using XFEEDToolBox.Core.Galaxy;

namespace XFEEDToolBox.ViewModels;

public partial class ToolboxViewModel
{
    private readonly record struct GalaxyAppearanceBinding(int ProcessId,float? ColourBlend,bool? SmallMode);
    private GalaxyAppearanceBinding? galaxyAppearanceBinding;

    private void BindGalaxyAppearance(int processId,float? blend,bool? smallMode)
    {
        if(processId<=0){ResetGalaxyAppearanceBinding();return;}
        if(blend is{} value&&(!float.IsFinite(value)||value is <0 or >1))blend=null;
        var next=new GalaxyAppearanceBinding(processId,blend,smallMode);var previous=galaxyAppearanceBinding;
        if(previous==next)return;
        galaxyAppearanceBinding=next;
        // Small mode selects either immutable raw size in the current selection.
        // Only the already-mixed colour needs a new native appearance capture.
        var colourChanged=previous is not{} old||old.ProcessId!=next.ProcessId||old.ColourBlend!=next.ColourBlend;
        if(colourChanged){galaxyStreaming.Clear();galaxyCellStreaming.Clear();}
        RefreshCachedGalaxyAppearance(colourChanged,smallMode);
    }
    private void ResetGalaxyAppearanceBinding(bool stripCachedMix=true)
    {
        galaxyAppearanceBinding=null;
        if(stripCachedMix)RefreshCachedGalaxyAppearance(true,null);
    }
    private static GalacticSystem WithGalaxyAppearanceSmallMode(GalacticSystem system,bool? smallMode)
    {
        if(system.OriginalAppearance is not{} original||original.SmallSizeActive==smallMode)return system;
        return system with{OriginalAppearance=original with{SmallSizeActive=smallMode}};
    }
    private static GalacticSystem StripGalaxyAppearanceMix(GalacticSystem system,bool? smallMode)
    {
        if(system.OriginalAppearance is not{} original)return system;
        if(original.RealisticRgba is null&&original.ColourBlend is null)return WithGalaxyAppearanceSmallMode(system,smallMode);
        return system with{OriginalAppearance=original with{RealisticRgba=null,ColourBlend=null,SmallSizeActive=smallMode}};
    }
    private void RefreshCachedGalaxyAppearance(bool stripMix,bool? smallMode)
    {
        foreach(var name in galaxyCache.Keys.ToArray())
        {
            var previous=galaxyCache[name];var current=stripMix?StripGalaxyAppearanceMix(previous,smallMode):WithGalaxyAppearanceSmallMode(previous,smallMode);
            if(!ReferenceEquals(previous,current))galaxyCache[name]=current;
        }
    }
    private GalacticSystem ApplyGalaxyAppearanceBinding(GalacticSystem system,int? sourceProcessId,int? currentProcessId,bool recordedProbe)
    {
        if(recordedProbe||system.OriginalAppearance is not{} appearance)return system;
        // A local cached object has already passed this binding. An async native
        // result otherwise needs its actual originating process supplied by the
        // caller; merely assigning the current process to an old result is unsafe.
        if(sourceProcessId is null&&galaxyCache.TryGetValue(system.Name,out var cached)&&ReferenceEquals(cached,system))
            sourceProcessId=currentProcessId;
        var currentSmallMode=galaxyAppearanceBinding is{} current&&current.ProcessId==currentProcessId?current.SmallMode:null;
        if(galaxyAppearanceBinding is{} binding&&binding.ProcessId==sourceProcessId&&binding.ProcessId==currentProcessId&&
           binding.ColourBlend is{} expected&&appearance.ColourBlend==expected)return WithGalaxyAppearanceSmallMode(system,currentSmallMode);
        return StripGalaxyAppearanceMix(system,currentSmallMode);
    }
}