{ lib, config, pkgs, ... }:

let
  cfg = config.services.belenios;

  configFile = lib.writeText "beleniosserver.conf" cfg.config;

  inherit (lib) mkEnableOption mkPackageOption mkOption mkIf;
in
{
  options.services.belenios = {
    enable = mkEnableOption "Whether to enable the Belenios Web server.";

    package = mkPackageOption pkgs "belenios";

    config = mkOption {
      types = lib.types.str;
      description = ''
        The Belenios Web server configuration.
        See
        <https://gitlab.inria.fr/belenios/belenios/-/blob/stable/doc/web.md>
        for documentation.
      '';
      example = ''
        <!-- -*- Mode: Xml -*- -->
        <ocsigen>

          <server>

            <port>127.0.0.1:8001</port>

            <mimefile>_SHAREDIR_/mime.types</mimefile>

            <logdir>_VARDIR_/log</logdir>
            <datadir>_VARDIR_/lib</datadir>

            <uploaddir>_VARDIR_/upload</uploaddir>

            <!--
              The following limits are there to avoid flooding the server.
              <maxuploadfilesize> might need to be increased for handling large
              elections.
              <maxconnected> is related to the number of simultaneous voters
              visiting the server.
            -->
            <maxuploadfilesize>5120kB</maxuploadfilesize>
            <maxconnected>500</maxconnected>

            <commandpipe>_RUNDIR_/ocsigenserver_command</commandpipe>

            <charset>utf-8</charset>

            <extension name="staticmod"/>
            <extension name="redirectmod"/>

            <extension name="ocsipersist">
              <database file="_VARDIR_/lib/ocsidb"/>
            </extension>

            <extension name="eliom"/>

            <host charset="utf-8" hostfilter="*" defaulthostname="localhost">
              <!-- <redirect suburl="^$" dest="http://www.example.org"/> -->
              <site path="static" charset="utf-8">
                <static dir="_SHAREDIR_/static" cache="0"/>
              </site>
              <eliom name="belenios">
                <public-url prefix="http://127.0.0.1:8001"/>
                <!-- Domain name used in Message-ID -->
                <domain name="belenios.example.org"/>
                <!--
                  The following can be adjusted to the capacity of your system.
                  If <maxrequestbodysizeinmemory> is too small, large elections
                  might fail, in particular with so-called alternative questions
                  with many voters.
                  <maxmailsatonce> depends heavily on how sending emails is
                  handled by your system.
                -->
                <maxrequestbodysizeinmemory value="1048576"/>
                <maxmailsatonce value="1000"/>
                <tos uri="http://www.example.org/terms-of-service.html"/>
                <!-- <contact uri="mailto:contact@example.org"/> -->
                <server mail="noreply@example.org" return-path="bounces@example.org" name="Belenios public server"/>
                <auth-export name="builtin-password"/>
                <auth-export name="builtin-cas"/>
                <auth-export name="demo"><dummy/></auth-export> <!-- DEMO -->
                <auth-export name="email"><email/></auth-export> <!-- DEMO -->
                <auth name="demo"><dummy allowlist="demo_allowlist"/></auth> <!-- DEMO -->
                <auth name="local"><password db="local_passwords"/></auth> <!-- DEMO -->
                <auth name="public"><password db="public_passwords" allowsignups="true"/></auth>
                <auth name="email"><email/></auth> <!-- DEMO -->
                <auth name="captcha"><email use_captcha="true"/></auth> <!-- DEMO -->
                <!-- <auth name="google"><oidc server="https://accounts.google.com" client_id="client-id" client_secret="client-secret"/></auth> -->
                <source file="_SHAREDIR_/belenios.tar.gz"/>
                <logo file="_SHAREDIR_/static/placeholder.png" mime-type="image/png"/>
                <favicon file="_VARDIR_/favicon.ico" mime-type="image/png"/>
                <sealing file="demo/sealing.txt" mime-type="text/plain"/>
                <default-group group="Ed25519"/>
                <nh-group group="Ed25519"/>
                <share dir="_SHAREDIR_"/>
                <storage backend="filesystem">
                  <uuid length="14"/>
                  <spool dir="_VARDIR_/spool"/>
                  <accounts dir="_VARDIR_/accounts"/>
                  <map from="demo_allowlist" to="demo/dummy_logins.txt"/>
                  <map from="local_passwords" to="demo/password_db.csv"/>
                  <map from="public_passwords" to="_VARDIR_/password_db.csv"/>
                </storage>
                <admin-home file="_VARDIR_/admin-home.html"/>
                <success-snippet file="_VARDIR_/success-snippet.html"/>
                <warning file="_VARDIR_/warning.html"/>
                <footer file="_VARDIR_/footer.html"/>
                <!-- <deny-newelection/> -->
                <!--
                    Uncomment the following line to disable revoting. Note that
                    the ability to revote is important as a (light) measure
                    against coercion.
                -->
                <!-- <deny-revote/> -->
              </eliom>
            </host>

          </server>

        </ocsigen>
      '';
      #
    };
  };

  config = mkIf cfg.enable {
    users.users.belenios = {
      description = "Belenios Web server service user";
      isSystemUser = true;
      group = "belenios";
    };
    users.groups.belenios = { };
    
    systemd.services.belenios = {
      description = "Belenios Web server service";
      wantedBy = [ "multi-user.target" ];
      after = [ "network.target" ];

      serviceConfig = {
        ExecStart = "${cfg.package}/bin/belenios-server -c ${configFile}";
        Restart = "always";
        User = "belenios";
      };
    };
  };
}