//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
//     file="TimeFunction.cs"
//     Project: StgSharp
//     AuthorGroup: Nitload Space
//     Copyright (c) Nitload Space. All rights reserved.
//     
//     Permission is hereby granted, free of charge, to any person 
//     obtaining a copy of this software and associated documentation 
//     files (the “Software”), to deal in the Software without restriction, 
//     including without limitation the rights to use, copy, modify, merge,
//     publish, distribute, sublicense, and/or sell copies of the Software, 
//     and to permit persons to whom the Software is furnished to do so, 
//     subject to the following conditions:
//     
//     The above copyright notice and 
//     this permission notice shall be included in all copies 
//     or substantial portions of the Software.
//     
//     THE SOFTWARE IS PROVIDED “AS IS”, 
//     WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
//     INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
//     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
//     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
//     DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
//     ARISING FROM, OUT OF OR IN CONNECTION WITH 
//     THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//     
//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Text;

namespace StgSharp.Timing
{
    public class TimeFunction
    {

        private float _beginning, _ending;
        private Func<float, float> _timeRelatedCalculation;
        private TimeSpanProvider _timeProvider;

        internal TimeFunction() { }

        public TimeFunction(
            TimeSpanProvider timeSpanProvider,
            Func<float, float> timeRelatedCalculation,
            float range )
        {
            _timeProvider = timeSpanProvider;
            _timeRelatedCalculation = timeRelatedCalculation;
            if( timeSpanProvider == null ) {
                return;
            }
            _beginning = _timeProvider.CurrentSecond;
            _ending = _timeProvider.CurrentSecond + range;
        }

        public virtual bool IsComplete
        {
            get => _timeProvider.CurrentSecond > _ending;
        }

        public Func<float, float> TimeRelatedCalculation
        {
            get { return _timeRelatedCalculation; }
            set { _timeRelatedCalculation = value; }
        }

        public static TimeFunction One
        {
            get => new TimeFunctionOne();
        }

        public TimeSpanProvider TimeSpanProvider
        {
            get { return _timeProvider; }
            set { _timeProvider = value; }
        }

        public virtual float Calculate()
        {
            if( _timeProvider.CurrentSecond < _ending ) {
                return 0;
            }
            return _timeRelatedCalculation(
                _timeProvider.CurrentSecond - _beginning );
        }

        public static TimeFunction Proportional(
            TimeSpanProvider time,
            float begin,
            float range )
        {
            return new TimeFunction( time, ( float t ) => t + begin, range );
        }

        public virtual TimeFunction Renew(
            (Func<float, float> func, float range) funcPair )
        {
            return new TimeFunction(
                _timeProvider, funcPair.func, funcPair.range );
        }

        public virtual TimeFunction Renew(
            Func<float, float> func,
            float range )
        {
            return new TimeFunction( _timeProvider, func, range );
        }

        public void Reset()
        {
            float range = _ending - _beginning;
            _beginning = _timeProvider.CurrentSecond;
            _ending = _beginning + range;
        }

        public virtual TimeFunction Reverse()
        {
            float range = _ending - _beginning;
            return new TimeFunction(
                _timeProvider, p => _timeRelatedCalculation( range - p ),
                range );
        }

    }

    public sealed class TimeFunctionOne : TimeFunction
    {

        internal TimeFunctionOne() : base() { }

        public override bool IsComplete
        {
            get => true;
        }

        public override float Calculate()
        {
            return 1;
        }

        public override TimeFunction Renew(
            (Func<float, float> func, float range) funcPair )
        {
            throw new NotSupportedException();
        }

        public override TimeFunction Renew(
            Func<float, float> func,
            float range )
        {
            throw new NotSupportedException();
        }

        #pragma warning disable CA1822 
        public new void Reset()
 #pragma warning restore CA1822 
 { }

    }
}