{ lib, pkgs, config, ... }:
let
  sieve_bin = pkgs.runCommand "sieve_bin" {
    buildInputs = [ pkgs.makeWrapper ];
  } ''
    cp -a ${./sieve_bin} $out
    chmod -R u+w $out
    patchShebangs $out
    for i in $out/*; do
      wrapProgram "$i" --prefix PATH : ${lib.makeBinPath [ pkgs.coreutils ]}
    done
    '';
in
{
  config = lib.mkIf config.myServices.mail.enable {
    services.duplyBackup.profiles.mail.excludeFile = ''
      + /var/lib/dhparams
      + /var/lib/dovecot
      '';
    secrets.keys = [
      {
        dest = "dovecot/ldap";
        user = config.services.dovecot2.user;
        group = config.services.dovecot2.group;
        permissions = "0400";
        text = ''
          hosts = ${config.myEnv.mail.dovecot.ldap.host}
          tls = yes

          dn = ${config.myEnv.mail.dovecot.ldap.dn}
          dnpass = ${config.myEnv.mail.dovecot.ldap.password}

          auth_bind = yes

          ldap_version = 3

          base = ${config.myEnv.mail.dovecot.ldap.base}
          scope = subtree

          pass_filter = ${config.myEnv.mail.dovecot.ldap.filter}
          pass_attrs = ${config.myEnv.mail.dovecot.ldap.pass_attrs}

          user_attrs = ${config.myEnv.mail.dovecot.ldap.user_attrs}
          user_filter = ${config.myEnv.mail.dovecot.ldap.filter}
          iterate_attrs = ${config.myEnv.mail.dovecot.ldap.iterate_attrs}
          iterate_filter = ${config.myEnv.mail.dovecot.ldap.iterate_filter}
          '';
      }
    ];

    users.users.vhost = {
      group = "vhost";
      uid = config.ids.uids.vhost;
    };
    users.groups.vhost.gid = config.ids.gids.vhost;

    # https://blog.zeninc.net/index.php?post/2018/04/01/Un-annuaire-pour-les-gouverner-tous.......
    services.dovecot2 = {
      enable = true;
      enablePAM = false;
      enablePop3 = true;
      enableImap = true;
      enableLmtp = true;
      protocols = [ "sieve" ];
      modules = [
        pkgs.dovecot_pigeonhole
        pkgs.dovecot_fts-xapian
      ];
      mailUser = "vhost";
      mailGroup = "vhost";
      createMailUser = false;
      mailboxes = [
        { name = "Trash";  auto = "subscribe"; specialUse = "Trash"; }
        { name = "Junk";   auto = "subscribe"; specialUse = "Junk"; }
        { name = "Sent";   auto = "subscribe"; specialUse = "Sent"; }
        { name = "Drafts"; auto = "subscribe"; specialUse = "Drafts"; }
      ];
      mailLocation = "mbox:~/Mail:INBOX=~/Mail/Inbox:INDEX=~/.imap";
      sslServerCert = "/var/lib/acme/mail/fullchain.pem";
      sslServerKey = "/var/lib/acme/mail/key.pem";
      sslCACert = "/var/lib/acme/mail/fullchain.pem";
      extraConfig = builtins.concatStringsSep "\n" [
        ''
          postmaster_address = postmaster@immae.eu
          mail_attribute_dict = file:%h/dovecot-attributes
          imap_idle_notify_interval = 20 mins
          namespace inbox {
            type = private
            separator = /
            inbox = yes
            list = yes
          }
        ''

        # ACL
        ''
          mail_plugins = $mail_plugins acl
          plugin {
            acl = vfile:${pkgs.writeText "dovecot-acl" ''
              Backup/* owner lrp
              ''}
            acl_globals_only = yes
          }
        ''

        # Full text search
        ''
          # needs to be bigger than any mailbox size
          default_vsz_limit = 2GB
          mail_plugins = $mail_plugins fts fts_xapian
          plugin {
            plugin = fts fts_xapian
            fts = xapian
            fts_xapian = partial=2 full=20
            fts_autoindex = yes
            fts_autoindex_exclude = \Junk
            fts_autoindex_exclude2 = \Trash
            fts_autoindex_exclude3 = Virtual/*
          }
        ''

        # Antispam
        # https://docs.iredmail.org/dovecot.imapsieve.html
        ''
        # imap_sieve plugin added below

        plugin {
            sieve_plugins = sieve_imapsieve sieve_extprograms
            imapsieve_url = sieve://127.0.0.1:4190

            sieve_before = file:${./sieve_scripts}/backup.sieve;bindir=/var/lib/vhost/.sieve_bin

            # From elsewhere to Junk folder
            imapsieve_mailbox1_name = Junk
            imapsieve_mailbox1_causes = COPY APPEND
            imapsieve_mailbox1_before = file:${./sieve_scripts}/report_spam.sieve;bindir=/var/lib/vhost/.imapsieve_bin

            # From Junk folder to elsewhere
            imapsieve_mailbox2_name = *
            imapsieve_mailbox2_from = Junk
            imapsieve_mailbox2_causes = COPY
            imapsieve_mailbox2_before = file:${./sieve_scripts}/report_ham.sieve;bindir=/var/lib/vhost/.imapsieve_bin

            # From anywhere to NoJunk folder
            imapsieve_mailbox3_name = NoJunk
            imapsieve_mailbox3_causes = COPY APPEND
            imapsieve_mailbox3_before = file:${./sieve_scripts}/report_ham.sieve;bindir=/var/lib/vhost/.imapsieve_bin

            sieve_pipe_bin_dir = ${sieve_bin}

            sieve_global_extensions = +vnd.dovecot.pipe +vnd.dovecot.environment
        }
        ''
        # Services to listen
        ''
        service imap-login {
          inet_listener imap {
          }
          inet_listener imaps {
          }
        }
        service pop3-login {
          inet_listener pop3 {
          }
          inet_listener pop3s {
          }
        }
        service imap {
        }
        service pop3 {
        }
        service auth {
          unix_listener auth-userdb {
          }
          unix_listener ${config.services.postfix.config.queue_directory}/private/auth {
            mode = 0666
          }
        }
        service auth-worker {
        }
        service dict {
          unix_listener dict {
          }
        }
        service stats {
          unix_listener stats-reader {
            user = vhost
            group = vhost
            mode = 0660
          }
          unix_listener stats-writer {
            user = vhost
            group = vhost
            mode = 0660
          }
        }
        ''

        # Authentification
        ''
        first_valid_uid = ${toString config.ids.uids.vhost}
        disable_plaintext_auth = yes
        passdb {
          driver = ldap
          args = ${config.secrets.fullPaths."dovecot/ldap"}
        }
        userdb {
          driver = ldap
          args = ${config.secrets.fullPaths."dovecot/ldap"}
        }
        ''

        # Zlib
        ''
        mail_plugins = $mail_plugins zlib
        plugin {
          zlib_save_level = 6
          zlib_save = gz
        }
        ''

        # Sieve
        ''
        plugin {
          sieve = file:~/sieve;bindir=~/.sieve-bin;active=~/.dovecot.sieve
        }
        service managesieve-login {
        }
        service managesieve {
        }
        ''

        # Virtual mailboxes
        ''
        mail_plugins = $mail_plugins virtual
        namespace Virtual {
          prefix = Virtual/
          location = virtual:~/Virtual
        }
        ''

        # Protocol specific configuration
        # Needs to come last if there are mail_plugins entries
        ''
        protocol imap {
          mail_plugins = $mail_plugins imap_sieve imap_acl
        }
        protocol lda {
          mail_plugins = $mail_plugins sieve
        }
        ''
      ];
    };
    networking.firewall.allowedTCPPorts = [ 110 143 993 995 4190 ];
    system.activationScripts.dovecot = {
      deps = [ "users" ];
      text  =''
        install -m 0755 -o vhost -g vhost -d /var/lib/vhost
        '';
    };

    services.cron.systemCronJobs = let
      cron_script = pkgs.writeScriptBin "cleanup-imap-folders" ''
        ${pkgs.dovecot}/bin/doveadm expunge -A MAILBOX "Backup/*" NOT UID 1:256 2>&1 > /dev/null | grep -v "Mailbox doesn't exist:" | grep -v "Info: Opening DB"
        ${pkgs.dovecot}/bin/doveadm expunge -A MAILBOX Junk SEEN NOT FLAGGED BEFORE 4w 2>&1 > /dev/null | grep -v "Mailbox doesn't exist:" | grep -v "Info: Opening DB"
        ${pkgs.dovecot}/bin/doveadm expunge -A MAILBOX Trash NOT FLAGGED BEFORE 4w 2>&1 > /dev/null | grep -v "Mailbox doesn't exist:" | grep -v "Info: Opening DB"
        '';
      in
      [
        "0 2 * * * root ${cron_script}/bin/cleanup-imap-folders"
      ];
    security.acme.certs."mail" = {
      postRun = ''
        systemctl restart dovecot2.service
      '';
      extraDomains = {
        "imap.immae.eu" = null;
        "pop3.immae.eu" = null;
      };
    };
  };
}