using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
using QYZH.InteractiveMagazine.Infrastructure.Cache;
using QYZH.InteractiveMagazine.Models.Settings;
using System.IdentityModel.Tokens.Jwt;

namespace QYZH.InteractiveMagazine.Infrastructure.Middleware;

public class JwtAutoRefreshMiddleware
{
    private readonly RequestDelegate _next;
    private readonly IConfiguration _configuration;
    private const string TokenKeyPrefix = "InteractiveMagazine:AdminAuth:Token";
    private const int RefreshThresholdMinutes = 10;

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

    public async Task InvokeAsync(HttpContext context)
    {
        var authHeader = context.Request.Headers.Authorization.FirstOrDefault();
        if (!string.IsNullOrEmpty(authHeader) && authHeader.StartsWith("Bearer "))
        {
            var token = authHeader.Substring("Bearer ".Length).Trim();
            await TryAutoRefreshTokenAsync(context, token);
        }

        await _next(context);
    }

    private async Task TryAutoRefreshTokenAsync(HttpContext context, string token)
    {
        try
        {
            var tokenHandler = new JwtSecurityTokenHandler();
            if (tokenHandler.ReadToken(token) is not JwtSecurityToken jwtToken)
            {
                return;
            }

            var expiryTime = jwtToken.ValidTo;
            var remainingTime = expiryTime - DateTime.Now;

            if (remainingTime <= TimeSpan.FromMinutes(RefreshThresholdMinutes) && remainingTime > TimeSpan.Zero)
            {
                var userId = jwtToken.Claims.FirstOrDefault(c => c.Type == System.Security.Claims.ClaimTypes.NameIdentifier)?.Value;
                var userName = jwtToken.Claims.FirstOrDefault(c => c.Type == System.Security.Claims.ClaimTypes.Name)?.Value;

                if (string.IsNullOrEmpty(userId) || string.IsNullOrEmpty(userName))
                {
                    return;
                }

                var jwtSettings = _configuration.GetSection("JwtSettings").Get<JwtSettings>();
                if (jwtSettings == null)
                {
                    return;
                }

                var newToken = QYZH.InteractiveMagazine.Infrastructure.Auth.JwtHelper.GenerateToken(
                    long.Parse(userId), userName, jwtSettings);

                await RedisHelper.StringSetAsync(
                    $"{TokenKeyPrefix}:{userId}",
                    newToken,
                    TimeSpan.FromMinutes(jwtSettings.ExpiryMinutes));

                context.Response.Headers["X-New-Token"] = newToken;
            }
        }
        catch
        {
            // 忽略自动刷新异常，由后续认证中间件处理
        }
    }
}