package org.simantics.district.network.ui.techtype.table;

import java.io.IOException;
import java.io.StringReader;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.stream.Collectors;

import org.apache.commons.csv.CSVRecord;
import org.eclipse.nebula.widgets.nattable.data.IDataProvider;
import org.simantics.district.imports.DistrictImportUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class TechTypeTableDataProvider implements IDataProvider {

    @SuppressWarnings("unused")
    private final static Logger LOGGER = LoggerFactory.getLogger(TechTypeTableDataProvider.class);

    private List<CSVRecord> records = new ArrayList<>();
    private List<CSVRecord> filteredRecords = new ArrayList<>();
    private String filter = "";
    private List<String> variables = null;
    private List<String> headers = null;

    public TechTypeTableDataProvider(String data) {
        // load csv
        setData(data);
    }

    public String getVariableName(int columnIndex) {
        return variables != null && columnIndex < variables.size() ? variables.get(columnIndex) : null;
    }

    public int getVariableIndex(String variableName) {
        return variables != null ? variables.indexOf(variableName) : -1;
    }

    public String getHeaderValue(int columnIndex) {
        if (headers == null) {
            return "<empty>";
        }
        return headers.get(columnIndex);
    }

    @Override
    public Object getDataValue(int columnIndex, int rowIndex) {
        return filteredRecords.get(rowIndex).get(columnIndex);
    }

    @Override
    public void setDataValue(int columnIndex, int rowIndex, Object newValue) {

    }

    @Override
    public int getColumnCount() {
        if (records.isEmpty()) {
            return 0;
        }
        return records.get(0).size();
    }

    @Override
    public int getRowCount() {
        return filteredRecords.size();
    }

    public boolean isEditable(int columnIndex, int rowIndex) {
        return false;
    }

    public void setFilter(String text) {
        this.filter = text.toLowerCase();

        filteredRecords = records.stream().filter(record -> {
            for (int i = 0; i < record.size(); i++) {
                String columnContent = record.get(i);
                if (columnContent.toLowerCase().contains(filter)) {
                    return true;
                }
            }
            return false;
        }).collect(Collectors.toList());
    }

    /**
     * Read a CSV file into table contents.
     * 
     * Set path to null to create an empty table.
     * 
     * @param path  The path of the CSV file to be read.
     */
    public void setPath(String path) {
        records.clear();
        filteredRecords.clear();
        if (path != null) {
            Path techTypeCsv = Paths.get(path);
            try {
                DistrictImportUtils.consumeCSV(techTypeCsv, ';', false, record -> {
                    records.add(record);
                    return true;
                });
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        setFilter("");
    }

    /**
     * Set table data contents to a given string of CSV data.
     * 
     * Set 'data' to null to create an empty table.
     * 
     * @param data  The CSV data to be shown in the table.
     */
    public void setData(String data) {
        records.clear();
        filteredRecords.clear();
        if (data != null) {
            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);
            try {
                DistrictImportUtils.consumeCSV(reader, delim, false, record -> {
                    records.add(record);
                    return true;
                });
            } catch (IOException e) {
                LOGGER.error("Error reading CSV file", e);
                return;
            }

            CSVRecord header = records.remove(0);
            CSVRecord units = records.remove(0);

            variables = new ArrayList<>();
            headers = new ArrayList<>();

            Iterator<String> it = header.iterator();
            Iterator<String> uit = units.iterator();

            while (it.hasNext()) {
                String variable = it.next().trim();
                String unit = uit.hasNext() ? uit.next().trim() : null;

                variables.add(variable);
                headers.add(variable + (unit != null && !unit.isEmpty() && !(unit.startsWith("(") && unit.endsWith(")")) ? " [" + unit + "]" : ""));
            }
        }

        setFilter("");
    }

}