using Microsoft.AspNetCore.Identity;
using Microsoft.Extensions.Logging;
using MediatR;
using X1.Domain.Entities;
using X1.Domain.Repositories;
using X1.Domain.Services;
using System.Threading.Tasks;
using System.Threading;
using X1.Domain.Common;
using Microsoft.AspNetCore.Http;
using System.Security.Claims;
using System;
using System.Linq;
using System.Collections.Generic;
using Microsoft.EntityFrameworkCore;
using X1.Application.Features.Auth.Models;
using X1.Domain.Entities.Logging;
using X1.Domain.Repositories.Identity;
using X1.Domain.Repositories.Base;
using X1.Domain.Options;
using Microsoft.Extensions.Options;

namespace X1.Application.Features.Auth.Commands;

/// <summary>
/// 登录命令处理器基类
/// </summary>
public abstract class BaseLoginCommandHandler<TCommand, TResponse> : IRequestHandler<TCommand, OperationResult<TResponse>>
    where TCommand : IRequest<OperationResult<TResponse>>
    where TResponse : class
{
    protected readonly UserManager<AppUser> _userManager;
    protected readonly IJwtProvider _jwtProvider;
    protected readonly ILogger _logger;
    protected readonly IUserRoleRepository _userRoleRepository;
    protected readonly IRolePermissionRepository _rolePermissionRepository;
    protected readonly IUnitOfWork _unitOfWork;
    protected readonly ILoginLogRepository _loginLogRepository;
    protected readonly IHttpContextAccessor _httpContextAccessor;
    protected readonly ISessionManagementService _sessionManagementService;
    protected readonly JwtOptions _jwtOptions;
    private const int MaxRetryAttempts = 3;

    /// <summary>
    /// 初始化处理器
    /// </summary>
    protected BaseLoginCommandHandler(
        UserManager<AppUser> userManager,
        IJwtProvider jwtProvider,
        ILogger logger,
        IUserRoleRepository userRoleRepository,
        IRolePermissionRepository rolePermissionRepository,
        IUnitOfWork unitOfWork,
        ILoginLogRepository loginLogRepository,
        IHttpContextAccessor httpContextAccessor,
        ISessionManagementService sessionManagementService,
        IOptions<JwtOptions> jwtOptions)
    {
        _userManager = userManager;
        _jwtProvider = jwtProvider;
        _logger = logger;
        _userRoleRepository = userRoleRepository;
        _rolePermissionRepository = rolePermissionRepository;
        _unitOfWork = unitOfWork;
        _loginLogRepository = loginLogRepository;
        _httpContextAccessor = httpContextAccessor;
        _sessionManagementService = sessionManagementService;
        _jwtOptions = jwtOptions.Value;
    }

    /// <summary>
    /// 处理登录请求
    /// </summary>
    public abstract Task<OperationResult<TResponse>> Handle(TCommand request, CancellationToken cancellationToken);

    /// <summary>
    /// 查找用户
    /// </summary>
    protected abstract Task<AppUser?> FindUserAsync(TCommand request);

    /// <summary>
    /// 获取用户标识
    /// </summary>
    protected abstract string GetUserIdentifier(TCommand request);

    /// <summary>
    /// 获取密码
    /// </summary>
    protected abstract string GetPassword(TCommand request);

    /// <summary>
    /// 验证凭据
    /// </summary>
    protected virtual async Task<bool> ValidateCredentialsAsync(TCommand request, AppUser user)
    {
        return await _userManager.CheckPasswordAsync(user, GetPassword(request));
    }

    /// <summary>
    /// 处理登录逻辑
    /// </summary>
    protected async Task<OperationResult<TResponse>> HandleLoginAsync(TCommand request, CancellationToken cancellationToken)
    {
        try
        {
            var httpContext = _httpContextAccessor.HttpContext;
            var ipAddress = httpContext?.Connection.RemoteIpAddress?.ToString() ?? "Unknown";
            var userAgent = httpContext?.Request.Headers["User-Agent"].ToString() ?? "Unknown";

            // 检查IP是否被限制
            if (await _loginLogRepository.IsIpRestrictedAsync(ipAddress, cancellationToken))
            {
                _logger.LogWarning("IP {IpAddress} 已被限制登录", ipAddress);
                return OperationResult<TResponse>.CreateFailure("登录尝试次数过多，请稍后再试");
            }

            // 解析设备信息
            var parser = UAParser.Parser.GetDefault();
            var clientInfo = parser.Parse(userAgent);

            // 查找用户
            var user = await FindUserAsync(request);
            var userIdentifier = GetUserIdentifier(request);

            // 创建登录日志
            var loginLog = LoginLog.Create(
                userId: user?.Id ?? "Unknown",
                ipAddress: ipAddress,
                userAgent: userAgent,
                isSuccess: false,
                loginType: "Password",
                loginSource: "Web",
                browser: clientInfo.UA.ToString(),
                operatingSystem: clientInfo.OS.ToString());

            if (user == null)
            {
                loginLog.UpdateFailureReason("用户不存在");
                await _loginLogRepository.RecordLoginAsync(loginLog, cancellationToken);
                _logger.LogWarning("用户 {UserIdentifier} 不存在", userIdentifier);
                return OperationResult<TResponse>.CreateFailure("用户不存在");
            }

            // 检查用户是否已删除
            if (user.IsDeleted)
            {
                loginLog.UpdateFailureReason("用户已被删除");
                await _loginLogRepository.RecordLoginAsync(loginLog, cancellationToken);
                _logger.LogWarning("用户 {UserIdentifier} 已被删除", userIdentifier);
                return OperationResult<TResponse>.CreateFailure("用户已被删除");
            }

            // 检查用户是否已禁用
            if (!user.IsActive)
            {
                loginLog.UpdateFailureReason("用户已被禁用");
                await _loginLogRepository.RecordLoginAsync(loginLog, cancellationToken);
                _logger.LogWarning("用户 {UserIdentifier} 已被禁用", userIdentifier);
                return OperationResult<TResponse>.CreateFailure("用户已被禁用");
            }

            // 验证凭据
            var isValidCredentials = await ValidateCredentialsAsync(request, user);
            if (!isValidCredentials)
            {
                loginLog.UpdateFailureReason("验证失败");
                await _loginLogRepository.RecordLoginAsync(loginLog, cancellationToken);
                _logger.LogWarning("用户 {UserIdentifier} 验证失败", userIdentifier);
                return OperationResult<TResponse>.CreateFailure("验证失败");
            }

            // 更新最后登录时间（带并发控制）
            var retryCount = 0;
            var updateSuccess = false;

            while (!updateSuccess && retryCount < MaxRetryAttempts)
            {
                try
                {
                    await _unitOfWork.ExecuteTransactionAsync(async () =>
                    {
                        user.LastLoginTime = DateTime.UtcNow;
                        var result = await _userManager.UpdateAsync(user);
                        if (!result.Succeeded)
                        {
                            var errors = result.Errors.Select(e => e.Description).ToList();
                            _logger.LogWarning("更新用户最后登录时间失败: {Errors}", string.Join(", ", errors));
                            throw new InvalidOperationException(string.Join(", ", errors));
                        }
                    }, cancellationToken: cancellationToken);
                    updateSuccess = true;
                }
                catch (DbUpdateConcurrencyException)
                {
                    retryCount++;
                    _logger.LogWarning("用户 {UserIdentifier} 更新时发生并发冲突，重试次数: {RetryCount}",
                        userIdentifier, retryCount);

                    if (retryCount >= MaxRetryAttempts)
                    {
                        _logger.LogError("用户 {UserIdentifier} 更新失败，超过最大重试次数", userIdentifier);
                        return OperationResult<TResponse>.CreateFailure("系统繁忙，请稍后重试");
                    }

                    // 重新获取最新数据
                    user = await _userManager.FindByIdAsync(user.Id);
                    if (user == null)
                    {
                        return OperationResult<TResponse>.CreateFailure("用户不存在");
                    }
                }
            }

            // 获取用户角色
            var roles = await _userRoleRepository.GetUserRolesAsync(user.Id, cancellationToken);

            // 创建用户声明
            var claims = new List<Claim>
            {
                new(ClaimTypes.NameIdentifier, user.Id),
                new(ClaimTypes.Name, user.UserName!),
                new(ClaimTypes.Email, user.Email!)
            };

            // 添加最后登录时间声明（如果存在）
            if (user.LastLoginTime.HasValue)
            {
                claims.Add(new Claim("LastLoginTime", user.LastLoginTime.Value.ToUniversalTime().ToString("o")));
            }

            // 添加角色声明
            claims.AddRange(roles.Select(role => new Claim(ClaimTypes.Role, role)));

            // 获取所有角色的权限
            var permissionCodes = new HashSet<string>();
            if (roles.Any())
            {
                var allRolePermissions = await _rolePermissionRepository.GetRolePermissionsByRolesAsync(roles, cancellationToken);
                foreach (var rolePermission in allRolePermissions)
                {
                    if (rolePermission.Permission != null)
                    {
                        permissionCodes.Add(rolePermission.Permission.Code);
                    }
                }
            }

            // 生成会话ID
            var sessionId = Guid.NewGuid().ToString();

            // 添加会话ID到Claims（在生成令牌之前）- 使用ClaimTypes.UserData
            claims.Add(new Claim(ClaimTypes.UserData, sessionId));

            // 生成访问令牌
            var accessToken = _jwtProvider.GenerateAccessToken(claims);

            // 生成刷新令牌
            var refreshToken = _jwtProvider.GenerateRefreshToken(claims);

            // 获取令牌过期时间
            var expiresAt = _jwtProvider.GetTokenExpiration(accessToken);

            // 创建设备信息
            var deviceInfo = $"{clientInfo.OS.Family} {clientInfo.OS.Major}.{clientInfo.OS.Minor} - {clientInfo.UA.Family} {clientInfo.UA.Major}.{clientInfo.UA.Minor}";

            // 创建用户会话（踢出其他登录）
            var sessionExpiry = TimeSpan.FromMinutes(_jwtOptions.ExpiryMinutes);
            var sessionCreated = await _sessionManagementService.CreateSessionAsync(
                user.Id,
                sessionId,
                accessToken,
                deviceInfo,
                sessionExpiry);

            if (!sessionCreated)
            {
                _logger.LogError("创建用户会话失败: {UserId}", user.Id);
                return OperationResult<TResponse>.CreateFailure("创建会话失败，请稍后重试");
            }

            // 创建用户信息
            var userInfo = new UserInfo(
                user.Id,
                user.UserName!,
                user.RealName,
                user.Email!,
                user.PhoneNumber,
                roles.ToList().AsReadOnly(),
                permissionCodes.ToList().AsReadOnly());

            // 记录成功的登录日志
            loginLog = LoginLog.Create(
                userId: user.Id,
                ipAddress: ipAddress,
                userAgent: userAgent,
                isSuccess: true,
                loginType: "Password",
                loginSource: "Web",
                browser: clientInfo.UA.ToString(),
                operatingSystem: clientInfo.OS.ToString());

            await _loginLogRepository.RecordLoginAsync(loginLog, cancellationToken);
            await _unitOfWork.SaveChangesAsync(cancellationToken);
            _logger.LogInformation("用户 {UserIdentifier} 认证成功", userIdentifier);

            // 返回认证结果
            var response = (TResponse)Activator.CreateInstance(
                typeof(TResponse),
                accessToken,
                refreshToken,
                expiresAt,
                userInfo)!;

            return OperationResult<TResponse>.CreateSuccess(response);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "用户认证失败");
            return OperationResult<TResponse>.CreateFailure("认证失败，请稍后重试");
        }
    }
}