Build(flake): Enable direnv integration

[Direnv](1) in combination with some sort of [Nix integration](2)
— in this case [Nix-direnv](3) — allows for reproducible development
environments (and allows uncluttering the default PATH, as cargo and
other development tools are no longer needed in it).

Setting it up is rather easy, just see [Nix-direnv's install
instructions](4).

[1]: https://github.com/direnv/direnv
[2]: https://github.com/direnv/direnv/wiki/Nix
[3]: https://github.com/nix-community/nix-direnv
[4]: https://github.com/nix-community/nix-direnv#installation

.envrc

@@ -0,0 +1,7 @@
+use flake || use nix
+watch_file flake.nix
+
+if on_git_branch; then
+  echo && git status --short --branch &&
+  echo && git fetch --verbose
+fi

.gitignore

@@ -1,6 +1,10 @@
-target/
 userdata/
 trinitrix.log
 
+# build
+/target
+/result
+
 # IDE stuff
 .idea
+.direnv

flake.lock

@@ -0,0 +1,132 @@
+{
+  "nodes": {
+    "crane": {
+      "inputs": {
+        "flake-compat": [
+          "flake-compat"
+        ],
+        "flake-utils": [
+          "flake-utils"
+        ],
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "rust-overlay": [
+          "rust-overlay"
+        ]
+      },
+      "locked": {
+        "lastModified": 1688772518,
+        "narHash": "sha256-ol7gZxwvgLnxNSZwFTDJJ49xVY5teaSvF7lzlo3YQfM=",
+        "owner": "ipetkov",
+        "repo": "crane",
+        "rev": "8b08e96c9af8c6e3a2b69af5a7fa168750fcf88e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "ipetkov",
+        "repo": "crane",
+        "type": "github"
+      }
+    },
+    "flake-compat": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1673956053,
+        "narHash": "sha256-4gtG9iQuiKITOjNQQeQIpoIB6b16fm+504Ch3sNKLd8=",
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "rev": "35bb57c0c8d8b62bbfd284272c928ceb64ddbde9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1687709756,
+        "narHash": "sha256-Y5wKlQSkgEK2weWdOu4J3riRd+kV/VCgHsqLNTTWQ/0=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "dbabf0ca0c0c4bce6ea5eaf65af5cb694d2082c7",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1688829822,
+        "narHash": "sha256-hv56yK1fPHPt7SU2DboxBtdSbIuv9nym7Dss7Cn2jic=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "ed6afb10dfdfc97b6bcf0703f1bad8118e9e961b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "crane": "crane",
+        "flake-compat": "flake-compat",
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "flake-utils": [
+          "flake-utils"
+        ],
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1688870171,
+        "narHash": "sha256-8tD8fheWPa7TaJoxzcU3iHkCrQQpOpdMN+HYqgZ1N5A=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "5a932f10ac4bd59047d6e8b5780750ec76ea988a",
+        "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 +1,89 @@
+{
+  description = "A terminal UI client for the matrix chat protocol";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+
+    # inputs for following
+    flake-compat = {
+      url = "github:edolstra/flake-compat";
+      flake = false;
+    };
+    crane = {
+      url = "github:ipetkov/crane";
+      inputs = {
+        nixpkgs.follows = "nixpkgs";
+        flake-compat.follows = "flake-compat";
+        flake-utils.follows = "flake-utils";
+        rust-overlay.follows = "rust-overlay";
+      };
+    };
+    flake-utils = {
+      url = "github:numtide/flake-utils";
+      inputs = {};
+    };
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs = {
+        nixpkgs.follows = "nixpkgs";
+        flake-utils.follows = "flake-utils";
+      };
+    };
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    crane,
+    flake-utils,
+    rust-overlay,
+    ...
+  }:
+    flake-utils.lib.eachDefaultSystem (system: let
+      pkgs = import nixpkgs {
+        inherit system;
+        overlays = [(import rust-overlay)];
+      };
+
+      #rust-nightly = pkgs.rust-bin.selectLatestNightlyWith (toolchain: toolchain.default);
+      rust-stable = pkgs.rust-bin.stable.latest.default;
+
+      craneLib = (crane.mkLib pkgs).overrideToolchain rust-stable;
+
+      nativeBuildInputs = with pkgs; [
+        pkg-config
+      ];
+      buildInputs = with pkgs; [
+        openssl
+      ];
+
+      craneBuild = craneLib.buildPackage {
+        src = craneLib.cleanCargoSource ./.;
+
+        doCheck = true;
+        inherit nativeBuildInputs buildInputs;
+      };
+    in {
+      packages.default = craneBuild;
+
+      app.default = {
+        type = "app";
+        program = "${self.packages.${system}.default}/bin/trinitix";
+      };
+
+      devShells.default = pkgs.mkShell {
+        packages = with pkgs; [
+          nil
+          alejandra
+          statix
+          ltex-ls
+
+          rust-stable
+          rust-analyzer
+          cargo-edit
+        ];
+      };
+    });
+}
+# vim: ts=2
+