Add initial prototype of NixOS module

Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>

flake.lock

@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1766736597,
+        "narHash": "sha256-BASnpCLodmgiVn0M1MU2Pqyoz0aHwar/0qLkp7CjvSQ=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "f560ccec6b1116b22e6ed15f4c510997d99d5852",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-25.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,29 @@
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-25.11";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+        let
+	  pkgs = import nixpkgs { inherit system; };
+	  joann-pupper-bot = pkgs.crystal.buildCrystalPackage {
+	    pname = "joann-pupper-bot";
+	    version = "0.1.0";
+	    src = ./.;
+            lockFile = ./shard.lock;
+	    shardsFile = ./shards.nix;
+	    format = "shards";
+	    buildInputs = [pkgs.sqlite];
+	  };
+        in
+          {
+            packages = { inherit joann-pupper-bot; };
+            defaultPackage = joann-pupper-bot;
+          }
+    ) // {
+      nixosModules.joann-pupper-bot = import ./module.nix;
+    };
+}

module.nix

@@ -0,0 +1,71 @@
+{ config, lib, pkgs, ... }:
+with lib;
+let cfg = config.services.joann-pupper-bot; in {
+  options.services.joann-pupper-bot = {
+    enable = mkEnableOption "Joann's Pupper Bot";
+    user = mkOption {
+      type = types.str;
+      default = "joann-pupper-bot";
+      example = "myuser";
+      description = "Which user should be running Joann's Pupper Bot";
+    };
+    group = mkOption {
+      type = types.str;
+      default = "joann-pupper-bot";
+      example = "mygroup";
+      description = "Which group should be running Joann's Pupper Bot";
+    };
+    stateDir = mkOption {
+      type = types.str;
+      default = "/var/lib/joann-pupper-bot";
+      description = "Which directory the bot should use for storage";
+    };
+    config.token = mkOption {
+      type = types.str;
+      description = "Bot token used for Telegram";
+    };
+    config.subreddits = mkOption {
+      type = types.listOf types.str;
+      description = "Which subreddits to draw images from";
+      default = ["rarepuppers"];
+    };
+    config.sendCron = mkOption {
+      type = types.str;
+      description = "cron-style string determining when images should be sent";
+      default = "*/30 8-21 * * *";
+    };
+    config.refreshCron = mkOption {
+      type = types.str;
+      description = "cron-style string determining when the bot polls Reddit for new images";
+      default = "*/15 * * * *";
+    };
+    config.recipients = mkOption {
+      type = types.listOf types.int;
+      description = "Telegram chat IDs for each of the image recipients";
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.tmpfiles.rules = [
+      "d '${cfg.stateDir}' 0750 ${cfg.user} ${cfg.group} - -"
+    ];
+    systemd.services.joann-pupper-bot = {
+      description = "Joann's Pupper Bot";
+      wantedBy = [ "multi-user.target" ];
+
+      preStart =
+        let
+          yml = generators.toYAML {} cfg.config;
+          configFile = pkgs.writeText "config.yaml" yml;
+        in
+        ''
+          cp -f '${configFile}' '${cfg.stateDir}'/config.yaml
+        '';
+
+      serviceConfig = {
+	Type = "oneshot";
+        ExecStart = "/bin/sh -c :";
+      };
+    };
+  };
+}

shards.nix

@@ -0,0 +1,27 @@
+{
+  "cron_parser" = {
+    url = "https://github.com/kostya/cron_parser.git";
+    rev = "v0.4.0";
+    sha256 = "17fgg2nvyx99v05l10h6cnxfr7swz8yaxhmnk4l47kg2spi8w90a";
+  };
+  "cron_scheduler" = {
+    url = "https://github.com/kostya/cron_scheduler.git";
+    rev = "v0.4.0";
+    sha256 = "0jd0maw1h87hjgjpqhbwxb4yz83g8shlrwfivyf0sd6x3l5lspns";
+  };
+  "db" = {
+    url = "https://github.com/crystal-lang/crystal-db.git";
+    rev = "v0.14.0";
+    sha256 = "1s67fs5abzgg2yyjsm2la967mk881i91h8jdnal072fb9qh9wr58";
+  };
+  "sqlite3" = {
+    url = "https://github.com/crystal-lang/crystal-sqlite3.git";
+    rev = "v0.22.0";
+    sha256 = "1lc8ixnzjx8nsp96qj9yxmfk7g334id8v87g3h5bwgkhkbx5ghqn";
+  };
+  "telepathy" = {
+    url = "https://dev.danilafe.com/Crystal-Bots/telepathy";
+    rev = "v0.2.0";
+    sha256 = "1zhjlpa31vldgd9f6l1hdfj7a97hlqkxkvxzisfs2zfnvc86aiyc";
+  };
+}