Fact.cs

    public OnLineFact(string pid, string rid, string uri, FactOrganizer organizer) : base(organizer)
    {
        this.Pid = pid;
        this.Rid = rid;
        this._URI = uri;
        _ = this.Label;
    }

    /// \copydoc Fact.parseFact(Scroll.ScrollFact)
    public new static OnLineFact parseFact(Scroll.ScrollFact fact)
    {
        string uri = fact.@ref.uri;

        string lineUri = "";
        string pointUri = "";
        
        if (((OMA)((OMA)((Scroll.ScrollSymbolFact)fact).tp).arguments[0]).arguments[0] is OMS)
        {
            // standard case
            lineUri = ((OMS)((OMA)((OMA)((Scroll.ScrollSymbolFact)fact).tp).arguments[0]).arguments[0]).uri;
            pointUri = ((OMS)((OMA)((OMA)((Scroll.ScrollSymbolFact)fact).tp).arguments[0]).arguments[1]).uri;
        }
        else {
            // case when line Uri has a projl on the line Argument 
            lineUri = ((OMS)((OMA)((OMA)((OMA)((Scroll.ScrollSymbolFact)fact).tp).arguments[0]).arguments[0]).arguments[0]).uri;
            pointUri = ((OMS)((OMA)((OMA)((Scroll.ScrollSymbolFact)fact).tp).arguments[0]).arguments[1]).uri;


        }
        if (StageStatic.stage.factState.ContainsKey(pointUri)
         && StageStatic.stage.factState.ContainsKey(lineUri))
            return new OnLineFact(pointUri, lineUri, uri, StageStatic.stage.factState);

        //If dependent facts do not exist return null
        else
            return null;
    }

    /// \copydoc Fact.generateLabel
    protected override string generateLabel()
    {
        return _Facts[Pid].Label + "∈" + _Facts[Rid].Label;
    }

    /// \copydoc Fact.hasDependentFacts
    public override Boolean hasDependentFacts()
    {
        return true;
    }

    /// \copydoc Fact.getDependentFactIds
    public override string[] getDependentFactIds()
    {
        return new string[] { Pid, Rid };
    }

    /// \copydoc Fact.instantiateDisplay(GameObject, Transform)
    public override GameObject instantiateDisplay(GameObject prefab, Transform transform)
    {
        var obj = GameObject.Instantiate(prefab, Vector3.zero, Quaternion.identity, transform);
        obj.transform.GetChild(0).gameObject.GetComponent<TextMeshProUGUI>().text = _Facts[this.Pid].Label;
        obj.transform.GetChild(1).gameObject.GetComponent<TextMeshProUGUI>().text = _Facts[this.Rid].Label;
        obj.GetComponent<FactWrapper>().fact = this;
        return obj;
    }

    /// \copydoc Fact.GetHashCode
    public override int GetHashCode()
    {
        return this.Pid.GetHashCode() ^ this.Rid.GetHashCode();
    }

    /// \copydoc Fact.Equivalent(Fact, Fact)
    protected override bool EquivalentWrapped(OnLineFact f1, OnLineFact f2)
    {
        if (f1.Pid == f2.Pid && f1.Rid == f2.Rid)
            return true;

        PointFact pf1 = (PointFact)_Facts[f1.Pid];
        RayFact rf1 = (RayFact)_Facts[f1.Rid];
        PointFact pf2 = (PointFact)_Facts[f2.Pid];
        RayFact rf2 = (RayFact)_Facts[f2.Rid];

        return pf1.Equivalent(pf2) && rf1.Equivalent(rf2);
    }
}

/// <summary>
/// Angle comprised of three <see cref="PointFact">PointFacts</see> [A,B,C]
/// </summary>
public class AngleFact : FactWrappedCRTP<AngleFact>
{
    /// @{ <summary>
    /// One <see cref="Fact.Id">Id</see> of three <see cref="PointFact">PointFacts</see> defining Angle [<see cref="Pid1"/>, <see cref="Pid2"/>, <see cref="Pid3"/>].
    /// </summary>
    public string Pid1, Pid2, Pid3;
    /// @}

    /// <summary> <see langword="true"/>, if AngleFact is approximately 90° or 270°</summary>
    public bool is_right_angle;


    /// <summary> \copydoc Fact.Fact </summary>
    public AngleFact() : base()
    {
        this.Pid1 = null;
        this.Pid2 = null;
        this.Pid3 = null;
        this.is_right_angle = false;
    }

    /// <summary>
    /// Copies <paramref name="fact"/> by initiating new MMT %Fact.
    /// </summary>
    /// <param name="fact">Fact to be copied</param>
    /// <param name="old_to_new"><c>Dictionary</c> mapping <paramref name="fact"/>.<see cref="getDependentFactIds"/> in <paramref name="fact"/>.<see cref="Fact._Facts"/> to corresponding <see cref="Fact.Id"/> in <paramref name="organizer"/> </param>
    /// <param name="organizer">sets <see cref="_Facts"/></param>
    public AngleFact(AngleFact fact, Dictionary<string, string> old_to_new, FactOrganizer organizer) : base(fact, organizer)
    {
        init(old_to_new[fact.Pid1], old_to_new[fact.Pid2], old_to_new[fact.Pid3]);
    }

    /// <summary>
    /// Standard Constructor
    /// </summary>
    /// <param name="pid1">sets <see cref="Pid1"/></param>
    /// <param name="pid2">sets <see cref="Pid2"/></param>
    /// <param name="pid3">sets <see cref="Pid3"/></param>
    /// <param name="organizer">sets <see cref="Fact._Facts"/></param>
    public AngleFact(string pid1, string pid2, string pid3, FactOrganizer organizer) : base(organizer)
    {
        init(pid1, pid2, pid3);
    }

    /// <summary>
    /// Initiates <see cref="Pid1"/>, <see cref="Pid2"/>, <see cref="Pid3"/>, <see cref="is_right_angle"/>, <see cref="Fact._URI"/> and creates MMT %Fact Server-Side
    /// </summary>
    /// <param name="pid1">sets <see cref="Pid1"/></param>
    /// <param name="pid2">sets <see cref="Pid2"/></param>
    /// <param name="pid3">sets <see cref="Pid3"/></param>
    private void init(string pid1, string pid2, string pid3)
    {
        this.Pid1 = pid1;
        this.Pid2 = pid2;
        this.Pid3 = pid3;

        PointFact pf1 = _Facts[pid1] as PointFact;
        PointFact pf2 = _Facts[pid2] as PointFact;
        PointFact pf3 = _Facts[pid3] as PointFact;

        float v = GetAngle(); // sets is_right_angle
        if (Mathf.Abs(Mathf.Abs(v) - 90.0f) < 0.1)
        {
            // also generate a RightAngleFact 
            RightAngleFact rightAngle = new RightAngleFact(pid1, pid2, pid3, StageStatic.stage.factState);
            // I have no clue if this is actually necessary
            bool exists;
            StageStatic.stage.factState.Add(rightAngle, out exists, true);
        }


        MMTDeclaration mmtDecl;
        string p1URI = pf1.Id;
        string p2URI = pf2.Id;
        string p3URI = pf3.Id;
       // if (is_right_angle)
       //     mmtDecl = generate90DegreeAngleDeclaration(v, p1URI, p2URI, p3URI);
       // else
          mmtDecl = generateNot90DegreeAngleDeclaration(v, p1URI, p2URI, p3URI);

        AddFactResponse.sendAdd(mmtDecl, out this._URI);
    }

    /// <summary>
    /// Bypasses initialization of new MMT %Fact by using existend URI, _which is not checked for existence_.
    /// </summary>
    /// <param name="Pid1">sets <see cref="Pid1"/></param>
    /// <param name="Pid2">sets <see cref="Pid2"/></param>
    /// <param name="Pid3">sets <see cref="Pid3"/></param>
    /// <param name="backendURI">MMT URI</param>
    /// <param name="organizer">sets <see cref="Fact._Facts"/></param>
    public AngleFact(string Pid1, string Pid2, string Pid3, string backendURI, FactOrganizer organizer) : base(organizer)
    {
        this.Pid1 = Pid1;
        this.Pid2 = Pid2;
        this.Pid3 = Pid3;

        float v = GetAngle();

        if (Mathf.Abs(Mathf.Abs(v) - 90.0f) < 0.1)
        {
            // also generate an orthogonal circle line fact

            RightAngleFact rightAngle = new RightAngleFact(Pid1, Pid2, Pid3, StageStatic.stage.factState);
            // is it necessary to make a boolean variable here?
            bool exists;
            StageStatic.stage.factState.Add(rightAngle, out exists, true);
        }



        this._URI = backendURI;
        _ = this.Label;
    }

    public AngleFact(string Pid1, string Pid2, string Pid3,float angle, string backendURI, FactOrganizer organizer) : base(organizer)
    {
        this.Pid1 = Pid1;
        this.Pid2 = Pid2;
        this.Pid3 = Pid3;

        if (Mathf.Abs(Mathf.Abs(angle) - 90.0f) < 0.1)
        {
            // also generate an orthogonal circle line fact

            RightAngleFact rightAngle = new RightAngleFact(Pid1, Pid2, Pid3, StageStatic.stage.factState);
            // I have no clue if this is actually necessary
            bool exists;
            StageStatic.stage.factState.Add(rightAngle, out exists, true);
        }
        this._URI = backendURI;
        _ = this.Label;
    }



    /// \copydoc Fact.parseFact(Scroll.ScrollFact)
    public new static AngleFact parseFact(Scroll.ScrollFact fact)
    {
        string uri = fact.@ref.uri;
        string
            pointAUri,
            pointBUri,
            pointCUri;

        float angle = 0.0f;
        //If angle is not a 90Degree-Angle
        if (fact.GetType().Equals(typeof(Scroll.ScrollValueFact)))
        {
            OMA df = (OMA)((Scroll.ScrollValueFact)fact).lhs;

            if (df == null)
                return null;

      

            if (((Scroll.ScrollValueFact)fact).value != null)
                angle = ((OMF)(((Scroll.ScrollValueFact)fact).value)).f;


            pointAUri = ((OMS)((OMA)((Scroll.ScrollValueFact)fact).lhs).arguments[0]).uri;
            pointBUri = ((OMS)((OMA)((Scroll.ScrollValueFact)fact).lhs).arguments[1]).uri;
            pointCUri = ((OMS)((OMA)((Scroll.ScrollValueFact)fact).lhs).arguments[2]).uri;

        }
        // this should never happen anymore
        //If angle is a 90Degree-Angle
        else {
            Debug.Log("Angle 90 degrees parsed. This shouldn't happen anymore");
            
            pointAUri = ((OMS)((OMA)((OMA)((OMA)((Scroll.ScrollSymbolFact)fact).tp).arguments[0]).arguments[1]).arguments[0]).uri;
            pointBUri = ((OMS)((OMA)((OMA)((OMA)((Scroll.ScrollSymbolFact)fact).tp).arguments[0]).arguments[1]).arguments[1]).uri;
            pointCUri = ((OMS)((OMA)((OMA)((OMA)((Scroll.ScrollSymbolFact)fact).tp).arguments[0]).arguments[1]).arguments[2]).uri;
        }

        if (StageStatic.stage.factState.ContainsKey(pointAUri)
         && StageStatic.stage.factState.ContainsKey(pointBUri)
         && StageStatic.stage.factState.ContainsKey(pointCUri))
        {
//                return new AngleFact(pointAUri, pointBUri, pointCUri, uri, StageStatic.stage.factState);
                return new AngleFact(pointAUri, pointBUri, pointCUri,angle, uri, StageStatic.stage.factState);
        }
        else
        {   //If dependent facts do not exist return null
            return null;
        }
    }

    /// \copydoc Fact.generateLabel
    protected override string generateLabel()
    {
        return (is_right_angle ? "⊾" : "∠") + _Facts[Pid1].Label + _Facts[Pid2].Label + _Facts[Pid3].Label;
    }

    /// <summary>
    /// Computes smallest angle and sets <see cref="is_right_angle"/>
    /// </summary>
    /// <returns>Smallets angle between [<see cref="Pid1"/>, <see cref="Pid2"/>] and [<see cref="Pid2"/>, <see cref="Pid3"/>]</returns>
    private float GetAngle()
    {
        PointFact pf1 = _Facts[Pid1] as PointFact;
        PointFact pf2 = _Facts[Pid2] as PointFact;
        PointFact pf3 = _Facts[Pid3] as PointFact;

        float v = Vector3.Angle((pf1.Point - pf2.Point), (pf3.Point - pf2.Point));
        this.is_right_angle = Mathf.Abs(v - 90.0f) < 0.01;

        return is_right_angle ? 90f : v;
    }

    /// <summary>
    /// Constructs struct for right-angled MMT %Fact <see cref="AddFactResponse"/>
    /// </summary>
    /// <param name="val">Angle == 90f, _not checked_</param>
    /// <param name="p1URI"><see cref="Pid1"/></param>
    /// <param name="p2URI"><see cref="Pid2"/></param>
    /// <param name="p3URI"><see cref="Pid3"/></param>
    /// <returns>struct for <see cref="AddFactResponse"/></returns>
    private MMTDeclaration generate90DegreeAngleDeclaration(float val, string p1URI, string p2URI, string p3URI) {

        MMTTerm argument = new OMA(
            new OMS(MMTURIs.Eq),
            new List<MMTTerm> {
                new OMS(MMTURIs.RealLit),
                new OMA(
                    new OMS(MMTURIs.Angle),
                    new List<MMTTerm> {
                        new OMS(p1URI),
                        new OMS(p2URI),
                        new OMS(p3URI)
                    }
                ),
                new OMF(val) // 90f
            }
        );
        
        MMTTerm tp = new OMA(new OMS(MMTURIs.Ded), new List<MMTTerm> {argument});
        MMTTerm df = null;

        return new MMTSymbolDeclaration(this.Label, tp, df);
    }

    /// <summary>
    /// Constructs struct for not-right-angled MMT %Fact <see cref="AddFactResponse"/>
    /// </summary>
    /// <param name="val">Angle != 90f, _not checked_</param>
    /// <param name="p1URI"><see cref="Pid1"/></param>
    /// <param name="p2URI"><see cref="Pid2"/></param>
    /// <param name="p3URI"><see cref="Pid3"/></param>
    /// <returns>struct for <see cref="AddFactResponse"/></returns>
    private MMTDeclaration generateNot90DegreeAngleDeclaration(float val, string p1URI, string p2URI, string p3URI)
    {
        MMTTerm lhs =
            new OMA(
                new OMS(MMTURIs.Angle),
                new List<MMTTerm> {
                    new OMS(p1URI),
                    new OMS(p2URI),
                    new OMS(p3URI)
                }
            );

        MMTTerm valueTp = new OMS(MMTURIs.RealLit);
        MMTTerm value = new OMF(val);
        
        return new MMTValueDeclaration(this.Label, lhs, valueTp, value);
    }

    /// \copydoc Fact.hasDependentFacts
    public override Boolean hasDependentFacts()
    {
        return true;
    }

    /// \copydoc Fact.getDependentFactIds
    public override string[] getDependentFactIds()
    {
        return new string[] { Pid1, Pid2, Pid3 };
    }

    /// \copydoc Fact.instantiateDisplay(GameObject, Transform)
    public override GameObject instantiateDisplay(GameObject prefab, Transform transform) {
        var obj = GameObject.Instantiate(prefab, Vector3.zero, Quaternion.identity, transform);
        obj.transform.GetChild(0).gameObject.GetComponent<TextMeshProUGUI>().text = _Facts[this.Pid1].Label;
        obj.transform.GetChild(1).gameObject.GetComponent<TextMeshProUGUI>().text = _Facts[this.Pid2].Label;
        obj.transform.GetChild(2).gameObject.GetComponent<TextMeshProUGUI>().text = _Facts[this.Pid3].Label;
        obj.GetComponent<FactWrapper>().fact = this;
        return obj;
    }

    /// \copydoc Fact.GetHashCode
    public override int GetHashCode()
    {
        return this.Pid1.GetHashCode() ^ this.Pid2.GetHashCode() ^ this.Pid3.GetHashCode();
    }

    /// \copydoc Fact.Equivalent(Fact, Fact)
    protected override bool EquivalentWrapped(AngleFact f1, AngleFact f2)
    {
        if ((f1.Pid1 == f2.Pid1 && f1.Pid2 == f2.Pid2 && f1.Pid3 == f2.Pid3))// || 
            //(f1.Pid1 == f2.Pid3 && f1.Pid2 == f2.Pid2 && f1.Pid3 == f2.Pid1))
            return true;

        PointFact p1f1 = (PointFact)_Facts[f1.Pid1];
        PointFact p2f1 = (PointFact)_Facts[f1.Pid2];
        PointFact p3f1 = (PointFact)_Facts[f1.Pid3];
        PointFact p1f2 = (PointFact)_Facts[f2.Pid1];
        PointFact p2f2 = (PointFact)_Facts[f2.Pid2];
        PointFact p3f2 = (PointFact)_Facts[f2.Pid3];

        return (p1f1.Equivalent(p1f2) && p2f1.Equivalent(p2f2) && p3f1.Equivalent(p3f2));
        //|| (p1f1.Equivalent(p3f2) && p2f1.Equivalent(p2f2) && p1f1.Equivalent(p3f2));
    }
}


/// TODO Work in Progress
/// <summary>
/// Two parallel Lines comprised of two <see cref="LineFact">LineFacts</see> 
/// </summary>
public class ParallelLineFact : FactWrappedCRTP<ParallelLineFact>
{
    /// @{ <summary>
    /// One <see cref="Fact.Id">Id</see> of thwo <see cref="LineFact">PointFacts</see> defining Angle [<see cref="Lid1"/>, <see cref="Lid2"/>].
    /// </summary>
    public string Lid1, Lid2;
    /// @}




    /// <summary> \copydoc Fact.Fact </summary>
    public ParallelLineFact() : base()
    {
        this.Lid1 = null;
        this.Lid2 = null;
    }

    /// <summary>
    /// Copies <paramref name="fact"/> by initiating new MMT %Fact.
    /// </summary>
    /// <param name="fact">Fact to be copied</param>
    /// <param name="old_to_new"><c>Dictionary</c> mapping <paramref name="fact"/>.<see cref="getDependentFactIds"/> in <paramref name="fact"/>.<see cref="Fact._Facts"/> to corresponding <see cref="Fact.Id"/> in <paramref name="organizer"/> </param>
    /// <param name="organizer">sets <see cref="_Facts"/></param>
    public ParallelLineFact(ParallelLineFact fact, Dictionary<string, string> old_to_new, FactOrganizer organizer) : base(fact, organizer)
    {
        init(old_to_new[fact.Lid1], old_to_new[fact.Lid2]);
    }

    /// <summary>
    /// Standard Constructor
    /// </summary>
    /// <param name="lid1">sets <see cref="Lid1"/></param>
    /// <param name="lid2">sets <see cref="Lid2"/></param>
    /// <param name="organizer">sets <see cref="Fact._Facts"/></param>
    public ParallelLineFact(string lid1, string lid2, FactOrganizer organizer) : base(organizer)
    {
        init(lid1, lid2);
    }

    /// <summary>
    /// Initiates <see cref="Lid1"/>, <see cref="Lid2"/>, <see cref="Fact._URI"/> and creates MMT %Fact Server-Side
    /// </summary>
    /// <param name="lid1">sets <see cref="Lid1"/></param>
    /// <param name="lid2">sets <see cref="Lid2"/></param>
    private void init(string lid1, string lid2)
    {
        //TODO must be parallel lines 
        this.Lid1 = lid1;
        this.Lid2 = lid2;

        RayFact lf1 = _Facts[lid1] as RayFact;
        RayFact lf2 = _Facts[lid2] as RayFact;

        MMTDeclaration mmtDecl;
        string l1URI = lf1.Id;
        string l2URI = lf2.Id;
        mmtDecl = generateParallelLineDeclaration( l1URI, l2URI);
    
        AddFactResponse.sendAdd(mmtDecl, out this._URI);
    }

    /// <summary>
    /// Bypasses initialization of new MMT %Fact by using existend URI, _which is not checked for existence_.
    /// </summary>
    /// <param name="Lid1">sets <see cref="Lid1"/></param>
    /// <param name="Lid2">sets <see cref="Lid2"/></param>
    /// <param name="backendURI">MMT URI</param>
    /// <param name="organizer">sets <see cref="Fact._Facts"/></param>
    public ParallelLineFact(string Lid1, string Lid2, string backendURI, FactOrganizer organizer) : base(organizer)
    {
        this.Lid1 = Lid1;
        this.Lid2 = Lid2;

        this._URI = backendURI;
        _ = this.Label;
    }

    /// \copydoc Fact.parseFact(Scroll.ScrollFact)
    public new static ParallelLineFact parseFact(Scroll.ScrollFact fact)
    {
        OMA tp = (OMA)((Scroll.ScrollSymbolFact)fact).tp;
        if (tp == null)
            return null;

        string lineAUri = "";
        string lineBUri = "";

        string uri = fact.@ref.uri;
        OMA proof_OMA = (OMA)((Scroll.ScrollSymbolFact)fact).tp; // proof DED
   

        OMA parallel_lines_OMA = (OMA) proof_OMA.arguments[0]; // parallel

        if (parallel_lines_OMA.arguments[0] is OMS) {
            // Normaler Fall 
            lineAUri = ((OMS)((OMA)((OMA)((Scroll.ScrollSymbolFact)fact).tp).arguments[0]).arguments[0]).uri;
            lineBUri = ((OMS)((OMA)((OMA)((Scroll.ScrollSymbolFact)fact).tp).arguments[0]).arguments[1]).uri;

        }
        // Second case might be redundant by now
        else {
            OMA Projl_line_A_OMA = (OMA)parallel_lines_OMA.arguments[0]; // ProjectL
            lineAUri = ((OMS)Projl_line_A_OMA.arguments[0]).uri;
            OMA Projl_line_B_OMA = (OMA)parallel_lines_OMA.arguments[1]; // ProjectL
            lineBUri = ((OMS)Projl_line_B_OMA.arguments[0]).uri;


        }


        if (StageStatic.stage.factState.ContainsKey(lineAUri)
         && StageStatic.stage.factState.ContainsKey(lineBUri))

            return new ParallelLineFact(lineAUri,lineBUri, uri, StageStatic.stage.factState);

        else    //If dependent facts do not exist return null
            return null;
    }

    /// \copydoc Fact.generateLabel
    protected override string generateLabel()
    {
        return "||" + _Facts[Lid1].Label + _Facts[Lid2].Label;
    }



    /// <summary>
    /// Constructs struct for right-angled MMT %Fact <see cref="AddFactResponse"/>
    /// </summary>
    /// <param name="l1URI"><see cref="Lid1"/></param>
    /// <param name="l2URI"><see cref="Lid2"/></param>
    /// <returns>struct for <see cref="AddFactResponse"/></returns>
    private MMTDeclaration generateParallelLineDeclaration(string l1URI, string l2URI)
    {
        
        List<MMTTerm> innerArguments = new List<MMTTerm>
        {
            new OMS(l1URI),
            new OMS(l2URI)
        };

        List<MMTTerm> outerArguments = new List<MMTTerm>
        {
            new OMA(new OMS(MMTURIs.ParallelLine), innerArguments)
        };

        //OMS constructor generates full URI
        MMTTerm tp = new OMA(new OMS(MMTURIs.Ded), outerArguments);
        MMTTerm df = null;

        MMTSymbolDeclaration mmtDecl = new MMTSymbolDeclaration(this.Label, tp, df);
        AddFactResponse.sendAdd(mmtDecl, out this._URI);


        return mmtDecl;
    }


    /// \copydoc Fact.hasDependentFacts
    public override Boolean hasDependentFacts()
    {
        return true;
    }

    /// \copydoc Fact.getDependentFactIds
    public override string[] getDependentFactIds()
    {
        return new string[] { Lid1, Lid2 };
    }

    /// \copydoc Fact.instantiateDisplay(GameObject, Transform)
    public override GameObject instantiateDisplay(GameObject prefab, Transform transform)
    {
        var obj = GameObject.Instantiate(prefab, Vector3.zero, Quaternion.identity, transform);
        obj.transform.GetChild(0).gameObject.GetComponent<TextMeshProUGUI>().text = _Facts[this.Lid1].Label;
        obj.transform.GetChild(1).gameObject.GetComponent<TextMeshProUGUI>().text = _Facts[this.Lid2].Label;
        obj.GetComponent<FactWrapper>().fact = this;
        return obj;
    }

    /// \copydoc Fact.GetHashCode
    public override int GetHashCode()
    {
        return this.Lid1.GetHashCode() ^ this.Lid2.GetHashCode() ;
    }

    /// \copydoc Fact.Equivalent(Fact, Fact)
    protected override bool EquivalentWrapped(ParallelLineFact f1, ParallelLineFact f2)
    {
        if ((f1.Lid1 == f2.Lid1 && f1.Lid2 == f2.Lid2))
            return true;

        RayFact r1f1 = (RayFact)_Facts[f1.Lid1];
        RayFact r2f1 = (RayFact)_Facts[f1.Lid2];
        RayFact r1f2 = (RayFact)_Facts[f2.Lid1];
        RayFact r2f2 = (RayFact)_Facts[f2.Lid2];

        return (r1f1.Equivalent(r1f2) && r2f1.Equivalent(r2f2)) ;
    }
}




//TODO big work in progress Circle Wrapper

/// TODO Work in Progress
/// <summary>
/// A Circle that is made out of a middle point, a plane and a radius  
/// </summary>
public class CircleFact : FactWrappedCRTP<CircleFact>
{
   
    /// <summary> defining the middle point of the circle  </summary>
    public string Pid1;
    /// <summary>  defining the base point of the circle plane </summary>
    public string Pid2;
    /// <summary>  radius of the circle </summary>
    public float radius;
    /// <summary> normal vector of the plane </summary>
    public Vector3 normal;
   
    /// <summary> \copydoc Fact.Fact </summary>
    public CircleFact() : base()
    {
        this.normal = Vector3.zero;
        this.Pid1 = null;
        this.Pid2 = null;
        this.radius = 0;
    }

    /// <summary>
    /// Copies <paramref name="fact"/> by initiating new MMT %Fact.
    /// </summary>
    /// <param name="fact">Fact to be copied</param>
    /// <param name="old_to_new"><c>Dictionary</c> mapping <paramref name="fact"/>.<see cref="getDependentFactIds"/> in <paramref name="fact"/>.<see cref="Fact._Facts"/> to corresponding <see cref="Fact.Id"/> in <paramref name="organizer"/> </param>
    /// <param name="organizer">sets <see cref="_Facts"/></param>
    public CircleFact(CircleFact fact, Dictionary<string, string> old_to_new, FactOrganizer organizer) : base(fact, organizer)
    {
        init(old_to_new[fact.Pid1], old_to_new[fact.Pid2], fact.radius, fact.normal);
    }

    /// <summary>
    /// Standard Constructor
    /// </summary>
    /// <param name="pid1">sets <see cref="Pid1"/></param>
    /// <param name="pid2">sets <see cref="Pid2"/></param>
    /// <param name="radius">sets <see cref="radius"/></param>
    /// <param name="normal">sets <see cref="normal"/></param>
    /// <param name="organizer">sets <see cref="Fact._Facts"/></param>
    public CircleFact(string pid1, string pid2, float radius, Vector3 normal, FactOrganizer organizer) : base(organizer)
    {
        init(pid1, pid2, radius, normal);
    }

    /// <summary>
    /// Initiates <see cref="Pid1"/>, <see cref="Pid2"/>, <see cref="radius"/>,<see cref="dir1"/>,<see cref="dir2"/>, <see cref="Fact._URI"/> and creates MMT %Fact Server-Side
    /// </summary>
    /// <param name="pid1">sets <see cref="Pid1"/></param>
    /// <param name="pid2">sets <see cref="Pid2"/></param>
    /// <param name="radius">sets <see cref="radius"/></param>
    /// <param name="normal">sets <see cref="normal"/></param>
    private void init(string pid1, string pid2, float radius, Vector3 normal)
    {
        this.Pid1 = pid1;
        this.Pid2 = pid2;

        PointFact pf1 = _Facts[pid1] as PointFact;
        PointFact pf2 = _Facts[pid2] as PointFact;


        this.radius = radius;
        this.normal = normal;

        MMTDeclaration mmtDecl;
        string p1URI = pf1.Id;
        string p2URI = pf2.Id;

        mmtDecl = generateCircleFactDeclaration(p1URI, p2URI, radius, normal);

        AddFactResponse.sendAdd(mmtDecl, out this._URI);
    }

    /// <summary>
    /// Bypasses initialization of new MMT %Fact by using existend URI, _which is not checked for existence_.
    /// </summary>
    /// <param name="Pid1">sets <see cref="Pid1"/></param>
    /// <param name="Pid2">sets <see cref="Pid2"/></param>
    /// <param name="radius">sets <see cref="radius"/></param>
    /// <param name="normal">sets <see cref="normal"/></param>
    /// <param name="backendURI">MMT URI</param>
    /// <param name="organizer">sets <see cref="Fact._Facts"/></param>
    public CircleFact(string Pid1, string Pid2, float radius, Vector3 normal, string backendURI, FactOrganizer organizer) : base(organizer)
    {
        this.Pid1 = Pid1;
        this.Pid2 = Pid2;

        this.radius = radius;
        this.normal = normal;
 
        this._URI = backendURI;
        _ = this.Label;
    }

    /// <summary>
    /// parses the Circlefact response of the MMT-Server
    /// </summary>
    /// \copydoc Fact.parseFact(Scroll.ScrollFact) 
    public new static CircleFact parseFact(Scroll.ScrollFact fact)
    {
        string uri = fact.@ref.uri;
        string M_uri = "";
        string A_uri = "";
        float radius = 0.0f;
        Vector3 normal = Vector3.zero;
        OMA df = (OMA)((Scroll.ScrollSymbolFact)fact).df;

        if (df == null)
            return null;

        Scroll.ScrollSymbolFact casted_fact = (Scroll.ScrollSymbolFact)fact;
        


        // get the mid point uri
        string parse_id_M = ParsingDictionary.MMTermToString(((OMA)casted_fact.df).arguments[1]);

        Debug.Log("parse_id_M " + parse_id_M);
        M_uri = ParsingDictionary.parseTermsToId[parse_id_M];
        Debug.Log("M URI " + M_uri);

        // get the radius
        radius = ((OMF)((OMA)casted_fact.df).arguments[2]).f;

        OMA planeOMA = (OMA)((OMA)casted_fact.df).arguments[0];
        string planeApplicant = ((OMS)planeOMA.applicant).uri;


        // Getting the plane
        // IN case of a normale plane
        if (planeApplicant.Equals(MMTURIs.pointNormalPlane))
        {
            Debug.Log("planeApplicant" + planeApplicant);

            OMA pointAOMA = (OMA)planeOMA.arguments[0];

            string parse_id_A = ParsingDictionary.MMTermToString(planeOMA.arguments[0]);
            A_uri = ParsingDictionary.parseTermsToId[parse_id_A];

            OMA n = (OMA)planeOMA.arguments[1];
            normal = new Vector3(((OMF)n.arguments[0]).f, ((OMF)n.arguments[1]).f, ((OMF)n.arguments[2]).f);
            Debug.Log("Norm " + normal.ToString());


        }
        // In case of parametrized plane
        else if(planeApplicant.Equals(MMTURIs.ParametrizedPlane))
        {
            Debug.Log("planeApplicant" + planeApplicant);

            OMA pointAOMA = (OMA)planeOMA.arguments[0];
            string parse_id_A = ParsingDictionary.MMTermToString(planeOMA.arguments[0]);
            A_uri = ParsingDictionary.parseTermsToId[parse_id_A];


            OMA vOMA = (OMA)planeOMA.arguments[1];
            OMA wOMA = (OMA)planeOMA.arguments[2];

            Vector3 v = new Vector3(((OMF)vOMA.arguments[0]).f, ((OMF)vOMA.arguments[1]).f, ((OMF)vOMA.arguments[2]).f);
            Vector3 w = new Vector3(((OMF)wOMA.arguments[0]).f, ((OMF)wOMA.arguments[1]).f, ((OMF)wOMA.arguments[2]).f);

            normal = Vector3.Cross(v, w).normalized;

            Debug.Log("Para "+normal.ToString());

        }
        else {
            Debug.Log("planeApplicant" + planeApplicant);
            Debug.Log("?? " + MMTURIs.pointNormalPlane);

            return null;
        }



        if (StageStatic.stage.factState.ContainsKey(M_uri)
         && StageStatic.stage.factState.ContainsKey(A_uri))
              return new CircleFact(M_uri,A_uri,radius,normal, uri, StageStatic.stage.factState);

        else    //If dependent facts do not exist return null
            return null;
    }

    /// \copydoc Fact.generateLabel
    protected override string generateLabel()
    {

        return  "○"+_Facts[Pid1].Label;
    }



    /// <summary>
    /// Constructs struct for right-angled MMT %Fact <see cref="AddFactResponse"/>
    /// </summary>
    /// <param name="p1URI"> <see cref="Pid1"/></param>
    /// <param name="p2URI"> <see cref="Pid2"/></param>
    /// <param name="radius"> <see cref="radius"/></param>
    /// <returns>struct for <see cref="AddFactResponse"/></returns>
    private MMTDeclaration generateCircleFactDeclaration( string p1URI, string p2URI, float radius, Vector3 normal)
    {
        PointFact p1 = _Facts[p1URI] as PointFact;
        PointFact p2 = _Facts[p2URI] as PointFact;


        List<MMTTerm> normalArgs = new List<MMTTerm>
        {
            new OMF(normal.x),
            new OMF(normal.y),
            new OMF(normal.z)
        };
        OMA NormalVector = new OMA(new OMS(MMTURIs.Tuple), normalArgs);



        List<MMTTerm> planeArgs = new List<MMTTerm>
        {
            new OMS(p2URI),
            NormalVector //n
        };

        OMA CirclePlane = new OMA(new OMS(MMTURIs.pointNormalPlane), planeArgs);
        OMS middlePoint = new OMS(p1URI);
        OMF Radius = new OMF(radius);

        List<MMTTerm> outerArguments = new List<MMTTerm>
        {
           CirclePlane,
           middlePoint,
           Radius
        };

        //OMS constructor generates full URI
        // Do i need this here? doubt 
        MMTTerm tp = new OMS(MMTURIs.CircleType3d);
        MMTTerm df = new OMA(new OMS(MMTURIs.MkCircle3d), outerArguments);

        MMTSymbolDeclaration mmtDecl = new MMTSymbolDeclaration(this.Label, tp, df);
        AddFactResponse.sendAdd(mmtDecl, out this._URI);


        return mmtDecl;
    }


    /// \copydoc Fact.hasDependentFacts
    public override Boolean hasDependentFacts()
    {
        return true;
    }

    public Vector3 getNormal() 
    {
        return normal;
    }


    /// \copydoc Fact.getDependentFactIds
    public override string[] getDependentFactIds()
    {
        return new string[] { Pid1,Pid2 };
    }

    /// \copydoc Fact.instantiateDisplay(GameObject, Transform)
    public override GameObject instantiateDisplay(GameObject prefab, Transform transform)
    {
        var obj = GameObject.Instantiate(prefab, Vector3.zero, Quaternion.identity, transform);
        obj.transform.GetChild(0).gameObject.GetComponent<TextMeshProUGUI>().text = _Facts[this.Pid1].Label;
 
        // obj.transform.GetChild(1).gameObject.GetComponent<TextMeshProUGUI>().text = _Facts[this.Lid2].Label;

        obj.GetComponent<FactWrapper>().fact = this;
        return obj;
    }

    /// \copydoc Fact.GetHashCode
    public override int GetHashCode()
    {
        return  this.Pid1.GetHashCode() ^ this.Pid2.GetHashCode() ;
    }

    /// \copydoc Fact.Equivalent(Fact, Fact)
    protected override bool EquivalentWrapped(CircleFact f1, CircleFact f2)
    {
        if ( f1.Pid1 == f2.Pid1 && f1.normal == f2.normal && f1.radius == f2.radius)
            return true;

        PointFact p1f1 = (PointFact)_Facts[f1.Pid1];
        PointFact p1f2 = (PointFact)_Facts[f2.Pid1];

        return (p1f1.Equivalent(p1f2) && f1.normal == f2.normal && f1.radius == f2.radius);
    }
}


/// <summary>
/// A <see cref="PointFact"/> on a <see cref="CircleFact"/>
/// </summary>
public class OnCircleFact : FactWrappedCRTP<OnCircleFact>
{
    /// <summary> the point on the circle  </summary>
    public string Pid;
    /// <summary> the circle, which the point is on  </summary>
    public string Cid;

    /// <summary> \copydoc Fact.Fact </summary>
    public OnCircleFact() : base()
    {
        this.Pid = null;
        this.Cid = null;
    }

    /// <summary>
    /// Copies <paramref name="fact"/> by initiating new MMT %Fact.
    /// </summary>
    /// <param name="fact">Fact to be copied</param>
    /// <param name="old_to_new"><c>Dictionary</c> mapping <paramref name="fact"/>.<see cref="getDependentFactIds"/> in <paramref name="fact"/>.<see cref="Fact._Facts"/> to corresponding <see cref="Fact.Id"/> in <paramref name="organizer"/> </param>
    /// <param name="organizer">sets <see cref="_Facts"/></param>
    public OnCircleFact(OnCircleFact fact, Dictionary<string, string> old_to_new, FactOrganizer organizer) : base(fact, organizer)
    {
        init(old_to_new[fact.Pid], old_to_new[fact.Cid]);
    }

    /// <summary>
    /// Standard Constructor
    /// </summary>
    /// <param name="pid">sets <see cref="Pid"/></param>
    /// <param name="cid">sets <see cref="Cid"/></param>
    /// <param name="organizer">sets <see cref="Fact._Facts"/></param>
    public OnCircleFact(string pid, string cid, FactOrganizer organizer) : base(organizer)
    {
        init(pid, cid);
    }

    /// <summary>
    /// Initiates <see cref="Pid"/>, <see cref="Rid"/>, <see cref="Fact._URI"/> and creates MMT %Fact Server-Side
    /// </summary>
    /// <param name="pid">sets <see cref="Pid"/></param>
    /// <param name="cid">sets <see cref="Cid"/></param>
    private void init(string pid, string cid)
    {
        this.Pid = pid;
        this.Cid = cid;

        PointFact pf = _Facts[pid] as PointFact;
        CircleFact cf = _Facts[cid] as CircleFact;
        string pURI = pf.Id;
        string cURI = cf.Id;

        List<MMTTerm> innerArguments = new List<MMTTerm>
        {
            new OMS(cURI),
            new OMS(pURI)
        };

        List<MMTTerm> outerArguments = new List<MMTTerm>
        {
            new OMA(new OMS(MMTURIs.OnCircle), innerArguments)
        };

        //OMS constructor generates full URI
        MMTTerm tp = new OMA(new OMS(MMTURIs.Ded), outerArguments);
        MMTTerm df = null;

        MMTSymbolDeclaration mmtDecl = new MMTSymbolDeclaration(this.Label, tp, df);
        AddFactResponse.sendAdd(mmtDecl, out this._URI);
    }

    /// <summary>
    /// Bypasses initialization of new MMT %Fact by using existend URI, _which is not checked for existence_.
    /// </summary>
    /// <param name="pid">sets <see cref="Pid"/></param>
    /// <param name="cid">sets <see cref="Cid"/></param>
    /// <param name="uri">MMT URI</param>
    /// <param name="organizer">sets <see cref="Fact._Facts"/></param>
    public OnCircleFact(string pid, string cid, string uri, FactOrganizer organizer) : base(organizer)
    {
        this.Pid = pid;