using System.Net;
using System.Text.Json;
using AmtScanner.Api.Models;

namespace AmtScanner.Api.Middleware;

/// <summary>
/// 全局异常处理中间件
/// </summary>
public class GlobalExceptionMiddleware
{
    private readonly RequestDelegate _next;
    private readonly ILogger<GlobalExceptionMiddleware> _logger;

    public GlobalExceptionMiddleware(RequestDelegate next, ILogger<GlobalExceptionMiddleware> logger)
    {
        _next = next;
        _logger = logger;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        try
        {
            await _next(context);
        }
        catch (Exception ex)
        {
            await HandleExceptionAsync(context, ex);
        }
    }

    private async Task HandleExceptionAsync(HttpContext context, Exception exception)
    {
        _logger.LogError(exception, "An unhandled exception occurred: {Message}", exception.Message);

        var response = context.Response;
        response.ContentType = "application/json";

        var (statusCode, code, message) = exception switch
        {
            UnauthorizedAccessException => (HttpStatusCode.Unauthorized, 401, "未授权访问"),
            ArgumentException argEx => (HttpStatusCode.BadRequest, 400, argEx.Message),
            KeyNotFoundException => (HttpStatusCode.NotFound, 404, "资源不存在"),
            InvalidOperationException invEx => (HttpStatusCode.BadRequest, 400, invEx.Message),
            _ => (HttpStatusCode.InternalServerError, 500, "服务器内部错误")
        };

        response.StatusCode = (int)statusCode;

        var result = JsonSerializer.Serialize(new ApiResponse
        {
            Code = code,
            Msg = message,
            Data = null
        }, new JsonSerializerOptions
        {
            PropertyNamingPolicy = JsonNamingPolicy.CamelCase
        });

        await response.WriteAsync(result);
    }
}

/// <summary>
/// 中间件扩展方法
/// </summary>
public static class GlobalExceptionMiddlewareExtensions
{
    public static IApplicationBuilder UseGlobalExceptionHandler(this IApplicationBuilder app)
    {
        return app.UseMiddleware<GlobalExceptionMiddleware>();
    }
}