Add nix support (#45)

flake.nix

@@ -0,0 +1,56 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = {self, nixpkgs, flake-utils}: flake-utils.lib.eachDefaultSystem (system:
+    let
+      pkgs = import nixpkgs { inherit system; };
+    in
+  {
+    packages.default = pkgs.stdenv.mkDerivation
+    {
+      name = "yandex-download-music";
+      version = "v1.5";
+      src = ./.;
+
+      nativeBuildInputs = [
+        pkgs.makeWrapper
+      ];
+
+      buildInputs = [
+        pkgs.perl
+        (pkgs.buildEnv {
+          name = "rt-perl-deps";
+          paths = with pkgs.perlPackages; (requiredPerlModules [
+              FileUtil
+              MP3Tag
+              GetoptLongDescriptive LWPUserAgent
+              LWPProtocolHttps
+              HTTPCookies
+              MozillaCA
+          ]);
+        })
+      ];
+
+      installPhase = ''
+        mkdir -p $out/bin
+        cp src/ya.pl $out/bin/ya-music
+        # cat src/ya.pl | perl -p -e "s/basename\(__FILE__\)/'ya-music'/g" > $out/bin/ya-music
+        # chmod +x $out/bin/ya-music
+      '';
+
+      postFixup = ''
+        # wrapProgram will rename ya-music into .ya-music-wrapped
+        # so replace all __FILE__ calls
+        substituteInPlace $out/bin/ya-music \
+          --replace "basename(__FILE__)" "'ya-music'"
+
+        wrapProgram $out/bin/ya-music \
+          --prefix PERL5LIB : $PERL5LIB
+      '';
+    };
+  });
+
+}