feat: bring back nix support and fix the beaker-src

Co-authored-by: beeb5k <beebeeb5k@gmail.com>

README.md

@@ -47,6 +47,32 @@ On Alpine, `shadow` is needed for the user creation process during the install.
 # xbps-install -S libxml2-devel libcurl-devel
 ```
 
+### NixOS
+Add the flake to your inputs and import the module. That is all you need.
+Here's an example of using the modules in a flake:
+```
+# flake.nix
+{
+  inputs = {
+    omnisearch = {
+      url = "git+https://git.bwaaa.monster/omnisearch";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = { self, nixpkgs, omnisearch, ... }: {
+    nixosConfigurations.mySystem = nixpkgs.lib.nixosSystem {
+      modules = [
+        omnisearch.nixosModules.default
+        {
+          services.omnisearch.enable = true;
+        }
+      ];
+    };
+  };
+}
+```
+
 ### macOS (Homebrew)
 ```
 $ brew install libxml2 curl openssl pkg-config

flake.lock

@@ -0,0 +1,46 @@
+{
+  "nodes": {
+    "beaker-src": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1773884524,
+        "narHash": "sha256-1dnlofWaxI/YRID+WPz2jHZNDyloBubDt/bAQk9ePLU=",
+        "ref": "refs/heads/master",
+        "rev": "abc598baf15d6f8a4de395a27ba34b1e769558e1",
+        "revCount": 21,
+        "shallow": false,
+        "type": "git",
+        "url": "https://git.bwaaa.monster/beaker"
+      },
+      "original": {
+        "shallow": false,
+        "type": "git",
+        "url": "https://git.bwaaa.monster/beaker"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1773734432,
+        "narHash": "sha256-IF5ppUWh6gHGHYDbtVUyhwy/i7D261P7fWD1bPefOsw=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "cda48547b432e8d3b18b4180ba07473762ec8558",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "beaker-src": "beaker-src",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,76 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    beaker-src = {
+      url = "git+https://git.bwaaa.monster/beaker?shallow=0";
+      flake = false;
+    };
+  };
+
+  outputs =
+    {
+      self,
+      nixpkgs,
+      beaker-src,
+    }:
+    let
+      supportedSystems = [
+        "x86_64-linux"
+        "aarch64-linux"
+      ];
+      forAllSystems = nixpkgs.lib.genAttrs supportedSystems;
+    in
+    {
+      formatter = forAllSystems (system: nixpkgs.legacyPackages.${system}.nixfmt);
+      packages = forAllSystems (
+        system:
+        let
+          pkgs = import nixpkgs { inherit system; };
+
+          beaker = pkgs.stdenv.mkDerivation {
+            pname = "beaker";
+            version = "git";
+            src = beaker-src;
+            makeFlags = [
+              "INSTALL_PREFIX=$(out)/"
+              "LDCONFIG=true"
+            ];
+          };
+        in
+        {
+          default = pkgs.stdenv.mkDerivation {
+            pname = "omnisearch";
+            version = "git";
+            src = ./.;
+
+            buildInputs = [
+              pkgs.libxml2.dev
+              pkgs.curl.dev
+              pkgs.openssl
+              beaker
+            ];
+
+            preBuild = ''
+              makeFlagsArray+=(
+                "PREFIX=$out"
+                "CFLAGS=-Wall -Wextra -O2 -Isrc -I${pkgs.libxml2.dev}/include/libxml2"
+                "LIBS=-lbeaker -lcurl -lxml2 -lpthread -lm -lssl -lcrypto"
+              )
+            '';
+
+            installPhase = ''
+              mkdir -p $out/bin $out/share/omnisearch
+              install -Dm755 bin/omnisearch $out/bin/omnisearch
+              cp -r templates static -t $out/share/omnisearch/
+            '';
+
+            meta = {
+              description = "Lightweight metasearch engine in C";
+              platforms = pkgs.lib.platforms.linux;
+            };
+          };
+        }
+      );
+      nixosModules.default = import ./module.nix self;
+    };
+}