using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Abstractions;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;
using BO.AppServer.Metadata.Dto;
using Quadarax.Foundation.Core.Data.Interface;
using Quadarax.Foundation.Core.Data.Interface.Entity;
using Quadarax.Foundation.Core.Data.Interface.Entity.Dto;
using Quadarax.Foundation.Core.Json;
using Quadarax.Foundation.Core.Logging;
using Quadarax.Foundation.Core.Object;
using Quadarax.Foundation.Core.Value.Extensions;

namespace BO.Connector
{
    public abstract class AbstractConnection : DisposableObject
    {
        #region *** Private fields ***
        private HttpClient _client;
        private Uri _uriApiBase;
        private ILogHandler _log;
        private TimeSpan _timeout;
        private string _ticket;
        private Binder _binder;
        private bool _isDumpContentEnabled;

        protected abstract string ApiName { get; }
        protected bool IsOpen => !string.IsNullOrEmpty(_ticket);
        protected string Ticket => _ticket;
        #endregion


        #region *** Constructors ***
        protected AbstractConnection(Uri uriApiBase, TimeSpan timeout, ILogHandler log = null, bool isDumpContentEnabled = false)
        {
            _uriApiBase = uriApiBase ?? throw new ArgumentNullException(nameof(uriApiBase));
            _uriApiBase = new Uri(_uriApiBase.AbsoluteUri + ApiName + "/");
            _log = log;
            _timeout = timeout;
            _binder = new Binder(new FileSystem());
            _binder.SerializerOptions.IgnoreReadOnlyProperties = true;
            _binder.SerializerOptions.IgnoreNullValues = true;
            _isDumpContentEnabled = isDumpContentEnabled;
        }
        #endregion

        #region *** Public Operations ***
        public void Open(string userName, string userPassword, string magicKey)
        {
            Log(LogSeverityEnum.Trace, $"Opening Connector '{ApiName}' open with magicKey='{magicKey}'");
            _client = CreateClient();
            InitTicket(magicKey);
            Login(userName, userPassword);
            OnOpening();
            Log(LogSeverityEnum.Debug, $"Connector '{ApiName}' open for user '{userName}' with timeout setting {_timeout}.");
        }


        public void Close()
        {
            _client?.CancelPendingRequests();
            _client?.Dispose();
            _client = null;
            _ticket = string.Empty;
            Log(LogSeverityEnum.Debug, $"Connector '{ApiName}' closed.");
        }

        public bool Ping(out TimeSpan duration, out string status)
        {
            CheckIsOpen();
            var start = DateTime.Now;
            var ping = Task.Run(() =>CallRequestAsync<ResultValueDto<PingDto>>($"{_ticket}/ping", RestCallTypeEnum.Get, null, null, true));
            ping.Wait();
            duration = DateTime.Now - start;
            if (ping.Result == null)
            {
                status = string.Empty;
                return false;
            }
            status = ping.Result.Value.Status;
            return ping.Result.IsSuccess;
        }
        #endregion


        #region *** Virtuals & Overrides ***
        protected override void OnDisposing()
        {
            _client?.Dispose();
        }
        #endregion

        #region *** Private Operations ***

        protected void CheckIsOpen()
        {
            if (!IsOpen)
                throw new InvalidOperationException(
                    "Connector is not open to call specific operation. Call Open() first.");
        }
        protected void Log(LogSeverityEnum type, string message, Exception e = null)
        {
            _log?.Log(type, message, e);
        }

        protected void InitTicket(string magicKey)
        {
            var result = Task.Run(() => CallRequestAsync<ResultValueDto<AuthDto>>($"{magicKey}/auth", RestCallTypeEnum.Get));;
            result.Wait();
            if (!result.Result.IsSuccess)
                throw result.Result.ToAggregateException();
            _ticket = result.Result.Value.Ticket;
        }

        protected void Login(string userName, string userPassword)
        {
            var headerAtts = new Dictionary<string, string>();
            headerAtts.Add("userName",userName);
            headerAtts.Add("userPassword",userPassword);
            var result = Task.Run(() => CallRequestAsync<ResultValueDto<UserRDto>>($"{_ticket}/login", RestCallTypeEnum.Post, new ResultPlain(), headerAtts));
            result.Wait();
            if (!result.Result.IsSuccess)
                throw result.Result.ToAggregateException();
            Log(LogSeverityEnum.Info,$"User '{result.Result.Value.Name}' is logged in.");
        }

        protected IDictionary<string, string> GetPagingHeaderAttributes(PagingDto paging, IDictionary<string,string> source = null)
        {
            if (paging == null || paging.IsDisabled)
                return null;//paging = new PagingDto();

            if (source == null)
                source = new Dictionary<string, string>();

            var result = new Dictionary<string, string>
            {
                { "page", paging.Page.ToString() },
                { "pageSize", paging.PageSize.ToString() }
            };
            return result;
        }

        protected IDictionary<string, string> GetApiPasswordHeaderAttributes(string apiKeyPassword, IDictionary<string,string> source = null)
        {
            if (source == null)
                source = new Dictionary<string, string>();

            var result = new Dictionary<string, string>
            {
                { "apiKeyPassword", apiKeyPassword },
            };
            return result;
        }

        protected IDictionary<string, string> GetUserContextHeaderAttributes(string userNameContext, IDictionary<string,string> source = null)
        {
            if (source == null)
                source = new Dictionary<string, string>();

            var result = new Dictionary<string, string>
            {
                { "context", userNameContext },
            };
            return result;
        }



        protected async Task<Stream> CallGetStreamAsync(string relativeUrlApiCall,
            IDictionary<string, string> headerAttributes = null, bool silent = false)
        {
            Log(LogSeverityEnum.Trace, $"Calling REST API GET STREAM {_uriApiBase.AbsoluteUri + relativeUrlApiCall}");
            if (headerAttributes != null)
            {
                foreach (var key in headerAttributes.Keys)
                {
                    _client.DefaultRequestHeaders.Remove(key);
                    _client.DefaultRequestHeaders.Add(key,headerAttributes[key]);
                }
            }

         
            return await _client.GetStreamAsync(relativeUrlApiCall);
        }

        protected async Task<TResult> CallPostStreamMultipartAsync<TResult>(string relativeUrlApiCall,
            IDto data,Stream stream, IDictionary<string, string> headerAttributes = null, bool silent = false)
            where TResult : ResultDto
        {
            Log(LogSeverityEnum.Trace, $"Calling REST API POST-MULTI-STREAM {_uriApiBase.AbsoluteUri + relativeUrlApiCall}");

            var rqData = new StringContent(_binder.SaveToString(data));
            var rqStream = new StreamContent(stream);
            var req = new MultipartContent();
            req.Add(rqData);
            req.Add(rqStream);
            if (headerAttributes!=null)
                foreach (var key in headerAttributes.Keys)
                    req.Headers.Add(key,headerAttributes[key]);
            req.Headers.ContentType = new MediaTypeHeaderValue("application/json");
            var start = DateTime.Now;
            var resp = await _client.PostAsync(relativeUrlApiCall, req);
         
         
            Log(LogSeverityEnum.Trace, $"REST API POST-MULTI-STREAM {_uriApiBase.AbsoluteUri + relativeUrlApiCall} done @ {(DateTime.Now - start).ToReadableString()}");
            if (!resp.IsSuccessStatusCode)
            {
                var message = $"Calling REST API POST-MULTI-STREAM {_uriApiBase.AbsoluteUri + relativeUrlApiCall} ends with result code '{resp.StatusCode}'";
                Log(LogSeverityEnum.Warn, message);
                throw new Exception(message);
            }

            var content = await resp.Content.ReadAsStringAsync();
            if (_isDumpContentEnabled)
                Log(LogSeverityEnum.Trace, content);

            var result = (TResult)_binder.LoadFromString(content, typeof(TResult));
            if (result.IsSuccess) return result;
            if (silent) return result;

            // handle errors
            var excps = new List<Exception>();
            foreach (var err in result.Errors)
            {
                var exc = new Exception($"[{err.Code}] {err.Message}");
                exc.Data.Add("Code", err.Code);
                excps.Add(exc);
            }

            throw new AggregateException(excps);
        }


        protected async Task<TResult> CallRequestAsync<TResult>(string relativeUrlApiCall,RestCallTypeEnum method, IDto data = null,IDictionary<string,string> headerAttributes = null, bool silent = false) 
            where TResult : ResultDto
        {
            if (data == null)
                if(method != RestCallTypeEnum.Get && method != RestCallTypeEnum.GetStream && method != RestCallTypeEnum.Delete)
                    throw new ArgumentNullException(nameof(data), $"For REST API method '{method}' data must be specified!");

            Log(LogSeverityEnum.Trace, $"Calling REST API {method} {_uriApiBase.AbsoluteUri + relativeUrlApiCall}");
            var start = DateTime.Now;
            HttpResponseMessage resp = null;

            switch (method)
            {
                case RestCallTypeEnum.Get:
                    if (headerAttributes != null)
                    {
                        foreach (var key in headerAttributes.Keys)
                        {
                            _client.DefaultRequestHeaders.Remove(key);
                            _client.DefaultRequestHeaders.Add(key,headerAttributes[key]);
                        }
                    }
                    resp = await _client.GetAsync(relativeUrlApiCall);
                    break;
                case RestCallTypeEnum.Post:
                    var req = new StringContent(_binder.SaveToString(data));
                    if (headerAttributes!=null)
                        foreach (var key in headerAttributes.Keys)
                            req.Headers.Add(key,headerAttributes[key]);
                    req.Headers.ContentType = new MediaTypeHeaderValue("application/json");
                    resp = await _client.PostAsync(relativeUrlApiCall, req);
                    break;
                case RestCallTypeEnum.Put:
                    req = new StringContent(_binder.SaveToString(data));
                    if (headerAttributes!=null)
                        foreach (var key in headerAttributes.Keys)
                            req.Headers.Add(key,headerAttributes[key]);
                    req.Headers.ContentType = new MediaTypeHeaderValue("application/json");
                    resp = await _client.PutAsync(relativeUrlApiCall, req);
                    break;
                case RestCallTypeEnum.Delete:
                    resp = await _client.DeleteAsync(relativeUrlApiCall);
                    break;
                default:
                    throw new NotSupportedException($"{method} REST API operation is not implemented.");
            }
            

            // may remove paging headers after call
            /*
            if (headerAttributes != null)
                foreach (var key in headerAttributes.Keys)
                    _client.DefaultRequestHeaders.Remove(key);
            */

            Log(LogSeverityEnum.Trace, $"REST API {method} {_uriApiBase.AbsoluteUri + relativeUrlApiCall} done @ {(DateTime.Now - start).ToReadableString()}");
            if (!resp.IsSuccessStatusCode)
            {
                var message = $"Calling REST API {method} {_uriApiBase.AbsoluteUri + relativeUrlApiCall} ends with result code '{resp.StatusCode}'";
                Log(LogSeverityEnum.Warn, message);
                throw new Exception(message);
            }

            var content = await resp.Content.ReadAsStringAsync();
            if (_isDumpContentEnabled)
                Log(LogSeverityEnum.Trace, content);

            var result = (TResult)_binder.LoadFromString(content, typeof(TResult));
            if (result.IsSuccess) return result;
            if (silent) return result;

            // handle errors
            var excps = new List<Exception>();
            foreach (var err in result.Errors)
            {
                var exc = new Exception($"[{err.Code}] {err.Message}");
                exc.Data.Add("Code", err.Code);
                excps.Add(exc);
            }

            throw new AggregateException(excps);
        }
        protected virtual void OnOpening()
        {
        }

        private HttpClient CreateClient()
        {
            var client = new HttpClient();
            client.BaseAddress = new Uri(_uriApiBase, ApiName);
            client.Timeout = _timeout;
            client.DefaultRequestHeaders.Accept.Clear();
            client.DefaultRequestHeaders.Add("User-Agent", "BO.Connector." + ApiName);
            // Add an Accept header for JSON format.
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
            return client;
        }

        #endregion

    }
}