using System.Diagnostics;
using CoreAgent.Infrastructure.Options;
using System.Text;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;

namespace CoreAgent.Infrastructure.Extensions.Logging;

/// <summary>
/// 请求日志中间件
/// </summary>
public class RequestLoggingMiddleware
{
    private readonly RequestDelegate _next;
    private readonly ILogger<RequestLoggingMiddleware> _logger;
    private readonly RequestLoggingOptions _options;

    public RequestLoggingMiddleware(
        RequestDelegate next,
        ILogger<RequestLoggingMiddleware> logger,
        IOptions<RequestLoggingOptions> options)
    {
        _next = next;
        _logger = logger;
        _options = options.Value;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        if (ShouldSkipLogging(context))
        {
            await _next(context);
            return;
        }

        var sw = Stopwatch.StartNew();
        var requestBody = string.Empty;

        try
        {
            if (_options.LogRequestBody && context.Request.Body != null)
            {
                requestBody = await ReadRequestBodyAsync(context.Request);
            }

            _logger.LogInformation(
                "Request started: {Method} {Path} {QueryString} {RequestBody}",
                context.Request.Method,
                context.Request.Path,
                context.Request.QueryString,
                requestBody);

            await _next(context);
        }
        finally
        {
            sw.Stop();
            _logger.LogInformation(
                "Request completed: {Method} {Path} in {ElapsedMilliseconds}ms with status code {StatusCode}",
                context.Request.Method,
                context.Request.Path,
                sw.ElapsedMilliseconds,
                context.Response.StatusCode);
        }
    }

    private bool ShouldSkipLogging(HttpContext context)
    {
        if (_options.ExcludePaths.Any(p => context.Request.Path.StartsWithSegments(p)))
        {
            return true;
        }

        if (_options.ExcludeMethods.Contains(context.Request.Method))
        {
            return true;
        }

        return false;
    }

    private async Task<string> ReadRequestBodyAsync(HttpRequest request)
    {
        if (!request.Body.CanRead || !request.Body.CanSeek)
        {
            return string.Empty;
        }

        var originalPosition = request.Body.Position;
        request.Body.Position = 0;

        try
        {
            using var reader = new StreamReader(
                request.Body,
                encoding: Encoding.UTF8,
                detectEncodingFromByteOrderMarks: false,
                bufferSize: 1024 * 45,
                leaveOpen: true);

            var body = await reader.ReadToEndAsync();
            return body.Length > _options.MaxRequestBodySize
                ? body.Substring(0, _options.MaxRequestBodySize) + "..."
                : body;
        }
        finally
        {
            request.Body.Position = originalPosition;
        }
    }
}