{config, pkgs, inputs, system, ...}:


let
  unstable = import inputs.nixpkgs-unstable {
    inherit system;
    overlays = [ (self: super: rec {
      beamPackages = super.beam.packagesWith super.erlang_nox;
      elixir = beamPackages.elixir_1_13;
    }) ];
  };
  staticDir = "/var/lib/akkoma/static";
  inherit ((pkgs.formats.elixirConf {}).lib) mkAtom mkTuple;
in
{
  sops.secrets = {
    "akkoma/keyBase" = {};
    "akkoma/signingSalt" = {};
    "akkoma/jokenDefaultSigner" = {};
  };

  containers.pleroma = {
    autoStart = true;
    privateNetwork = true;
    
    hostAddress = "192.168.42.30";
    localAddress = "192.168.42.31";
    hostAddress6 = "fd00::42:30";
    localAddress6 = "fd00::42:31";

    bindMounts."/sops" = {
      hostPath = "/run/secrets/akkoma";
      isReadOnly = true;
    };

    config = {pkgs, config, ...}: {

      # generating the manual will fail when mixing nixos channels,
      # so disable it here or this won't build at all.
      documentation.enable = false;

      imports = [
        ("${inputs.nixpkgs-unstable}/nixos/modules/services/web-apps/akkoma.nix")
      ];

      # the pleroma_ctl wrapper uses pkgs.elixir, which without this is not the same
      # as akkoma's elixir
      nixpkgs.overlays = [
        (self: super: {
          elixir = unstable.beamPackages.elixir_1_13;
        })
      ];

      system.stateVersion = "22.11";

      services.akkoma = {
        enable = true;

        package = unstable.akkoma;
        frontends = {
          primary = {
            package = unstable.akkoma-frontends.akkoma-fe;
            name = "pleroma-fe";
            ref = "stable";
          };
          admin = {
            package = unstable.akkoma-frontends.admin-fe;
            name = "admin-fe";
            ref = "stable";
          };
        };

        extraStatic."static/terms-of-service.html" = pkgs.writeText "terms-of-service-html" ''
          <p>toki!</p>
          <p>lawa kepeken pi tomo akkoma ni li lili: sina li mi la, sina ken kepeken e tomo ni.</p>
        '';

        config = {
          ":pleroma"."Pleroma.Web.Endpoint" = {
            "url" = { host = "pleroma.stuebinm.eu"; scheme = "https"; port = 443; };
            "http" = { ip = "::"; port = 4000; };
            secret_key_base._secret = "/sops/keyBase";
            signing_salt._secret = "/sops/signingSalt";
          };
          ":joken".":default_signer"._secret = "/sops/jokenDefaultSigner";

          ":pleroma" = {
            ":instance" = {
              name = "Pleroma";
              limit = 5000;
              registrations_open = false;
              federating = true;
              healthcheck = true;
              allow_relay = true;
              description = "a test instance";
              email = "dings@dings";
            };
            ":media_proxy" = {
              enabled = false;
              redirect_on_failure = true;
            };
            ":mrf_simple" = {
              reject = [
                (mkTuple ["mastodon.social" "spam"])
                (mkTuple ["mstdn.social" "scraping for language model"])
                (mkTuple ["uden.ai" "lol"])
              ];
            };
            ":mrf".policies = map mkAtom [
              "Pleroma.Web.ActivityPub.MRF.SimplePolicy"
            ];
            "Pleroma.Upload" = {
              filters = map mkAtom [
                "Pleroma.Upload.Filter.Exiftool"
                "Pleroma.Upload.Filter.AnonymizeFilename"
                "Pleroma.Upload.Filter.Dedupe"
              ];
            };
            # "Pleroma.Uploaders.Local".uploads = "/var/lib/akkoma/uploads";
            "Pleroma.Repo" = {
              adapter = "Ecto.Adapters.Postgres";
              username = "pleroma";
              database = "pleroma";
              socket_dir = "/run/postgresql";
              pool_size = 10;
              # prepare = ":named";
              show_sensitive_data_on_connection_error = true;
              parameters = { plan_cache_mode = "force_custom_plan"; };
            };
            ":database".run_enabled = false;
            ":configurable_from_database" = false;
            ":instance".static_dir = "/var/lib/akkoma/static";
          };
        };
      };

      systemd.services.akkoma = {
        path = [ pkgs.exiftool ];
        bindsTo = [ "akkoma-static.service" ];
        after = [ "akkoma-static.service" ];
      };

      # symlink the parts of the static dir that are inside the nix store,
      # so I can still have imperatively defined emojis etc.
      # (for some reason the module doesn't do that)
      systemd.services.akkoma-static = {
        description = "Akkoma static dir wrangling";
        unitConfig.PropagatesReloadTo = [ "akkoma.service" ];
        path = [ pkgs.coreutils ];
        serviceConfig = {
          Type = "oneshot";
          RemainAfterExit = true;
        };
        script = with pkgs.lib; ''
          ${concatStringsSep "\n" (mapAttrsToList (key: val: ''
            mkdir -p ${staticDir}/frontends/${escapeShellArg val.name}/
            ln -sfT ${escapeShellArg val.package} ${staticDir}/frontends/${escapeShellArg val.name}/${escapeShellArg val.ref}
          '') config.services.akkoma.frontends)}
          ${optionalString (config.services.akkoma.extraStatic != null)
            (concatStringsSep "\n" (mapAttrsToList (key: val: ''
            mkdir -p "${staticDir}/$(dirname ${escapeShellArg key})"
            ln -sfT ${escapeShellArg val} ${staticDir}/${escapeShellArg key}
          '') config.services.akkoma.extraStatic))}
        '';
      };

      services.postgresql = {
        enable = true;
        package = pkgs.postgresql_12;

        ensureDatabases = [ "pleroma" ];
        ensureUsers = [ {
          name = "pleroma";
          ensurePermissions."DATABASE pleroma" = "ALL PRIVILEGES";
        } ];

        # give pleroma access. must be done with lib.mkForce, for some reason
        authentication = pkgs.lib.mkForce ''
          # Generated file; do not edit!
          local all all              trust
          host  pleroma akkoma ::1/128      trust
        '';

        # this is basically legacy. even if I ever reset the database,
        # the initDb option of the akkoma module probably does about this.
        initialScript = pkgs.writeScript "postgres-pleroma-initial" ''
          CREATE USER pleroma;
          CREATE DATABASE pleroma OWNER pleroma;
          \c pleroma;
          --Extensions made by ecto.migrate that need superuser access
          CREATE EXTENSION IF NOT EXISTS citext;
          CREATE EXTENSION IF NOT EXISTS pg_trgm;
          CREATE EXTENSION IF NOT EXISTS "uuid-ossp";
        '';
      };

      networking.firewall.allowedTCPPorts = [ 4000 ];

      environment.etc."resolv.conf".text =
        "nameserver 1.1.1.1";
    };
  };

  # give the container access to the external internet (necessary for
  # fetching content from other instances). Doesn't appear to work with
  # IPv6, though ...
  networking.nat = {
    enable = true;
    internalInterfaces = [ "ve-pleroma" ];
    externalInterface = "ens3";
  };

  services.nginx.virtualHosts."pleroma.stuebinm.eu" = {
    forceSSL = true;
    enableACME = true;

    locations."/" = {
      proxyPass = "http://[${config.containers.pleroma.localAddress6}]:4000";
      proxyWebsockets = true;
      # these headers are in the example config in the NixOS manual.
      # take some time to figure out what they all do, and if these
      # are necessary
      extraConfig = ''
        add_header 'Access-Control-Allow-Origin' '*' always;
        add_header 'Access-Control-Allow-Methods' 'POST, PUT, DELETE, GET, PATCH, OPTIONS' always;
        add_header 'Access-Control-Allow-Headers' 'Authorization, Content-Type, Idempotency-Key' always;
        add_header 'Access-Control-Expose-Headers' 'Link, X-RateLimit-Reset, X-RateLimit-Limit, X-RateLimit-Remaining, X-Request-Id' always;
        if ($request_method = OPTIONS) {
            return 204;
        }
        add_header X-XSS-Protection "1; mode=block";
        add_header X-Permitted-Cross-Domain-Policies none;
        add_header X-Frame-Options DENY;
        add_header X-Content-Type-Options nosniff;
        add_header Referrer-Policy same-origin;
        add_header X-Download-Options noopen;
        client_max_body_size 16m;
      '';
    };
  };
}