#  nixos-mailserver: a simple mail server
#  Copyright (C) 2016-2018  Robin Raymond
#
#  This program is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation, either version 3 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program. If not, see <http://www.gnu.org/licenses/>

{ pkgs ? import <nixpkgs> {}, ...}:

pkgs.nixosTest {
  name = "external";
  nodes = {
    server = { config, pkgs, ... }:
        {
            imports = [
                ../default.nix
                ./lib/config.nix
            ];

            virtualisation.memorySize = 1024;

            services.rsyslogd = {
              enable = true;
              defaultConfig = ''
              *.*   /dev/console
              '';
            };


            mailserver = {
              enable = true;
              debug = true;
              fqdn = "mail.example.com";
              domains = [ "example.com" "example2.com" ];
              rewriteMessageId = true;
              dkimKeyBits = 1535;
              dmarcReporting = {
                enable = true;
                domain = "example.com";
                organizationName = "ACME Corp";
              };

              loginAccounts = {
                  "user1@example.com" = {
                      hashedPassword = "$6$/z4n8AQl6K$kiOkBTWlZfBd7PvF5GsJ8PmPgdZsFGN1jPGZufxxr60PoR0oUsrvzm2oQiflyz5ir9fFJ.d/zKm/NgLXNUsNX/";
                      aliases = [ "postmaster@example.com" ];
                      catchAll = [ "example.com" ];
                  };
                  "user2@example.com" = {
                      hashedPassword = "$6$u61JrAtuI0a$nGEEfTP5.eefxoScUGVG/Tl0alqla2aGax4oTd85v3j3xSmhv/02gNfSemv/aaMinlv9j/ZABosVKBrRvN5Qv0";
                      aliases = [ "chuck@example.com" ];
                  };
                  "user@example2.com" = {
                      hashedPassword = "$6$u61JrAtuI0a$nGEEfTP5.eefxoScUGVG/Tl0alqla2aGax4oTd85v3j3xSmhv/02gNfSemv/aaMinlv9j/ZABosVKBrRvN5Qv0";
                  };
                  "lowquota@example.com" = {
                      hashedPassword = "$6$u61JrAtuI0a$nGEEfTP5.eefxoScUGVG/Tl0alqla2aGax4oTd85v3j3xSmhv/02gNfSemv/aaMinlv9j/ZABosVKBrRvN5Qv0";
                      quota = "1B";
                  };
              };

              extraVirtualAliases = {
                "single-alias@example.com" = "user1@example.com";
                "multi-alias@example.com" = [ "user1@example.com" "user2@example.com" ];
              };

              enableImap = true;
              enableImapSsl = true;
              fullTextSearch = {
                enable = true;
                autoIndex = true;
                # special use depends on https://github.com/NixOS/nixpkgs/pull/93201
                autoIndexExclude = [ (if (pkgs.lib.versionAtLeast pkgs.lib.version "21") then "\\Junk" else "Junk") ];
                enforced = "yes";
                # fts-xapian warns when memory is low, which makes the test fail
                memoryLimit = 100000;
              };
            };
        };
      client = { nodes, config, pkgs, ... }: let
        serverIP = nodes.server.config.networking.primaryIPAddress;
        clientIP = nodes.client.config.networking.primaryIPAddress;
        grep-ip = pkgs.writeScriptBin "grep-ip" ''
          #!${pkgs.stdenv.shell}
          echo grep '${clientIP}' "$@" >&2
          exec grep '${clientIP}' "$@"
        '';
        check-mail-id = pkgs.writeScriptBin "check-mail-id" ''
          #!${pkgs.stdenv.shell}
          echo grep '^Message-ID:.*@mail.example.com>$' "$@" >&2
          exec grep '^Message-ID:.*@mail.example.com>$' "$@"
        '';
        test-imap-spam = pkgs.writeScriptBin "imap-mark-spam" ''
          #!${pkgs.python3.interpreter}
          import imaplib

          with imaplib.IMAP4_SSL('${serverIP}') as imap:
            imap.login('user1@example.com', 'user1')
            imap.select()
            status, [response] = imap.search(None, 'ALL')
            msg_ids = response.decode("utf-8").split(' ')
            print(msg_ids)
            assert status == 'OK'
            assert len(msg_ids) == 1

            imap.copy(','.join(msg_ids), 'Junk')
            for num in msg_ids:
              imap.store(num, '+FLAGS', '\\Deleted')
            imap.expunge()

            imap.select('Junk')
            status, [response] = imap.search(None, 'ALL')
            msg_ids = response.decode("utf-8").split(' ')
            print(msg_ids)
            assert status == 'OK'
            assert len(msg_ids) == 1

            imap.close()
        '';
        test-imap-ham = pkgs.writeScriptBin "imap-mark-ham" ''
          #!${pkgs.python3.interpreter}
          import imaplib

          with imaplib.IMAP4_SSL('${serverIP}') as imap:
            imap.login('user1@example.com', 'user1')
            imap.select('Junk')
            status, [response] = imap.search(None, 'ALL')
            msg_ids = response.decode("utf-8").split(' ')
            print(msg_ids)
            assert status == 'OK'
            assert len(msg_ids) == 1

            imap.copy(','.join(msg_ids), 'INBOX')
            for num in msg_ids:
              imap.store(num, '+FLAGS', '\\Deleted')
            imap.expunge()

            imap.select('INBOX')
            status, [response] = imap.search(None, 'ALL')
            msg_ids = response.decode("utf-8").split(' ')
            print(msg_ids)
            assert status == 'OK'
            assert len(msg_ids) == 1

            imap.close()
        '';
        search = pkgs.writeScriptBin "search" ''
          #!${pkgs.python3.interpreter}
          import imaplib
          import sys

          [_, mailbox, needle] = sys.argv

          with imaplib.IMAP4_SSL('${serverIP}') as imap:
            imap.login('user1@example.com', 'user1')
            imap.select(mailbox)
            status, [response] = imap.search(None, 'BODY', repr(needle))
            msg_ids = [ i for i in response.decode("utf-8").split(' ') if i ]
            print(msg_ids)
            assert status == 'OK'
            assert len(msg_ids) == 1
            status, response = imap.fetch(msg_ids[0], '(RFC822)')
            assert status == "OK"
            assert needle in repr(response)
            imap.close()
        '';
      in {
        imports = [
            ./lib/config.nix
        ];
        environment.systemPackages = with pkgs; [
          fetchmail msmtp procmail findutils grep-ip check-mail-id test-imap-spam test-imap-ham search
        ];
        environment.etc = {
          "root/.fetchmailrc" = {
            text = ''
                poll ${serverIP} with proto IMAP
                user 'user1@example.com' there with password 'user1' is 'root' here
                mda procmail
            '';
            mode = "0700";
          };
          "root/.fetchmailRcLowQuota" = {
            text = ''
                poll ${serverIP} with proto IMAP
                user 'lowquota@example.com' there with password 'user2' is 'root' here
                mda procmail
            '';
            mode = "0700";
          };
          "root/.procmailrc" = {
            text = "DEFAULT=$HOME/mail";
          };
          "root/.msmtprc" = {
            text = ''
              account        test
              host           ${serverIP}
              port           587
              from           user2@example.com
              user           user2@example.com
              password       user2

              account        test2
              host           ${serverIP}
              port           587
              from           user@example2.com
              user           user@example2.com
              password       user2

              account        test3
              host           ${serverIP}
              port           587
              from           chuck@example.com
              user           user2@example.com
              password       user2

              account        test4
              host           ${serverIP}
              port           587
              from           postmaster@example.com
              user           user1@example.com
              password       user1

              account        test5
              host           ${serverIP}
              port           587
              from           single-alias@example.com
              user           user1@example.com
              password       user1
            '';
          };
          "root/email1".text = ''
            Message-ID: <12345qwerty@host.local.network>
            From: User2 <user2@example.com>
            To: User1 <user1@example.com>
            Cc:
            Bcc:
            Subject: This is a test Email from user2 to user1
            Reply-To:

            Hello User1,

            how are you doing today?
          '';
          "root/email2".text = ''
            Message-ID: <232323abc@host.local.network>
            From: User <user@example2.com>
            To: User1 <user1@example.com>
            Cc:
            Bcc:
            Subject: This is a test Email from user@example2.com to user1
            Reply-To:

            Hello User1,

            how are you doing today?

            XOXO User1
          '';
          "root/email3".text = ''
            Message-ID: <asdfghjkl42@host.local.network>
            From: Postmaster <postmaster@example.com>
            To: Chuck <chuck@example.com>
            Cc:
            Bcc:
            Subject: This is a test Email from postmaster\@example.com to chuck
            Reply-To:

            Hello Chuck,

            I think I may have misconfigured the mail server
            XOXO Postmaster
          '';
          "root/email4".text = ''
            Message-ID: <sdfsdf@host.local.network>
            From: Single Alias <single-alias@example.com>
            To: User1 <user1@example.com>
            Cc:
            Bcc:
            Subject: This is a test Email from single-alias\@example.com to user1
            Reply-To:

            Hello User1,

            how are you doing today?

            XOXO User1 aka Single Alias
          '';
          "root/email5".text = ''
            Message-ID: <789asdf@host.local.network>
            From: User2 <user2@example.com>
            To: Multi Alias <multi-alias@example.com>
            Cc:
            Bcc:
            Subject: This is a test Email from user2\@example.com to multi-alias
            Reply-To:

            Hello Multi Alias,

            how are we doing today?

            XOXO User1
          '';
          "root/email6".text = ''
            Message-ID: <123457qwerty@host.local.network>
            From: User2 <user2@example.com>
            To: User1 <user1@example.com>
            Cc:
            Bcc:
            Subject: This is a test Email from user2 to user1
            Reply-To:

            Hello User1,

            this email contains the needle:
            576a4565b70f5a4c1a0925cabdb587a6 
          '';
          "root/email7".text = ''
            Message-ID: <1234578qwerty@host.local.network>
            From: User2 <user2@example.com>
            To: User1 <user1@example.com>
            Cc:
            Bcc:
            Subject: This is a test Email from user2 to user1
            Reply-To:

            Hello User1,

            this email does not contain the needle :(
          '';
        };
      };
    };

  testScript = { nodes, ... }:
      ''
      start_all()

      server.wait_for_unit("multi-user.target")
      client.wait_for_unit("multi-user.target")

      # TODO put this blocking into the systemd units?
      server.wait_until_succeeds(
          "set +e; timeout 1 ${nodes.server.nixpkgs.pkgs.netcat}/bin/nc -U /run/rspamd/rspamd-milter.sock < /dev/null; [ $? -eq 124 ]"
      )

      client.execute("cp -p /etc/root/.* ~/")
      client.succeed("mkdir -p ~/mail")
      client.succeed("ls -la ~/ >&2")
      client.succeed("cat ~/.fetchmailrc >&2")
      client.succeed("cat ~/.procmailrc >&2")
      client.succeed("cat ~/.msmtprc >&2")

      with subtest("imap retrieving mail"):
          # fetchmail returns EXIT_CODE 1 when no new mail
          client.succeed("fetchmail --nosslcertck -v || [ $? -eq 1 ] >&2")

      with subtest("submission port send mail"):
          # send email from user2 to user1
          client.succeed(
              "msmtp -a test --tls=on --tls-certcheck=off --auth=on user1\@example.com < /etc/root/email1 >&2"
          )
          # give the mail server some time to process the mail
          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')

      with subtest("imap retrieving mail 2"):
          client.execute("rm ~/mail/*")
          # fetchmail returns EXIT_CODE 0 when it retrieves mail
          client.succeed("fetchmail --nosslcertck -v >&2")

      with subtest("remove sensitive information on submission port"):
          client.succeed("cat ~/mail/* >&2")
          ## make sure our IP is _not_ in the email header
          client.fail("grep-ip ~/mail/*")
          client.succeed("check-mail-id ~/mail/*")

      with subtest("have correct fqdn as sender"):
          client.succeed("grep 'Received: from mail.example.com' ~/mail/*")

      with subtest("dkim has user-specified size"):
          server.succeed(
              "openssl rsa -in /var/dkim/example.com.mail.key -text -noout | grep 'Private-Key: (1535 bit'"
          )

      with subtest("dkim singing, multiple domains"):
          client.execute("rm ~/mail/*")
          # send email from user2 to user1
          client.succeed(
              "msmtp -a test2 --tls=on --tls-certcheck=off --auth=on user1\@example.com < /etc/root/email2 >&2"
          )
          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
          # fetchmail returns EXIT_CODE 0 when it retrieves mail
          client.succeed("fetchmail  --nosslcertck -v")
          client.succeed("cat ~/mail/* >&2")
          # make sure it is dkim signed
          client.succeed("grep DKIM ~/mail/*")

      with subtest("aliases"):
          client.execute("rm ~/mail/*")
          # send email from chuck to postmaster
          client.succeed(
              "msmtp -a test3 --tls=on --tls-certcheck=off --auth=on postmaster\@example.com < /etc/root/email2 >&2"
          )
          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
          # fetchmail returns EXIT_CODE 0 when it retrieves mail
          client.succeed("fetchmail --nosslcertck -v")

      with subtest("catchAlls"):
          client.execute("rm ~/mail/*")
          # send email from chuck to non exsitent account
          client.succeed(
              "msmtp -a test3 --tls=on --tls-certcheck=off --auth=on lol\@example.com < /etc/root/email2 >&2"
          )
          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
          # fetchmail returns EXIT_CODE 0 when it retrieves mail
          client.succeed("fetchmail --nosslcertck -v")

          client.execute("rm ~/mail/*")
          # send email from user1 to chuck
          client.succeed(
              "msmtp -a test4 --tls=on --tls-certcheck=off --auth=on chuck\@example.com < /etc/root/email2 >&2"
          )
          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
          # fetchmail returns EXIT_CODE 1 when no new mail
          # if this succeeds, it means that user1 recieved the mail that was intended for chuck.
          client.fail("fetchmail --nosslcertck -v")

      with subtest("extraVirtualAliases"):
          client.execute("rm ~/mail/*")
          # send email from single-alias to user1
          client.succeed(
              "msmtp -a test5 --tls=on --tls-certcheck=off --auth=on user1\@example.com < /etc/root/email4 >&2"
          )
          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
          # fetchmail returns EXIT_CODE 0 when it retrieves mail
          client.succeed("fetchmail --nosslcertck -v")

          client.execute("rm ~/mail/*")
          # send email from user1 to multi-alias (user{1,2}@example.com)
          client.succeed(
              "msmtp -a test --tls=on --tls-certcheck=off --auth=on multi-alias\@example.com < /etc/root/email5 >&2"
          )
          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
          # fetchmail returns EXIT_CODE 0 when it retrieves mail
          client.succeed("fetchmail --nosslcertck -v")

      with subtest("quota"):
          client.execute("rm ~/mail/*")
          client.execute("mv ~/.fetchmailRcLowQuota ~/.fetchmailrc")

          client.succeed(
              "msmtp -a test3 --tls=on --tls-certcheck=off --auth=on lowquota\@example.com < /etc/root/email2 >&2"
          )
          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
          # fetchmail returns EXIT_CODE 0 when it retrieves mail
          client.fail("fetchmail --nosslcertck -v")

      with subtest("imap sieve junk trainer"):
          # send email from user2 to user1
          client.succeed(
              "msmtp -a test --tls=on --tls-certcheck=off --auth=on user1\@example.com < /etc/root/email1 >&2"
          )
          # give the mail server some time to process the mail
          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')

          client.succeed("imap-mark-spam >&2")
          server.wait_until_succeeds("journalctl -u dovecot2 | grep -i sa-learn-spam.sh >&2")
          client.succeed("imap-mark-ham >&2")
          server.wait_until_succeeds("journalctl -u dovecot2 | grep -i sa-learn-ham.sh >&2")

      with subtest("full text search and indexation"):
          # send 2 email from user2 to user1
          client.succeed(
              "msmtp -a test --tls=on --tls-certcheck=off --auth=on user1\@example.com < /etc/root/email6 >&2"
          )
          client.succeed(
              "msmtp -a test --tls=on --tls-certcheck=off --auth=on user1\@example.com < /etc/root/email7 >&2"
          )
          # give the mail server some time to process the mail
          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')

          # should find exactly one email containing this
          client.succeed("search INBOX 576a4565b70f5a4c1a0925cabdb587a6 >&2")
          # should fail because this folder is not indexed
          client.fail("search Junk a >&2")
          # check that search really goes through the indexer
          server.succeed(
              "journalctl -u dovecot2 | grep -E 'indexer-worker.* Done indexing .INBOX.' >&2"
          )
          # check that Junk is not indexed
          server.fail("journalctl -u dovecot2 | grep 'indexer-worker' | grep -i 'JUNK' >&2")

      with subtest("dmarc reporting"):
          server.systemctl("start rspamd-dmarc-reporter.service")

      with subtest("no warnings or errors"):
          server.fail("journalctl -u postfix | grep -i error >&2")
          server.fail("journalctl -u postfix | grep -i warning >&2")
          server.fail("journalctl -u dovecot2 | grep -v 'imap-login: Debug: SSL error: Connection closed' | grep -i error >&2")
          # harmless ? https://dovecot.org/pipermail/dovecot/2020-August/119575.html
          server.fail(
              "journalctl -u dovecot2 |grep -v 'Expunged message reappeared, giving a new UID'| grep -v 'FTS Xapian: Box is empty' | grep -i warning >&2"
          )
    '';
}