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

with lib;

let

  cfg = config.services.ejabberd;

in

{

  ###### interface

  options = {

    services.ejabberd = {

      enable = mkOption {
        default = false;
        description = "Whether to enable ejabberd server";
      };

      spoolDir = mkOption {
        default = "/var/lib/ejabberd";
        description = "Location of the spooldir of ejabberd";
      };

      logsDir = mkOption {
        default = "/var/log/ejabberd";
        description = "Location of the logfile directory of ejabberd";
      };

      confDir = mkOption {
        default = "/var/ejabberd";
        description = "Location of the config directory of ejabberd";
      };

      virtualHosts = mkOption {
        default = "\"localhost\"";
        description = "Virtualhosts that ejabberd should host. Hostnames are surrounded with doublequotes and separated by commas";
      };

      loadDumps = mkOption {
        default = [];
        description = "Configuration dump that should be loaded on the first startup";
        example = literalExample "[ ./myejabberd.dump ]";
      };
    };

  };


  ###### implementation

  config = mkIf cfg.enable {
    environment.systemPackages = [ pkgs.ejabberd ];

    systemd.services.ejabberd = {
      description = "EJabberd server";
      after = [ "network-interfaces.target" ];
      wantedBy = [ "multi-user.target" ];
      path = with pkgs; [ ejabberd coreutils bash gnused ];

      preStart = ''
        # Initialise state data
        mkdir -p ${cfg.logsDir}

        if ! test -d ${cfg.spoolDir}
        then
            initialize=1
            cp -av ${pkgs.ejabberd}/var/lib/ejabberd /var/lib
        fi

        if ! test -d ${cfg.confDir}
        then
            mkdir -p ${cfg.confDir}
            cp ${pkgs.ejabberd}/etc/ejabberd/* ${cfg.confDir}
            sed -e 's|{hosts, \["localhost"\]}.|{hosts, \[${cfg.virtualHosts}\]}.|' ${pkgs.ejabberd}/etc/ejabberd/ejabberd.cfg > ${cfg.confDir}/ejabberd.cfg
        fi

        ejabberdctl --config-dir ${cfg.confDir} --logs ${cfg.logsDir} --spool ${cfg.spoolDir} start

        ${if cfg.loadDumps == [] then "" else
          ''
            if [ "$initialize" = "1" ]
            then
                # Wait until the ejabberd server is available for use
                count=0
                while ! ejabberdctl --config-dir ${cfg.confDir} --logs ${cfg.logsDir} --spool ${cfg.spoolDir} status
                do
                    if [ $count -eq 30 ]
                    then
                        echo "Tried 30 times, giving up..."
                        exit 1
                    fi

                    echo "Ejabberd daemon not yet started. Waiting for 1 second..."
                    count=$((count++))
                    sleep 1
                done

                ${concatMapStrings (dump:
                  ''
                    echo "Importing dump: ${dump}"

                    if [ -f ${dump} ]
                    then
                        ejabberdctl --config-dir ${cfg.confDir} --logs ${cfg.logsDir} --spool ${cfg.spoolDir} load ${dump}
                    elif [ -d ${dump} ]
                    then
                        for i in ${dump}/ejabberd-dump/*
                        do
                            ejabberdctl --config-dir ${cfg.confDir} --logs ${cfg.logsDir} --spool ${cfg.spoolDir} load $i
                        done
                    fi
                  '') cfg.loadDumps}
            fi
          ''}
      '';

      postStop = ''
        ejabberdctl --config-dir ${cfg.confDir} --logs ${cfg.logsDir} --spool ${cfg.spoolDir} stop
      '';
    };

    security.pam.services.ejabberd = {};

  };

}