package com.intelligt.modbus.jlibmodbus.serial;

import com.google.android.things.pio.PeripheralManager;
import com.google.android.things.pio.UartDevice;
import com.intelligt.modbus.jlibmodbus.Modbus;
import com.intelligt.modbus.jlibmodbus.utils.ByteFifo;

import java.io.IOException;

/*
 * Copyright (C) 2017 Vladislav Y. Kochedykov
 *
 * [http://jlibmodbus.sourceforge.net]
 *
 * This file is part of JLibModbus.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Authors: Vladislav Y. Kochedykov, software engineer.
 * email: vladislav.kochedykov@gmail.com
 */

public class SerialPortAT extends SerialPort {

    private UartDevice port;
    byte[] buffer = new byte[Modbus.MAX_PDU_LENGTH];
    volatile long readTime = 0;

    public SerialPortAT(SerialParameters sp) {
        super(sp);
        port = null;
    }

    @Override
    public void write(int b) throws IOException {
        try {
            port.write(new byte[]{(byte)(b&0xff)}, 1);
        } catch (Exception e) {
            throw new IOException(e);
        }
    }

    @Override
    public void write(byte[] bytes) throws IOException {
        try {
            port.write(bytes, bytes.length);
        } catch (Exception e) {
            throw new IOException(e);
        }
    }

    @Override
    public void open() throws SerialPortException {
        try {
            SerialParameters sp = getSerialParameters();
            port = PeripheralManager.getInstance().openUartDevice(sp.getDevice());
            port.setBaudrate(sp.getBaudRate());
            port.setDataSize(sp.getDataBits());
            port.setParity(sp.getParity().getValue());
            port.setStopBits(sp.getStopBits());
            port.setHardwareFlowControl(UartDevice.HW_FLOW_CONTROL_NONE);
        } catch (Exception ex) {
            throw new SerialPortException(ex);
        }
    }

    @Override
    public int read() throws IOException {
        try {
            readTime = System.currentTimeMillis();
            while (port.read(buffer, 1) < 1) {
                if ((System.currentTimeMillis() - readTime) > getReadTimeout()) {
                    throw new IOException("Read timeout");
                }
            }
            return buffer[0];
        } catch (Exception e) {
            throw new IOException(e);
        }
    }

    @Override
    public int read(byte[] b, int off, final int len) throws IOException {
        try {
            readTime = System.currentTimeMillis();
            int read;
            int count = 0;

            int length = len-off;

            if (length < 0 || b.length < off+len)
                throw new ArrayIndexOutOfBoundsException("len + off is greater than b.length");

            while (count < length) {
                read = port.read(buffer, length-count);
                count += read;
                if (count > length) {
                    int diff = count - length;
                    read -= diff;
                    count -= diff;
                }
                System.arraycopy(buffer, 0, b, off, read);
                off += read;

                if ((System.currentTimeMillis() - readTime) > getReadTimeout()) {
                    throw new IOException("Read timeout");
                }
            }
            return count;
        } catch (Exception e) {
            throw new IOException(e);
        }
    }

    @Override
    public void close() {
        if (isOpened()) {
            try {
                synchronized (this) {
                    port.close();
                    port = null;
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    @Override
    synchronized public boolean isOpened() {
        return port != null;
    }
}