stream-cinema/CinemaWeb/Pages/LinkPage.cs

using System;
using System.Web;
using Microsoft.Extensions.Primitives;
using Cinema.Webshare;
using CinemaLib.API;
using CinemaWeb.Layouts;
using LinkGenerator = Cinema.Webshare.LinkGenerator;

namespace CinemaWeb.Pages;

public class LinkPage : BasicLayout
{
  private readonly string _provider;
  private readonly string _ident;
  private readonly string _name;
  private readonly string _title;

  public LinkPage(string provider, string ident, string name, string title)
  {
    this._provider = provider;
    this._ident = ident;
    this._name = name;
    this._title = title;
  }

  protected override string Title => _title;

  protected override async Task RenderContentAsync(HttpRequest req, TextWriter w)
  {
    w.WriteLine("<h1>" + HttpUtility.HtmlEncode(_title) + "</h1>");

    Uri link;
    switch (_provider)
    {
      case "webshare": link = await LinkGenerator.GenerateDownloadLinkAsync(_ident, _name, req.HttpContext.RequestAborted); break;
      default:
        w.WriteLine("<em>Provider '" + HttpUtility.HtmlEncode(_provider) + "' není aktuálně podporován.</em>");
        return;
    }

    w.WriteLine("<div><a href=\"" + link.ToString() + "\">" + HttpUtility.HtmlEncode(link.ToString()) + "</a></div>");

    // External subtitles
    StringValues subs = req.Query["sub"];
    if (subs.Count != 0) {
      w.WriteLine("<h2>Externí titulky</h2>");
      foreach (string i in subs) {
        (string lang, Uri uri) = await ProcessSubtitleLinkAsync(i, req.HttpContext.RequestAborted);
        w.WriteLine("<div><a href=\"" + uri.ToString() + "\">" + HttpUtility.HtmlEncode(lang) + "</a></div>");
      }
    }
  }

  private static async Task<(string, Uri)> ProcessSubtitleLinkAsync(string link, CancellationToken cancel) {
    if (link == null)
      throw new ArgumentNullException();

    // Format: <lang>:<provider>:<id>
    int a = link.IndexOf(':');
    int b = link.IndexOf(':', a + 1);
    if (a < 0 || b < 0)
      throw new FormatException();
    
    string lang = link.Substring(0, a);
    string provider = link.Substring(a + 1, b - a - 1);
    string rawId = link.Substring(b + 1);
    Uri result;
    switch (provider) {
      case "webshare":
        result = await LinkGenerator.GenerateDownloadLinkAsync(rawId, "", cancel);
        break;
      case "http":
        result = new Uri(rawId);
        break;
      default:
        throw new NotSupportedException();
    }
    return (lang, result);
  }
}