package info.peper.vz.rest;

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.time.Instant;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.time.temporal.ChronoUnit;
import java.time.temporal.TemporalAccessor;

public class ReadDbMain2 {

	private static final DateTimeFormatter DTF = DateTimeFormatter.ISO_LOCAL_DATE_TIME.withZone(ZoneId.systemDefault());
	private static final int[] CHANNELS_TO_USE = new int[] {4};
	
	public static void main(String[] args) throws Exception {
		try (final Connection con = DriverManager.getConnection(
				"jdbc:mariadb://mariadb.fritz.box/volkszaehler",
				"vz",
				getPassword())) {
			try (final PreparedStatement stmt = con.prepareStatement("SELECT timestamp FROM volkszaehler.data WHERE channel_id=4 AND timestamp >= 1740697200000 ORDER BY timestamp"); final ResultSet rs = stmt.executeQuery()) {
				long lastTime = 0;
				long longestDiff = 0;
				while (rs.next()) {
					if (lastTime > 0) {
						long diff = rs.getLong("timestamp") - lastTime;
						if (diff > longestDiff) {
							longestDiff = diff;
						}
					}
					lastTime = rs.getLong("timestamp");
				}
				System.out.println(longestDiff);
			}
		}
	}

	private static String getPassword() throws IOException {
		try (final InputStream is = new FileInputStream("db-password.txt")) {
			final BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(is));
			return bufferedReader.readLine();
		}
	}

	private static long getTimestamp(final String dateTime) {
		final TemporalAccessor tempAccessor = DTF.parse(dateTime);
		final Instant instant = Instant.from(tempAccessor);
		return Instant.EPOCH.until(instant, ChronoUnit.MILLIS);
	}
	
	private static void saveValues(final Connection con,
			final long startTimestamp,
			final long endTimestamp,
			final int channelId,
			final long[] values) throws SQLException {
		try (final PreparedStatement stmt = con.prepareStatement("INSERT INTO tobias_aggregate (channel_id, timestamp_start, timestamp_end, sum_positive, sum_negative) VALUES (?, ?, ?, ?, ?)")) {
			stmt.setInt(1, channelId);
			stmt.setLong(2, startTimestamp);
			stmt.setLong(3, endTimestamp);
			stmt.setLong(4, values[0]);
			stmt.setLong(5, values[1]);
			stmt.execute();
		}
	}
	
	private static long[] getValues(final Connection con,
			final long startTimestamp,
			final long endTimestamp,
			final int channelId) throws SQLException {
		long currentTimestamp = startTimestamp;
		long wattMillisecondsPos = 0;
		long wattMillisecondsNeg = 0;
		
		while (currentTimestamp < endTimestamp) {
			try (final PreparedStatement stmt = con.prepareStatement("SELECT * FROM volkszaehler.data WHERE channel_id=? AND timestamp>? ORDER BY timestamp;")) {
				stmt.setMaxRows(1000);
				stmt.setInt(1, channelId);
				stmt.setLong(2, currentTimestamp);
				try (final ResultSet rs = stmt.executeQuery()) {
					while (rs.next() && currentTimestamp <= endTimestamp) {
						final long rsTimestamp = rs.getLong("timestamp");
						final long rsValue = rs.getLong("value");
						final long tsDiff = rsTimestamp - Math.min(endTimestamp, currentTimestamp);
						currentTimestamp = rsTimestamp;
						if (rsValue > 0) {
							wattMillisecondsPos += (rsValue * tsDiff);
						} else if (rsValue < 0) {
							wattMillisecondsNeg += (-rsValue * tsDiff);
						}
					}
				}
			}
		}
		return new long[] {wattMillisecondsPos/3600, wattMillisecondsNeg/3600};

	}
	
}