using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Net;
using System.Threading;
using System.Threading.Tasks;
using Amazon.SellingPartnerApiSDK.AmazonSpApiSDK.Models.Exceptions;
using Amazon.SellingPartnerApiSDK.AmazonSpApiSDK.Models.Token;
using Amazon.SellingPartnerApiSDK.Misc;
using Amazon.SellingPartnerApiSDK.Parameters;
using Newtonsoft.Json;
using RestSharp;
using RestSharp.Serializers.NewtonsoftJson;
using Method = RestSharp.Method;
using static Amazon.SellingPartnerApiSDK.Misc.Constants;
using static Amazon.SellingPartnerApiSDK.AmazonSpApiSDK.Models.Token.CacheTokenData;

namespace Amazon.SellingPartnerApiSDK.Services
{
    public class RequestService : ApiUrls
    {
        public static readonly string AccessTokenHeaderName = "x-amz-access-token";
        public static readonly string SecurityTokenHeaderName = "x-amz-security-token";
        public static readonly string ShippingBusinessIdHeaderName = "x-amzn-shipping-business-id";
        private const string RateLimitLimitHeaderName = "x-amzn-RateLimit-Limit";

        protected RequestService(AmazonCredential amazonCredential)
        {
            AmazonCredential = amazonCredential;
            AmazonSandboxUrl = amazonCredential.MarketPlace.Region.SandboxHostUrl;
            AmazonProductionUrl = amazonCredential.MarketPlace.Region.HostUrl;
        }

        protected RestClient RequestClient { get; set; }
        protected RestRequest Request { get; set; }
        protected AmazonCredential AmazonCredential { get; set; }
        protected string AmazonSandboxUrl { get; set; }
        protected string AmazonProductionUrl { get; set; }
        protected string AccessToken { get; set; }
        protected IList<KeyValuePair<string, string>> LastHeaders { get; set; }

        protected string ApiBaseUrl => AmazonCredential.Environment == Constants.Environments.Sandbox
            ? AmazonSandboxUrl
            : AmazonProductionUrl;

        public IList<KeyValuePair<string, string>> LastResponseHeader => LastHeaders;

        private void CreateRequest(string url, Method method)
        {
            if (string.IsNullOrWhiteSpace(AmazonCredential.ProxyAddress))
            {
                var options = new RestClientOptions(ApiBaseUrl);
                RequestClient = new RestClient(options,
                    configureSerialization: s => s.UseNewtonsoftJson());
            }
            else
            {
                var options = new RestClientOptions(ApiBaseUrl)
                {
                    Proxy = new WebProxy()
                    {
                        Address = new Uri(AmazonCredential.ProxyAddress)
                    }
                };

                RequestClient = new RestClient(options,
                    configureSerialization: s => s.UseNewtonsoftJson());
            }

            Request = new RestRequest(url, method);
        }

        protected async Task CreateAuthorizedRequestAsync(string url, Method method,
            List<KeyValuePair<string, string>> queryParameters = null, object postJsonObj = null,
            CacheTokenData.TokenDataType tokenDataType = CacheTokenData.TokenDataType.Normal, object parameter = null,
            CancellationToken cancellationToken = default)
        {
            if (parameter is IParameterBasedPII piiObject && piiObject.IsNeedRestrictedDataToken)
            {
                await RefreshTokenAsync(CacheTokenData.TokenDataType.PII, piiObject.RestrictedDataTokenRequest, cancellationToken);
            }
            else
            {
                await RefreshTokenAsync(tokenDataType, cancellationToken: cancellationToken);
            }

            CreateRequest(url, method);
            if (postJsonObj != null)
                AddJsonBody(postJsonObj);
            if (queryParameters != null)
                AddQueryParameters(queryParameters);
        }

        private async Task<T> ExecuteRequestTry<T>(RateLimitType rateLimitType = RateLimitType.UNSET,
            CancellationToken cancellationToken = default) where T : new()
        {
            RestHeader();
            AddAccessToken();
            var response = await RequestClient.ExecuteAsync<T>(Request, cancellationToken);
            LogRequest(Request, response);
            SaveLastRequestHeader(response.Headers);
            await SleepForRateLimit(response.Headers, rateLimitType, cancellationToken);
            ParseResponse(response);

            if (response.StatusCode == HttpStatusCode.OK && !string.IsNullOrEmpty(response.Content) &&
                response.Data == null) response.Data = JsonConvert.DeserializeObject<T>(response.Content);
            return response.Data;
        }

        private void SaveLastRequestHeader(IReadOnlyCollection<HeaderParameter> parameters)
        {
            LastHeaders = new List<KeyValuePair<string, string>>();
            foreach (RestSharp.Parameter parameter in parameters ?? Enumerable.Empty<HeaderParameter>())
                if (parameter != null && parameter.Name != null && parameter.Value != null)
                    LastHeaders.Add(new KeyValuePair<string, string>(parameter.Name, parameter.Value.ToString()));
        }

        private void LogRequest(RestRequest request, RestResponse response)
        {
            if (AmazonCredential.IsDebugMode)
            {
                var requestToLog = new
                {
                    resource = request.Resource,
                    parameters = request.Parameters.Select(parameter => new
                    {
                        name = parameter.Name,
                        value = parameter.Value,
                        type = parameter.Type.ToString()
                    }),
                    method = request.Method.ToString()
                };

                var responseToLog = new
                {
                    statusCode = response.StatusCode,
                    content = response.Content,
                    headers = response.Headers,
                    responseUri = response.ResponseUri,
                    errorMessage = response.ErrorMessage
                };
                Console.WriteLine("\n\n");
                Console.WriteLine("Request completed, \nRequest: {0} \n\nResponse: {1}",
                    JsonConvert.SerializeObject(requestToLog), JsonConvert.SerializeObject(responseToLog));
            }
        }

        private void RestHeader()
        {
            lock (Request)
            {
                Request?.Parameters?.RemoveParameter(AccessTokenHeaderName);
                Request?.Parameters?.RemoveParameter(SecurityTokenHeaderName);
                Request?.Parameters?.RemoveParameter(ShippingBusinessIdHeaderName);
            }
        }

        protected async Task<T> ExecuteRequestAsync<T>(RateLimitType rateLimitType = RateLimitType.UNSET,
            CancellationToken cancellationToken = default) where T : new()
        {
            var tryCount = 0;
            while (true)
                try
                {
                    return await ExecuteRequestTry<T>(rateLimitType, cancellationToken);
                }
                catch (AmazonQuotaExceededException ex)
                {
                    if (tryCount >= AmazonCredential.MaxThrottledRetryCount)
                    {
                        if (AmazonCredential.IsDebugMode)
                            Console.WriteLine("已达到最大的尝试次数");

                        throw;
                    }

                    cancellationToken.ThrowIfCancellationRequested();

                    AmazonCredential.UsagePlansTimings[rateLimitType].Delay();
                    tryCount++;
                }
        }

        private async Task SleepForRateLimit(IReadOnlyCollection<Parameter> headers,
            RateLimitType rateLimitType = RateLimitType.UNSET, CancellationToken cancellationToken = default)
        {
            try
            {
                decimal rate = 0;
                var limitHeader = headers.FirstOrDefault(a => a.Name == RateLimitLimitHeaderName);
                if (limitHeader != null)
                {
                    var rateLimitValue = limitHeader.Value.ToString();
                    decimal.TryParse(rateLimitValue, NumberStyles.Any, CultureInfo.InvariantCulture, out rate);
                }

                if (AmazonCredential.IsActiveLimitRate)
                {
                    if (rateLimitType == RateLimitType.UNSET)
                    {
                        if (rate > 0)
                        {
                            var sleepTime = (int)(1 / rate * 1000);
                            await Task.Delay(sleepTime, cancellationToken);
                        }
                    }
                    else
                    {
                        if (rate > 0) AmazonCredential.UsagePlansTimings[rateLimitType].SetRateLimit(rate);
                        var time = AmazonCredential.UsagePlansTimings[rateLimitType].NextRate(rateLimitType);
                    }
                }
            }
            catch (Exception)
            {
                // ignored
            }
        }

        private void ParseResponse(RestResponse response)
        {
            if (response.StatusCode == HttpStatusCode.OK || response.StatusCode == HttpStatusCode.Accepted ||
                response.StatusCode == HttpStatusCode.Created || response.StatusCode == HttpStatusCode.NoContent)
                return;
            else if (response.StatusCode == HttpStatusCode.NotFound)
            {
                throw new AmazonNotFoundException("Resource that you are looking for is not found", response);
            }
            else
            {
                if (AmazonCredential.IsDebugMode)
                    Console.WriteLine("Amazon Api didn't respond with Okay, see exception for more details" +
                                      response.Content);

                var errorResponse = response.Content.ConvertToErrorResponse();
                if (errorResponse != null)
                {
                    var error = errorResponse.Errors.FirstOrDefault();

                    switch (error.Code)
                    {
                        case "Unauthorized":
                            throw new AmazonUnauthorizedException(error.Message, response);
                        case "InvalidSignature":
                            throw new AmazonInvalidSignatureException(error.Message, response);
                        case "InvalidInput":
                            throw new AmazonInvalidInputException(error.Message, error.Details, response);
                        case "QuotaExceeded":
                            throw new AmazonQuotaExceededException(error.Message, response);
                        case "InternalFailure":
                            throw new AmazonInternalErrorException(error.Message, response);
                    }
                }
            }

            if (response.StatusCode == HttpStatusCode.BadRequest)
            {
                throw new AmazonBadRequestException(
                    "BadRequest see https://developer-docs.amazon.com/sp-api/changelog/api-request-validation-for-400-errors-with-html-response for advice",
                    response);
            }

            throw new AmazonException("Amazon Api didn't respond with Okay, see exception for more details", response);
        }

        private void AddQueryParameters(List<KeyValuePair<string, string>> queryParameters)
        {
            if (queryParameters != null)
                queryParameters.ForEach(qp => Request.AddQueryParameter(qp.Key, qp.Value));
        }

        private void AddJsonBody(object jsonData)
        {
            var json = JsonConvert.SerializeObject(jsonData);
            Request.AddJsonBody(json);
        }

        private void AddAccessToken()
        {
            lock (Request)
            {
                Request.AddOrUpdateHeader(AccessTokenHeaderName, AccessToken);
            }
        }

        private async Task RefreshTokenAsync(CacheTokenData.TokenDataType tokenDataType = CacheTokenData.TokenDataType.Normal,
            CreateRestrictedDataTokenRequest requestPii = null, CancellationToken cancellationToken = default)
        {
            var token = AmazonCredential.GetToken(tokenDataType);
            if (token == null)
            {
                if (tokenDataType == CacheTokenData.TokenDataType.PII)
                {
                    var pii = await CreateRestrictedDataTokenAsync(requestPii, cancellationToken);
                    if (pii != null)
                        token = new TokenResponse
                        {
                            access_token = pii.RestrictedDataToken,
                            expires_in = pii.ExpiresIn
                        };
                    else
                        throw new ArgumentNullException(nameof(pii));
                }
                else
                {
                    token = await TokenGeneration.RefreshAccessTokenAsync(AmazonCredential, tokenDataType,
                        cancellationToken);
                }

                AmazonCredential.SetToken(tokenDataType, token);
            }

            AccessToken = token.access_token;
        }

        private async Task<CreateRestrictedDataTokenResponse> CreateRestrictedDataTokenAsync(
            CreateRestrictedDataTokenRequest createRestrictedDataTokenRequest,
            CancellationToken cancellationToken = default)
        {
            await CreateAuthorizedRequestAsync(TokenApiUrls.RestrictedDataToken, Method.Post,
                postJsonObj: createRestrictedDataTokenRequest, cancellationToken: cancellationToken);
            var response = await ExecuteRequestAsync<CreateRestrictedDataTokenResponse>(
                RateLimitType.Token_CreateRestrictedDataToken, cancellationToken: cancellationToken);
            return response;
        }
    }
}