GetFtsCollections.cs

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Model;
using Waher.Script.Objects;
using Waher.Script.Objects.VectorSpaces;
 
namespace Waher.Script.FullTextSearch.Functions
{
    public class GetFtsCollections : FunctionMultiVariate
    {
        public GetFtsCollections(int Start, int Length, Expression Expression)
            : base(Array.Empty<ScriptNode>(), argumentTypes0, Start, Length, Expression)
        {
        }
 
        public GetFtsCollections(ScriptNode IndexCollection,
            int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { IndexCollection }, argumentTypes1Scalar,
                  Start, Length, Expression)
        {
        }
 
        public override string FunctionName => nameof(GetFtsCollections);
 
        public override string[] DefaultArgumentNames => new string[]
        {
            "Index"
        };
 
        public override bool IsAsynchronous => true;
 
        public override IElement Evaluate(IElement[] Arguments, Variables Variables)
        {
            return this.EvaluateAsync(Arguments, Variables).Result;
        }
 
        public override async Task<IElement> EvaluateAsync(IElement[] Arguments, Variables Variables)
        {
            if (Arguments.Length == 0)
            {
                Dictionary<string, string[]> Collections = await Waher.Persistence.FullTextSearch.Search.GetCollectionNames();
                Dictionary<string, IElement> Result = new Dictionary<string, IElement>();
 
                foreach (KeyValuePair<string, string[]> Rec in Collections)
                    Result[Rec.Key] = new ObjectVector(Rec.Value);
 
                return new ObjectValue(Result);
            }
            else
            {
                string Index = ToString(Arguments[0]) ?? string.Empty;
                string[] Collections = await Waher.Persistence.FullTextSearch.Search.GetCollectionNames(Index);
 
                return new ObjectVector(Collections);
            }
        }
    }
}