Convert to nix flake; fix systemd service to use nix run

- Add flake.nix with nixos-unstable nixpkgs, devShell and slopbot package
- Add flake.lock
- Update .envrc to 'use flake .'
- Update slopbot.service: use 'nix run' instead of nix-shell, remove
  broken sandbox options (ProtectHome, InaccessiblePaths, ProtectSystem,
  ReadOnlyPaths, ReadWritePaths, PrivateTmp) that block nix store access
- Delete shell.nix
- Add 'result' to .gitignore
- Restore openai to requirements.txt (was accidentally dropped)

1 files changed, 34 insertions, 0 deletions

diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..7a028d0
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,34 @@
+{
+  description = "slopbot - Zulip bot with stock price lookups and LLM replies";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  };
+
+  outputs = { self, nixpkgs }:
+    let
+      system = "x86_64-linux";
+      pkgs = nixpkgs.legacyPackages.${system};
+
+      pythonEnv = pkgs.python3.withPackages (ps: [
+        ps.zulip
+        ps.yfinance
+        ps.openai
+        ps.requests
+      ]);
+    in
+    {
+      devShells.${system}.default = pkgs.mkShell {
+        buildInputs = [ pythonEnv ];
+        shellHook = ''
+          echo "slopbot dev shell ready"
+          echo "Run: python main.py"
+        '';
+      };
+
+      packages.${system}.default = pkgs.writeShellScriptBin "slopbot" ''
+        cd /home/ben/src/bsima/slopbot
+        exec ${pythonEnv}/bin/python ${./main.py}
+      '';
+    };
+}