package org.lucares.pdbui;

import java.io.IOException;
import java.net.ConnectException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.SocketChannel;
import java.nio.charset.StandardCharsets;
import java.nio.file.Path;
import java.nio.file.StandardOpenOption;
import java.time.Instant;
import java.time.OffsetDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;

import org.lucares.collections.LongList;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.fasterxml.jackson.databind.ObjectMapper;

public class PdbTestUtil {
    private static final Logger LOGGER = LoggerFactory.getLogger(PdbTestUtil.class);

    static final Map<String, Object> POISON = new HashMap<>();

    public static final void send(final String format, final Collection<Map<String, Object>> entries, final int port)
            throws IOException, InterruptedException {
        switch (format) {
        case "csv":
            sendAsCsv(entries, port);
            break;
        case "json":
            sendAsJson(entries, port);
            break;
        default:
            throw new IllegalStateException("unhandled format: " + format);
        }
    }

    @SafeVarargs
    public static final void sendAsCsv(final int port, final Map<String, Object>... entries)
            throws IOException, InterruptedException {
        sendAsCsv(Arrays.asList(entries), port);
    }

    public static final void sendAsCsv(final Collection<Map<String, Object>> entries, final int port)
            throws IOException, InterruptedException {

        final Set<String> keys = entries.stream().map(Map::keySet).flatMap(Set::stream).collect(Collectors.toSet());

        sendAsCsv(keys, entries, port);
    }

    public static final void sendAsCsv(final Collection<String> keys, final Collection<Map<String, Object>> entries,
            final int port) throws IOException, InterruptedException {

        final StringBuilder csv = new StringBuilder();

        csv.append(String.join(",", keys));
        csv.append("\n");

        for (final Map<String, Object> entry : entries) {
            final List<String> line = new ArrayList<>();
            for (final String key : keys) {
                final String value = String.valueOf(entry.getOrDefault(key, ""));
                line.add(value);
            }
            csv.append(String.join(",", line));
            csv.append("\n");
        }
        System.out.println("sending: " + csv);
        send(csv.toString(), port);
    }

    @SafeVarargs
    public static final void sendAsJson(final int port, final Map<String, Object>... entries)
            throws IOException, InterruptedException {

        sendAsJson(Arrays.asList(entries), port);
    }

    public static final void sendAsJson(final Collection<Map<String, Object>> entries, final int port)
            throws IOException, InterruptedException {
        final LinkedBlockingDeque<Map<String, Object>> queue = new LinkedBlockingDeque<>(entries);
        queue.put(POISON);
        sendAsJson(queue, port);
    }

    public static final void sendAsJson(final BlockingQueue<Map<String, Object>> aEntriesSupplier, final int port)
            throws IOException {

        final ObjectMapper mapper = new ObjectMapper();
        final SocketChannel channel = connect(port);

        Map<String, Object> entry;
        while ((entry = aEntriesSupplier.poll()) != POISON) {

            final StringBuilder streamData = new StringBuilder();
            streamData.append(mapper.writeValueAsString(entry));
            streamData.append("\n");

            final ByteBuffer src = ByteBuffer.wrap(streamData.toString().getBytes(StandardCharsets.UTF_8));
            channel.write(src);
        }

        try {
            // ugly workaround: the channel was closed too early and not all
            // data was received
            TimeUnit.MILLISECONDS.sleep(10);
        } catch (final InterruptedException e) {
            throw new IllegalStateException(e);
        }
        channel.close();
        LOGGER.trace("closed sender connection");
    }

    public static final void send(final String data, final int port) throws IOException {

        final SocketChannel channel = connect(port);

        final StringBuilder streamData = new StringBuilder();
        streamData.append(data);

        final ByteBuffer src = ByteBuffer.wrap(streamData.toString().getBytes(StandardCharsets.UTF_8));
        channel.write(src);

        try {
            // ugly workaround: the channel was closed too early and not all
            // data was received
            TimeUnit.MILLISECONDS.sleep(10);
        } catch (final InterruptedException e) {
            throw new IllegalStateException(e);
        }
        channel.close();
        LOGGER.trace("closed sender connection");
    }

    public static void send(final Path file, final int port) throws IOException {
        final SocketChannel outputChannel = connect(port);

        try (final FileChannel inputChannel = FileChannel.open(file, StandardOpenOption.READ)) {
            inputChannel.transferTo(0, Long.MAX_VALUE, outputChannel);
        }

        try {
            // ugly workaround: the channel was closed too early and not all
            // data was received
            TimeUnit.MILLISECONDS.sleep(10);
        } catch (final InterruptedException e) {
            throw new IllegalStateException(e);
        }
        outputChannel.close();
        LOGGER.trace("closed sender connection");
    }

    private static SocketChannel connect(final int port) throws IOException {

        SocketChannel result = null;

        while (true) {
            try {
                result = SocketChannel.open();
                result.configureBlocking(true);
                result.connect(new InetSocketAddress("127.0.0.1", port));
                break;
            } catch (final ConnectException e) {
                // server socket not yet ready, it should be ready any time soon
            }
        }

        return result;
    }

    public static String timeValueLongListToString(final LongList timeValueLongList) {
        final StringBuilder result = new StringBuilder();

        int i = 0;
        while (i < timeValueLongList.size()) {
            final OffsetDateTime time = OffsetDateTime.ofInstant(Instant.ofEpochMilli(timeValueLongList.get(i)),
                    ZoneOffset.UTC);
            i++;
            final long value = timeValueLongList.get(i);
            i++;

            result.append(time.format(DateTimeFormatter.ISO_DATE_TIME));
            result.append("=");
            result.append(value);
            result.append("\n");
        }

        return result.toString();
    }

}