From c5bc6d503ef595745f77e2d9c550651c198879ac Mon Sep 17 00:00:00 2001
From: NotAShelf <raf@notashelf.dev>
Date: Fri, 4 Apr 2025 09:52:23 +0300
Subject: [PATCH] neovim/diagnostics: init module

---
 docs/release-notes/rl-0.8.md        |   8 ++-
 modules/neovim/init/default.nix     |   1 +
 modules/neovim/init/diagnostics.nix | 102 ++++++++++++++++++++++++++++
 3 files changed, 109 insertions(+), 2 deletions(-)
 create mode 100644 modules/neovim/init/diagnostics.nix

diff --git a/docs/release-notes/rl-0.8.md b/docs/release-notes/rl-0.8.md
index 368df9f5..49da794b 100644
--- a/docs/release-notes/rl-0.8.md
+++ b/docs/release-notes/rl-0.8.md
@@ -87,6 +87,10 @@
 - Add [oil.nvim] as an alternative file explorer. It will be available under
   `vim.utility.oil-nvim`.
 
+- Add `vim.diagnostics` to interact with Neovim's diagnostics module. Available
+  options for `vim.diagnostic.config()` can now be customized through the
+  [](#opt-vim.diagnostics.config) in nvf.
+
 [amadaluzia](https://github.com/amadaluzia):
 
 [haskell-tools.nvim]: https://github.com/MrcJkb/haskell-tools.nvim
@@ -253,8 +257,8 @@
   [friendly-snippets](https://github.com/rafamadriz/friendly-snippets) so
   blink.cmp can source snippets from it.
 - Fix [blink.cmp] breaking when built-in sources were modified.
-- Fix [conform.nvim] not allowing disabling formatting on and after save.
-  Use `null` value to disable them if conform is enabled.
+- Fix [conform.nvim] not allowing disabling formatting on and after save. Use
+  `null` value to disable them if conform is enabled.
 
 [TheColorman](https://github.com/TheColorman):
 
diff --git a/modules/neovim/init/default.nix b/modules/neovim/init/default.nix
index ac9d29e5..0e7a4c6b 100644
--- a/modules/neovim/init/default.nix
+++ b/modules/neovim/init/default.nix
@@ -3,6 +3,7 @@
     ./autocmds.nix
     ./basic.nix
     ./debug.nix
+    ./diagnostics.nix
     ./highlight.nix
     ./spellcheck.nix
   ];
diff --git a/modules/neovim/init/diagnostics.nix b/modules/neovim/init/diagnostics.nix
new file mode 100644
index 00000000..26ca6e84
--- /dev/null
+++ b/modules/neovim/init/diagnostics.nix
@@ -0,0 +1,102 @@
+{
+  config,
+  lib,
+  ...
+}: let
+  inherit (lib.modules) mkIf;
+  inherit (lib.options) mkOption mkEnableOption literalExpression;
+  inherit (lib.types) attrsOf anything oneOf bool submodule;
+  inherit (lib.nvim.dag) entryAfter;
+  inherit (lib.nvim.types) luaInline;
+  inherit (lib.nvim.lua) toLuaObject;
+
+  cfg = config.vim.diagnostics;
+
+  diagnosticType = oneOf [(attrsOf anything) bool luaInline];
+  diagnosticsSubmodule = submodule {
+    freeformType = attrsOf diagnosticType;
+    underline = mkOption {
+      type = diagnosticType;
+      default = true;
+      description = "Use underline for diagnostics.";
+    };
+
+    virtual_text = mkOption {
+      type = diagnosticType;
+      default = false;
+      example = literalExpression ''
+        {
+          format = lib.generators.mkLuaInline '''
+            function(diagnostic)
+              return string.format("%s (%s)", diagnostic.message, diagnostic.source)
+            end
+          ''';
+        }
+      '';
+
+      description = ''
+        Use virtual text for diagnostics. If multiple diagnostics are set for a namespace,
+        one prefix per diagnostic + the last diagnostic message are shown.
+      '';
+    };
+
+    virtual_lines = mkOption {
+      type = diagnosticType;
+      default = false;
+      description = ''
+        Use virtual lines for diagnostics.
+      '';
+    };
+
+    signs = mkOption {
+      type = diagnosticType;
+      default = false;
+      example = {
+        signs.text = {
+          "vim.diagnostic.severity.ERROR" = "󰅚 ";
+          "vim.diagnostic.severity.WARN" = "󰀪 ";
+        };
+      };
+      description = ''
+        Use signs for diagnostics. See {command}`:help diagnostic-signs`.
+      '';
+    };
+
+    update_in_insert = mkOption {
+      type = bool;
+      default = false;
+      description = ''
+        Update diagnostics in Insert mode. If `false`, diagnostics will
+        be updated on InsertLeave ({command}`:help InsertLeave`).
+      '';
+    };
+  };
+in {
+  options.vim = {
+    diagnostics = {
+      enable = mkEnableOption "diagostics module for Neovim";
+      config = mkOption {
+        type = diagnosticsSubmodule;
+        default = {};
+        description = ''
+          Values that will be passed to `vim.diagnostic.config` after being converted
+          to a Lua table. Possible values for each key can be found in the help text
+          for `vim.diagnostics.Opts`. You may find more about the diagnostics API of
+          Neovim in {command}`:help diagnostic-api`.
+
+          :::{.note}
+          This option is freeform. You may set values that are not present in nvf
+          documentation, but those values will not be fully type checked. Please
+          refer to the help text for `vim.diagnostic.Opts` for appropriate values.
+          :::
+        '';
+      };
+    };
+  };
+
+  config.vim = mkIf cfg.enable {
+    luaConfigRC.diagnostics = entryAfter ["basic"] ''
+      vim.diagnostic.config(${toLuaObject cfg.config})
+    '';
+  };
+}