neovim/init: initial diagnostics module implementation

modules/neovim/init/default.nix

@@ -3,7 +3,12 @@
     ./autocmds.nix
     ./basic.nix
     ./debug.nix
+<<<<<<< Updated upstream
     ./highlight.nix
+||||||| Stash base
+=======
+    ./diagnostics.nix
+>>>>>>> Stashed changes
     ./spellcheck.nix
   ];
 }

modules/neovim/init/diagnostics.nix

@@ -0,0 +1,100 @@
+{
+  config,
+  lib,
+  ...
+}: let
+  inherit (lib.modules) mkIf;
+  inherit (lib.options) mkOption;
+  inherit (lib.types) either bool attrsOf submodule anything str;
+  inherit (lib.nvim.lua) toLuaObject;
+  inherit (lib.nvim.types) luaInline;
+  inherit (lib.nvim.dag) entryBefore;
+
+  cfg = config.vim.diagnostics;
+in {
+  options.vim.diagnostics = {
+    enable = mkOption {
+      type = either bool luaInline;
+      default = false;
+      description = ''
+        Whether to enable Neovim's built-in diagnostics module.
+
+        [Neovim documentation on diagnostics]: https://neovim.io/doc/user/diagnostic.html)
+
+        Can be either a boolean, or a Lua function that evaluates to
+        a boolean. Please refer to [Neovim documentation on diagnostics]
+        for more details on this option, and the module as a whole.
+      '';
+    };
+
+    settings = mkOption {
+      default = {};
+      type = attrsOf (submodule {
+        freeformType = attrsOf anything;
+        options = {
+          underline = mkOption {
+            type = bool;
+            default = true;
+            description = "Whether to use underline for diagnostics";
+          };
+
+          virtual_text = mkOption {
+            type = bool;
+            default = false;
+            description = ''
+              Whether to use underline for diagnostics.
+
+              If multiple diagnostics are set for a namespace, one prefix per diagnostic
+              plus the last diagnostic message are shown.
+            '';
+          };
+
+          signs = mkOption {
+            type = bool;
+            default = true;
+            description = "Whether to use signs for diagnostics";
+          };
+        };
+      });
+
+      description = ''
+        [`vim.diagnostics.config()`]: https://neovim.io/doc/user/diagnostic.html#vim.diagnostic.config()
+
+        Attribute set of settings that will be converted to a Lua table for
+        `vim.diagnostics.config`. Can be overridden with additional options
+        as defined in [`vim.diagnostics.config()`] on Neovim manual.
+      '';
+    };
+
+    signs = let
+      mkDiagnosticOption = icon: hl: signVariant:
+        mkOption {
+          type = attrsOf str;
+          default = {inherit icon hl;};
+          description = "Diagnostic icon to be used while signs are enabled for ${signVariant}";
+        };
+    in {
+      info = mkDiagnosticOption "󰌵" "DiagnosticSignInfo" "info";
+      hint = mkDiagnosticOption "" "DiagnosticsSignHint" "hint";
+      warn = mkDiagnosticOption "" "DiagnosticsSignWarn" "warn";
+      error = mkDiagnosticOption "" "DiagnosticsSignError" "error";
+    };
+  };
+
+  config = {
+    vim = {
+      luaConfigRC.diagnostics = entryBefore ["pluginConfigs"] ''
+        vim.diagnostics.config(${toLuaObject cfg.settings})
+
+        local nvf_diagnostics_group = vim.api.nvim_create_augroup("NvfDiagnosticsGroup", { clear = true })
+        vim.api.nvim_create_autocmd("BufEnter", {
+        	pattern = "*",
+          group = nvf_diagnostics_group,
+        	callback = function()
+        		vim.diagnostics.enable(${toLuaObject cfg.enable})
+          end,
+        })
+      '';
+    };
+  };
+}