using BMA.EHR.Domain.Common;
using BMA.EHR.Domain.Shared;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
using Nest;
using Newtonsoft.Json;
using System.Diagnostics;
using System.Net;
using System.Net.Http.Headers;
using System.Security.Claims;
using System.Text.Encodings.Web;
using System.Text.Json;
using JsonSerializer = System.Text.Json.JsonSerializer;

namespace BMA.EHR.Domain.Middlewares
{
    public class CombinedErrorHandlerAndLoggingMiddleware
    {
        private readonly RequestDelegate _next;
        private readonly IConfiguration _configuration;

        private string Uri = "";
        private string IndexFormat = "";
        private string SystemName = "";

        public CombinedErrorHandlerAndLoggingMiddleware(RequestDelegate next, IConfiguration configuration)
        {
            _next = next;
            _configuration = configuration;

            Uri = _configuration["ElasticConfiguration:Uri"] ?? "http://192.168.1.40:9200";
            IndexFormat = _configuration["ElasticConfiguration:IndexFormat"] ?? "bma-ehr-log-index";
            SystemName = _configuration["ElasticConfiguration:SystemName"] ?? "Unknown";
        }

        public async Task Invoke(HttpContext context)
        {
            Console.WriteLine("=== CombinedErrorHandlerAndLoggingMiddleware Start ===");

            var settings = new ConnectionSettings(new Uri(Uri))
                .DefaultIndex(IndexFormat);
            var client = new ElasticClient(settings);

            var startTime = DateTime.UtcNow;
            var stopwatch = Stopwatch.StartNew();
            string? responseBodyJson = null;
            string? requestBodyJson = null;
            Exception? caughtException = null;

            // อ่าน Request Body
            string requestBody = await ReadRequestBodyAsync(context);
            if (!string.IsNullOrEmpty(requestBody))
            {
                requestBodyJson = await FormatRequestBody(context, requestBody);
            }

            var originalBodyStream = context.Response.Body;

            using (var memoryStream = new MemoryStream())
            {
                // เปลี่ยน stream ของ Response เพื่อให้สามารถอ่านได้
                context.Response.Body = memoryStream;

                string keycloakId = Guid.Empty.ToString("D");
                var token = context.Request.Headers["Authorization"];
                GetProfileByKeycloakIdLocal? pf = null;

                // ลองดึง keycloakId จาก JWT token ก่อน (ถ้ามี)
                try
                {
                    keycloakId = await ExtractKeycloakIdFromToken(token);
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"Error extracting keycloakId from token: {ex.Message}");
                }

                try
                {
                    if (Guid.TryParse(keycloakId, out var parsedId) && parsedId != Guid.Empty)
                    {
                        pf = await GetProfileByKeycloakIdAsync(parsedId, token);
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"Error getting profile: {ex.Message}");
                }

                try
                {
                    await _next(context);
                    Console.WriteLine($"Request completed with status: {context.Response.StatusCode}");

                    // หลังจาก Authentication middleware ทำงานแล้ว ลองดึง claims อีกครั้ง
                    if (context.User?.Identity?.IsAuthenticated == true)
                    {
                        var authenticatedKeycloakId = context.User.FindFirst(ClaimTypes.NameIdentifier)?.Value 
                                                   ?? context.User.FindFirst("sub")?.Value;
                        if (!string.IsNullOrEmpty(authenticatedKeycloakId) && authenticatedKeycloakId != keycloakId)
                        {
                            keycloakId = authenticatedKeycloakId;
                            Console.WriteLine($"Updated keycloakId from authenticated user: {keycloakId}");
                            
                            // อัพเดต profile ด้วย keycloakId ที่ถูกต้อง
                            try
                            {
                                if (Guid.TryParse(keycloakId, out var parsedId))
                                {
                                    pf = await GetProfileByKeycloakIdAsync(parsedId, token);
                                }
                            }
                            catch (Exception ex)
                            {
                                Console.WriteLine($"Error updating profile after authentication: {ex.Message}");
                            }
                        }
                    }

                    // จัดการ response format หลังจาก request ผ่าน pipeline แล้ว
                    await FormatResponse(context, memoryStream);
                }
                catch (ObjectDisposedException)
                {
                    Console.WriteLine("ObjectDisposedException caught in main Invoke");
                    caughtException = new ObjectDisposedException("Response");
                    return;
                }
                catch (OperationCanceledException)
                {
                    Console.WriteLine("OperationCanceledException caught in main Invoke");
                    caughtException = new OperationCanceledException("Operation was cancelled");
                    return;
                }
                catch (Exception error)
                {
                    Console.WriteLine($"Exception caught in main Invoke: {error.Message}");
                    caughtException = error;
                    // จัดการ exception และ format เป็น response
                    await FormatExceptionResponse(context, error, memoryStream);
                }
                finally
                {
                    stopwatch.Stop();
                    await LogRequest(context, client, startTime, stopwatch, pf, keycloakId, requestBodyJson, memoryStream, caughtException);
                    
                    // เขียนข้อมูลกลับไปยัง original Response body
                    if (memoryStream.Length > 0)
                    {
                        memoryStream.Seek(0, SeekOrigin.Begin);
                        await memoryStream.CopyToAsync(originalBodyStream);
                    }
                }
            }

            Console.WriteLine("=== CombinedErrorHandlerAndLoggingMiddleware End ===");
        }

        private async Task<string> FormatRequestBody(HttpContext context, string requestBody)
        {
            try
            {
                if (context.Request.HasFormContentType)
                {
                    var form = await context.Request.ReadFormAsync();
                    var formData = new Dictionary<string, object>();
                    
                    foreach (var field in form)
                    {
                        formData[field.Key] = field.Value.ToString();
                    }

                    if (form.Files.Count > 0)
                    {
                        var fileDataList = new List<object>();
                        foreach (var file in form.Files)
                        {
                            fileDataList.Add(new
                            {
                                FileName = file.FileName,
                                ContentType = file.ContentType,
                                Size = file.Length
                            });
                        }
                        formData["Files"] = fileDataList;
                    }

                    var jsonOptions = new JsonSerializerOptions 
                    { 
                        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
                        Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping, 
                        WriteIndented = true, 
                        Converters = { new DateTimeFixConverter() } 
                    };
                    return JsonSerializer.Serialize(formData, jsonOptions);
                }
                else
                {
                    var jsonOptions = new JsonSerializerOptions 
                    { 
                        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
                        Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping, 
                        WriteIndented = true, 
                        Converters = { new DateTimeFixConverter() } 
                    };
                    return JsonSerializer.Serialize(JsonSerializer.Deserialize<object>(requestBody), jsonOptions);
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error formatting request body: {ex.Message}");
                return requestBody;
            }
        }

        private static async Task FormatResponse(HttpContext context, MemoryStream memoryStream)
        {
            try
            {
                if (context?.Response == null)
                    return;

                var response = context.Response;
                var statusCode = response.StatusCode;
                
                
                string? message = null;
                string? responseBodyJson = null;
                if (memoryStream.Length > 0)
                {
                    memoryStream.Seek(0, SeekOrigin.Begin);
                    var responseBody = new StreamReader(memoryStream).ReadToEnd();

                    var jsonOptions = new JsonSerializerOptions
                    {
                        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
                        Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping,
                        WriteIndented = true,
                        Converters = { new DateTimeFixConverter() }
                    };
                    responseBodyJson =
                        JsonSerializer.Serialize(JsonSerializer.Deserialize<object>(responseBody), jsonOptions);

                    var json = JsonSerializer.Deserialize<JsonElement>(responseBody);
                    if (json.ValueKind == JsonValueKind.Array)
                    {
                        message = "success";
                    }
                    else
                    {
                        if (json.TryGetProperty("message", out var messageElement))
                        {
                            message = messageElement.GetString();
                        }
                    }
                }

                Console.WriteLine($"FormatResponse: StatusCode={statusCode}, HasStarted={response.HasStarted}");

                // จัดการ response format แม้กับ status code จาก Authentication middleware
                if (!response.HasStarted && ShouldFormatResponse(statusCode))
                {
                    Console.WriteLine($"Formatting response for status: {statusCode}");
                    
                    var responseModel = CreateResponseModel(statusCode,message);
                    
                    // Clear memory stream และเขียน response ใหม่
                    memoryStream.SetLength(0);
                    memoryStream.Position = 0;
                    
                    // ไม่เปลี่ยน status code ที่ Authentication middleware ตั้งไว้
                    response.ContentType = "application/json; charset=utf-8";
                    
                    var jsonOptions = new JsonSerializerOptions
                    {
                        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
                        WriteIndented = false
                    };
                    var jsonResponse = JsonSerializer.Serialize(responseModel, jsonOptions);
                    var bytes = System.Text.Encoding.UTF8.GetBytes(jsonResponse);
                    
                    // กำหนด Content-Length ให้ตรงกับขนาดจริง
                    response.ContentLength = bytes.Length;

                    await memoryStream.WriteAsync(bytes, 0, bytes.Length);
                    
                    Console.WriteLine($"Response formatted successfully: {jsonResponse}");
                }
                // หากเป็น 401/403 แต่ยังไม่มี response body ให้สร้างใหม่
                else if (!response.HasStarted && (statusCode == 401 || statusCode == 403) && memoryStream.Length == 0)
                {
                    Console.WriteLine($"Creating response body for {statusCode} status");
                    
                    var responseModel = CreateResponseModel(statusCode,message);
                    response.ContentType = "application/json; charset=utf-8";
                    
                    var jsonOptions = new JsonSerializerOptions
                    {
                        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
                        WriteIndented = false
                    };
                    var jsonResponse = JsonSerializer.Serialize(responseModel, jsonOptions);
                    var bytes = System.Text.Encoding.UTF8.GetBytes(jsonResponse);
                    
                    // กำหนด Content-Length ให้ตรงกับขนาดจริง
                    response.ContentLength = bytes.Length;

                    await memoryStream.WriteAsync(bytes, 0, bytes.Length);
                    
                    Console.WriteLine($"Response body created: {jsonResponse}");
                }
            }
            catch (ObjectDisposedException)
            {
                Console.WriteLine("ObjectDisposedException in FormatResponse");
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error in FormatResponse: {ex.Message}");
            }
        }

        private static async Task FormatExceptionResponse(HttpContext context, Exception error, MemoryStream memoryStream)
        {
            try
            {
                Console.WriteLine($"FormatExceptionResponse: Error={error.Message}");
                
                if (context?.Response == null)
                    return;

                var response = context.Response;
                Console.WriteLine($"Response HasStarted: {response.HasStarted}");

                if (!response.HasStarted)
                {
                    // Clear memory stream และเขียน error response
                    memoryStream.SetLength(0);
                    memoryStream.Position = 0;
                    
                    response.StatusCode = (int)HttpStatusCode.InternalServerError;
                    response.ContentType = "application/json; charset=utf-8";

                    var responseModel = new ResponseObject
                    {
                        Status = response.StatusCode,
                        Message = GetErrorMessage(error),
                        Result = null
                    };

                    var jsonOptions = new JsonSerializerOptions
                    {
                        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
                        WriteIndented = false
                    };
                    var jsonResponse = JsonSerializer.Serialize(responseModel, jsonOptions);
                    var bytes = System.Text.Encoding.UTF8.GetBytes(jsonResponse);
                    
                    // กำหนด Content-Length ให้ตรงกับขนาดจริง
                    response.ContentLength = bytes.Length;

                    
                    await memoryStream.WriteAsync(bytes, 0, bytes.Length);
                    
                    Console.WriteLine($"Exception response formatted: {jsonResponse}");
                }
                else
                {
                    Console.WriteLine("Cannot format exception response - response already started");
                }
            }
            catch (ObjectDisposedException)
            {
                Console.WriteLine("ObjectDisposedException in FormatExceptionResponse");
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error in FormatExceptionResponse: {ex.Message}");
            }
        }

        private async Task LogRequest(HttpContext context, ElasticClient client, DateTime startTime, Stopwatch stopwatch, 
            GetProfileByKeycloakIdLocal? pf, string keycloakId, string? requestBodyJson, MemoryStream memoryStream, Exception? caughtException)
        {
            try
            {
                var processTime = stopwatch.ElapsedMilliseconds;
                var endTime = DateTime.UtcNow;
                
                var statusCode = caughtException != null ? (int)HttpStatusCode.InternalServerError : context.Response.StatusCode;
                
                var logType = caughtException != null ? "error" : statusCode switch
                {
                    >= 500 => "error",
                    >= 400 => "warning",
                    _ => "info"
                };

                string? message = null;
                string? responseBodyJson = null;

                // อ่านข้อมูลจาก Response
                if (memoryStream.Length > 0)
                {
                    memoryStream.Seek(0, SeekOrigin.Begin);
                    var responseBody = new StreamReader(memoryStream).ReadToEnd();
                    
                    if (!string.IsNullOrEmpty(responseBody))
                    {
                        var contentType = context.Response.ContentType;
                        var isFileResponse = !contentType.StartsWith("application/json") && !contentType.StartsWith("text/html") && (
                            contentType.StartsWith("application/") ||
                            contentType.StartsWith("image/") ||
                            contentType.StartsWith("audio/") ||
                            context.Response.Headers.ContainsKey("Content-Disposition")
                        );

                        if (isFileResponse)
                        {
                            responseBodyJson = "";
                            message = "success";
                        }
                        else
                        {
                            try
                            {
                                var jsonOptions = new JsonSerializerOptions 
                                { 
                                    PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
                                    Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping, 
                                    WriteIndented = true, 
                                    Converters = { new DateTimeFixConverter() } 
                                };
                                responseBodyJson = JsonSerializer.Serialize(JsonSerializer.Deserialize<object>(responseBody), jsonOptions);

                                var json = JsonSerializer.Deserialize<JsonElement>(responseBody);
                                if (json.ValueKind == JsonValueKind.Array)
                                {
                                    message = "success";
                                }
                                else
                                {
                                    if (json.TryGetProperty("message", out var messageElement))
                                    {
                                        message = messageElement.GetString();
                                    }
                                }
                            }
                            catch
                            {
                                responseBodyJson = responseBody;
                                message = caughtException?.Message ?? "Unknown error";
                            }
                        }
                    }
                }

                if (caughtException != null)
                {
                    message = caughtException.Message;
                }

                var logData = new
                {
                    logType = logType,
                    ip = context.Connection.RemoteIpAddress?.ToString(),
                    rootId = pf?.RootId,
                    systemName = SystemName,
                    startTimeStamp = startTime.ToString("o"),
                    endTimeStamp = endTime.ToString("o"),
                    processTime = processTime,
                    host = context.Request.Host.Value,
                    method = context.Request.Method,
                    endpoint = context.Request.Path + context.Request.QueryString,
                    responseCode = statusCode == 304 ? "200" : statusCode.ToString(),
                    responseDescription = message,
                    input = requestBodyJson,
                    output = responseBodyJson,
                    userId = keycloakId,
                    userName = $"{pf?.Prefix ?? ""}{pf?.FirstName ?? ""} {pf?.LastName ?? ""}",
                    user = pf?.CitizenId ?? "",
                    exception = caughtException?.ToString()
                };

                await client.IndexDocumentAsync(logData);
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error logging request: {ex.Message}");
            }
        }

        private static bool ShouldFormatResponse(int statusCode)
        {
            return statusCode == (int)HttpStatusCode.Unauthorized ||
                   statusCode == (int)HttpStatusCode.Forbidden ||
                   statusCode == (int)HttpStatusCode.BadRequest ||
                   statusCode == (int)HttpStatusCode.NotFound ||
                   statusCode == (int)HttpStatusCode.Conflict ||
                   statusCode == (int)HttpStatusCode.UnprocessableEntity ||
                   statusCode == (int)HttpStatusCode.InternalServerError;
        }

        private static ResponseObject CreateResponseModel(int statusCode,string? error)
        {
            var message = statusCode switch
            {
                (int)HttpStatusCode.Unauthorized => GlobalMessages.NotAuthorized,
                (int)HttpStatusCode.Forbidden => GlobalMessages.ForbiddenAccess,
                (int)HttpStatusCode.BadRequest => "Bad Request",
                (int)HttpStatusCode.NotFound => "Resource Not Found",
                (int)HttpStatusCode.Conflict => "Conflict",
                (int)HttpStatusCode.UnprocessableEntity => "Validation Error",
                (int)HttpStatusCode.InternalServerError => GlobalMessages.ExceptionOccured,
                _ => "Error"
            };

            return new ResponseObject
            {
                Status = statusCode,
                Message = error ?? message
            };
        }

        private static string GetErrorMessage(Exception error)
        {
            var msg = error.Message;
            var inner = error.InnerException;
            while (inner != null)
            {
                msg += $" {inner.Message}\r\n";
                inner = inner.InnerException;
            }
            return msg;
        }

        private async Task<string> ExtractKeycloakIdFromToken(string? authorizationHeader)
        {
            try
            {
                if (string.IsNullOrEmpty(authorizationHeader) || !authorizationHeader.StartsWith("Bearer "))
                {
                    return Guid.Empty.ToString("D");
                }

                var token = authorizationHeader.Replace("Bearer ", "");
                
                // แยก JWT token เพื่อดึง payload (แบบง่าย โดยไม่ verify signature)
                var parts = token.Split('.');
                if (parts.Length != 3)
                {
                    return Guid.Empty.ToString("D");
                }

                // Decode Base64 payload
                var payload = parts[1];
                
                // เพิ่ม padding ถ้าจำเป็น
                var padLength = 4 - (payload.Length % 4);
                if (padLength != 4)
                {
                    payload += new string('=', padLength);
                }

                var payloadBytes = Convert.FromBase64String(payload);
                var payloadJson = System.Text.Encoding.UTF8.GetString(payloadBytes);
                
                Console.WriteLine($"JWT Payload: {payloadJson}");

                // Parse JSON และดึง sub (subject) claim
                var jsonDoc = JsonDocument.Parse(payloadJson);
                
                // ลองหา keycloak ID ใน claims ต่างๆ
                string? keycloakId = null;
                
                if (jsonDoc.RootElement.TryGetProperty("sub", out var subElement))
                {
                    keycloakId = subElement.GetString();
                }
                else if (jsonDoc.RootElement.TryGetProperty("nameid", out var nameidElement))
                {
                    keycloakId = nameidElement.GetString();
                }
                else if (jsonDoc.RootElement.TryGetProperty("user_id", out var userIdElement))
                {
                    keycloakId = userIdElement.GetString();
                }

                return keycloakId ?? Guid.Empty.ToString("D");
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error extracting keycloak ID from token: {ex.Message}");
                return Guid.Empty.ToString("D");
            }
        }

        protected async Task<string> GetExternalAPIAsync(string apiPath, string accessToken, string apiKey)
        {
            try
            {
                using (var client = new HttpClient())
                {
                    client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken.Replace("Bearer ", ""));
                    client.DefaultRequestHeaders.Add("api_key", apiKey);
                    var _res = await client.GetAsync(apiPath);
                    if (_res.IsSuccessStatusCode)
                    {
                        var _result = await _res.Content.ReadAsStringAsync();
                        return _result;
                    }
                    return string.Empty;
                }
            }
            catch
            {
                throw;
            }
        }

        public async Task<GetProfileByKeycloakIdLocal?> GetProfileByKeycloakIdAsync(Guid keycloakId, string? accessToken)
        {
            try
            {
                var apiPath = $"{_configuration["API"]}/org/dotnet/keycloak/{keycloakId}";
                var apiKey = _configuration["API_KEY"];

                var apiResult = await GetExternalAPIAsync(apiPath, accessToken ?? "", apiKey);
                if (apiResult != null)
                {
                    var raw = JsonConvert.DeserializeObject<GetProfileByKeycloakIdResultLocal>(apiResult);
                    if (raw != null)
                        return raw.Result;
                }

                return null;
            }
            catch
            {
                throw;
            }
        }

        private async Task<string> ReadRequestBodyAsync(HttpContext context)
        {
            context.Request.EnableBuffering();
            using var reader = new StreamReader(context.Request.Body, leaveOpen: true);
            var body = await reader.ReadToEndAsync();
            context.Request.Body.Position = 0;
            return body;
        }
    }

    // Model classes
    public class GetProfileByKeycloakIdLocal
    {
        public Guid Id { get; set; }
        public string? Prefix { get; set; }
        public string? FirstName { get; set; }
        public string? LastName { get; set; }
        public string? CitizenId { get; set; }
        public string? Root { get; set; }
        public string? Child1 { get; set; }
        public string? Child2 { get; set; }
        public string? Child3 { get; set; }
        public string? Child4 { get; set; }
        public Guid? RootId { get; set; }
        public Guid? Child1Id { get; set; }
        public Guid? Child2Id { get; set; }
        public Guid? Child3Id { get; set; }
        public Guid? Child4Id { get; set; }
        public Guid? RootDnaId { get; set; }
        public Guid? Child1DnaId { get; set; }
        public Guid? Child2DnaId { get; set; }
        public Guid? Child3DnaId { get; set; }
        public Guid? Child4DnaId { get; set; }
        public double? Amount { get; set; }
        public double? PositionSalaryAmount { get; set; }
        public string? Commander { get; set; }
        public Guid? CommanderId { get; set; }
        public Guid? CommanderKeycloak { get; set; }
    }

    public class GetProfileByKeycloakIdResultLocal
    {
        public string Message { get; set; } = string.Empty;
        public int Status { get; set; } = -1;
        public GetProfileByKeycloakIdLocal? Result { get; set; }
    }

}