;;; development/nix.el -*- lexical-binding: t; -*-

(use-package! nix-mode
  :mode "\\.nix\\'"
  :hook (nix-mode . lsp-deferred)
  :config
  ;; Configure nil LSP server
  (after! lsp-mode
    (add-to-list 'lsp-language-id-configuration '(nix-mode . "nix"))
    (lsp-register-client
     (make-lsp-client :new-connection (lsp-stdio-connection "nil")
                      :major-modes '(nix-mode)
                      :server-id 'nil-ls
                      :priority 0)))

  ;; Function to check if we're in a nixpkgs repository
  (defun in-nixpkgs-repo-p ()
    (when-let ((root (or (locate-dominating-file default-directory ".git")
                         (vc-root-dir))))
      (or (string-match-p "/nixpkgs/?$" root)
          (file-exists-p (expand-file-name "pkgs/top-level/all-packages.nix" root))
          (file-exists-p (expand-file-name ".nixpkgs-version.json" root)))))

  ;; Set up format-all-mode to use our custom formatter selection
  (set-formatter! 'nixfmt
    '("nixfmt")
    :modes '(nix-mode))

  (set-formatter! 'alejandra
    '("alejandra" "--quiet")
    :modes '(nix-mode))

  ;; Add hooks to handle all formatting scenarios
  (add-hook! 'nix-mode-hook
             ;; Disable LSP formatting
             (setq-local +format-with-lsp nil)

             ;; Set formatter for format-all-mode (+format/buffer)
             (setq-local +format-with
                         (if (in-nixpkgs-repo-p)
                             'nixfmt
                           'alejandra))

             ;; Handle format-on-save
             (when (bound-and-true-p format-all-mode)
               (format-all-mode -1))
             (add-hook! 'before-save-hook :local
               (when (eq major-mode 'nix-mode)
                 (if (in-nixpkgs-repo-p)
                     (format-all-buffer 'nixfmt)
                   (format-all-buffer 'alejandra))))

             ;; Override lsp-format-buffer
             (advice-add 'lsp-format-buffer :around
                         (lambda (orig-fun &rest args)
                           (if (eq major-mode 'nix-mode)
                               (let ((fmt (if (in-nixpkgs-repo-p)
                                              (executable-find "nixfmt")
                                            (executable-find "alejandra"))))
                                 (when fmt
                                   (format-all-buffer (intern (file-name-nondirectory fmt)))))
                             (apply orig-fun args))))))

;; Enable format-on-save globally if desired
(setq +format-on-save-enabled-modes '(nix-mode))

(use-package! llvm-ts-mode
  :mode "\\.ll\\'"          ; LLVM IR files
  :mode "\\.td\\'"          ; TableGen files
  :hook (llvm-ts-mode . tree-sitter-mode))

(after! tree-sitter
  (add-to-list 'tree-sitter-major-mode-language-alist '(llvm-ts-mode . llvm)))