// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Globalization;
using Microsoft.AspNetCore.Diagnostics;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.WebUtilities;
using Microsoft.Extensions.DependencyInjection;
 
namespace Microsoft.AspNetCore.Builder;
 
/// <summary>
/// Options for <see cref="StatusCodePagesMiddleware"/>.
/// </summary>
public class StatusCodePagesOptions
{
    /// <summary>
    /// Creates a default <see cref="StatusCodePagesOptions"/> whose handler attempts to generate a
    /// <see cref="Microsoft.AspNetCore.Mvc.ProblemDetails"/> response using <see cref="IProblemDetailsService"/>, and falls back
    /// to a plaintext response containing the status code and reason phrase when that service is unavailable
    /// or cannot write a response.
    /// </summary>
    public StatusCodePagesOptions()
    {
        HandleAsync = async context =>
        {
            var statusCode = context.HttpContext.Response.StatusCode;
            var problemDetailsService = context.HttpContext.RequestServices.GetService<IProblemDetailsService>();
 
            if (problemDetailsService == null ||
                !await problemDetailsService.TryWriteAsync(new() { HttpContext = context.HttpContext, ProblemDetails = { Status = statusCode } }))
            {
                // TODO: Render with a pre-compiled html razor view
                var body = BuildResponseBody(statusCode);
 
                context.HttpContext.Response.ContentType = "text/plain";
                await context.HttpContext.Response.WriteAsync(body);
            }
        };
    }
 
    private static string BuildResponseBody(int httpStatusCode)
    {
        // Note the 500 spaces are to work around an IE 'feature'
        var internetExplorerWorkaround = new string(' ', 500);
 
        var reasonPhrase = ReasonPhrases.GetReasonPhrase(httpStatusCode);
 
        return string.Format(CultureInfo.InvariantCulture, "Status Code: {0}{1}{2}{3}",
                                                                httpStatusCode,
                                                                string.IsNullOrWhiteSpace(reasonPhrase) ? "" : "; ",
                                                                reasonPhrase,
                                                                internetExplorerWorkaround);
    }
 
    /// <summary>
    /// The handler that generates the response body for the given <see cref="StatusCodeContext"/>.
    /// By default this attempts to generate a <see cref="Microsoft.AspNetCore.Mvc.ProblemDetails"/> response
    /// using <see cref="IProblemDetailsService"/> and falls back to a plain text response that includes the
    /// status code.
    /// </summary>
    public Func<StatusCodeContext, Task> HandleAsync { get; set; }
 
    /// <summary>
    /// Gets or sets whether the handler needs to create a separate <see cref="IServiceProvider"/> scope and
    /// replace it on <see cref="HttpContext.RequestServices"/> when re-executing the request.
    /// </summary>
    /// <remarks>The default value is <see langword="false"/>.</remarks>
    public bool CreateScopeForStatusCodePages { get; set; }
 
    internal string? PathFormat { get; set; }
}