{ config, pkgs, ... }:

with pkgs.lib;

let

  cfg = config.services.solr;

in {

  options = {
    services.solr = {
      enable = mkOption {
        type = types.bool;
        default = false;
        description = ''
          Enables the solr service.
        '';
      };

      javaPackage = mkOption {
        type = types.package;
        default = pkgs.openjre;
        description = ''
          Which Java derivation to use for running solr.
        '';
      };

      solrPackage = mkOption {
        type = types.package;
        default = pkgs.solr;
        description = ''
          Which solr derivation to use for running solr.
        '';
      };

      log4jConfiguration = mkOption {
        type = types.lines;
        default = ''
          log4j.rootLogger=INFO, stdout
          log4j.appender.stdout=org.apache.log4j.ConsoleAppender
          log4j.appender.stdout.Target=System.out
          log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
          log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
        '';
        description = ''
          Contents of the <literal>log4j.properties</literal> used. By default,
          everything is logged to stdout (picked up by systemd) with level INFO.
        '';
      };

      user = mkOption {
        type = types.str;
        description = ''
          The user that should run the solr process and.
          the working directories.
        '';
      };

      group = mkOption {
        type = types.str;
        description = ''
          The group that will own the working directory.
        '';
      };

      solrHome = mkOption {
        type = types.str;
        description = ''
          The solr home directory. It is your own responsibility to
          make sure this directory contains a working solr configuration,
          and is writeable by the the user running the solr service.
          Failing to do so, the solr will not start properly.
        '';
      };

      extraJavaOptions = mkOption {
        type = types.listOf types.str;
        default = [];
        description = ''
          Extra command line options given to the java process running
          solr.
        '';
      };

      extraWinstoneOptions = mkOption {
        type = types.listOf types.str;
        default = [];
        description = ''
          Extra command line options given to the Winstone, which is
          the servlet container hosting solr.
        '';
      };
    };
  };

  config = mkIf cfg.enable {

    services.winstone.solr = {
      serviceName = "solr";
      inherit (cfg) user group javaPackage;
      warFile = "${cfg.solrPackage}/lib/solr.war";
      extraOptions = [
        "--commonLibFolder=${cfg.solrPackage}/lib/ext"
      ] ++ cfg.extraWinstoneOptions;
      extraJavaOptions = [
        "-Dsolr.solr.home=${cfg.solrHome}"
        "-Dlog4j.configuration=file://${pkgs.writeText "log4j.properties" cfg.log4jConfiguration}"
      ] ++ cfg.extraJavaOptions;
    };

  };

}