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.time.Instant;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.time.temporal.ChronoUnit;
import java.time.temporal.TemporalAccessor;

public class ReadDbMain {

	private static final DateTimeFormatter DTF = DateTimeFormatter.ISO_LOCAL_DATE_TIME.withZone(ZoneId.systemDefault());
	private static final int[] CHANNELS_TO_USE = new int[] {1, 4, };
	
	public static void main(String[] args) throws Exception {
		try (final Connection con = DriverManager.getConnection(
				"jdbc:mariadb://mariadb.fritz.box/volkszaehler",
				"vz",
				getPassword())) {
			long startTimeStamp = getTimestamp("2022-06-01T00:00:00");
			long endTimeStamp = startTimeStamp + (24*60*60*1000);
			final long finalEndTimeStamp = getTimestamp("2025-02-24T00:00:00");
			while (endTimeStamp < finalEndTimeStamp) {
				for (int channelId : CHANNELS_TO_USE) {
					final long[] values = getValues(con, startTimeStamp, endTimeStamp, channelId);
					saveValues(con, startTimeStamp, endTimeStamp, channelId, values);
					System.out.println(DTF.format(Instant.ofEpochMilli(startTimeStamp)) + ": " + channelId);
				}
//				final long[] zaehler = getValues(con, startTimeStamp, endTimeStamp, 1);
//				final long[] solar = getValues(con, startTimeStamp, endTimeStamp, 4);
//				System.out.println(DTF.format(Instant.ofEpochMilli(startTimeStamp)) +
//						"\t" +
//						DTF.format(Instant.ofEpochMilli(endTimeStamp)) +
//						"\t" +
//						zaehler[0] +
//						"\t" +
//						zaehler[1] +
//						"\t" +
//						solar[0]
//						);
				startTimeStamp += 24*60*60*1000;
				endTimeStamp += 24*60*60*1000;
			}
		}
	}
	
	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 {
		try (final PreparedStatement stmt = con.prepareStatement("SELECT * FROM volkszaehler.data WHERE channel_id=? AND timestamp>? AND timestamp<=? ORDER BY timestamp;")) {
			long currentTimestamp = startTimestamp;
			long wattMillisecondsPos = 0;
			long wattMillisecondsNeg = 0;
			stmt.setInt(1, channelId);
			stmt.setLong(2, startTimestamp);
			stmt.setLong(3, endTimestamp + 24*60*60*1000);
			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};
		}

	}
	
}