using BotSharp.Core.Agents;
using BotSharp.Core.Intents;
using BotSharp.Core.Models;
using BotSharp.Core.Conversations;
using DotNetToolkit;
using EntityFrameworkCore.BootKit;
using Microsoft.EntityFrameworkCore;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using Newtonsoft.Json.Serialization;
using RestSharp;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace BotSharp.Core.Engines
{
    public static class RequestExtension
    {
        public static AIResponse TextRequest(this RasaAi rasa, string text, RequestExtras requestExtras)
        {
            return rasa.TextRequest(new AIRequest(text, requestExtras));
        }

        public static AIResponse TextRequest(this RasaAi rasa, AIRequest request)
        {
            AIResponse aiResponse = new AIResponse();
            Database dc = rasa.dc;

#if MODEL_PER_CONTEXTS
            string model = GetModelPerContexts(rasa, request);
            var result = CallRasa(rasa.agent.Id, request.Query.First(), model);
#else
            var result = CallRasa(rasa.agent.Id, request.Query.First(), rasa.agent.Id);
#endif
            RasaResponse response = result.Data;
            aiResponse.Id = Guid.NewGuid().ToString();
            aiResponse.Lang = rasa.agent.Language;
            aiResponse.Status = new AIResponseStatus { };
            aiResponse.SessionId = rasa.AiConfig.SessionId;
            aiResponse.Timestamp = DateTime.UtcNow;

            var intentResponse = HandleIntentPerContextIn(rasa, request, result.Data);
            bool missedRequiredField = HandleParameter(rasa.agent, intentResponse, response, request);

            HandleMessage(intentResponse);

            aiResponse.Result = new AIResponseResult
            {
                Source = "agent",
                ResolvedQuery = request.Query.First(),
                Action = intentResponse?.Action,
                Parameters = intentResponse?.Parameters?.ToDictionary(x => x.Name, x=> x.Value),
                Score = response.Intent.Confidence,
                Metadata = new AIResponseMetadata { IntentId = intentResponse?.IntentId, IntentName = intentResponse?.IntentName },
                Fulfillment = new AIResponseFulfillment
                {
                    Messages = intentResponse?.Messages?.Select(x => {
                        if (x.Type == AIResponseMessageType.Custom)
                        {
                            return (new
                            {
                                x.Type,
                                Payload = JsonConvert.DeserializeObject(x.PayloadJson)
                            }) as Object;
                        }
                        else
                        {
                            return (new { x.Type, x.Speech }) as Object;
                        }
                        
                    }).ToList()
                }
            };

            HandleContext(dc, rasa, intentResponse, aiResponse);

            Console.WriteLine(JsonConvert.SerializeObject(aiResponse.Result));

            return aiResponse;
        }

        private static IntentResponse HandleIntentPerContextIn(RasaAi rasa, AIRequest request, RasaResponse response)
        {
            Database dc = rasa.dc;

            // Merge input contexts
            var contexts = dc.Table<ConversationContext>()
                .Where(x => x.ConversationId == rasa.AiConfig.SessionId && x.Lifespan > 0)
                .ToList()
                .Select(x => new AIContext { Name = x.Context.ToLower(), Lifespan = x.Lifespan })
                .ToList();

            contexts.AddRange(request.Contexts.Select(x => new AIContext { Name = x.Name.ToLower(), Lifespan = x.Lifespan }));
            contexts = contexts.OrderBy(x => x.Name).ToList();

            // search all potential intents which input context included in contexts
            var intents = rasa.agent.Intents.Where(it =>
            {
                if (contexts.Count == 0)
                {
                    return it.Contexts.Count() == 0;
                }
                else
                {
                    return it.Contexts.Count() == 0 ||
                        it.Contexts.Count(x => contexts.Select(ctx => ctx.Name).Contains(x.Name.ToLower())) == it.Contexts.Count;
                }
            }).OrderByDescending(x => x.Contexts.Count).ToList();

            if (response.IntentRanking == null)
            {
                response.IntentRanking = new List<RasaResponseIntent>
                {
                    response.Intent
                };
            }

            response.IntentRanking = response.IntentRanking.Where(x => x.Confidence > decimal.Parse("0.3")).ToList();
            response.IntentRanking = response.IntentRanking.Where(x => intents.Select(i => i.Name).Contains(x.Name)).ToList();

            // add Default Fallback Intent 
            if (response.IntentRanking.Count == 0)
            {
                var defaultFallbackIntent = rasa.agent.Intents.FirstOrDefault(x => x.Name == "Default Fallback Intent");
                response.IntentRanking.Add(new RasaResponseIntent
                {
                    Name = defaultFallbackIntent.Name,
                    Confidence = decimal.Parse("0.8")
                });
            }

            response.Intent = response.IntentRanking.First();

            var intent = (dc.Table<Intent>().Where(x => x.AgentId == rasa.agent.Id && x.Name == response.Intent.Name)
                .Include(x => x.Responses).ThenInclude(x => x.Contexts)
                .Include(x => x.Responses).ThenInclude(x => x.Parameters)
                .Include(x => x.Responses).ThenInclude(x => x.Messages)).First();

            var intentResponse = ArrayHelper.GetRandom(intent.Responses);
            intentResponse.IntentName = intent.Name;

            return intentResponse;

        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="agent"></param>
        /// <param name="intentResponse"></param>
        /// <param name="response"></param>
        /// <param name="request"></param>
        /// <returns>Required field is missed</returns>
        private static bool HandleParameter(Agent agent, IntentResponse intentResponse, RasaResponse response, AIRequest request)
        {
            if (intentResponse == null) return false;

            intentResponse.Parameters.ForEach(p => {
                string query = request.Query.First();
                var entity = response.Entities.FirstOrDefault(x => x.Entity == p.Name);
                if (entity != null)
                {
                    p.Value = query.Substring(entity.Start, entity.End - entity.Start);
                }

                // convert to Standard entity value
                if (!String.IsNullOrEmpty(p.Value) && !p.DataType.StartsWith("@sys."))
                {
                    p.Value = agent.Entities
                        .FirstOrDefault(x => x.Name == p.DataType.Substring(1))
                        .Entries
                        .FirstOrDefault((entry) =>
                        {
                            return entry.Value.ToLower() == p.Value.ToLower() ||
                                entry.Synonyms.Select(synonym => synonym.Synonym.ToLower()).Contains(p.Value.ToLower());
                        })?.Value;
                }

                // fixed entity per request
                if (request.Entities != null)
                {
                    var fixedEntity = request.Entities.FirstOrDefault(x => x.Name == p.Name);
                    if (fixedEntity != null)
                    {
                        if (query.ToLower().Contains(fixedEntity.Entries.First().Value.ToLower()))
                        {
                            p.Value = fixedEntity.Entries.First().Value;
                        }
                    }
                }
            });

            return intentResponse.Parameters.Any(x => x.Required && String.IsNullOrEmpty(x.Value));
        }

        private static void HandleMessage(IntentResponse intentResponse)
        {
            if (intentResponse == null) return;

            intentResponse.Messages = intentResponse.Messages.OrderBy(x => x.UpdatedTime).ToList();
            intentResponse.Messages.ToList()
                .ForEach(msg =>
                {
                    if (msg.Type == AIResponseMessageType.Custom)
                    {

                    }
                    else
                    {
                        if (msg.Speech != "[]")
                        {
                            msg.Speech = msg.Speech.StartsWith("[") ?
                            ArrayHelper.GetRandom(msg.Speech.Substring(2, msg.Speech.Length - 4).Split("\",\"").ToList()) :
                            msg.Speech;

                            msg.Speech = ReplaceParameters4Response(intentResponse.Parameters, msg.Speech);
                        }
                    }
                });
        }

        private static string ReplaceParameters4Response(List<IntentResponseParameter> parameters, string text)
        {
            var reg = new Regex(@"\$\w+");

            reg.Matches(text).ToList().ForEach(token => {
                var parameter = parameters.FirstOrDefault(x => x.Name == token.Value.Substring(1));
                if(parameter != null)
                {
                    text = text.Replace(token.Value, parameter?.Value?.ToString());
                }
            });

            return text;
        }

        private static void HandleContext(Database dc, RasaAi rasa, IntentResponse intentResponse, AIResponse aiResponse)
        {
            if (intentResponse == null) return;

            // Merge context lifespan
            // override if exists, otherwise add, delete if lifespan is zero
            dc.DbTran(() =>
            {
                var sessionContexts = dc.Table<ConversationContext>().Where(x => x.ConversationId == rasa.AiConfig.SessionId).ToList();

                // minus 1 round
                sessionContexts.Where(x => !intentResponse.Contexts.Select(ctx => ctx.Name).Contains(x.Context))
                    .ToList()
                    .ForEach(ctx => ctx.Lifespan = ctx.Lifespan - 1);

                intentResponse.Contexts.ForEach(ctx =>
                {
                    var session1 = sessionContexts.FirstOrDefault(x => x.Context == ctx.Name);

                    if (session1 != null)
                    {
                        if (ctx.Lifespan == 0)
                        {
                            dc.Table<ConversationContext>().Remove(session1);
                        }
                        else
                        {
                            session1.Lifespan = ctx.Lifespan;
                        }
                    }
                    else
                    {
                        dc.Table<ConversationContext>().Add(new ConversationContext
                        {
                            ConversationId = rasa.AiConfig.SessionId,
                            Context = ctx.Name,
                            Lifespan = ctx.Lifespan
                        });
                    }
                });
            });

            aiResponse.Result.Contexts = dc.Table<ConversationContext>()
                .Where(x => x.Lifespan > 0 && x.ConversationId == rasa.AiConfig.SessionId)
                .Select(x => new AIContext { Name = x.Context.ToLower(), Lifespan = x.Lifespan })
                .ToArray();
        }

        private static IRestResponse<RasaResponse> CallRasa(string projectId, string text, string model)
        {
            var client = new RestClient($"{Database.Configuration.GetSection("Rasa:Nlu").Value}");

            var rest = new RestRequest("parse", Method.POST);
            string json = JsonConvert.SerializeObject(new { Project = projectId, Q = text, Model = model },
                new JsonSerializerSettings
                {
                    ContractResolver = new CamelCasePropertyNamesContractResolver()
                });
            rest.AddParameter("application/json", json, ParameterType.RequestBody);

            return client.Execute<RasaResponse>(rest);
        }

        private static string GetModelPerContexts(RasaAi rasa, AIRequest request)
        {
            Database dc = rasa.dc;

            // Merge input contexts
            var contexts = dc.Table<ConversationContext>()
                .Where(x => x.ConversationId == rasa.AiConfig.SessionId && x.Lifespan > 0)
                .ToList()
                .Select(x => new AIContext { Name = x.Context.ToLower(), Lifespan = x.Lifespan })
                .ToList();

            contexts.AddRange(request.Contexts.Select(x => new AIContext { Name = x.Name.ToLower(), Lifespan = x.Lifespan }));
            contexts = contexts.OrderBy(x => x.Name).ToList();

            // search all potential intents which input context included in contexts
            var intents = rasa.agent.Intents.Where(it =>
            {
                if (contexts.Count == 0)
                {
                    return it.Contexts.Count() == 0;
                }
                else
                {
                    return it.Contexts.Count() > 0 &&
                        it.Contexts.Count(x => contexts.Select(ctx => ctx.Name).Contains(x.Name.ToLower())) == it.Contexts.Count;
                }
            }).OrderByDescending(x => x.Contexts.Count).ToList();

            // query per request contexts
            var contextHashs = intents.Select(x => x.ContextHash).Distinct().ToList();

            return contextHashs.FirstOrDefault();
        }
    }
}