{ config, pkgs, lib, ... }:
let
  cfg = config.my.services.gerrit;
  oauth = pkgs.fetchurl {
    url =
      "https://github.com/davido/gerrit-oauth-provider/releases/download/v3.5.1/gerrit-oauth-provider.jar";
    sha256 = "312dc494c454ac15f89a289f95ea4c11344add26804aaa6a3b79d49fd92adc69";
  };
in {
  options.my.services.gerrit = with lib; {
    enable = mkEnableOption "gerrit git server";
    vhostName = mkOption {
      type = types.str;
      example = "cl.fcuny.net";
      description = "Name for the virtual host";
    };
  };

  config = lib.mkIf cfg.enable {
    services.gerrit = {
      enable = true;
      listenAddress = "[::]:4778";
      serverId = "36bc0ffe-8f33-4045-bf8b-de5f88815fc0";
      builtinPlugins = [ "download-commands" "hooks" ];
      jvmHeapLimit = "4g";

      plugins = [ oauth ];

      # The default JDK is incompatible with gerrit.
      jvmPackage = pkgs.openjdk11_headless;

      settings = {
        core.packedGitLimit = "100m";
        log.jsonLogging = true;
        log.textLogging = false;
        sshd.advertisedAddress = "git.fcuny.net:29418";
        cache.web_sessions.maxAge = "3 months";
        plugins.allowRemoteAdmin = false;
        change.enableAttentionSet = true;
        change.enableAssignee = false;

        gerrit = {
          canonicalWebUrl = "https://${cfg.vhostName}";
          docUrl = "/Documentation";
        };

        httpd.listenUrl = "proxy-https://localhost:4778";

        download.command = [ "checkout" "cherry_pick" "format_patch" "pull" ];

        auth.type = "OAUTH";

        # users can change their emails
        oauth.allowRegisterNewEmail = true;

        # use gerrit HTTP password
        auth.gitBasicAuthPolicy = "HTTP";

        # Receiving email is not currently supported.
        sendemail = { enable = false; };
      };
    };

    systemd.services.gerrit = {
      serviceConfig = {
        # Using DynamicUser fails to generate correctly the ssh keys
        # needed for the ssh server that is managed by gerrit.
        # Instead, let's re-use the git user.
        DynamicUser = lib.mkForce false;
        User = "git";
        Group = "git";
      };
    };

    services.nginx.virtualHosts."${cfg.vhostName}" = {
      forceSSL = true;
      enableACME = true;
      locations."/" = { proxyPass = "http://127.0.0.1:4778"; };
    };
  };
}