/*
 * QUANTCONNECT.COM - Democratizing Finance, Empowering Individuals.
 * Lean Algorithmic Trading Engine v2.0. Copyright 2014 QuantConnect Corporation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
*/

using Newtonsoft.Json.Linq;
using QuantConnect.Interfaces;
using System;
using System.Collections.Generic;
using System.IO;
using System.Net.Http;

namespace QuantConnect.Algorithm.Framework.Portfolio.SignalExports
{
    /// <summary>
    /// Exports signals of the desired positions to CrunchDAO API.
    /// Accepts signals in percentage i.e ticker:"SPY", date: "2020-10-04", signal:0.54
    /// </summary>
    public class CrunchDAOSignalExport : BaseSignalExport
    {
        /// <summary>
        /// CrunchDAO API key
        /// </summary>
        private readonly string _apiKey;

        /// <summary>
        /// CrunchDAO API endpoint
        /// </summary>
        private readonly Uri _destination;

        /// <summary>
        /// Model ID or Name
        /// </summary>
        private readonly string _model;

        /// <summary>
        /// Submission Name (Optional)
        /// </summary>
        private readonly string _submissionName;

        /// <summary>
        /// Comment (Optional)
        /// </summary>
        private readonly string _comment;

        /// <summary>
        /// Algorithm being ran
        /// </summary>
        private IAlgorithm _algorithm;

        /// <summary>
        /// HashSet of allowed SecurityTypes for CrunchDAO
        /// </summary>
        private readonly HashSet<SecurityType> _allowedSecurityTypes = new()
        {
            SecurityType.Equity
        };

        /// <summary>
        /// The name of this signal export
        /// </summary>
        protected override string Name { get; } = "CrunchDAO";

        /// <summary>
        /// HashSet property of allowed SecurityTypes for CrunchDAO
        /// </summary>
        protected override HashSet<SecurityType> AllowedSecurityTypes => _allowedSecurityTypes;

        /// <summary>
        /// CrunchDAOSignalExport constructor. It obtains the required information for CrunchDAO API requests.
        /// See (https://colab.research.google.com/drive/1YW1xtHrIZ8ZHW69JvNANWowmxPcnkNu0?authuser=1#scrollTo=aPyWNxtuDc-X)
        /// </summary>
        /// <param name="apiKey">API key provided by CrunchDAO</param>
        /// <param name="model">Model ID or Name</param>
        /// <param name="submissionName">Submission Name (Optional)</param>
        /// <param name="comment">Comment (Optional)</param>
        public CrunchDAOSignalExport(string apiKey, string model, string submissionName = "", string comment = "")
        {
            _apiKey = apiKey;
            _model = model;
            _submissionName = submissionName;
            _comment = comment;
            _destination = new Uri($"https://api.tournament.crunchdao.com/v3/alpha-submissions?apiKey={apiKey}");
        }

        /// <summary>
        /// Verifies every holding is a stock, creates a message with the desired positions
        /// using the expected CrunchDAO API format, verifies there is an open round and then
        /// sends the positions with the other required body features. If another signal was 
        /// submitted before, it deletes the last signal and sends the new one</summary>
        /// <param name="parameters">A list of holdings from the portfolio,
        /// expected to be sent to CrunchDAO API and the algorithm being ran</param>
        /// <returns>True if the positions were sent to CrunchDAO succesfully and errors were returned, false otherwise</returns>
        public override bool Send(SignalExportTargetParameters parameters)
        {
            if (!base.Send(parameters))
            {
                return false;
            }

            if (!ConvertToCSVFormat(parameters, out string positions))
            {
                return false;
            }

            if (!GetCurrentRoundID(out int currentRoundId))
            {
                return false;
            }

            if (GetLastSubmissionId(currentRoundId, out int lastSubmissionId))
            {
                _algorithm.Debug($"You have already submitted a signal for round {currentRoundId}. Your last submission is going to be overwritten with the new one");
                if (!DeleteLastSubmission(lastSubmissionId))
                {
                    return false;
                }
            }

            var result = SendPositions(positions);
            return result;
        }

        /// <summary>
        /// Converts the list of holdings into a CSV format string
        /// </summary>
        /// <param name="parameters">A list of holdings from the portfolio,
        /// expected to be sent to CrunchDAO API and the algorithm being ran</param>
        /// <param name="positions">A CSV format string of the given holdings with the required features(ticker, date, signal)</param>
        /// <returns>True if a string message with the positions could be obtained, false otherwise</returns>
        protected bool ConvertToCSVFormat(SignalExportTargetParameters parameters, out string positions)
        {
            var holdings = parameters.Targets;
            _algorithm = parameters.Algorithm;
            positions = "ticker,date,signal\n";

            foreach (var holding in holdings)
            {
                if (holding.Quantity < 0 || holding.Quantity > 1)
                {
                    _algorithm.Error($"All signals must be between 0 and 1, but {holding.Symbol.Value} signal was {holding.Quantity}");
                    return false;
                }

                positions += $"{_algorithm.Ticker(holding.Symbol)},{_algorithm.Securities[holding.Symbol].LocalTime.ToString("yyyy-MM-dd")},{holding.Quantity.ToStringInvariant()}\n";
            }
            
            return true;
        }

        /// <summary>
        /// Sends the desired positions, with the other required features, to CrunchDAO API using a POST request. It logs
        /// the message retrieved by the API if there was a HttpRequestException
        /// </summary>
        /// <param name="positions">A CSV format string of the given holdings with the required features</param>
        /// <returns>True if the positions were sent to CrunchDAO successfully and errors were returned. False, otherwise</returns>
        private bool SendPositions(string positions)
        {
            // Create positions stream
            var positionsStream = new MemoryStream();
            using var writer = new StreamWriter(positionsStream);
            writer.Write(positions);
            writer.Flush();
            positionsStream.Position = 0;

            // Create the required body features for the POST request
            using var file = new StreamContent(positionsStream);
            using var model = new StringContent(_model);
            using var submissionName = new StringContent(_submissionName);
            using var comment = new StringContent(_comment);

            // Crete the httpMessage to be sent and add the different POST request body features
            using var httpMessage = new MultipartFormDataContent
            {
                { model, "model" },
                { submissionName, "label" },
                { comment, "comment" },
                { file, "file", "submission.csv" }
            };

            // Send the httpMessage
            using HttpResponseMessage response = HttpClient.PostAsync(_destination, httpMessage).Result;
            if (response.StatusCode == System.Net.HttpStatusCode.Locked || response.StatusCode == System.Net.HttpStatusCode.Forbidden)
            {
                var responseContent = response.Content.ReadAsStringAsync().Result;
                var parsedResponseContent = JObject.Parse(responseContent);
                _algorithm.Error($"CrunchDAO API returned code: {parsedResponseContent["code"]} message:{parsedResponseContent["message"]}");
                return false;
            }

            if (!response.IsSuccessStatusCode)
            {
                _algorithm.Error($"CrunchDAO API returned HttpRequestException {response.StatusCode}");
                return false;
            }

            return true;
        }

        /// <summary>
        /// Checks if there is an open round, if so it assigns the current round ID to currentRoundId
        /// parameter
        /// </summary>
        /// <param name="currentRoundId">Current round ID</param>
        /// <returns>True if there is an open round, false otherwise</returns>
        private bool GetCurrentRoundID(out int currentRoundId)
        {
            // Assign a default value to currentRoundId
            currentRoundId = -1;
            using HttpResponseMessage roundIdResponse = HttpClient.GetAsync("https://api.tournament.crunchdao.com/v2/rounds/@current").Result;
            if (roundIdResponse.StatusCode == System.Net.HttpStatusCode.NotFound)
            {
                var responseContent = roundIdResponse.Content.ReadAsStringAsync().Result;
                var parsedResponseContent = JObject.Parse(responseContent);
                _algorithm.Error($"CrunchDAO API returned code: {parsedResponseContent["code"]} message:{parsedResponseContent["message"]}");
                return false;
            } 
            else if (!roundIdResponse.IsSuccessStatusCode)
            {
                _algorithm.Error($"CrunchDAO API returned HttpRequestException {roundIdResponse.StatusCode}");
                return false;
            }

            var roundIdResponseContent = roundIdResponse.Content.ReadAsStringAsync().Result;
            currentRoundId = (int)(JObject.Parse(roundIdResponseContent)["id"]);
            return true;
        }

        /// <summary>
        /// Checks if there is a submission for the current round, if so it assigns its ID to
        /// lastSubmissionId
        /// </summary>
        /// <param name="currentRoundId">Current round ID</param>
        /// <param name="lastSubmissionId">Last submission ID (for the current round)</param>
        /// <returns>True if there's a submission for the current round, false otherwise</returns>
        private bool GetLastSubmissionId(int currentRoundId, out int lastSubmissionId)
        {
            using HttpResponseMessage submissionIdResponse = HttpClient.GetAsync($"https://tournament.crunchdao.com/api/v3/alpha-submissions?includeAll=false&roundId={currentRoundId}&apiKey={_apiKey}").Result;

            if (!submissionIdResponse.IsSuccessStatusCode)
            {
                _algorithm.Error($"CrunchDAO API returned the following Error Code: {submissionIdResponse.StatusCode}");
                lastSubmissionId = -1;
                return false;
            }

            var submissionIdResponseContent = submissionIdResponse.Content.ReadAsStringAsync().Result;
            var parsedSubmissionIdResponseContent = JArray.Parse(submissionIdResponseContent);
            if (!parsedSubmissionIdResponseContent.HasValues)
            {
                // Default value for lastSubmissionId
                lastSubmissionId = -1;
                return false;
            }

            lastSubmissionId = (int)parsedSubmissionIdResponseContent[0]["id"];
            return true;
        }

        /// <summary>
        /// Deletes the last submission for the current round
        /// </summary>
        /// <param name="lastSubmissionId">Last submission ID for the current round</param>
        /// <returns>True if the last submission could be deleted sucessfully, false otherwise</returns>
        private bool DeleteLastSubmission(int lastSubmissionId)
        {
            using HttpResponseMessage deleteSubmissionResponse = HttpClient.DeleteAsync($"https://tournament.crunchdao.com/api/v3/alpha-submissions/{lastSubmissionId}?&apiKey={_apiKey}").Result;
            if (!deleteSubmissionResponse.IsSuccessStatusCode)
            {
                var responseContent = deleteSubmissionResponse.Content.ReadAsStringAsync().Result;
                var parsedResponseContent = JObject.Parse(responseContent);
                _algorithm.Error($"CrunchDAO API returned code: {parsedResponseContent["code"]} message:{parsedResponseContent["message"]}. Last submission could not be deleted");
                return false;
            }

            _algorithm.Debug($"Last submission has been deleted");
            return true;
        }
    }
}