using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Net;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using CryptoExchange.Net.Authentication;
using CryptoExchange.Net.Interfaces;
using CryptoExchange.Net.Objects;
using CryptoExchange.Net.Objects.Options;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

namespace CryptoExchange.Net
{
    /// <summary>
    /// Base API for all API clients
    /// </summary>
    public abstract class BaseApiClient : IDisposable, IBaseApiClient
    {
        /// <summary>
        /// Logger
        /// </summary>
        protected ILogger _logger;

        /// <summary>
        /// If we are disposing
        /// </summary>
        protected bool _disposing;

        /// <summary>
        /// The authentication provider for this API client. (null if no credentials are set)
        /// </summary>
        public AuthenticationProvider? AuthenticationProvider { get; private set; }

        /// <summary>
        /// Where to put the parameters for requests with different Http methods
        /// </summary>
        public Dictionary<HttpMethod, HttpMethodParameterPosition> ParameterPositions { get; set; } = new Dictionary<HttpMethod, HttpMethodParameterPosition>
        {
            { HttpMethod.Get, HttpMethodParameterPosition.InUri },
            { HttpMethod.Post, HttpMethodParameterPosition.InBody },
            { HttpMethod.Delete, HttpMethodParameterPosition.InBody },
            { HttpMethod.Put, HttpMethodParameterPosition.InBody }
        };

        /// <summary>
        /// Request body content type
        /// </summary>
        public RequestBodyFormat requestBodyFormat = RequestBodyFormat.Json;

        /// <summary>
        /// Whether or not we need to manually parse an error instead of relying on the http status code
        /// </summary>
        public bool manualParseError = false;

        /// <summary>
        /// How to serialize array parameters when making requests
        /// </summary>
        public ArrayParametersSerialization arraySerialization = ArrayParametersSerialization.Array;

        /// <summary>
        /// What request body should be set when no data is send (only used in combination with postParametersPosition.InBody)
        /// </summary>
        public string requestBodyEmptyContent = "{}";

        /// <summary>
        /// The environment this client communicates to
        /// </summary>
        public string BaseAddress { get; }

        /// <summary>
        /// Output the original string data along with the deserialized object
        /// </summary>
        public bool OutputOriginalData { get; }

        /// <summary>
        /// A default serializer
        /// </summary>
        private static readonly JsonSerializer _defaultSerializer = JsonSerializer.Create(new JsonSerializerSettings
        {
            DateTimeZoneHandling = DateTimeZoneHandling.Utc,
            Culture = CultureInfo.InvariantCulture
        });

        /// <summary>
        /// Api options
        /// </summary>
        public ApiOptions ApiOptions { get; }

        /// <summary>
        /// Client Options
        /// </summary>
        public ExchangeOptions ClientOptions { get; }

        /// <summary>
        /// ctor
        /// </summary>
        /// <param name="logger">Logger</param>
        /// <param name="outputOriginalData">Should data from this client include the orginal data in the call result</param>
        /// <param name="baseAddress">Base address for this API client</param>
        /// <param name="apiCredentials">Api credentials</param>
        /// <param name="clientOptions">Client options</param>
        /// <param name="apiOptions">Api options</param>
        protected BaseApiClient(ILogger logger, bool outputOriginalData, ApiCredentials? apiCredentials, string baseAddress, ExchangeOptions clientOptions, ApiOptions apiOptions)
        {
            _logger = logger;

            ClientOptions = clientOptions;
            ApiOptions = apiOptions;
            OutputOriginalData = outputOriginalData;
            BaseAddress = baseAddress;

            if (apiCredentials != null)
            {
                AuthenticationProvider?.Dispose();
                AuthenticationProvider = CreateAuthenticationProvider(apiCredentials.Copy());
            }
        }

        /// <summary>
        /// Create an AuthenticationProvider implementation instance based on the provided credentials
        /// </summary>
        /// <param name="credentials"></param>
        /// <returns></returns>
        protected abstract AuthenticationProvider CreateAuthenticationProvider(ApiCredentials credentials);

        /// <inheritdoc />
        public void SetApiCredentials<T>(T credentials) where T : ApiCredentials
        {
            if (credentials != null)
            {
                AuthenticationProvider?.Dispose();
                AuthenticationProvider = CreateAuthenticationProvider(credentials.Copy());
            }
        }

        /// <summary>
        /// Tries to parse the json data and return a JToken, validating the input not being empty and being valid json
        /// </summary>
        /// <param name="data">The data to parse</param>
        /// <returns></returns>
        protected CallResult<JToken> ValidateJson(string data)
        {
            if (string.IsNullOrEmpty(data))
            {
                var info = "Empty data object received";
                _logger.Log(LogLevel.Error, info);
                return new CallResult<JToken>(new DeserializeError(info, data));
            }

            try
            {
                return new CallResult<JToken>(JToken.Parse(data));
            }
            catch (JsonReaderException jre)
            {
                var info = $"Deserialize JsonReaderException: {jre.Message}, Path: {jre.Path}, LineNumber: {jre.LineNumber}, LinePosition: {jre.LinePosition}";
                return new CallResult<JToken>(new DeserializeError(info, data));
            }
            catch (JsonSerializationException jse)
            {
                var info = $"Deserialize JsonSerializationException: {jse.Message}";
                return new CallResult<JToken>(new DeserializeError(info, data));
            }
            catch (Exception ex)
            {
                var exceptionInfo = ex.ToLogString();
                var info = $"Deserialize Unknown Exception: {exceptionInfo}";
                return new CallResult<JToken>(new DeserializeError(info, data));
            }
        }

        /// <summary>
        /// Deserialize a string into an object
        /// </summary>
        /// <typeparam name="T">The type to deserialize into</typeparam>
        /// <param name="data">The data to deserialize</param>
        /// <param name="serializer">A specific serializer to use</param>
        /// <param name="requestId">Id of the request the data is returned from (used for grouping logging by request)</param>
        /// <returns></returns>
        protected CallResult<T> Deserialize<T>(string data, JsonSerializer? serializer = null, int? requestId = null)
        {
            var tokenResult = ValidateJson(data);
            if (!tokenResult)
            {
                _logger.Log(LogLevel.Error, tokenResult.Error!.Message);
                return new CallResult<T>(tokenResult.Error);
            }

            return Deserialize<T>(tokenResult.Data, serializer, requestId);
        }

        /// <summary>
        /// Deserialize a JToken into an object
        /// </summary>
        /// <typeparam name="T">The type to deserialize into</typeparam>
        /// <param name="obj">The data to deserialize</param>
        /// <param name="serializer">A specific serializer to use</param>
        /// <param name="requestId">Id of the request the data is returned from (used for grouping logging by request)</param>
        /// <returns></returns>
        protected CallResult<T> Deserialize<T>(JToken obj, JsonSerializer? serializer = null, int? requestId = null)
        {
            serializer ??= _defaultSerializer;

            try
            {
                return new CallResult<T>(obj.ToObject<T>(serializer)!);
            }
            catch (JsonReaderException jre)
            {
                var info = $"{(requestId != null ? $"[{requestId}] " : "")}Deserialize JsonReaderException: {jre.Message} Path: {jre.Path}, LineNumber: {jre.LineNumber}, LinePosition: {jre.LinePosition}, data: {obj}";
                _logger.Log(LogLevel.Error, info);
                return new CallResult<T>(new DeserializeError(info, obj));
            }
            catch (JsonSerializationException jse)
            {
                var info = $"{(requestId != null ? $"[{requestId}] " : "")}Deserialize JsonSerializationException: {jse.Message} data: {obj}";
                _logger.Log(LogLevel.Error, info);
                return new CallResult<T>(new DeserializeError(info, obj));
            }
            catch (Exception ex)
            {
                var exceptionInfo = ex.ToLogString();
                var info = $"{(requestId != null ? $"[{requestId}] " : "")}Deserialize Unknown Exception: {exceptionInfo}, data: {obj}";
                _logger.Log(LogLevel.Error, info);
                return new CallResult<T>(new DeserializeError(info, obj));
            }
        }

        /// <summary>
        /// Deserialize a stream into an object
        /// </summary>
        /// <typeparam name="T">The type to deserialize into</typeparam>
        /// <param name="stream">The stream to deserialize</param>
        /// <param name="serializer">A specific serializer to use</param>
        /// <param name="requestId">Id of the request the data is returned from (used for grouping logging by request)</param>
        /// <param name="elapsedMilliseconds">Milliseconds response time for the request this stream is a response for</param>
        /// <returns></returns>
        protected async Task<CallResult<T>> DeserializeAsync<T>(Stream stream, JsonSerializer? serializer = null, int? requestId = null, long? elapsedMilliseconds = null)
        {
            serializer ??= _defaultSerializer;
            string? data = null;

            try
            {
                // Let the reader keep the stream open so we're able to seek if needed. The calling method will close the stream.
                using var reader = new StreamReader(stream, Encoding.UTF8, false, 512, true);
                // If we have to output the original json data or output the data into the logging we'll have to read to full response
                // in order to log/return the json data
                if (OutputOriginalData == true)
                {
                    data = await reader.ReadToEndAsync().ConfigureAwait(false);
                    _logger.Log(LogLevel.Debug, $"{(requestId != null ? $"[{requestId}] " : "")}Response received{(elapsedMilliseconds != null ? $" in {elapsedMilliseconds}" : " ")}ms: " + data);
                    var result = Deserialize<T>(data, serializer, requestId);
                    result.OriginalData = data;
                    return result;
                }

                // If we don't have to keep track of the original json data we can use the JsonTextReader to deserialize the stream directly
                // into the desired object, which has increased performance over first reading the string value into memory and deserializing from that
                using var jsonReader = new JsonTextReader(reader);
                _logger.Log(LogLevel.Debug, $"{(requestId != null ? $"[{requestId}] " : "")}Response received{(elapsedMilliseconds != null ? $" in {elapsedMilliseconds}" : " ")}ms");
                return new CallResult<T>(serializer.Deserialize<T>(jsonReader)!);
            }
            catch (JsonReaderException jre)
            {
                if (data == null)
                {
                    if (stream.CanSeek)
                    {
                        // If we can seek the stream rewind it so we can retrieve the original data that was sent
                        stream.Seek(0, SeekOrigin.Begin);
                        data = await ReadStreamAsync(stream).ConfigureAwait(false);
                    }
                    else
                    {
                        data = "[Data only available in Trace LogLevel]";
                    }
                }
                _logger.Log(LogLevel.Error, $"{(requestId != null ? $"[{requestId}] " : "")}Deserialize JsonReaderException: {jre.Message}, Path: {jre.Path}, LineNumber: {jre.LineNumber}, LinePosition: {jre.LinePosition}, data: {data}");
                return new CallResult<T>(new DeserializeError($"Deserialize JsonReaderException: {jre.Message}, Path: {jre.Path}, LineNumber: {jre.LineNumber}, LinePosition: {jre.LinePosition}", data));
            }
            catch (JsonSerializationException jse)
            {
                if (data == null)
                {
                    if (stream.CanSeek)
                    {
                        stream.Seek(0, SeekOrigin.Begin);
                        data = await ReadStreamAsync(stream).ConfigureAwait(false);
                    }
                    else
                    {
                        data = "[Data only available in Trace LogLevel]";
                    }
                }

                _logger.Log(LogLevel.Error, $"{(requestId != null ? $"[{requestId}] " : "")}Deserialize JsonSerializationException: {jse.Message}, data: {data}");
                return new CallResult<T>(new DeserializeError($"Deserialize JsonSerializationException: {jse.Message}", data));
            }
            catch (Exception ex)
            {
                if (data == null)
                {
                    if (stream.CanSeek)
                    {
                        stream.Seek(0, SeekOrigin.Begin);
                        data = await ReadStreamAsync(stream).ConfigureAwait(false);
                    }
                    else
                    {
                        data = "[Data only available in Trace LogLevel]";
                    }
                }

                var exceptionInfo = ex.ToLogString();
                _logger.Log(LogLevel.Error, $"{(requestId != null ? $"[{requestId}] " : "")}Deserialize Unknown Exception: {exceptionInfo}, data: {data}");
                return new CallResult<T>(new DeserializeError($"Deserialize Unknown Exception: {exceptionInfo}", data));
            }
        }

        private static async Task<string> ReadStreamAsync(Stream stream)
        {
            using var reader = new StreamReader(stream, Encoding.UTF8, false, 512, true);
            return await reader.ReadToEndAsync().ConfigureAwait(false);
        }

        /// <summary>
        /// Dispose
        /// </summary>
        public virtual void Dispose()
        {
            _disposing = true;
            AuthenticationProvider?.Dispose();
        }
    }
}