// Watchdog timer services using libsimpleio

// Copyright (C)2017-2026, Philip Munts dba Munts Technologies.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

package com.munts.libsimpleio;

import com.munts.interfaces.Watchdog.Timer;
import com.munts.libsimpleio.bindings.libwatchdog;
import com.munts.libsimpleio.errno;
import com.sun.jna.ptr.IntByReference;

public final class Watchdog
{

  private Watchdog()
  {
  }

  private static class TimerSubclass implements Timer
  {
    int fd;

    // Watchdog timer object constructor

    TimerSubclass(String devname, int timeout)
    {
      IntByReference fd = new IntByReference();
      IntByReference error = new IntByReference();
      IntByReference newtimeout = new IntByReference();

      // Open the watchdog timer device node

      libwatchdog.WATCHDOG_open(devname, fd, error);

      if (error.getValue() != errno.EOK)
        throw new RuntimeException("ERROR: WATCHDOG_open() failed, " +
          errno.strerror(error.getValue()));

      this.fd = fd.getValue();

      // Check for initial timeout setting

      if (timeout == 0)
        return;

      // Change the timeout setting

      libwatchdog.WATCHDOG_set_timeout(this.fd, timeout, newtimeout, error);

      if (error.getValue() != errno.EOK)
        throw new RuntimeException("ERROR: WATCHDOG_set_timeout() failed, " +
          errno.strerror(error.getValue()));
    }

    public int GetTimeout()
    {
      IntByReference timeout = new IntByReference();
      IntByReference error = new IntByReference();

      libwatchdog.WATCHDOG_get_timeout(this.fd, timeout, error);

      if (error.getValue() != errno.EOK)
        throw new RuntimeException("ERROR: WATCHDOG_get_timeout() failed, " +
          errno.strerror(error.getValue()));

      return timeout.getValue();
    }

    public void SetTimeout(int timeout)
    {
      IntByReference newtimeout = new IntByReference();
      IntByReference error = new IntByReference();

      libwatchdog.WATCHDOG_set_timeout(this.fd, timeout, newtimeout, error);

      if (error.getValue() != errno.EOK)
        throw new RuntimeException("ERROR: WATCHDOG_set_timeout() failed, " +
          errno.strerror(error.getValue()));
    }

    public void Kick()
    {
      IntByReference error = new IntByReference();

      libwatchdog.WATCHDOG_kick(this.fd, error);

      if (error.getValue() != errno.EOK)
        throw new RuntimeException("ERROR: WATCHDOG_kick() failed, " +
          errno.strerror(error.getValue()));
    }

    public void finalize()
    {
      IntByReference error = new IntByReference();

      libwatchdog.WATCHDOG_close(this.fd, error);

      this.fd = -1;
    }
  }

  // Create a watchdog timer

  public static Timer Create(String devname, int timeout)
  {
    return new TimerSubclass(devname, timeout);
  }

  // Create a watchdog timer with default timeout

  public static Timer Create(String devname)
  {
    return new TimerSubclass(devname, 0);
  }

  // Create a watchdog timer with default device and timeout

  public static Timer Create()
  {
    return new TimerSubclass("/dev/watchdog", 0);
  }
}