neovim/spellcheck: allow disabling spellchecking for filetypes

modules/neovim/init/spellcheck.nix

@@ -0,0 +1,66 @@
+{
+  config,
+  lib,
+  ...
+}: let
+  inherit (lib.modules) mkIf;
+  inherit (lib.options) mkOption mkEnableOption literalExpression literalMD;
+  inherit (lib.types) listOf str;
+  inherit (lib.nvim.lua) listToLuaTable;
+  inherit (lib.nvim.dag) entryAfter;
+
+  cfg = config.vim.spellChecking;
+in {
+  options.vim.spellChecking = {
+    enable = mkEnableOption "neovim's built-in spellchecking";
+    languages = mkOption {
+      type = listOf str;
+      default = ["en"];
+      example = literalExpression ''["en" "de"]'';
+      description = literalMD ''
+        A list of languages that should be used for spellchecking.
+
+        To add your own language files, you may place your `spell`
+        directory in either {path}`~/.config/nvim` or the
+        [additionalRuntimePaths](#opt-vim.additionalRuntimePaths)
+        directory provided by neovim-flake.
+      '';
+    };
+
+    ignoredFiletypes = mkOption {
+      type = listOf str;
+      default = ["toggleterm"];
+      example = literalExpression ''["markdown" "gitcommit"]'';
+      description = ''
+        A list of filetypes for which spellchecking will be disabled.
+
+        You may use `echo &filetype` in neovim to find out the
+        filetype for a specific buffer.
+      '';
+    };
+
+    programmingWordlist.enable = mkEnableOption ''
+      vim-dirtytalk, a wordlist for programmers containing
+      common programming terms.
+
+      Setting this value as `true` has the same effect
+      as setting {option}`vim.spellCheck.enable`
+    '';
+  };
+
+  config = mkIf cfg.enable {
+    vim.luaConfigRC.spellchecking = entryAfter ["basic"] ''
+      vim.opt.spell = true
+      vim.opt.spelllang = ${listToLuaTable cfg.languages}
+
+      -- Disable spellchecking for certain filetypes
+      -- as configured by `vim.spellChecking.ignoredFiletypes`
+      vim.api.nvim_create_autocmd({ "FileType" }, {
+        pattern = ${listToLuaTable cfg.ignoredFiletypes},
+        callback = function()
+          vim.opt_local.spell = false
+        end,
+      })
+    '';
+  };
+}