flake.nix

{
  description = "A flake for building and developing uml-cpp with nix";

  inputs.nixpkgs.url = "github:NixOS/nixpkgs/release-24.05";
  inputs.flake-utils.url = "github:numtide/flake-utils";
  inputs.egm.url = "github:nemears/egm";

  outputs = { self, nixpkgs, flake-utils, egm }:
    flake-utils.lib.eachDefaultSystem
      (system:
        let 
          pkgs = nixpkgs.legacyPackages.${system};
          mkUmlCpp = { src } : 
          let
             # this is how im reading the version from the meson.build might not be most efficient but works 
             currentVersion = pkgs.runCommandWith {
               name = "getVersion";
               derivationArgs.nativBuildInputs = [ src ] ;
             } "grep -Po  \"(?<=version: ').*(?=')\" ${src}/meson.build > $out";
             version = builtins.readFile currentVersion;
           in
           pkgs.stdenv.mkDerivation {
            inherit src;
            name = "uml-cpp";
            nativeBuildInputs = with pkgs; [ pkg-config ];
            installPhase = ''
              mkdir -p $out/lib/pkgconfig $out/include
              cp -r $src/include/uml $out/include
              echo "prefix=$out
              
              Name: uml
              Description: uml modeling C++ api
              Version: ${version}
              Cflags: -I$out/include" > $out/lib/pkgconfig/uml-cpp.pc                
            '';
          };
 
          # function to create uml-cpp derivation from certain source
          mkUmlCppPre05 = { src , version } : pkgs.stdenv.mkDerivation {
            inherit src;
            name = "uml-cpp";
            nativeBuildInputs = with pkgs; [pkg-config];
            buildInputs = with pkgs; [cmake pkg-config clang gnumake coreutils yaml-cpp egm.outputs.packages.${system}.default ];
            cmakeFlags = [
              "-DUML_BUILD_TESTS=OFF"
              "-DCMAKE_BUILD_TYPE=RELEASE"
            ];
            installPhase = 
            ''
              mkdir -p $out/lib/pkgconfig $out/include
              cp -r libuml.so $out/lib
              cp -r $src/include/uml $out/include
              touch $out/lib/pkgconfig/uml-cpp.pc
              echo "prefix=$out

              Name: uml
              Description: uml modeling C++ api
              Version: ${version}
              Libs: -L$out/lib -luml
              Cflags: -I$out/include" > $out/lib/pkgconfig/uml-cpp.pc

              export PKG_CONFIG_PATH=PKG_CONFIG_PATH:$out/lib/pkgconfig
            '';
          };
        in
        {
          # dev shell for nix develop (good for commandline dev)
          devShells.default = (pkgs.mkShell.override { stdenv = pkgs.clangStdenv; }) {
            packages = with pkgs; [ 
              # build dependencies
              clang
              meson
              ninja
              pkg-config
              gtest
              yaml-cpp
              egm.outputs.packages.${system}.default

              # dev dependencies
              websocketpp 
              asio
              openssl

              # debug dependencies
              gdb
              valgrind
            ];
            stdenv = pkgs.clangStdenv;
          };

          packages = {
            uml-cpp_0_4_2= pkgs.stdenvNoCC.mkDerivation {
              src = pkgs.fetchurl {
                url = "https://github.com/nemears/uml-cpp/releases/download/v0.4.2/uml-cpp-0.4.2.tar.gz";
                hash = "sha256-82tcL2GUFo/MH3cJTch7dZINF/54GPAXoMYEzHXHWLo=";
              };
              name = "uml-cpp";
              installPhase = ''
                mkdir $out
                cp -r . $out
              '';
            };
            uml-cpp = mkUmlCpp {
              src = ./.;
            };
            uml-cpp_0_3_5 = mkUmlCppPre05 {
              src = pkgs.fetchFromGitHub {
                owner = "nemears";
                repo = "uml-cpp";
                rev = "v0.3.5";
                hash = "sha256-HzzOe+9s67LwWlHWYIa+vxbWMBVCsVY7RXfFDkElwpY=";
              };
              version = "0.3.5";
            };
            default = self.packages.${system}.uml-cpp;
          };
          overlay = final : prev: {
            uml-cpp = self.packages.${system}.uml-cpp;
            uml-cpp_0_3_5 = self.packages.${system}.uml-cpp_0_3_5;
          };
        }
      );
}