//
// Copyright (c) 2010-2018 Antmicro
// Copyright (c) 2011-2015 Realtime Embedded
//
// This file is licensed under the MIT License.
// Full license text is available in 'licenses/MIT.txt'.
//
using System;
using Antmicro.Renode.Core;
using Antmicro.Renode.Peripherals.Bus;
using Antmicro.Renode.Time;
using Antmicro.Renode.Logging;
using System.Threading;

namespace Antmicro.Renode.Peripherals.Timers
{
    public class BSOCTickTimer : IDoubleWordPeripheral, IKnownSize
    {
        public BSOCTickTimer(ulong periodInMs, Machine machine)
        {
            running = true;
            machine.ClockSource.AddClockEntry(new ClockEntry(periodInMs, ClockEntry.FrequencyToRatio(this, 1000), OnTick, this, String.Empty));
        }

        public long Size
        {
            get
            {
                return 0x400;
            }
        }

        public virtual uint ReadDoubleWord(long offset)
        {
            if (offset == 0)
                return 0;
            else if (offset == 4)
                offset = 40;
            else if (offset == 8)
                offset = 32;
            else if (offset == 12)
                offset = 24;
            else if (offset == 16)
                offset = 16;
            else if (offset == 20)
                offset = 8;
            else if (offset == 24)
                offset = 0;
            else {
                this.LogUnhandledRead(offset);
                return 0;
            }
            return (uint)(Interlocked.CompareExchange(ref counter, 0, 0) >> (int)offset);
        }

        public virtual void WriteDoubleWord(long offset, uint value)
        {
            if (offset == 0) {
                if ((value & 1) == 1)
                    Interlocked.Exchange(ref counter, 0);
                running = ((value & 2) != 2);
                return;
            }
            this.LogUnhandledWrite(offset, value);
        }

        public virtual void Reset()
        {
            Interlocked.Exchange(ref counter, 0);
        }

        private void OnTick()
        {
            if (running)
                Interlocked.Increment(ref counter);
        }

        private long counter;
        private bool running;
    }
}