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

with lib;
let
  ipv4 = {
    address = "95.216.74.104";
    gateway = "95.216.74.65";
    netmask = "255.255.255.192";
    prefixLength = 26; # https://www.pawprint.net/designresources/netmask-converter.php
  };
  ipv6 = {
    address = "2a01:4f9:2b:a98::";
    gateway = "fe80::1";
    prefixLength = 64;
  };
  networkInterface = "eth0";
  hostName = "cobalt";
  hostId = "712ae82a";
  hostAddr = "cobalt.exotic.sh";

  sefidelKeys = [ "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILN14b5Fu+StHeMXq4ClyLG4G+/vCAfS7adxceEFria/ openpgp:0x1D5BCD11" ];
  maintainerKeys = [ ] ++ sefidelKeys;

  poorObfuscation = y: x: "${x}@${y}";
in
{
  deployment = {
    targetHost = hostAddr;
    targetPort = 22;
    targetUser = "root";
  };

  imports = [ ./hardware-configuration.nix ];

  boot.supportedFilesystems = [ "zfs" ];
  networking.hostId = hostId;

  boot.loader.grub.enable = true;
  # boot.loader.grub.version = 2;
  boot.loader.grub.efiSupport = false;
  # boot.loader.grub.device = "nodev";

  # This should be done automatically, but explicitly declare it just in case.
  boot.loader.grub.copyKernels = true;
  # Make sure that you've listed all of the boot partitions here.
  boot.loader.grub.mirroredBoots = [
    { path = "/boot"; devices = [ "/dev/disk/by-id/ata-ST4000NM0245-1Z2107_ZC17GW7G" ]; }
    { path = "/boot-fallback"; devices = [ "/dev/disk/by-id/ata-ST4000NM0245-1Z2107_ZC17GWB2" ]; }
  ];

  # Boot normally when one of the boot partitions are missing
  fileSystems."/boot".options = [ "nofail" ];
  fileSystems."/boot-fallback".options = [ "nofail" ];

  # Erase your darlings
  boot.initrd.postDeviceCommands = lib.mkAfter ''
    zfs rollback -r rpool/local/root@blank
  '';

  # NOTE: replace these to boot.initrd.availableKernelModules?
  boot.kernelModules = [ "e1000e" ];
  boot.initrd.kernelModules = [ "e1000e" ];

  boot.kernelParams = [
    # See <https:#www.kernel.org/doc/Documentation/filesystems/nfs/nfsroot.txt> for documentation.
    # ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>:<dns0-ip>:<dns1-ip>:<ntp0-ip>
    # The server ip refers to the NFS server -- not needed in this case.
    "ip=${ipv4.address}::${ipv4.gateway}:${ipv4.netmask}:${hostName}-initrd:${networkInterface}:off:8.8.8.8"
  ];

  boot.initrd.network.enable = true;
  boot.initrd.network.ssh = {
    enable = true;

    # Using the same port as the actual SSH will cause clients to throw errors
    # related to host key mismatch.
    port = 2222;

    # This takes 'path's, not 'string's.
    hostKeys = [
      /boot/initrd-ssh-key
      /boot-fallback/initrd-ssh-key
    ];

    # Public ssh key to log into the initrd ssh
    authorizedKeys = maintainerKeys;
  };
  boot.initrd.network.postCommands = ''
    cat <<EOF > /root/.profile
    if pgrep -x "zfs" > /dev/null
    then
      zfs load-key -a
      killall zfs
    else
      echo "ZFS is not running -- this could be a sign of failure."
    fi
    EOF
  '';

  hardware.enableRedistributableFirmware = true;

  networking.hostName = hostName;

  networking.useDHCP = false;
  networking.interfaces.${networkInterface} = {
    ipv4 = { addresses = [{ address = ipv4.address; prefixLength = ipv4.prefixLength; }]; };
    ipv6 = { addresses = [{ address = ipv6.address; prefixLength = ipv6.prefixLength; }]; };
  };
  networking.defaultGateway = ipv4.gateway;
  networking.defaultGateway6 = { address = ipv6.gateway; interface = networkInterface; };
  networking.nameservers = [ "8.8.8.8" ];

  networking.firewall.enable = true;

  time.timeZone = "UTC";

  sops.secrets.root-password.neededForUsers = true;
  sops.secrets.sefidel-password.neededForUsers = true;

  users.users.root.hashedPasswordFile = config.sops.secrets.root-password.path;
  users.users.root.openssh.authorizedKeys.keys = maintainerKeys;

  users.users.sefidel = {
    isNormalUser = true;
    shell = pkgs.zsh;
    hashedPasswordFile = config.sops.secrets.sefidel-password.path;
    openssh.authorizedKeys.keys = sefidelKeys;

    extraGroups = [ "wheel" ];
  };
  programs.zsh.enable = true;

  services.openssh.enable = true;
  services.openssh.settings.PermitRootLogin = "prohibit-password";

  services.openssh.hostKeys = [
    {
      path = "/persist/ssh/ssh_host_ed25519_key";
      type = "ed25519";
    }
    {
      path = "/persist/ssh/ssh_host_rsa_key";
      type = "rsa";
      bits = 4096;
    }
  ];

  # impermanence requirement
  fileSystems."/persist".neededForBoot = true;

  environment.systemPackages = with pkgs; [
    bsd-finger
  ];

  sops.secrets.borg-cobalt-rolling-pass = { };
  sops.secrets.grafana-admin-pass = { owner = "grafana"; };
  sops.secrets.acme-envs = {
    owner = "acme";
  };
  sops.secrets.matrix-server-key = { };
  sops.secrets.dendrite-envs = { };
  sops.secrets.sliding-sync-secret = { };
  sops.secrets.mjolnir-password = { owner = "mjolnir"; };
  sops.secrets.mautrix-telegram-envs = { };
  sops.secrets.turn-secret = { };
  # sops.secrets.openldap-admin-key = {
  # owner = "openldap";
  # };
  sops.secrets.searx-env = { };

  nix.experimentalFeatures = "nix-command flakes";

  services.openssh.knownHosts."hk-s020.rsync.net".publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILcPl9x9JfRFwsn09NnDw/xBZbAN80ZQck+h6AqlVqPH";

  modules = {
    sops.enable = true;

    services.backup = {
      enable = true;

      paths = [
        "/persist"
        "/home"
      ];
      exclude = [
        # Rust build files
        "/home/**/target"

        # Static backup created in /persist/var/backup/postgresql
        "/persist/var/lib/postgresql"
      ];

      repo = "20963@hk-s020.rsync.net:rolling/exotic/cobalt";
      repoKeyPath = config.sops.secrets.borg-cobalt-rolling-pass.path;
      sshKeyPath = "/persist/ssh/ssh_host_ed25519_key";
      rsyncNet = true;
    };

    services.metrics = {
      enable = true;
      domain = "status.exotic.sh";
      tls.acmeHost = "exotic.sh";
      secrets.adminPassword = config.sops.secrets.grafana-admin-pass.path;
    };

    services.coredns.enable = false;
    services.nginx.enable = true;
    services.acme = {
      enable = true;
      email = poorObfuscation "exotic.sh" "postmaster";

      certs = {
        "exotic.sh" = {
          subDomains = [
            "git"
            "matrix"
            "*.labs"
            "social"
            "bouncer"
            "meet"
            "chat"
            "schildi"
            "turn"
            "status"
            "mail"
            "webmail"
            "todo"
          ];
        };
        "nand.moe" = {
          subDomains = [ ];
        };
        "sefidel.net" = {
          subDomains = [ ];
        };
      };

      secrets.acme-credentials = config.sops.secrets.acme-envs.path;
    };

    services.gitolite = {
      enable = true;
      adminPubkey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILN14b5Fu+StHeMXq4ClyLG4G+/vCAfS7adxceEFria/ openpgp:0x1D5BCD11";
    };
    services.gitDaemon.enable = true;
    services.cgit = {
      enable = true;
      domain = "exotic.sh";
      realHost = "git.exotic.sh";
      settings.description = "Out of sync since Y2K";
    };
    services.fail2ban.enable = true;
    services.postgresql.enable = true;
    services.dendrite = {
      enable = true;
      domain = "exotic.sh";
      realHost = "matrix.exotic.sh";
      slidingSyncHost = "slidingsync.labs.exotic.sh";
      turn = {
        enable = true;
        domain = "turn.exotic.sh";
        shared_secret = "$TURN_SECRET"; # dendrite envs
      };
      secrets = {
        matrix-server-key = config.sops.secrets.matrix-server-key.path;
        dendrite-envs = config.sops.secrets.dendrite-envs.path;
        sliding-sync-secret = config.sops.secrets.sliding-sync-secret.path;
      };
    };
    services.coturn = {
      enable = true;
      domain = "turn.exotic.sh";
      tls.acmeHost = "exotic.sh";
      shared_secret = config.sops.secrets.turn-secret.path;
    };
    services.matrix-moderation = {
      enable = true;
      domain = "exotic.sh";
      secrets.userPassword = config.sops.secrets.mjolnir-password.path;
    };
    services.matrix-bridge = {
      enable = true;
      domain = "exotic.sh";
      secrets.mautrix-envs = config.sops.secrets.mautrix-telegram-envs.path;
    };
    services.element-web = {
      enable = true;
      hostName = "chat.exotic.sh";
      matrix = {
        baseUrl = "https://matrix.exotic.sh";
        serverName = "exotic.sh";
      };
      tls.acmeHost = "exotic.sh";
      jitsi.domain = "meet.exotic.sh";
    };
    services.schildichat-web = {
      enable = true;
      hostName = "schildi.exotic.sh";
      matrix = {
        baseUrl = config.modules.services.element-web.matrix.baseUrl;
        serverName = config.modules.services.element-web.matrix.serverName;
      };
      tls.acmeHost = config.modules.services.element-web.tls.acmeHost;
      jitsi.domain = config.modules.services.element-web.jitsi.domain;
    };
    services.akkoma = {
      enable = true;
      domain = "exotic.sh";
      realHost = "social.exotic.sh";
      instanceName = "exotic.sh social";
    };
    services.soju = {
      enable = true;
      hostName = "bouncer.exotic.sh";
      tls.enable = true;
      tls.acmeHost = "exotic.sh";
    };
    services.vikunja = {
      enable = true;
      domain = "exotic.sh";
      realHost = "todo.exotic.sh";
    };
    services.searx = {
      enable = false;
      domain = "exotic.sh";
      realHost = "searx.labs.exotic.sh";
      secrets.searx-env = config.sops.secrets.searx-env.path;
    };

    # TODO: replace with dovecot.nix?
    services.nixos-mailserver = {
      enable = true;
      webmail = {
        enable = true;
        domain = "exotic.sh";
        realHost = "webmail.exotic.sh";
      };
    };

    services.jitsi = {
      enable = true;
      hostName = "meet.exotic.sh";
      tls.acmeHost = "exotic.sh";
    };

    services.ldap = {
      enable = false;
      dc = "exotic";
      tld = "sh";
      tls.acmeHost = "exotic.sh";
      secrets.rootPass = config.sops.secrets.openldap-admin-key.path;
    };

    services.sefidel-web.enable = true;
  };

  # This value determines the NixOS release from which the default
  # settings for stateful data, like file locations and database versions
  # on your system were taken. It‘s perfectly fine and recommended to leave
  # this value at the release version of the first install of this system.
  # Before changing this value read the documentation for this option
  # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
  system.stateVersion = "23.05"; # Did you read the comment?
}