using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using Tango.Core.Helpers;

namespace Tango.Scripting.Basic
{
    public class ReferenceAssembly
    {
        private static Dictionary<String, Assembly> _assembliesCache;

        static ReferenceAssembly()
        {
            _assembliesCache = new Dictionary<string, Assembly>();
        }

        public String File { get; set; }

        public Type HintType { get; set; }

        [JsonIgnore]
        public String Name
        {
            get { return Path.GetFileNameWithoutExtension(File); }
        }

        public static ReferenceAssembly FromType(Type type)
        {
            ReferenceAssembly reference = new ReferenceAssembly();
            reference.HintType = type;
            var assembly = type.Assembly;
            reference.File = assembly.Location;
            return reference;
        }

        public static ReferenceAssembly FromFile(String file)
        {
            return new ReferenceAssembly() { File = file };
        }

        public Assembly Load()
        {
            Assembly loaded = null;
            if (!_assembliesCache.TryGetValue(Name, out loaded))
            {
                try
                {
                    if (HintType != null)
                    {
                        loaded = HintType.Assembly;
                    }
                    else
                    {
                        loaded = Assembly.LoadFrom(File);
                    }

                    _assembliesCache.Add(Name, loaded);
                }
                catch
                {
                    try
                    {
                        String dotNetPath = AssemblyHelper.GetAssemblyTargetFrameworkFolder(Assembly.GetExecutingAssembly());
                        String dotNetAsm = Path.Combine(dotNetPath, Name + ".dll");
                        loaded = Assembly.LoadFrom(dotNetAsm);
                        _assembliesCache.Add(Name, loaded);
                    }
                    catch (Exception ex)
                    {
                        throw new FileNotFoundException($"Could not load assembly '{Name}'. File not found.", ex);
                    }
                }
            }

            return loaded;
        }

        public override string ToString()
        {
            return Name;
        }
    }
}