using System;

using System.Collections.Concurrent;

using System.Collections.Generic;

using System.Dynamic;

using System.Linq;



namespace Simple.Data.Commands

{

    using Extensions;



    class FindByCommand : ICommand

    {

        public bool IsCommandFor(string method)

        {

            return method.StartsWith("FindBy") || method.StartsWith("find_by_", StringComparison.InvariantCultureIgnoreCase);

        }



        public Func<object[], object> CreateDelegate(DataStrategy dataStrategy, DynamicTable table, InvokeMemberBinder binder, object[] args)

        {

            if (dataStrategy is SimpleTransaction) return null;



            var criteriaDictionary = CreateCriteriaDictionary(binder, args);

            if (criteriaDictionary == null) return null;



            var criteriaExpression = ExpressionHelper.CriteriaDictionaryToExpression(table.GetQualifiedName(), criteriaDictionary);

            try

            {

                var func = dataStrategy.GetAdapter().CreateFindOneDelegate(table.GetQualifiedName(), criteriaExpression);

                return a =>

                           {

                               var data = func(a);

                               return (data != null && data.Count > 0)

                                          ? new SimpleRecord(data, table.GetQualifiedName(), dataStrategy)

                                          : null;

                           };

            }

            catch (NotImplementedException)

            {

                return null;

            }

        }



        private static IDictionary<string, object> CreateCriteriaDictionary(InvokeMemberBinder binder, IList<object> args)

        {

            IDictionary<string, object> criteriaDictionary = null;

            if (binder.Name.Equals("FindBy") || binder.Name.Equals("find_by"))

            {

                if (binder.CallInfo.ArgumentNames != null && binder.CallInfo.ArgumentNames.Count > 0)

                {

                    criteriaDictionary = binder.NamedArgumentsToDictionary(args);

                }

            }

            else

            {

                criteriaDictionary = MethodNameParser.ParseFromBinder(binder, args);

            }

            return criteriaDictionary;

        }



        public object Execute(DataStrategy dataStrategy, DynamicTable table, InvokeMemberBinder binder, object[] args)

        {

            var criteriaExpression = ExpressionHelper.CriteriaDictionaryToExpression(table.GetQualifiedName(), MethodNameParser.ParseFromBinder(binder, args));

            var data = dataStrategy.FindOne(table.GetQualifiedName(), criteriaExpression);

            return data != null ? new SimpleRecord(data, table.GetQualifiedName(), dataStrategy) : null;

        }

    }

}