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 * Copyright (c) 2005-2025 The OPC Foundation, Inc. All rights reserved.
 *
 * OPC Foundation MIT License 1.00
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
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 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
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 *
 * The above copyright notice and this permission notice shall be
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 * OTHER DEALINGS IN THE SOFTWARE.
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 * ======================================================================*/

using System;
using Microsoft.Extensions.Logging;
using Opc.Ua;

namespace Alarms
{
    /// <summary>
    /// Alarm controller
    /// </summary>
    public class AlarmController
    {
        private const int kDefaultCycleTime = 180;
        protected ILogger m_logger;
        protected BaseDataVariableState m_variable;
        protected int m_value;
        protected bool m_increment = true;
        protected DateTime m_nextTime = DateTime.Now;
        protected DateTime m_stopTime = DateTime.Now;
        protected int m_interval;
        protected bool m_isBoolean;
        protected bool m_allowChanges;
        protected bool m_reset;
        protected DateTime m_lastMaxValue;
        protected bool m_validLastMaxValue;
        protected int m_midpoint = AlarmDefines.NORMAL_START_VALUE;

        public AlarmController(BaseDataVariableState variable, int interval, bool isBoolean, ITelemetryContext telemetry)
        {
            m_logger = telemetry.CreateLogger<AlarmController>();
            m_variable = variable;
            m_interval = interval;
            m_isBoolean = isBoolean;
            m_increment = true;

            m_value = m_midpoint;
            m_stopTime = m_stopTime.AddYears(5);

            m_allowChanges = false;
        }

        /// <summary>
        /// Start the Alarm cycles for n seconds.
        /// </summary>
        public virtual void Start(uint seconds = 0)
        {
            Stop();

            m_logger.LogInformation("Start the Alarms for {Duration} seconds!", seconds);

            m_validLastMaxValue = false;

            m_nextTime = m_stopTime = DateTime.Now;
            m_stopTime = m_stopTime.AddSeconds(seconds == 0 ? kDefaultCycleTime : seconds);

            m_allowChanges = true;
        }

        public virtual void Stop()
        {
            m_logger.LogInformation("Stop the Alarms!");

            m_value = m_midpoint;
            m_increment = true;
            m_allowChanges = false;

            m_reset = true;
        }

        public virtual bool Update(ISystemContext systemContext)
        {
            bool valueSet = false;
            if (CanSetValue())
            {
                int value = 0;
                bool boolValue = false;
                GetValue(ref value, ref boolValue);

                m_logger.LogInformation("AlarmController Update Value = {Value}", value);

                if (m_isBoolean)
                {
                    m_variable.Value = boolValue;
                }
                else
                {
                    m_variable.Value = value;
                }
                m_variable.Timestamp = DateTime.UtcNow;
                m_variable.ClearChangeMasks(systemContext, false);

                valueSet = true;
            }

            return valueSet;
        }

        protected virtual void SetNextInterval()
        {
            m_nextTime = DateTime.Now;
            m_nextTime = m_nextTime.AddMilliseconds(m_interval);
        }

        public void ManualWrite(object value)
        {
            if (value.GetType().Name == "Int32")
            {
                // Don't let anyone write a value out of range
                int potentialWrite = (int)value;
                if (potentialWrite is >= AlarmDefines.MIN_VALUE and <= AlarmDefines.MAX_VALUE)
                {
                    m_value = potentialWrite;
                }
                else
                {
                    m_logger.LogError(
                        "AlarmController Received out of range manual write of {Value}",
                        value);
                }
            }
            else if ((bool)value)
            {
                m_value = 70;
                m_increment = true;
            }
            else
            {
                m_value = m_midpoint;
            }
        }

        public virtual bool CanSetValue()
        {
            bool setValue = false;

            if (DateTime.Now > m_stopTime)
            {
                Stop();
                m_stopTime = DateTime.MaxValue;
            }
            else if (m_allowChanges || m_reset)
            {
                m_reset = false;

                if (DateTime.Now > m_nextTime)
                {
                    SetNextInterval();
                    setValue = true;
                }
            }

            return setValue;
        }

        protected virtual void GetValue(ref int intValue, ref bool boolValue)
        {
            const int maxValue = 100;
            const int minValue = 0;

            TypicalGetValue(minValue, maxValue, ref intValue, ref boolValue);
        }

        public bool SupportsBranching { get; set; }

        public virtual void SetBranchCount(int count)
        {
        }

        protected void TypicalGetValue(
            int minValue,
            int maxValue,
            ref int intValue,
            ref bool boolValue)
        {
            int incrementValue = 5;
            if (m_isBoolean)
            {
                incrementValue = 10;
            }
            if (m_increment)
            {
                m_value += incrementValue;
                if (m_value >= maxValue)
                {
                    if (m_validLastMaxValue)
                    {
                        m_logger.LogInformation(
                            "Cycle Time {CycleTime} Interval {Interval}",
                            DateTime.Now - m_lastMaxValue,
                            m_interval);
                    }
                    m_lastMaxValue = DateTime.Now;
                    m_validLastMaxValue = true;

                    m_increment = false;
                }
            }
            else
            {
                m_value -= incrementValue;
                if (m_value <= minValue)
                {
                    m_increment = true;
                }
            }

            intValue = m_value;
            boolValue = IsBooleanActive();
        }

        public bool IsBooleanActive()
        {
            bool isActive = false;
            if (m_value is >= AlarmDefines.BOOL_HIGH_ALARM or <= AlarmDefines.BOOL_LOW_ALARM)
            {
                isActive = true;
            }

            return isActive;
        }

        public int GetValue()
        {
            return m_value;
        }

        public int GetSawtooth()
        {
            return m_value;
        }

        public int GetSine(int minValue, int maxValue)
        {
            return CalcSine(minValue, maxValue, m_value);
        }

        public int CalcSine(int minValue, int maxValue, int value)
        {
            // What I want is a sawtooth compared against a sine value.
            // This calculates a simular sine value that will have predictable differences between value and sine

            /*
             * https://www.mathsisfun.com/algebra/amplitude-period-frequency-phase-shift.html
             * Sine with Phase Shift and Vertical Shift!  This is what I want
             * y = A sin(B(x + C)) + D
             * A - Amplitude
             * B - relates to period - This should extend the time period
             * C - Phase Shift
             * D - Vertical Shift
             *
             */

            const double twoPi = Math.PI * 2;

            double normalSpan = maxValue - minValue;
            double amplitude = normalSpan / 2;
            double median = maxValue - amplitude;

            double offsetValue = value - minValue;
            double percentageOfRange = offsetValue / normalSpan;

            double reducedPeriod = percentageOfRange / 2;

            const double period = twoPi; // this would relate to the interval.  Ignore for now.
            const double phase = -0.25; // phaseShift;
            double verticalShift = median; // amplitude

            double calculated = (amplitude * Math.Sin(period * (reducedPeriod + phase))) +
                verticalShift;

            m_logger.LogTrace(
                " Phase {Phase:0.00} Value {Value} Sine {Sine:0.00}" +
                " Offset Value {OffsetValue:0.00} Span {NormalSpan:0.00}" +
                " Percentage of Range {PercentageOfRange:0.00}",
                phase,
                value,
                calculated,
                offsetValue,
                normalSpan,
                percentageOfRange);

            return (int)calculated;
        }

        public virtual bool ShouldSuppress()
        {
            return false;
        }

        public virtual bool ShouldUnsuppress()
        {
            return false;
        }

        public virtual void OnAddComment()
        {
        }

        public virtual void OnAcknowledge()
        {
        }

        public virtual void OnConfirm()
        {
        }
    }
}