# Source: https://github.com/sodiboo/system/blob/b63c7b27f49043e8701b3ff5e1441cd27d5a2fff/sharkey/module.nix
{
  config,
  lib,
  pkgs,
  vhackPackages,
  ...
}: let
  cfg = config.vhack.sharkey;

  createDB = cfg.database.host == "127.0.0.1" && cfg.database.createLocally;

  settingsFormat = pkgs.formats.yaml {};
  configFile = settingsFormat.generate "sharkey-config.yml" cfg.settings;
in {
  options.vhack.sharkey = {
    enable = lib.mkEnableOption "sharkey";

    fqdn = lib.mkOption {
      description = "The fully qualified domain name of this instance.";
      type = lib.types.str;
      example = "sharkey.shonk.social";
    };

    package = lib.mkOption {
      type = lib.types.package;
      default = vhackPackages.sharkey;
      defaultText = lib.literalExpression "vhackPackages.sharkey";
      description = "Sharkey package to use.";
    };

    dataDirectory = lib.mkOption {
      type = lib.types.path;
      default = "/var/lib/sharkey";
      description = "The directory where sharkey stores it's data.";

      # This is already set in the package.
      readOnly = true;
    };

    database = {
      createLocally = lib.mkOption {
        description = "Whether to enable local db creation.";
        type = lib.types.bool;
        default = true;
      };

      host = lib.mkOption {
        type = lib.types.str;
        default = "127.0.0.1";
        description = "The database host.";
      };

      port = lib.mkOption {
        type = lib.types.port;
        default = 5432;
        description = "The database port.";
      };

      name = lib.mkOption {
        type = lib.types.str;
        default = "sharkey";
        description = "The database name in postgresql.";
      };
    };

    settings = lib.mkOption {
      inherit (settingsFormat) type;
      default = {};
      description = ''
        Configuration for Sharkey, see
        <link xlink:href="https://activitypub.software/TransFem-org/Sharkey/-/blob/develop/.config/example.yml"/>
        for supported settings.
      '';
    };
  };

  config = lib.mkIf cfg.enable {
    environment.systemPackages = [cfg.package];

    vhack = {
      nginx.enable = true;

      sharkey.settings = {
        id = "aidx";

        url = "https://${cfg.fqdn}/";
        port = 5312;

        db = {
          inherit (cfg.database) host port;
          db = cfg.database.name;
          user = cfg.database.name;
          pass = "sharkey-password";
        };
        redis = {
          path = config.services.redis.servers."sharkey".unixSocket;
        };
      };

      persist.directories = [
        {
          directory = "${config.services.redis.servers."sharkey".settings.dir}";
          user = "sharkey";
          group = "redis-sharey";
          mode = "0770";
        }
        {
          directory = "${cfg.dataDirectory}";
          user = "sharkey";
          group = "sharkey";
          mode = "0770";
        }
      ];
    };

    services = {
      nginx.virtualHosts."${cfg.fqdn}" = {
        locations."/" = {
          proxyPass = "http://127.0.0.1:${toString cfg.settings.port}";
          proxyWebsockets = true;
        };

        # proxy_set_header Host $host;
        # proxy_http_version 1.1;
        # proxy_redirect off;
        #
        # # If it's behind another reverse proxy or CDN, remove the following.
        # proxy_set_header X-Real-IP $remote_addr;
        # proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        # proxy_set_header X-Forwarded-Proto https;
        #
        # # For WebSocket
        # proxy_set_header Upgrade $http_upgrade;
        # proxy_set_header Connection $connection_upgrade;
        #
        # # Cache settings
        # proxy_cache cache1;
        # proxy_cache_lock on;
        # proxy_cache_use_stale updating;
        # proxy_force_ranges on;
        # add_header X-Cache $upstream_cache_status;

        enableACME = true;
        forceSSL = true;
      };

      postgresql = lib.mkIf createDB {
        enable = true;
        settings.port = cfg.database.port;
        ensureUsers = [
          {
            inherit (cfg.database) name;
            ensureDBOwnership = true;
          }
        ];
        ensureDatabases = [cfg.database.name];
      };

      redis = {
        servers."sharkey" = {
          enable = true;

          user = "sharkey";

          # Disable TCP listening. (We have a UNIX socket)
          port = 0;
          bind = null;

          settings = {
            protected-mode = true;
            enable-protected-configs = false;
            enable-debug-command = false;
            enable-module-command = false;

            supervised = "systemd";
            stop-writes-on-bgsave-error = true;
            sanitize-dump-payload = "clients";
          };
        };
      };
    };

    systemd.services.postgresql.postStart = ''
      $PSQL -tAc "ALTER ROLE ${cfg.database.name} WITH ENCRYPTED PASSWORD 'sharkey-password';"
    '';

    systemd.services.sharkey = {
      requires =
        [
          "redis-sharkey.service"
          "network-online.target"
        ]
        ++ lib.optionals createDB ["postgresql.service"];

      after =
        [
          "redis-sharkey.service"
          "network-online.target"
        ]
        ++ lib.optionals createDB ["postgresql.service"];

      wantedBy = ["multi-user.target"];

      environment = {
        MISSKEY_CONFIG_YML = "${configFile}";
        NODE_ENV = "production";
      };

      serviceConfig = {
        Type = "simple";

        StateDirectory = "sharkey";
        StateDirectoryMode = "0700";
        CacheDirectory = "sharkey";
        RuntimeDirectory = "sharkey";
        RuntimeDirectoryMode = "0700";
        ExecStart = "${lib.getExe cfg.package} migrateandstart";

        TimeoutSec = 60;
        Restart = "no";

        StandardOutput = "journal";
        StandardError = "journal";
        SyslogIdentifier = "sharkey";

        User = "sharkey";
        Group = "sharkey";

        # Bind standard privileged ports
        AmbientCapabilities = [];
        CapabilityBoundingSet = [];

        ReadWritePaths = [
          "${cfg.dataDirectory}"
        ];

        # Hardening
        DeviceAllow = [""];
        LockPersonality = true;
        # Probably needed for v8's JIT (crashes with it on).
        MemoryDenyWriteExecute = false;
        PrivateDevices = true;
        PrivateUsers = true;
        ProcSubset = "pid";
        PrivateTmp = true;
        ProtectClock = true;
        ProtectControlGroups = true;
        ProtectHome = true;
        ProtectHostname = true;
        ProtectKernelLogs = true;
        ProtectKernelModules = true;
        ProtectKernelTunables = true;
        ProtectProc = "invisible";
        ProtectSystem = "strict";
        RestrictAddressFamilies = [
          "AF_UNIX" # Local communication                        unix(7)
          "AF_INET" # IPv4 Internet protocols                    ip(7)
          "AF_INET6" # IPv6 Internet protocols                   ipv6(7)
          # Needed for nodes `os.networkInterfaces()` function.
          "AF_NETLINK" # Kernel user interface device            netlink(7)
        ];
        RestrictNamespaces = true;
        RestrictRealtime = true;
        RestrictSUIDSGID = true;
        SystemCallArchitectures = "native";
        SystemCallFilter = [
          "@system-service"
          "~@privileged"
          "~@mount"
        ];
        UMask = "0077";
      };
    };

    users = {
      groups.sharkey = {
        gid = config.vhack.constants.ids.gids.sharkey;
      };
      users.sharkey = {
        isSystemUser = true;
        group = "sharkey";
        uid = config.vhack.constants.ids.uids.sharkey;
        home = cfg.package;
        packages = [cfg.package];
      };

      groups.redis-sharkey = {
        gid = config.vhack.constants.ids.gids.redis-sharkey;
      };
      users.redis-sharkey = {
        group = "redis-sharkey";
        uid = config.vhack.constants.ids.uids.redis-sharkey;
      };
    };
  };
}