chore: switch to nix for development (closes #2)

This commit add nix support for development shells. The developer can
use `nix develop` to setup a complete and reproducable devleopment
environment using Nix.

.editorconfig

@@ -0,0 +1,8 @@
+root = true
+charset = utf-8
+end_of_line = lf
+
+[*.nix]
+indent_style = space
+indent_size = 2
+insert_final_newline = true

.tool-versions

@@ -1,2 +0,0 @@
-elixir 1.15.5
-erlang 26.0.2

README.md

@@ -2,53 +2,30 @@
 
 [![status-badge](https://ci.nikos.gg/api/badges/nikos/prymn/status.svg)](https://ci.nikos.gg/nikos/prymn)
 
-## Project dependencies
+## Development
 
-- Elixir 1.15
-- Erlang 24 or later
-- Rust (recent version)
-- protoc for protobufs version 3
+### Nix
 
-## Setup
+The best way to setup your development environment is with
+[Nix](https://nixos.org/download). As a pre-requisite, you need to install Nix
+and enable the experimental features **nix-command** and **flakes**.
 
-Some basic steps to setup the project and its dependencies.
+After installation,
 
-- Install [asdf](https://github.com/asdf-vm/asdf) (curl is also required)
-    - Using git: `git clone https://github.com/asdf-vm/asdf.git ~/.asdf`
-    - or, using paru, `paru -S asdf-vm`
-    - Add asdf to path: `source /opt/asdf-vm/asdf.{bash,zsh,fish}`, or `~/.asdf/asdf.{bash,zsh,fish}`
-- Install erlang
-    - `asdf plugin add erlang`
-    - `asdf install erlang 25`
-- Install elixir
-    - `asdf plugin add elixir`
-    - `asdf install elixir 1.15`
-- Install rust
-    - Optionally, set `CARGO_HOME` and `RUSTUP_HOME` to a XDG directory (e.g `~/.local/share/cargo` and `~/.local/share/rustup`)
-    - Arch: `pacman -S rustup` 
-    - Other: `curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh`
-    - Make sure to add `$HOME/.cargo/bin` (or `$CARGO_HOME`) to `PATH`
-    - `rustup toolchain install stable`
-    - `rustup default stable`
-    - `rustup component add clippy`
-    - `rustup component add rust-analyzer`
-    - `rustup component add rustfmt`
-- Install [protoc](https://grpc.io/docs/protoc-installation/) version 3
-    - Arch: `pacman -S protobuf`
-    - Debian: `apt install -y protobuf-compiler`
-- (Optional) Install [inotify-tools](https://github.com/inotify-tools/inotify-tools/wiki)
-    - Arch: `pacman -S inotify-tools`
-    - Debian: `apt install -y inotify-tools`
-- Setup elixir
-    - Install hex: `mix local.hex`
-    - `cd app && mix escript.install hex protobuf`
-    - `asdf reshim`
+- Clone the repo: `git clone git@git.nikos.gg:prymn/prymn.git && cd prymn`
+- Run `nix develop` or `nix develop -c $SHELL` to use your shell
+- Optionally, install [rust-analyzer](https://github.com/rust-lang/rust-analyzer/)
+    - With nix: `nix profile install nixpkgs#rust-analyzer`
 
-## Preparing for development
+### Manual
 
-### Elixir app
+Alternatively, you can install all the dependencies manually. Here's a (maybe
+incomplete) list of packages to install:
 
-- `cd app`
-- Start the database: `docker-compose up -d`
-- `mix setup`
-- `mix phx.server`
+- gcc
+- inotify-tools
+- Elixir (v1.16)
+- Erlang (OTP 26)
+- protobuf
+- protoc-gen-elixir (via `mix escript.install hex protobuf`)
+- Rust stable toolchain (v1.72)

flake.lock

@@ -0,0 +1,96 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1681202837,
+        "narHash": "sha256-H+Rh19JDwRtpVPAWp64F+rlEtxUWBAQW28eAi3SRSzg=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "cfacdce06f30d2b68473a46042957675eebb3401",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1695318763,
+        "narHash": "sha256-FHVPDRP2AfvsxAdc+AsgFJevMz5VBmnZglFUMlxBkcY=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "e12483116b3b51a185a33a272bf351e357ba9a99",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1681358109,
+        "narHash": "sha256-eKyxW4OohHQx9Urxi7TQlFBTDWII+F+x2hklDOQPB50=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "96ba1c52e54e74c3197f4d43026b3f3d92e83ff9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs_2"
+      },
+      "locked": {
+        "lastModified": 1696039808,
+        "narHash": "sha256-7TbAr9LskWG6ISPhUdyp6zHboT7FsFrME5QsWKybPTA=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "a4c3c904ab29e04a20d3a6da6626d66030385773",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
+      }
+    },
+    "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 +1,43 @@
+{
+  description = "Prymn";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    rust-overlay.url = "github:oxalica/rust-overlay";
+  };
+
+  outputs = { self, nixpkgs, rust-overlay }:
+    let
+      #supportedSystems = [ "x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
+      system = "x86_64-linux";
+
+      overlays = [
+        (final: prev: {
+          elixir = prev.beam.packages.erlang_26.elixir_1_15;
+          elixir-ls = prev.beam.packages.erlang_26.elixir-ls.override { elixir = final.elixir; };
+          protoc-gen-elixir = prev.callPackage ./protoc-gen-elixir.nix { elixir = final.elixir; };
+        })
+
+        (import rust-overlay)
+      ];
+
+      pkgs = import nixpkgs {
+        inherit system overlays;
+      };
+    in
+    {
+      devShells.${system}.default = with pkgs; mkShell {
+        packages = [
+          elixir
+          elixir-ls
+          protobuf
+          protoc-gen-elixir
+          rust-bin.stable.latest.default
+        ] ++ lib.optionals stdenv.isLinux [ inotify-tools ];
+
+        inputsFrom = [
+          protoc-gen-elixir
+        ];
+      };
+    };
+}

protoc-gen-elixir.nix

@@ -0,0 +1,28 @@
+{ elixir, beamPackages, fetchFromGitHub }:
+
+beamPackages.mixRelease rec {
+  pname = "protoc-gen-elixir";
+
+  version = "v0.12.0";
+
+  inherit elixir;
+
+  src = fetchFromGitHub {
+    owner = "elixir-protobuf";
+    repo = "protobuf";
+    rev = "ce9a031a5cae97336d4674670d313d54f1f80bf6";
+    sha256 = "wLU3iM9jI/Zc96/HfPUjNvjteGryWos6IobIb/4zqpw=";
+  };
+
+  mixFodDeps = beamPackages.fetchMixDeps {
+    pname = "mix-deps-${pname}";
+    inherit src version;
+    sha256 = "H7yiBHoxuiqWcNbWwPU5X0Nnv8f6nM8z/ZAfZAGPZjE=";
+  };
+
+  installPhase = ''
+    mix escript.build
+    mkdir -p $out/bin
+    mv ./protoc-gen-elixir $out/bin
+  '';
+}