{ config, pkgs, ... }:
let
  # 1. create DNS entry `matrix.terranix.org A - 95.216.66.212`
  # 2. test with : https://federationtester.matrix.org/#terranix.org
  # 3. info at : https://silvio.github.io/docker-matrix/Example.configs.html

  name = "terranix";
  domain = "terranix.org";
  baseUrl = "https://matrix.${domain}";

  synapse_port = 8008;
  federation_port = 8448;

  matrix_create_user = pkgs.writers.writeBashBin "matrix-create-user-${name}" ''
    ${pkgs.matrix-synapse}/bin/register_new_matrix_user \
        -k $( ${pkgs.gojq}/bin/gojq \
            --yaml-input \
            --raw-output \
            '.registration_shared_secret' \
            ${config.sops.secrets.matrix_shared_secret.path} ) \
        http://localhost:${toString synapse_port}
  '';

  clientConfig."m.homeserver".base_url = baseUrl;
  serverConfig."m.server" = "matrix.${domain}:443";
  mkWellKnown = data: ''
    default_type application/json;
    add_header Access-Control-Allow-Origin *;
    return 200 '${builtins.toJSON data}';
  '';

  element-web =
    pkgs.runCommand "element-web-with-config"
      {
        nativeBuildInputs = [ pkgs.buildPackages.jq ];
      } ''
      cp -r ${pkgs.element-web} $out
      chmod -R u+w $out
      jq '."default_server_config"."m.homeserver" = { "base_url": "https://matrix.${domain}", "server_name": "${domain}" }' \
        > $out/config.json < ${pkgs.element-web}/config.json
      ln -s $out/config.json $out/config.matrix.${domain}.json
    '';
in
{

  networking.firewall.allowedTCPPorts = [ 80 443 federation_port ];
  networking.firewall.allowedUDPPorts = [ 80 443 federation_port ];

  environment.systemPackages = [ matrix_create_user ];

  sops.secrets.matrix_shared_secret.owner = "matrix-synapse";
  users.users.matrix-synapse = {
    isSystemUser = true;
    uid = config.ids.uids.matrix-synapse;
    group = "matrix-synapse";
  };
  users.groups.matrix-synapse.gid = config.ids.gids.matrix-synapse;

  containers."matrix-${name}" = {
    autoStart = true;
    privateNetwork = false;

    bindMounts = {
      rootpassword = {
        hostPath = config.sops.secrets.matrix_shared_secret.path;
        mountPoint = "/run/secrets/matrix-shared-secret";
        isReadOnly = true;
      };
    };

    config = { config, pkgs, lib, ... }: {
      system.stateVersion = "23.11";

      services.postgresql = {
        enable = true;
        initialScript = pkgs.writeText "synapse-init.sql" ''
          CREATE ROLE "matrix-synapse" WITH LOGIN PASSWORD 'synapse';
          CREATE DATABASE "matrix-synapse" WITH OWNER "matrix-synapse"
            TEMPLATE template0
            LC_COLLATE = "C"
            LC_CTYPE = "C";
        '';
      };

      services.matrix-synapse = {
        enable = true;
        settings.server_name = domain;
        # The public base URL value must match the `base_url` value set in `clientConfig` above.
        # The default value here is based on `server_name`, so if your `server_name` is different
        # from the value of `matrix.<domain>` above, you will likely run into some mismatched domain names
        # in client applications.
        settings.public_baseurl = baseUrl;
        extraConfigFiles = [ "/run/secrets/matrix-shared-secret" ];
        settings.listeners = [
          {
            port = synapse_port;
            bind_addresses = [ "::1" ];
            type = "http";
            tls = false;
            x_forwarded = true;
            resources = [
              {
                names = [ "client" ];
                compress = true;
              }
              {
                names = [ "federation" ];
                compress = false;
              }
            ];
          }
        ];
      };


    };
  };


  services.nginx = {
    enable = true;
    recommendedTlsSettings = true;
    recommendedOptimisation = true;
    recommendedGzipSettings = true;
    recommendedProxySettings = true;
    virtualHosts = {

      # lives on another host
      # # If the A and AAAA DNS records on example.org do not point on the same host as the
      # # records for myhostname.example.org, you can easily move the /.well-known
      # # virtualHost section of the code to the host that is serving example.org, while
      # # the rest stays on myhostname.example.org with no other changes required.
      # # This pattern also allows to seamlessly move the homeserver from
      # # myhostname.example.org to myotherhost.example.org by only changing the
      # # /.well-known redirection target.
      # "${domain}" = {
      #   enableACME = true;
      #   forceSSL = true;
      #   # This section is not needed if the server_name of matrix-synapse is equal to
      #   # the domain (i.e. example.org from @foo:example.org) and the federation port
      #   # is federation_port.
      #   # Further reference can be found in the docs about delegation under
      #   # https://element-hq.github.io/synapse/latest/delegate.html
      #   locations."= /.well-known/matrix/server".extraConfig = mkWellKnown serverConfig;
      #   # This is usually needed for homeserver discovery (from e.g. other Matrix clients).
      #   # Further reference can be found in the upstream docs at
      #   # https://spec.matrix.org/latest/client-server-api/#getwell-knownmatrixclient
      #   locations."= /.well-known/matrix/client".extraConfig = mkWellKnown clientConfig;
      # };

      "matrix.${domain}" = {
        listen = [
          {
            addr = "0.0.0.0";
            port = 80;
          }
          {
            addr = "0.0.0.0";
            port = 443;
            ssl = true;
          }
          # for federation
          {
            addr = "0.0.0.0";
            port = federation_port;
            ssl = true;
          }
        ];
        enableACME = true;
        forceSSL = true;
        # It's also possible to do a redirect here or something else, this vhost is not
        # needed for Matrix. It's recommended though to *not put* element
        # here, see also the section about Element.
        locations."/".extraConfig = ''
          return 404;
        '';
        # Forward all Matrix API calls to the synapse Matrix homeserver. A trailing slash
        # *must not* be used here.
        locations."/_matrix".proxyPass = "http://[::1]:${toString synapse_port}";
        # Forward requests for e.g. SSO and password-resets.
        #locations."/_synapse/client".proxyPass = "http://[::1]:${toString synapse_port}";
      };

      "element.${domain}" = {
        forceSSL = true;
        enableACME = true;
        extraConfig = ''
          proxy_set_header Host $host;
          proxy_set_header X-Real-IP $remote_addr;
          proxy_read_timeout 600;
        '';
        locations."/".root = element-web;
      };

    };

  };

}