using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
using Nest;
using System.Diagnostics;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Text.Encodings.Web;
using System.Text.Json;
using JsonSerializer = System.Text.Json.JsonSerializer;

namespace BMA.EHR.Recruit.Service.Core
{
    public class RequestLoggingMiddleware
    {
        private readonly RequestDelegate _next;
        private readonly IConfiguration _configuration;

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

        public RequestLoggingMiddleware(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 = "recruiting";
        }

        /// <summary>
        /// แกะ JWT token เพื่อดึง claims ต่างๆ
        /// </summary>
        private JwtSecurityToken? ParseToken(string token)
        {
            try
            {
                var tokenHandler = new JwtSecurityTokenHandler();
                var jwtToken = tokenHandler.ReadJwtToken(token.Replace("Bearer ", ""));
                return jwtToken;
            }
            catch
            {
                return null;
            }
        }

        /// <summary>
        /// ดึงค่า claim จาก token โดยลองชื่อหลายแบบ
        /// </summary>
        private string? GetClaimValue(JwtSecurityToken? token, params string[] claimNames)
        {
            if (token == null) return null;

            foreach (var name in claimNames)
            {
                var claim = token.Claims.FirstOrDefault(c => c.Type == name);
                if (claim != null)
                    return claim.Value;
            }
            return null;
        }

        /// <summary>
        /// ดึงค่า Guid claim จาก token
        /// </summary>
        private Guid? GetGuidClaim(JwtSecurityToken? token, params string[] claimNames)
        {
            var value = GetClaimValue(token, claimNames);
            if (Guid.TryParse(value, out var guid))
                return guid;
            return null;
        }

        public async Task Invoke(HttpContext context)
        {
            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;

            string requestBody = await ReadRequestBodyAsync(context);
            if (requestBody != "")
            {
                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;
                    }

                    requestBodyJson = JsonSerializer.Serialize(formData, new JsonSerializerOptions { Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping, WriteIndented = true, Converters = { new DateTimeFixConverter() } });
                }
                else
                {
                    requestBodyJson = JsonSerializer.Serialize(JsonSerializer.Deserialize<object>(requestBody), new JsonSerializerOptions { Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping, WriteIndented = true, Converters = { new DateTimeFixConverter() } });
                }
            }

            var originalBodyStream = context.Response.Body;

            using (var memoryStream = new MemoryStream())
            {
                context.Response.Body = memoryStream;

                var keycloakId = context.User?.FindFirst(ClaimTypes.NameIdentifier)?.Value ?? Guid.Empty.ToString("D");
                var tokenHeader = context.Request.Headers["Authorization"].ToString();

                // แกะ JWT token เพื่อดึง claims ต่างๆ
                var jwtToken = ParseToken(tokenHeader);

                // ดึงข้อมูลจาก claims โดยลองชื่อหลายแบบ (camelCase, snake_case, ฯลฯ)
                var prefix = GetClaimValue(jwtToken, "prefix", "Prefix", "PREFIX");
                var firstName = GetClaimValue(jwtToken, "given_name", "firstname", "firstName", "FirstName", "FIRSTNAME");
                var lastName = GetClaimValue(jwtToken, "family_name", "lastname", "lastName", "LastName", "LASTNAME");
                var preferredUsername = GetClaimValue(jwtToken, "preferred_username", "preferred_username", "PreferredUsername");
                var orgRootDnaId = GetGuidClaim(jwtToken, "orgRootDnaId", "org_root_dna_id", "OrgRootDnaId", "rootDnaId");
                var orgChild1Dna = GetGuidClaim(jwtToken, "orgChild1DnaId", "org_child1_dna", "OrgChild1Dna", "child1DnaId");
                var orgChild2Dna = GetGuidClaim(jwtToken, "orgChild2DnaId", "org_child2_dna", "OrgChild2Dna", "child2DnaId");
                var orgChild3Dna = GetGuidClaim(jwtToken, "orgChild3DnaId", "org_child3_dna", "OrgChild3Dna", "child3DnaId");
                var orgChild4Dna = GetGuidClaim(jwtToken, "orgChild4DnaId", "org_child4_dna", "OrgChild4Dna", "child4DnaId");

                await _next(context);

                stopwatch.Stop();
                var processTime = stopwatch.ElapsedMilliseconds;
                var endTime = DateTime.UtcNow;

                var logType = context.Response.StatusCode switch
                {
                    >= 500 => "error",
                    >= 400 => "warning",
                    _ => "info"
                };

                string? message = null;

                memoryStream.Seek(0, SeekOrigin.Begin);
                var responseBody = new StreamReader(memoryStream).ReadToEnd();

                if (!string.IsNullOrEmpty(responseBody))
                {
                    var contentType = context.Response.ContentType ?? "";

                    if (contentType.Equals(
                        "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
                        StringComparison.OrdinalIgnoreCase))
                    {
                        responseBodyJson = $"Excel file (Length={memoryStream.Length} bytes)";
                        message = "success";
                    }
                    else if (contentType.StartsWith("application/json", StringComparison.OrdinalIgnoreCase))
                    {
                        try
                        {
                            responseBodyJson = JsonSerializer.Serialize(
                                JsonSerializer.Deserialize<object>(responseBody),
                                new JsonSerializerOptions
                                {
                                    Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping,
                                    WriteIndented = true,
                                    Converters = { new DateTimeFixConverter() }
                                });

                            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 = "success";
                        }
                    }
                    else
                    {
                        responseBodyJson = responseBody;
                        message = "success";
                    }
                }

                var logData = new
                {
                    logType = logType,
                    ip = context.Connection.RemoteIpAddress?.ToString(),
                    rootId = orgRootDnaId?.ToString("D"),
                    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 = context.Response.StatusCode == 304 ? "200" : context.Response.StatusCode.ToString(),
                    responseDescription = message,
                    input = requestBodyJson,
                    output = responseBodyJson,
                    userId = keycloakId,
                    userName = $"{prefix ?? ""}{firstName ?? ""} {lastName ?? ""}",
                    user = preferredUsername ?? ""
                    //user = GetClaimValue(jwtToken, "citizen_id", "citizenId", "CitizenId") ?? ""
                };

                memoryStream.Seek(0, SeekOrigin.Begin);
                await memoryStream.CopyToAsync(originalBodyStream);

                client.IndexDocument(logData);
            }
        }

        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;
        }
    }
}