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

with lib;

let

  cfg = config.services.tomcat;
  tomcat = pkgs.tomcat6;
in

{

  ###### interface

  options = {

    services.tomcat = {

      enable = mkOption {
        default = false;
        description = "Whether to enable Apache Tomcat";
      };

      baseDir = mkOption {
        default = "/var/tomcat";
        description = "Location where Tomcat stores configuration files, webapplications and logfiles";
      };

      extraGroups = mkOption {
        default = [];
        example = [ "users" ];
        description = "Defines extra groups to which the tomcat user belongs.";
      };

      user = mkOption {
        default = "tomcat";
        description = "User account under which Apache Tomcat runs.";
      };

      group = mkOption {
        default = "tomcat";
        description = "Group account under which Apache Tomcat runs.";
      };

      javaOpts = mkOption {
        default = "";
        description = "Parameters to pass to the Java Virtual Machine which spawns Apache Tomcat";
      };

      catalinaOpts = mkOption {
        default = "";
        description = "Parameters to pass to the Java Virtual Machine which spawns the Catalina servlet container";
      };

      sharedLibs = mkOption {
        default = [];
        description = "List containing JAR files or directories with JAR files which are libraries shared by the web applications";
      };

      commonLibs = mkOption {
        default = [];
        description = "List containing JAR files or directories with JAR files which are libraries shared by the web applications and the servlet container";
      };

      webapps = mkOption {
        default = [ tomcat ];
        description = "List containing WAR files or directories with WAR files which are web applications to be deployed on Tomcat";
      };

      virtualHosts = mkOption {
        default = [];
        description = "List consisting of a virtual host name and a list of web applications to deploy on each virtual host";
      };

      logPerVirtualHost = mkOption {
        default = false;
        description = "Whether to enable logging per virtual host.";
      };

      axis2 = {

        enable = mkOption {
          default = false;
          description = "Whether to enable an Apache Axis2 container";
        };

        services = mkOption {
          default = [];
          description = "List containing AAR files or directories with AAR files which are web services to be deployed on Axis2";
        };

      };

    };

  };


  ###### implementation

  config = mkIf config.services.tomcat.enable {

    users.extraGroups = singleton
      { name = "tomcat";
        gid = config.ids.gids.tomcat;
      };

    users.extraUsers = singleton
      { name = "tomcat";
        uid = config.ids.uids.tomcat;
        description = "Tomcat user";
        home = "/homeless-shelter";
        extraGroups = cfg.extraGroups;
      };

    jobs.tomcat =
      { description = "Apache Tomcat server";

        startOn = "started network-interfaces";
        stopOn = "stopping network-interfaces";

        preStart =
          ''
            # Create the base directory
            mkdir -p ${cfg.baseDir}

            # Create a symlink to the bin directory of the tomcat component
            ln -sfn ${tomcat}/bin ${cfg.baseDir}/bin

            # Create a conf/ directory
            mkdir -p ${cfg.baseDir}/conf
            chown ${cfg.user}:${cfg.group} ${cfg.baseDir}/conf

            # Symlink the config files in the conf/ directory (except for catalina.properties and server.xml)
            for i in $(ls ${tomcat}/conf | grep -v catalina.properties | grep -v server.xml)
            do
                ln -sfn ${tomcat}/conf/$i ${cfg.baseDir}/conf/`basename $i`
            done

            # Create subdirectory for virtual hosts
            mkdir -p ${cfg.baseDir}/virtualhosts

            # Create a modified catalina.properties file
            # Change all references from CATALINA_HOME to CATALINA_BASE and add support for shared libraries
            sed -e 's|''${catalina.home}|''${catalina.base}|g' \
                -e 's|shared.loader=|shared.loader=''${catalina.base}/shared/lib/*.jar|' \
                ${tomcat}/conf/catalina.properties > ${cfg.baseDir}/conf/catalina.properties

            # Create a modified server.xml which also includes all virtual hosts
            sed -e "/<Engine name=\"Catalina\" defaultHost=\"localhost\">/a\  ${
                         toString (map (virtualHost: ''<Host name=\"${virtualHost.name}\" appBase=\"virtualhosts/${virtualHost.name}/webapps\" unpackWARs=\"true\" autoDeploy=\"true\" xmlValidation=\"false\" xmlNamespaceAware=\"false\" >${if cfg.logPerVirtualHost then ''<Valve className=\"org.apache.catalina.valves.AccessLogValve\" directory=\"logs/${virtualHost.name}\"  prefix=\"${virtualHost.name}_access_log.\" pattern=\"combined\" resolveHosts=\"false\"/>'' else ""}</Host>'') cfg.virtualHosts)}" \
                ${tomcat}/conf/server.xml > ${cfg.baseDir}/conf/server.xml

            # Create a logs/ directory
            mkdir -p ${cfg.baseDir}/logs
            chown ${cfg.user}:${cfg.group} ${cfg.baseDir}/logs
            ${if cfg.logPerVirtualHost then
               toString (map (h: ''
                                    mkdir -p ${cfg.baseDir}/logs/${h.name}
                                    chown ${cfg.user}:${cfg.group} ${cfg.baseDir}/logs/${h.name}
                                 '') cfg.virtualHosts) else ''''}

            # Create a temp/ directory
            mkdir -p ${cfg.baseDir}/temp
            chown ${cfg.user}:${cfg.group} ${cfg.baseDir}/temp

            # Create a lib/ directory
            mkdir -p ${cfg.baseDir}/lib
            chown ${cfg.user}:${cfg.group} ${cfg.baseDir}/lib

            # Create a shared/lib directory
            mkdir -p ${cfg.baseDir}/shared/lib
            chown ${cfg.user}:${cfg.group} ${cfg.baseDir}/shared/lib

            # Create a webapps/ directory
            mkdir -p ${cfg.baseDir}/webapps
            chown ${cfg.user}:${cfg.group} ${cfg.baseDir}/webapps

            # Symlink all the given common libs files or paths into the lib/ directory
            for i in ${tomcat} ${toString cfg.commonLibs}
            do
                if [ -f $i ]
                then
                    # If the given web application is a file, symlink it into the common/lib/ directory
                    ln -sfn $i ${cfg.baseDir}/lib/`basename $i`
                elif [ -d $i ]
                then
                    # If the given web application is a directory, then iterate over the files
                    # in the special purpose directories and symlink them into the tomcat tree

                    for j in $i/lib/*
                    do
                        ln -sfn $j ${cfg.baseDir}/lib/`basename $j`
                    done
                fi
            done

            # Symlink all the given shared libs files or paths into the shared/lib/ directory
            for i in ${toString cfg.sharedLibs}
            do
                if [ -f $i ]
                then
                    # If the given web application is a file, symlink it into the common/lib/ directory
                    ln -sfn $i ${cfg.baseDir}/shared/lib/`basename $i`
                elif [ -d $i ]
                then
                    # If the given web application is a directory, then iterate over the files
                    # in the special purpose directories and symlink them into the tomcat tree

                    for j in $i/shared/lib/*
                    do
                        ln -sfn $j ${cfg.baseDir}/shared/lib/`basename $j`
                    done
                fi
            done

            # Symlink all the given web applications files or paths into the webapps/ directory
            for i in ${toString cfg.webapps}
            do
                if [ -f $i ]
                then
                    # If the given web application is a file, symlink it into the webapps/ directory
                    ln -sfn $i ${cfg.baseDir}/webapps/`basename $i`
                elif [ -d $i ]
                then
                    # If the given web application is a directory, then iterate over the files
                    # in the special purpose directories and symlink them into the tomcat tree

                    for j in $i/webapps/*
                    do
                        ln -sfn $j ${cfg.baseDir}/webapps/`basename $j`
                    done

                    # Also symlink the configuration files if they are included
                    if [ -d $i/conf/Catalina ]
                    then
                        for j in $i/conf/Catalina/*
                        do
                            mkdir -p ${cfg.baseDir}/conf/Catalina/localhost
                            ln -sfn $j ${cfg.baseDir}/conf/Catalina/localhost/`basename $j`
                        done
                    fi
                fi
            done

            ${toString (map (virtualHost: ''
              # Create webapps directory for the virtual host
              mkdir -p ${cfg.baseDir}/virtualhosts/${virtualHost.name}/webapps

              # Modify ownership
              chown ${cfg.user}:${cfg.group} ${cfg.baseDir}/virtualhosts/${virtualHost.name}/webapps

              # Symlink all the given web applications files or paths into the webapps/ directory
              # of this virtual host
              for i in "${if virtualHost ? webapps then toString virtualHost.webapps else ""}"
              do
                  if [ -f $i ]
                  then
                      # If the given web application is a file, symlink it into the webapps/ directory
                      ln -sfn $i ${cfg.baseDir}/virtualhosts/${virtualHost.name}/webapps/`basename $i`
                  elif [ -d $i ]
                  then
                      # If the given web application is a directory, then iterate over the files
                      # in the special purpose directories and symlink them into the tomcat tree

                      for j in $i/webapps/*
                      do
                          ln -sfn $j ${cfg.baseDir}/virtualhosts/${virtualHost.name}/webapps/`basename $j`
                      done

                      # Also symlink the configuration files if they are included
                      if [ -d $i/conf/Catalina ]
                      then
                          for j in $i/conf/Catalina/*
                          do
                              mkdir -p ${cfg.baseDir}/conf/Catalina/${virtualHost.name}
                              ln -sfn $j ${cfg.baseDir}/conf/Catalina/${virtualHost.name}/`basename $j`
                          done
                      fi
                  fi
              done

              ''
            ) cfg.virtualHosts) }

            # Create a work/ directory
            mkdir -p ${cfg.baseDir}/work
            chown ${cfg.user}:${cfg.group} ${cfg.baseDir}/work

            ${if cfg.axis2.enable then
                ''
                # Copy the Axis2 web application
                cp -av ${pkgs.axis2}/webapps/axis2 ${cfg.baseDir}/webapps

                # Turn off addressing, which causes many errors
                sed -i -e 's%<module ref="addressing"/>%<!-- <module ref="addressing"/> -->%' ${cfg.baseDir}/webapps/axis2/WEB-INF/conf/axis2.xml

                # Modify permissions on the Axis2 application
                chown -R ${cfg.user}:${cfg.group} ${cfg.baseDir}/webapps/axis2

                # Symlink all the given web service files or paths into the webapps/axis2/WEB-INF/services directory
                for i in ${toString cfg.axis2.services}
                do
                    if [ -f $i ]
                    then
                        # If the given web service is a file, symlink it into the webapps/axis2/WEB-INF/services
                        ln -sfn $i ${cfg.baseDir}/webapps/axis2/WEB-INF/services/`basename $i`
                    elif [ -d $i ]
                    then
                        # If the given web application is a directory, then iterate over the files
                        # in the special purpose directories and symlink them into the tomcat tree

                        for j in $i/webapps/axis2/WEB-INF/services/*
                        do
                            ln -sfn $j ${cfg.baseDir}/webapps/axis2/WEB-INF/services/`basename $j`
                        done

                        # Also symlink the configuration files if they are included
                        if [ -d $i/conf/Catalina ]
                        then
                            for j in $i/conf/Catalina/*
                            do
                                ln -sfn $j ${cfg.baseDir}/conf/Catalina/localhost/`basename $j`
                            done
                        fi
                    fi
                done
                ''
            else ""}

            ${pkgs.su}/bin/su -s ${pkgs.bash}/bin/sh ${cfg.user} -c 'CATALINA_BASE=${cfg.baseDir} JAVA_HOME=${pkgs.jdk} JAVA_OPTS="${cfg.javaOpts}" CATALINA_OPTS="${cfg.catalinaOpts}" ${tomcat}/bin/startup.sh'
          '';

        postStop =
          ''
            echo "Stopping tomcat..."
            CATALINA_BASE=${cfg.baseDir} JAVA_HOME=${pkgs.jdk} ${pkgs.su}/bin/su -s ${pkgs.bash}/bin/sh ${cfg.user} -c ${tomcat}/bin/shutdown.sh
          '';

      };

  };

}
