using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Reflection;
using System.Text.Json;
using System.Text.Json.Serialization;
using Vinno.FIS.Sonopost.Helpers;
using Vinno.FIS.Sonopost.WebApi.Models;
using Vinno.IUS.Common.Log;

namespace Vinno.FIS.Sonopost.WebApi
{
    internal class WebApiEngine
    {
        private static readonly int CONTROLLER_STR_LEN = "Controller".Length;
        private readonly ConcurrentDictionary<string, Type> _controllerReference;

        public const string ROUTE_PREFIX = "/api/";

        internal WebApiEngine()
        {
            _controllerReference = new ConcurrentDictionary<string, Type>();
            Register();
        }

        private void Register()
        {
            Assembly assembly = GetType().Assembly;

            Type baseControllerType = typeof(BaseController);
            Type[] types = assembly.GetTypes()
                .Where(x => baseControllerType.IsAssignableFrom(x) && x != baseControllerType)
                .ToArray();
            foreach (Type type in types)
            {
                object[] attrs = type.GetCustomAttributes(typeof(WebApiControllerAttribute), false);
                if (attrs.Length == 0) continue;

                WebApiControllerAttribute attr = (WebApiControllerAttribute)attrs[0];
                string controllerName = attr.Name;
                if (string.IsNullOrWhiteSpace(controllerName))
                {
                    controllerName = type.Name.Substring(0, type.Name.Length - CONTROLLER_STR_LEN);
                }
                string key = controllerName.ToLower();
                if (!_controllerReference.ContainsKey(key))
                {
                    _controllerReference.TryAdd(key, type);
                }
            }
        }

        /// <summary>
        /// Handle Api Request
        /// </summary>
        /// <param name="route"></param>
        /// <param name="requestJson"></param>
        /// <returns>Response Json String</returns>
        public string Handle(string route, string requestJson, HttpListenerContext context)
        {
            string[] routeSplits = route.Split('/');
            string controllerName = routeSplits[0];
            string actionName = routeSplits[1];
            if (!_controllerReference.ContainsKey(controllerName))
            {
                return null;
            }
            Assembly assembly = GetType().Assembly;
            Type classType = _controllerReference[controllerName];
            BaseController instance = (BaseController)assembly.CreateInstance(classType.FullName);

            IEnumerable<FieldInfo> baseFieldInfos = classType.BaseType.GetRuntimeFields();
            foreach (FieldInfo fieldInfo in baseFieldInfos)
            {
                if (fieldInfo.FieldType.Equals(context.GetType()))
                {
                    fieldInfo.SetValue(instance, context);
                }
            }
            MethodInfo[] methodInfos = classType.GetMethods();
            foreach (MethodInfo methodInfo in methodInfos)
            {
                if (!methodInfo.IsPublic) continue;
                if (methodInfo.IsConstructor || methodInfo.IsStatic || methodInfo.IsVirtual || methodInfo.IsAbstract) continue;

                object[] attrs = methodInfo.GetCustomAttributes(typeof(WebApiActionAttribute), false);
                if (attrs.Length == 0) continue;

                WebApiActionAttribute attr = (WebApiActionAttribute)attrs[0];
                string attrActionName = string.IsNullOrWhiteSpace(attr.Name) ? methodInfo.Name : attr.Name;
                if (!actionName.Equals(attrActionName.ToLowerInvariant())) continue;

                object[] parameters = null;
                try
                {
                    ParameterInfo[] parameterInfos = methodInfo.GetParameters();
                    if (parameterInfos.Length > 0)
                    {
                        var parameter = JsonHelper.JsonToObj(requestJson, parameterInfos[0].ParameterType, new JsonSerializerOptions
                        {
                            NumberHandling = JsonNumberHandling.AllowReadingFromString
                        });
                        parameters = new object[] { parameter };
                    }
                    object result = methodInfo.Invoke(instance, parameters);
                    return JsonHelper.ToJson(result, new JsonSerializerOptions
                    {
                        NumberHandling = JsonNumberHandling.WriteAsString,
                        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
                    });
                }
                catch (Exception ex)
                {
                    Logger.WriteLineError($"[{nameof(WebApiEngine)}]{nameof(Handle)} error: {ex}");
                    return Result.Fail("RequestError").ToJson();
                }
            }
            return null;
        }
    }
}