{pkgs, lib, config, system, ...}:
let
  inherit (builtins) readFile;
  inherit (builtins.extraBuiltins) pass;
  inherit (lib) types;
  inherit (pkgs.lib) loadFile;
  inherit (config) networking;
  inherit (config.services) nginx;
  domainDir = dom: lib.concatStringsSep "/" (lib.reverseList (lib.splitString "." dom));
in
{
imports = [
  nginx/sourcephile.fr.nix
];
options = {
  services.nginx = {
    x509Dir = lib.mkOption {
      type    = types.str;
      default = "/var/lib/nginx/x509";
    };
    webDir = lib.mkOption {
      type    = types.str;
      default = "/var/www";
    };
    logDir = lib.mkOption {
      type    = types.str;
      default = "/var/log/nginx";
    };
    configs = lib.mkOption {
      type = types.attrsOf types.lines;
      default = {};
      description = ''
        Make some configs available to all virtual hosts.
        Useful to workaround the reset of add_header:
        https://blog.g3rt.nl/nginx-add_header-pitfall.html
      '';
      #apply = lib.mapAttrs (name: pkgs.writeText "${name}.conf");
    };
  };
};
config = {
  systemd.services.nginx = {
    preStart = lib.mkBefore ''
      install -D -d -o ${nginx.user} -g ${nginx.group} -m 0700 \
       ${nginx.x509Dir} \
       ${nginx.webDir} \
       ${nginx.logDir}
    '';
  };
  users.groups."acme".members = [nginx.user];
  services.nginx = {
    enable = true;
    package = pkgs.nginx.override {
      modules = with pkgs.nginxModules; [
        fancyindex
      ];
    };
    stateDir = "/dev/shm/nginx";
    eventsConfig = ''
      multi_accept on;
      use epoll;
      worker_connections 1024;
    '';
    clientMaxBodySize = "20m";
    recommendedGzipSettings = true;
    recommendedOptimisation = false;
    recommendedProxySettings = true;
    recommendedTlsSettings = true;
    resolver = {
      addresses = [ "127.0.0.1:53" ];
      valid = "";
      ipv6 = networking.defaultGateway6 != null;
    };
    serverTokens = false;
    # Only allow PFS-enabled ciphers with AES256
    #sslCiphers = "AES256+EECDH:AES256+EDH:!aNULL";
    #sslCiphers = "HIGH:!ADH:!MD5:!CAMELLIA:!SEED:!3DES:!DES:!RC4:!eNULL";
    #sslCiphers = "EECDH+aRSA+AESGCM:EDH+aRSA:EECDH+aRSA:+AES256:+AES128:+SHA1:!CAMELLIA:!SEED:!3DES:!DES:!RC4:!eNULL";
    sslDhparam = ../../../sec/openssl/dh.pem;
    sslProtocols = "TLSv1.3 TLSv1.2";
    configs = rec {
      http_add_headers = ''
        # Add HSTS header with preloading to HTTPS requests.
        # Adding this header to HTTP requests is discouraged
        # DOC: https://blog.qualys.com/securitylabs/2016/03/28/the-importance-of-a-proper-http-strict-transport-security-implementation-on-your-web-server
        add_header Strict-Transport-Security $hsts_header;

        # Enable CSP for your services.
        #add_header Content-Security-Policy "script-src 'self'; object-src 'none'; base-uri 'none';" always;

        # Minimize information leaked to other domains
        add_header 'Referrer-Policy' 'origin-when-cross-origin';

        # Disable embedding as a frame
        add_header X-Frame-Options DENY;

        # Prevent injection of code in other mime types (XSS Attacks)
        add_header X-Content-Type-Options nosniff;

        # Enable XSS protection of the browser.
        # May be unnecessary when CSP is configured properly (see above)
        add_header X-XSS-Protection "1; mode=block";
      '';
      https_add_headers = ''
        ${http_add_headers}
      '';
    };
    commonHttpConfig = ''
      log_format main '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

      log_format json escape=json
        '{'
          '"time_local":"$time_local",'
          '"remote_addr":"$remote_addr",'
          '"status": "$status",'
          '"request":"$request",'
          '"body_bytes_sent":"$body_bytes_sent",'
          '"http_referrer":"$http_referer",'
          '"http_user_agent":"$http_user_agent",'
          '"remote_user":"$remote_user",'
          '"request_time":"$request_time"'
        '}';
      charset UTF-8;
      types {
        text/html html5;
        text/plain md;
      }
      '' +
      lib.concatStringsSep "\n" (lib.attrValues {
        default = ''
          default_type application/octet-stream;
          root ${nginx.webDir};
        '';
        security = ''
          #error_page 403 = 404;

          ${nginx.configs.http_add_headers}

          # This might create errors
          proxy_cookie_path / "/; secure; HttpOnly; SameSite=strict";

          # If a client has a session ticket, it can present it to the server and re-negotiation is not necessary.
          ssl_session_tickets on;
        '';
        log = ''
          access_log ${nginx.logDir}/access.log main buffer=32k;
          error_log  ${nginx.logDir}/error.log warn;
          open_log_file_cache max=1000 inactive=20s min_uses=2 valid=1m;
        '';
        proxy = ''
          proxy_cache_use_stale updating;
          proxy_temp_path ${nginx.stateDir}/proxy_temp 1 2;
        '';
        fastcgi = ''
          # DOC: http://wiki.nginx.org/HttpFastcgiModule
          fastcgi_buffer_size 128k;
          fastcgi_buffers 256 4k;
          fastcgi_busy_buffers_size 256k;
          fastcgi_cache_key "$request_method $scheme://$http_host$request_uri";
          fastcgi_connect_timeout 60;
          fastcgi_ignore_client_abort off;
          fastcgi_intercept_errors on;
          fastcgi_max_temp_file_size 2M;
          #fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
          fastcgi_param SCRIPT_FILENAME $request_filename;
          fastcgi_temp_path ${nginx.stateDir}/fastcgi_temp 1 2;
        '';
        connection = ''
          sendfile on;
          # If the client stops reading data,
          # free up the stale client connection after this much time.
          send_timeout 60;
          # Causes nginx to attempt to send its HTTP response head
          # in one packet, instead of using partial frames.
          # This is useful for prepending headers before calling sendfile,
          # or for throughput optimization.
          tcp_nopush on;
          # Don't buffer data-sends (disable Nagle algorithm).
          # Good for sending frequent small bursts of data in real time.
          tcp_nodelay on;
          keepalive_timeout 20;
          reset_timedout_connection on;
          types_hash_max_size 4096;
          server_names_hash_bucket_size 128;
        '';
        map = ''
          map $time_iso8601 $date {
            default 'date-not-found';
            '~^(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})' $year-$month-$day;
          }

          map $scheme $hsts_header {
            https  "max-age=31536000; includeSubdomains; preload";
          }

          # User agents that are to be blocked.
          #map $http_user_agent $bad_bot {
          #  default 0;
          #  libwww-perl 1;
          #  ~(?i)(httrack|htmlparser|libwww) 1;
          #}
          # Referrers that are to be blocked.
          #map $http_referer $bad_referer {
          #  default 0;
          #  ~(?i)(babes|casino|click|diamond|forsale|girl|jewelry|love|nudit|organic|poker|porn|poweroversoftware|replica|sex|teen|webcam|zippo) 1;
          #}
          #geo $not_local {
          #  default 1;
          #  127.0.0.1 0;
          #}
        '';
        cache = ''
          client_body_buffer_size 4K;
            # getconf PAGESIZE
            # 4096
          client_body_temp_path ${nginx.stateDir}/client_body_temp 1 2;
          client_body_timeout 60;
          client_header_buffer_size 1k;
          client_header_timeout 60;
          large_client_header_buffers 4 8k;

          open_file_cache max=200000 inactive=20s;
          open_file_cache_errors on;
          open_file_cache_min_uses 2;
          open_file_cache_valid 30s;
        '';
      });
    appendConfig = ''
      worker_processes ${toString config.nix.maxJobs};
    '';
    virtualHosts."_" = {
      forceSSL = true;
      useACMEHost = networking.domain;
    };
  };
};
}