{ config, pkgs, lib, name, nodes, ... }:
let
  cfg = config.myServices.monitoring;
  activatedPlugins = [ "memory" "command" "bandwidth" ]
    ++ (if cfg.master then (masterObjects.activatedPlugins or []) else [])
    ++ (if cfg.master then (lib.flatten (map (v: v.activatedPlugins or []) otherObjects)) else [])
    ++ (hostObjects.activatedPlugins or [])
    ++ (if cfg.master then ["notify-primary"] else ["notify-secondary"]);
  allPluginsConfig = import ./myplugins.nix {
    inherit pkgs lib config;
    sudo = "/run/wrappers/bin/sudo";
  };
  mypluginsConfig = lib.getAttrs activatedPlugins allPluginsConfig;
  myplugins = let
    mypluginsChunk = builtins.concatStringsSep "\n" (lib.attrsets.mapAttrsToList (k: v: v.chunk or "") mypluginsConfig);
  in pkgs.runCommand "buildplugins" {
    buildInputs = [ pkgs.makeWrapper pkgs.perl ];
  } ''
    mkdir $out
    ${mypluginsChunk}
    '';
  toObjects = pkgs.callPackage ./to_objects.nix {};
  commonConfig = {
    dilion = {
      processWarn = "250"; processAlert = "400";
      loadWarn = "1.0"; loadAlert = "1.2";
      interface = "eth0";
    };
    eldiron = {
      processWarn = "550"; processAlert = "650";
      loadWarn = "1.0"; loadAlert = "1.2";
      interface = "eth0";
    };
    backup-2 = {
      processWarn = "60"; processAlert = "70";
      loadWarn = "1.0"; loadAlert = "2.0";
      interface = "ens3";
    };
    monitoring-1 = {
      processWarn = "50"; processAlert = "60";
      loadWarn = "4.0"; loadAlert = "6.0";
      load15Warn = "1.0"; load15Alert = "2.0";
      interface = "ens3";
    };
    quatresaisons = {
      processWarn = "250"; processAlert = "400";
      loadWarn = "1.0"; loadAlert = "1.2";
      interface = "eth0";
    };
  };
  externalObjects = lib.genAttrs [ "tiboqorl-fr" ]
    (n: pkgs.callPackage (./. + "/objects_" + n + ".nix") { inherit emailCheck; });
  masterPassiveObjects = let
    passiveNodes = lib.attrsets.filterAttrs (n: _: builtins.elem n ["backup-2" "eldiron" "quatresaisons" "dilion"]) nodes;
    toPassiveServices = map (s: s.passiveInfo.filter s // s.passiveInfo);
    passiveServices = lib.flatten (lib.attrsets.mapAttrsToList
      (_: n: toPassiveServices n.config.myServices.monitoring.services)
      passiveNodes
      ) ++ lib.flatten (lib.attrsets.mapAttrsToList
      (_: n: toPassiveServices n.service)
      externalObjects);
  in {
    service = passiveServices;
    host = lib.lists.foldr
      (a: b: a//b)
      {}
      (lib.attrsets.mapAttrsToList (_: h: h.config.myServices.monitoring.hosts) passiveNodes
      ++ lib.attrsets.mapAttrsToList (_: n: n.host) externalObjects);
  };
  emailCheck = host: hostFQDN: let
    allCfg = config.myEnv.monitoring.email_check;
    cfg = allCfg."${host}";
    reverseTargets = builtins.attrNames (lib.attrsets.filterAttrs (k: v: builtins.elem host v.targets) allCfg);
    to_email = cfg': host':
      let sep = if lib.strings.hasInfix "+" cfg'.mail_address then "_" else "+";
      in "${cfg'.mail_address}${sep}${host'}@${cfg'.mail_domain}";
    mails_to_send = builtins.concatStringsSep "," (map (n: to_email allCfg."${n}" host) cfg.targets);
    mails_to_receive = builtins.concatStringsSep "," (map (n: "${to_email cfg n}:${n}") reverseTargets);
    command = if cfg.local
    then
      [ "check_emails_local" "/var/lib/naemon/checks/email" mails_to_send mails_to_receive ]
    else
      [ "check_emails" cfg.login cfg.port mails_to_send mails_to_receive ];
  in
    {
      service_description = "${hostFQDN} email service is active";
      use = "mail-service";
      host_name = hostFQDN;
      servicegroups = "webstatus-email";
      check_command = command;
    };
  otherObjects = map
    (n: (pkgs.callPackage (./. + "/objects_" + n + ".nix") { inherit emailCheck; }))
    [ "ulminfo-fr" "phare" "eban" ];
  masterObjects = pkgs.callPackage ./objects_master.nix { inherit config; };
  commonObjects = pkgs.callPackage ./objects_common.nix ({
    master = cfg.master;
    hostFQDN = config.hostEnv.fqdn;
    hostName = name;
    inherit mypluginsConfig;
  } // builtins.getAttr name commonConfig);
  hostObjects =
    let
      specific_file = ./. + "/objects_" + name + ".nix";
    in
      lib.attrsets.optionalAttrs
        (builtins.pathExists specific_file)
        (pkgs.callPackage specific_file {
          inherit config nodes emailCheck;
          hostFQDN = config.hostEnv.fqdn;
          hostName = name;
        });
  objectsFiles = lib.mapAttrs' (name: value: lib.nameValuePair
    "=/${name}/objects.conf" { alias = pkgs.writeText "objects.conf" (toObjects value); }
  ) externalObjects;
in
{
  options = {
    myServices.monitoring = {
      enable = lib.mkOption {
        type = lib.types.bool;
        default = false;
        description = ''
          Whether to enable monitoring.
        '';
      };
      master = lib.mkOption {
        type = lib.types.bool;
        default = false;
        description = ''
          This instance is the master instance
        '';
      };
      hosts = lib.mkOption {
        readOnly = true;
        description = "Hosts list for this host";
        default = (commonObjects.host or {}) // (hostObjects.host or {});
      };
      services = lib.mkOption {
        readOnly = true;
        description = "Services list for this host";
        default = commonObjects.service ++ hostObjects.service;
      };
    };
  };

  config = lib.mkIf cfg.enable {
    services.nginx = lib.mkIf config.myServices.status.enable {
      virtualHosts."status.immae.eu".locations = objectsFiles // {
        "=/common/immae.cfg" = {
          alias = pkgs.writeText "immae.cfg" ''
            # put me for instance in /etc/naemon/module-conf.d/immae.cfg
            # Make sure that you have include_dir=module-conf.d in
            # naemon.cfg
            log_initial_states=1
            date_format=iso8601
            admin_email=${config.myEnv.monitoring.email}
            obsess_over_services=1
            ocsp_command=notify-master
          '';
        };
        "=/common/resource.cfg" = {
          alias = pkgs.writeText "resource.cfg" ''
            # Resource.cfg file
            # Replace this with path to monitoring plugins
            $USER1$=@@COMMON_PLUGINS@@
            # Replace this with a path to scripts from
            # https://git.immae.eu/cgit/perso/Immae/Config/Nix.git/tree/modules/private/monitoring/plugins
            $USER2$=@@IMMAE_PLUGINS@@
            $USER200$=https://status.immae.eu/
            $USER201$=@@TOKEN@@
          '';
        };
      };
    };

    security.sudo.extraRules = let
      pluginsSudo = lib.lists.remove null (lib.attrsets.mapAttrsToList (k: v:
        if (v ? sudo)
        then ({ users = [ "naemon" ]; } // (v.sudo myplugins))
        else null) mypluginsConfig);
    in [
      {
        commands = [
          { command = "${pkgs.mdadm}/bin/mdadm --monitor --scan -1"; options = [ "NOPASSWD" ]; }
          { command = "${pkgs.postfix}/bin/mailq"; options = [ "NOPASSWD" ]; }
        ];
        users = [ "naemon" ];
        runAs = "root";
      }
    ] ++ pluginsSudo;
    environment.etc."mdadm.conf" = {
      enable = true;
      mode = "0644";
      user = "root";
      text = "MAILADDR ${config.myEnv.monitoring.email}";
    };

    secrets.keys = {
      "naemon/id_rsa" = {
        user = "naemon";
        group = "naemon";
        permissions = "0400";
        text = config.myEnv.monitoring.ssh_secret_key;
      };
    } // lib.optionalAttrs cfg.master (
      lib.mapAttrs' (k: v: lib.nameValuePair "${k}_access_key" {
        user = "naemon";
        group = "naemon";
        permissions = "0400";
        text = ''
          export AWS_ACCESS_KEY_ID="${v.accessKeyId}"
          export AWS_SECRET_ACCESS_KEY="${v.secretAccessKey}"
          export BASE_URL="${v.remote "immae-eldiron"}"
        '';
      }) config.myEnv.backup.remotes
    );
    # needed since extraResource is not in the closure
    systemd.services.naemon.path = [ myplugins ];
    services.naemon = {
      enable = true;
      extraConfig = ''
        use_syslog=1
        log_initial_states=1
        date_format=iso8601
        admin_email=${config.myEnv.monitoring.email}
      '' + lib.optionalString (!cfg.master) ''
        obsess_over_services=1
        ocsp_command=notify-master
      '' + lib.optionalString (cfg.master) ''
        broker_module=${pkgs.naemon-livestatus}/lib/naemon-livestatus/livestatus.so ${config.services.naemon.runDir}/live
        broker_module=${pkgs.status_engine.module}/lib/status-engine/naemon/statusengine-${pkgs.naemon.status_engine_version}.o use_service_perfdata=1 use_process_data=0 use_system_command_data=0 use_external_command_data=0 use_flapping_data=0 use_program_status_data=0 use_notification_data=0 use_contact_status_data=0 use_contact_notification_data=0 use_event_handler_data=0 use_object_data=0
      '';
      extraResource = let
        resources = [hostObjects.resources or {}] ++ (lib.mapAttrsToList (k: v: v.resources or {}) mypluginsConfig);
        joined = lib.zipAttrsWith (n: v: if builtins.length (lib.unique v) == 1 then builtins.head v else abort "Non-unique resources names") resources;
        joinedStr = builtins.concatStringsSep "\n" (lib.mapAttrsToList (k: v: "$" + "${k}$=${v}") joined);
      in ''
        $USER2$=${myplugins}
        ${joinedStr}
      '';
      objectDefs = toObjects commonObjects
        + toObjects hostObjects
        + lib.optionalString cfg.master (toObjects masterObjects)
        + lib.optionalString cfg.master (toObjects masterPassiveObjects)
        + lib.optionalString cfg.master (builtins.concatStringsSep "\n" (map toObjects otherObjects));
    };
  };
}