using System;
namespace ProjectI.Combat
{
    public readonly struct GunTriggerBonus
    {
        public readonly float DamageBonus;
        public readonly bool Ultimate;
        public readonly float PierceFraction;
        public readonly int AdditionalPierceTargets;
        public GunTriggerBonus(float bonus,bool ultimate,float pierce,int additionalPierceTargets=0)
        {DamageBonus=bonus;Ultimate=ultimate;PierceFraction=pierce;AdditionalPierceTargets=additionalPierceTargets;}
    }
    public sealed class GunTriggerWindow
    {
        private sealed class Window
        {
            public AttackEnhancementTuning Tuning;
            public int Remaining;
            public double Until;
            public bool Granted;
            public EffectSourceKey Source;
            public bool Active(double now)=>Granted&&Finite(now)&&now<Until&&(Tuning.TriggerLimit==0||Remaining>0);
            public void Grant(double now,AttackEnhancementTuning tuning,double sourceUntil)
            {
                if(!Finite(now)||double.IsNaN(sourceUntil)||sourceUntil<=now)throw new ArgumentOutOfRangeException(nameof(now));
                Tuning=tuning;Remaining=tuning.TriggerLimit;Until=tuning.DurationSeconds>0?Math.Min(sourceUntil,now+tuning.DurationSeconds):sourceUntil;
                if(double.IsInfinity(Until)&&tuning.DurationSeconds>0)throw new ArgumentOutOfRangeException(nameof(tuning));
                Granted=true;
            }
            public void Clear(){Granted=false;Remaining=0;Until=0;}
        }
        private readonly Window focus=new Window(),rail=new Window();
        public int FocusRemaining(double now)=>focus.Active(now)?(focus.Tuning.TriggerLimit==0?-1:focus.Remaining):0;
        public int RailRemaining(double now)=>rail.Active(now)?(rail.Tuning.TriggerLimit==0?-1:rail.Remaining):0;
        public double FocusUntil=>focus.Until;
        public double RailUntil=>rail.Until;
        public void Focus(double now)=>Focus(now,AttackEnhancementTuning.FocusDefault);
        public void Rail(double now)=>Rail(now,AttackEnhancementTuning.RailDefault);
        public void Focus(double now,AttackEnhancementTuning tuning)=>Focus(now,tuning,double.PositiveInfinity);
        public void Rail(double now,AttackEnhancementTuning tuning)=>Rail(now,tuning,double.PositiveInfinity);
        // Infinite source lifetime is explicit: source removal and owner cleanup retire it.
        public void Focus(double now,AttackEnhancementTuning tuning,double sourceUntil)=>focus.Grant(now,tuning,sourceUntil);
        public void Rail(double now,AttackEnhancementTuning tuning,double sourceUntil)=>rail.Grant(now,tuning,sourceUntil);
        public void Focus(double now,AttackEnhancementTuning tuning,EffectSourceKey source,double sourceUntil=double.PositiveInfinity)
        {focus.Grant(now,tuning,sourceUntil);focus.Source=source;}
        public void Rail(double now,AttackEnhancementTuning tuning,EffectSourceKey source,double sourceUntil=double.PositiveInfinity)
        {rail.Grant(now,tuning,sourceUntil);rail.Source=source;}
        public void CopyActiveBuffs(System.Collections.Generic.List<PlayerBuffSnapshot> destination,double now)
        {CopyWindow(focus,destination,now);CopyWindow(rail,destination,now);}
        private static void CopyWindow(Window window,System.Collections.Generic.List<PlayerBuffSnapshot> destination,double now)
        {
            if(!window.Active(now))return;
            var value=new PlayerBuffSnapshot(window.Source,PlayerBuffEffect.WeaponDamage,window.Tuning.DamageBonusFraction,window.Until)
            {FiniteUses=window.Tuning.TriggerLimit>0,RemainingTriggers=window.Remaining};
            destination.Add(value);
            if(window.Tuning.AdditionalPierceTargets>0)
            {value.Effect=PlayerBuffEffect.Pierce;value.Magnitude=window.Tuning.PierceDamageFraction;value.Stacks=window.Tuning.AdditionalPierceTargets;destination.Add(value);}
        }
        public void RemoveFocus()=>focus.Clear();
        public void RemoveRail()=>rail.Clear();
        public GunTriggerBonus Consume(double now)
        {
            bool f=focus.Active(now),r=rail.Active(now);
            if(f&&focus.Tuning.TriggerLimit>0)focus.Remaining--;if(r&&rail.Tuning.TriggerLimit>0)rail.Remaining--;
            return new GunTriggerBonus((float)Math.Min(float.MaxValue,(double)(f?focus.Tuning.DamageBonusFraction:0)+(r?rail.Tuning.DamageBonusFraction:0)),
                r,Math.Max(f?focus.Tuning.PierceDamageFraction:0,r?rail.Tuning.PierceDamageFraction:0),
                Math.Max(f?focus.Tuning.AdditionalPierceTargets:0,r?rail.Tuning.AdditionalPierceTargets:0));
        }
        public void Clear(){focus.Clear();rail.Clear();}
        private static bool Finite(double value)=>!double.IsNaN(value)&&!double.IsInfinity(value)&&value>=0;
    }
}