (IOException e) {
			LOGGER.error("Error reading CSV data", e);
			return Collections.emptyMap();
		}

		CSVRecord header = records.remove(0);
		records.remove(0); // Eliminate units row
		
		int keyIndex = 0;
		for (int i = 0; i < header.size(); i++) {
			if (header.get(i).equals(keyName)) {
				keyIndex = i;
				break;
			}
		}

		for (CSVRecord r : records) {
			String key = r.get(keyIndex).intern();
			if (key == null)
				continue;
			
			Map<String, String> valueMap = new HashMap<>();
			map.put(key, valueMap);
			
			Iterator<String> h = header.iterator();
			Iterator<String> v = r.iterator();
			
			while (h.hasNext() && v.hasNext()) {
				String name = h.next().intern();
				String value = v.next();
				valueMap.put(name, value);
			}
		}
		
		return map;
	}
}