{ config, pkgs, lib, ... }: with lib; let
  rust-analyzer = if (pkgs ? rust-analyzer-nightly && config.class ? dev) then pkgs.rust-analyzer-nightly else pkgs.rust-analyzer;
  rust-sdk = with pkgs; if config.class ? dev then
    symlinkJoin
      {
        name = "nvim-fenix";
        paths = [
          (fenix.latest.withComponents [
            "cargo"
            "clippy-preview"
            "rust-src"
            "rust-std"
            "rustc"
            "rustfmt-preview"
          ])
          cargo-watch
        ];
      } else symlinkJoin { name = "nvim-rust"; paths = [ rustc cargo rustfmt clippy cargo-watch ]; };
in
{

  programs.neovim = {

    # https://github.com/nix-community/home-manager/blob/master/modules/programs/neovim.nix
    enable = true;
    vimAlias = true;
    withNodeJs = true;
    extraPackages = with pkgs; [ fzf xclip fish ];
    plugins = with pkgs.vimPlugins; [
      vim-fugitive
      neogit
      diffview-nvim
      vim-airline
      zephyr-nvim
      vim-nix
      vim-toml
      elm-vim
      vim-markdown
      split-term-vim
      #  vim-grammarous
      markdown-preview-nvim
      rainbow
      nvim-web-devicons
      fzf-vim
      editorconfig-nvim
      vim-vsnip
      # tmuxline-vim
      nvim-dap
      nvim-dap-ui
      nvim-notify
      nvim-cmp
      cmp-nvim-lsp
      cmp-nvim-lua
      cmp-buffer
      cmp-path
      cmp-spell
      cmp-vsnip
      cmp-conventionalcommits
      cmp-calc
      cmp-cmdline
      rustaceanvim
      (if config.programs.neovim.package.version == "0.10.0" then throw "lsp-inlayhints-nvim may be removed" else lsp-inlayhints-nvim) # https://github.com/mrcjkb/rustaceanvim/discussions/46#discussioncomment-7620822
      cmp-conventionalcommits
      cmp-calc
      cmp-cmdline
      rustaceanvim
      plenary-nvim
      crates-nvim
      nvim-lspconfig
      telescope-nvim
      telescope-undo-nvim
      oil-nvim
      distant-nvim
    ];
    extraLuaConfig =
      let
        paths = {
          lldb = pkgs.lldb;
          rust_analyzer = rust-analyzer;
        };
        pathsLua = pkgs.writeTextFile {
          name = "nvim-deps.lua";
          text = ''
            return {
             ${concatStringsSep ",\n " (mapAttrsToList (name: path: ''${name}_path = "${path}"'') paths)}
            }
          '';
        };
        confDir = lib.sourceFilesBySuffices ./. [ "lua" "vim" ];
      in
      with lib; ''
        vim.cmd [[source ${confDir}/init.vim]]
        package.path = package.path .. ";${confDir}/?.lua;${pathsLua};"  
        dofile("${confDir}/init.lua")
      '';
  };
  programs.git.ignores = [ ".nvim_session" ];
  xdg.configFile."nvim/coc-settings.json".text =
    let
      preferProjectEnv = binName: alternate: pkgs.writeShellScript "${binName}-switcher" ''
        if command -v ${binName}; then
          ${binName} ''${@}
        else
          ${alternate} ''${@}
        fi
      '';
      addSDK = { name, lsp, sdk }: with pkgs; runCommandLocal name
        {
          nativeBuildInputs = [ makeWrapper ];
        } ''
        makeWrapper ${lsp} $out \
         --prefix PATH : ${lib.makeBinPath sdk} 
      '';
    in
    builtins.toJSON {
      python = {
        pythonPath = preferProjectEnv "python3" (pkgs.python3 + "/bin/python3");
        formatting.autopep8Path = "${pkgs.python3Packages.autopep8}/bin/autopep8";
      };
      pyright = {
        enable = true;
      };
      # https://rust-analyzer.github.io/manual.html
      rust-analyzer = {
        cargo = {
          allFeatures = true;
          runBuildScripts = true;
          autoreload = true;
        };
        completion = {
          autoimport.enable = true;
          privateEditable.enable = true;
          fullFunctionSignatures.enable = true; # https://github.com/rust-lang/rust-analyzer/pull/15582
          snippets = {
            "return Err(..)" = {
              postfix = [ "reterr" ];
              body = ''return Err($${receiver});'';
              description = "return expression as Err";
              scope = "expr";
            };
            "format!(..)" = {
              postfix = [ "fmt" ];
              body = ''format!($${receiver})'';
              description = "use receiver as format string";
              scope = "expr";

            };
            "wrap { .. }" = {
              postfix = [ "brace" "wrap" ];
              body = ''{$${receiver}}'';
              description = "wrap this type in { .. }";
              scope = "expr";
            };
            "async move { .. }" = {
              postfix = [ "asyncm" ];
              body = ''async move {$${receiver}}'';
              description = "wrap this type in async move { .. }";
              scope = "expr";
            };
            "try { .. }" = {
              postfix = [ "try" ];
              body = ''let result: Result<_,_> = try {$${receiver}};'';
              description = "wrap this type in try { .. }";
              scope = "expr";
            };
            "while let Some(item) = { .. } {}" = {
              postfix = [ "letwhile" ];
              body = ''while let Some(item) = $${receiver} {}'';
              description = "wrap this type in while let Some";
              scope = "expr";
            };
            "let $x = $x.clone()" = {
              postfix = [ "cloned" ];
              body = ''let $${receiver} = $${receiver}.clone();'';
              description = "clone a variable into a new binding";
              scope = "expr";
            };
            "let $x = $x.into()" = {
              postfix = [ "into" ];
              body = ''let $${receiver} = $${receiver}.clone();'';
              description = "call into() and create a new binding";
              scope = "expr";
            };
            "assert_eq!($x, .. );" = {
              postfix = [ "asseq" ];
              body = ''assert_eq!($${receiver}, );'';
              description = "create an assertion for the expression";
              scope = "expr";
            };
          };
        };
        procMacro = { enable = true; attributes.enable = true; };
        serverPath = addSDK {
          name = "rust-env";
          lsp = "${rust-analyzer}/bin/rust-analyzer";
          sdk = [ rust-sdk ];
        };
        imports.group.enable = true;
        inlayHints = {
          closureReturnTypeHints.enable = false;
        };
        highlightRelated = {
          yieldPoints.enable = true;
          references.enable = true;
          exitPoints.enable = true;
          breakPoints.enable = true;
        };
        checkOnSave = {
          #https://github.com/rust-lang/rust-clippy/issues/9560
          enable = false;
          allFeatures = true;
          command = "clippy";
          # extraArgs = [ "--message-format=json" ];
        };
        diagnostics = {
          enable = true;
          experimental.enable = true;
        };
        files.excludeDirs = [ "result" "target" ];
        extraEnv = {
          RA_LOG = "debug";
        };
      };
      languageserver = {
        ccls = {
          command = preferProjectEnv "ccls" "${pkgs.ccls}/bin/ccls";
          filetypes = [ "c" "cc" "cpp" "c++" "objc" "objcpp" ];
          rootPatterns = [ ".ccls" "compile_commands.json" ".git/" ".hg/" ];
          initializationOptions = {
            cache = {
              directory = "${config.xdg.cacheHome}/ccls";
            };
          };
          clang.extraOptions = [ "-std=c++20" ];
        };
        nix = {
          command = "${pkgs.nil}/bin/nil";
          formatting.command = "${pkgs.nixpkgs-fmt}/bin/nixpkgs-fmt";
          flake = {
            autoArchive = true;
            autoEvalInputs = true;
          };
          maxMemoryMB = 1024 * 4;
          rootPatterns = [ "flake.nix" ];
          filetypes = [ "nix" ];
        };
        diagnostic-languageserver = {
          filetypes = {
            sh = [ "${pkgs.shellcheck}/bin/shellcheck" ];
          };
        };
        cSpell = { diagnosticLevel = "hint"; };
      };
    };
  home.sessionVariables = rec {
    EDITOR = "nvim";
    VISUAL_EDITOR = EDITOR;
  };
}