{ pkgs, ... }:

# most is taken from this discussion https://www.reddit.com/r/NixOS/comments/15trmac/how_would_you_do_a_nginx_snippets_in_nixos/
# with the following gist https://gist.github.com/aswan89/ee554406c39eb2eeb3126f73f74ab61c
let
  AUTHELIA_HOST = "http://localhost:9091";

  autheliaLocation = pkgs.writeText "authelia-location.conf" ''
    ## Essential Proxy Configuration
    internal;
    proxy_pass ${AUTHELIA_HOST}/api/verify;
    ## Headers
    ## The headers starting with X-* are required.
    proxy_set_header X-Original-URL $scheme://$http_host$request_uri;
    proxy_set_header X-Original-Method $request_method;
    proxy_set_header X-Forwarded-Method $request_method;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_set_header X-Forwarded-Host $http_host;
    proxy_set_header X-Forwarded-Uri $request_uri;
    proxy_set_header X-Forwarded-For $remote_addr;
    proxy_set_header Content-Length "";
    proxy_set_header Connection "";
    ## Basic Proxy Configuration
    proxy_pass_request_body off;
    proxy_next_upstream error timeout invalid_header http_500 http_502 http_503; # Timeout if the real server is dead
    proxy_redirect http:// $scheme://;
    proxy_http_version 1.1;
    proxy_cache_bypass $cookie_session;
    proxy_no_cache $cookie_session;
    proxy_buffers 4 32k;
    client_body_buffer_size 128k;
    ## Advanced Proxy Configuration
    send_timeout 5m;
    proxy_read_timeout 240;
    proxy_send_timeout 240;
    proxy_connect_timeout 240;
  '';
  autheliaRequest = pkgs.writeText "authelia-authrequest.conf" ''
    ### goes inside a location block to make the request to authelia
    ## Send a subrequest to Authelia to verify if the user is authenticated and has permission to access the resource.
    auth_request /authelia;
    ## Set the $target_url variable based on the original request.
    ## Comment this line if you're using nginx without the http_set_misc module.
    #set_escape_uri $target_url $scheme://$http_host$request_uri;
    ## Uncomment this line if you're using NGINX without the http_set_misc module.
    set $target_url $scheme://$http_host$request_uri;
    ## Save the upstream response headers from Authelia to variables.
    auth_request_set $user $upstream_http_remote_user;
    auth_request_set $groups $upstream_http_remote_groups;
    auth_request_set $name $upstream_http_remote_name;
    auth_request_set $email $upstream_http_remote_email;
    ## Inject the response headers from the variables into the request made to the backend.
    proxy_set_header Remote-User $user;
    proxy_set_header Remote-Groups $groups;
    proxy_set_header Remote-Name $name;
    proxy_set_header Remote-Email $email;
        ## If the subreqest returns 200 pass to the backend, if the subrequest returns 401 redirect to the portal.
    error_page 401 =302 https://auth.fricloud.dk/?rd=$target_url;
  '';
in {
  services.nginx.virtualHosts."test.fricloud.dk" = {
    forceSSL = true;
    enableACME = true;

    locations."/authelia" = {
      recommendedProxySettings = false;
      extraConfig = ''
        include ${autheliaLocation};
      '';
    };
    locations."/" = {
      root = pkgs.writeTextDir "index.html" ''
        ACCESS GRANTED!
      '';

      extraConfig = ''
        include ${autheliaRequest};
      '';
    };
  };
}