using System.Collections.Generic;
using System.Linq;



namespace AyaNova.DataList
{
    internal static class DataListFactory
    {
        // internal static IAyaDataList GetAyaDataList(string ListKey)
        // {
        //     switch (ListKey)
        //     {
        //         case nameof(TestWidgetUserEmailDataList):
        //             return new TestWidgetUserEmailDataList();
        //         case nameof(WidgetDataList):
        //             return new WidgetDataList();
        //         default:
        //             throw new System.ArgumentOutOfRangeException($"DataListFactory: Unknown list \"{ListKey}\"");
        //     }
        // }

        // private static List<string> DataListList = null;

        // //To be called at startup
        // private static void PopulateDataListCache()
        // {
        //     System.Reflection.Assembly ass = System.Reflection.Assembly.GetEntryAssembly();
        //     DataListList = new List<string>();
        //     foreach (System.Reflection.TypeInfo ti in ass.DefinedTypes)
        //     {
        //         if (!ti.IsAbstract && ti.ImplementedInterfaces.Contains(typeof(IAyaDataList)))
        //         {
        //             DataListList.Add(ti.Name);
        //         }
        //     }
        // }

        //Instantiate list object specified
        //this is safe as it's only called from our own code internally
        internal static IAyaDataList GetAyaDataList(string ListKey)
        {
            System.Reflection.Assembly ass = System.Reflection.Assembly.GetEntryAssembly();
            return ass.CreateInstance($"AyaNova.DataList.{ListKey}") as IAyaDataList;

            // if (DataListList == null)
            // {
            //     throw new System.NullReferenceException($"DataListFactory::GetAyaDataList({ListKey}) -> The data list cache is empty!");
            // }

            // System.Reflection.Assembly ass = System.Reflection.Assembly.GetEntryAssembly();

            // foreach (System.Reflection.TypeInfo ti in ass.DefinedTypes)
            // {
            //     // if (!ti.IsAbstract && ti.ImplementedInterfaces.Contains(typeof(IAyaDataList)))
            //     if (ti.Name == ListKey)
            //     {
            //         return ass.CreateInstance(ti.FullName) as IAyaDataList;
            //     }
            // }
            // throw new System.ArgumentOutOfRangeException($"DEV ERROR in DataListFactory.cs: ListKey {ListKey} specified doesn't exist");
        }

        internal static List<string> GetListOfAllDataListKeyNames()
        {
            //https://stackoverflow.com/a/42574373/8939

            List<string> ret = new List<string>();
            System.Reflection.Assembly ass = System.Reflection.Assembly.GetEntryAssembly();

            foreach (System.Reflection.TypeInfo ti in ass.DefinedTypes)
            {
                if (!ti.IsAbstract && ti.ImplementedInterfaces.Contains(typeof(IAyaDataList)))
                {
                    ret.Add(ti.Name);
                }
            }
            return ret;
        }


    }//eoc
}//eons