GroupObject.cs

using System;
using System.Collections.Generic;
using System.Numerics;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Model;
 
namespace Waher.Script.Persistence.SQL.Groups
{
    public class GroupObject
    {
        private readonly object[] objects;
        private readonly Variables variables;
        private readonly Dictionary<string, object> groupedValues = new Dictionary<string, object>();
        private readonly int objectCount;
        private readonly int groupCount;
        private ObjectProperties properties = null;
 
        public GroupObject(object[] Objects, object[] GroupByValues, ScriptNode[] GroupNames, Variables Variables)
        {
            this.objects = Objects;
            this.variables = Variables;
 
            int i;
 
            this.objectCount = this.objects.Length;
            this.groupCount = GroupNames.Length;
            if (GroupByValues.Length != this.groupCount)
                throw new ArgumentException("Length mismatch.", nameof(GroupByValues));
 
            string Name;
            ScriptNode Node;
            IElement E;
 
            for (i = 0; i < this.groupCount; i++)
            {
                Node = GroupNames[i];
                if (Node is null)
                    continue;
 
                if (Node is VariableReference Ref)
                    Name = Ref.VariableName;
                else
                {
                    E = Node.Evaluate(Variables);
                    Name = E.AssociatedObjectValue?.ToString();
                }
 
                if (!string.IsNullOrEmpty(Name))
                    this.groupedValues[Name] = GroupByValues[i];
            }
        }
 
        public object this[string Name]
        {
            get
            {
                if (this.groupedValues.TryGetValue(Name, out object Value))
                    return Value;
 
                if (this.objectCount == 1)
                {
                    object Result;
                    object Item = this.objects[0];
 
                    if (Item is null)
                        Result = null;
                    else
                    {
                        if (this.properties is null)
                            this.properties = new ObjectProperties(Item, this.variables);
                        else
                            this.properties.Object = Item;
 
                        if (this.properties.TryGetValue(Name, out Value))
                            Result = Value;
                        else
                            Result = null;
                    }
 
                    this.groupedValues[Name] = Result;
 
                    return Result;
                }
                else
                {
                    Type ItemType = null;
                    Type T;
                    object[] Result = new object[this.objectCount];
                    object Item;
                    int i;
 
                    for (i = 0; i < this.objectCount; i++)
                    {
                        Item = this.objects[i];
 
                        if (Item is null)
                        {
                            Result[i] = null;
                            ItemType = null;
                        }
                        else
                        {
                            if (this.properties is null)
                                this.properties = new ObjectProperties(Item, this.variables);
                            else
                                this.properties.Object = Item;
 
                            if (this.properties.TryGetValue(Name, out Value) && !(Value is null))
                            {
                                T = Value.GetType();
                                if (i == 0)
                                    ItemType = T;
                                else if (T != ItemType)
                                    ItemType = null;
 
                                Result[i] = Value;
                            }
                            else
                            {
                                Result[i] = null;
                                ItemType = null;
                            }
                        }
                    }
 
                    if (ItemType == typeof(double))
                    {
                        double[] TypedArray = new double[this.objectCount];
                        Array.Copy(Result, 0, TypedArray, 0, this.objectCount);
                        return TypedArray;
                    }
                    else if (ItemType == typeof(bool))
                    {
                        bool[] TypedArray = new bool[this.objectCount];
                        Array.Copy(Result, 0, TypedArray, 0, this.objectCount);
                        return TypedArray;
                    }
                    else if (ItemType == typeof(string))
                    {
                        string[] TypedArray = new string[this.objectCount];
                        Array.Copy(Result, 0, TypedArray, 0, this.objectCount);
                        return TypedArray;
                    }
                    else if (ItemType == typeof(DateTime))
                    {
                        DateTime[] TypedArray = new DateTime[this.objectCount];
                        Array.Copy(Result, 0, TypedArray, 0, this.objectCount);
                        return TypedArray;
                    }
                    else if (ItemType == typeof(Complex))
                    {
                        Complex[] TypedArray = new Complex[this.objectCount];
                        Array.Copy(Result, 0, TypedArray, 0, this.objectCount);
                        return TypedArray;
                    }
                    else
                    {
                        this.groupedValues[Name] = Result;
                        return Result;
                    }
                }
            }
 
            set
            {
                this.groupedValues[Name] = value;
            }
        }
 
        public int Count => this.objects.Length;
 
        public object[] Objects => this.objects;
 
    }
}