;;; baba-yaga-mode.el --- Major mode for Baba Yaga programming language -*- lexical-binding: t; -*-

;; Copyright (C) 2024 Your Name

;; Author: Your Name <your-email@example.com>
;; Version: 1.0.0
;; Keywords: languages, baba-yaga
;; URL: https://github.com/your-username/baba-yaga

;; This file is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 3, or (at your option)
;; any later version.

;; This file is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; Major mode for editing Baba Yaga programming language files.
;; Provides syntax highlighting, indentation, and basic editing features.

;;; Code:

(defgroup baba-yaga nil
  "Major mode for Baba Yaga programming language."
  :group 'languages)

(defcustom baba-yaga-indent-width 2
  "Indentation width for Baba Yaga mode."
  :type 'integer
  :group 'baba-yaga)

(defvar baba-yaga-mode-syntax-table
  (let ((table (make-syntax-table)))
    ;; Comments
    (modify-syntax-entry ?/ ". 124b" table)
    (modify-syntax-entry ?* ". 23" table)
    (modify-syntax-entry ?\n "> b" table)
    
    ;; Strings
    (modify-syntax-entry ?\" "\"" table)
    
    ;; Operators
    (modify-syntax-entry ?+ "." table)
    (modify-syntax-entry ?- "." table)
    (modify-syntax-entry ?* "." table)
    (modify-syntax-entry ?/ "." table)
    (modify-syntax-entry ?% "." table)
    (modify-syntax-entry ?= "." table)
    (modify-syntax-entry ?> "." table)
    (modify-syntax-entry ?< "." table)
    (modify-syntax-entry ?: "." table)
    (modify-syntax-entry ?. "." table)
    (modify-syntax-entry ?_ "w" table)
    
    ;; Brackets
    (modify-syntax-entry ?\( "()" table)
    (modify-syntax-entry ?\) ")(" table)
    (modify-syntax-entry ?\[ "(]" table)
    (modify-syntax-entry ?\] ")[" table)
    (modify-syntax-entry ?\{ "(}" table)
    (modify-syntax-entry ?\} "){" table)
    
    table)
  "Syntax table for Baba Yaga mode.")

(defvar baba-yaga-keywords
  '("when" "then" "is" "Ok" "Err")
  "Keywords in Baba Yaga.")

(defvar baba-yaga-with-keywords
  '("with" "rec")
  "With block keywords in Baba Yaga.")

(defvar baba-yaga-types
  '("Bool" "Int" "Float" "String" "List" "Table" "Result" "Number")
  "Types in Baba Yaga.")

(defvar baba-yaga-operators
  '("append" "set" "merge" "shape")
  "Operators in Baba Yaga.")

(defvar baba-yaga-io-functions
  '("io.out" "io.in" "io.emit" "io.listen")
  "IO functions in Baba Yaga.")

(defvar baba-yaga-functions
  '("map" "filter" "reduce" "pipe")
  "Built-in functions in Baba Yaga.")

(defvar baba-yaga-font-lock-keywords
  `(
    ;; Comments - must come first to override other highlighting
    ("//.*$" . font-lock-comment-face)
    ("/\\*.*?\\*/" . font-lock-comment-face)
    
    ;; Keywords
    (,(regexp-opt baba-yaga-keywords 'words) . font-lock-keyword-face)
    
    ;; With block keywords
    (,(regexp-opt baba-yaga-with-keywords 'words) . font-lock-keyword-face)
    
    ;; With blocks
    ("\\bwith\\b\\s*\\(?:rec\\s*\\)?(" . font-lock-keyword-face)
    ("\\)\\s*->" . font-lock-keyword-face)
    
    ;; With block entries
    ("\\b\\([a-zA-Z_][a-zA-Z0-9_]*\\)\\s*:" 1 font-lock-variable-name-face)
    
    ;; Types
    (,(regexp-opt baba-yaga-types 'words) . font-lock-type-face)
    
    ;; Operators
    (,(regexp-opt baba-yaga-operators 'words) . font-lock-function-name-face)
    
    ;; IO functions
    (,(regexp-opt baba-yaga-io-functions 'words) . font-lock-preprocessor-face)
    
    ;; Built-in functions
    (,(regexp-opt baba-yaga-functions 'words) . font-lock-builtin-face)
    
    ;; Function definitions
    ("\\b\\([a-zA-Z_][a-zA-Z0-9_]*\\)\\s*:" 1 font-lock-function-name-face)
    
    ;; Operators
    ("\\(->\\|=>\\|\\.\\.\\|[=><+\\-*/%]\\)" . font-lock-keyword-face)
    
    ;; Assignment operator
    (":" . font-lock-keyword-face)
    
    ;; Wildcard
    ("\\b_\\b" . font-lock-constant-face)
    
    ;; Numbers
    ("\\b\\([0-9]+\\)\\b" 1 font-lock-constant-face)
    ("\\b\\([0-9]+\\.[0-9]+\\)\\b" 1 font-lock-constant-face)
    
    ;; Strings
    ("\"[^\"]*\"" . font-lock-string-face)
    )
  "Font lock keywords for Baba Yaga mode.")

(defvar baba-yaga-font-lock-syntactic-keywords
  `(
    ;; Comments - syntactic highlighting takes precedence
    ("//.*$" . font-lock-comment-face)
    ("/\\*.*?\\*/" . font-lock-comment-face)
    )
  "Syntactic font lock keywords for Baba Yaga mode.")

(defun baba-yaga-indent-line ()
  "Indent current line in Baba Yaga mode."
  (interactive)
  (let ((indent-col 0))
    (save-excursion
      (beginning-of-line)
      (cond
       ;; Indent after opening brackets
       ((looking-at ".*[{([]")
        (setq indent-col (+ (current-indentation) baba-yaga-indent-width)))
       
       ;; Dedent after closing brackets
       ((looking-at ".*[})\]]")
        (setq indent-col (max 0 (- (current-indentation) baba-yaga-indent-width))))
       
       ;; Default indentation
       (t
        (setq indent-col (current-indentation)))))
    
    (indent-line-to indent-col)))

(defvar baba-yaga-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map (kbd "RET") 'newline-and-indent)
    map)
  "Keymap for Baba Yaga mode.")

;;;###autoload
(define-derived-mode baba-yaga-mode prog-mode "Baba Yaga"
  "Major mode for editing Baba Yaga programming language files."
  :group 'baba-yaga
  
  ;; Syntax table
  (set-syntax-table baba-yaga-mode-syntax-table)
  
  ;; Font lock
  (setq font-lock-defaults '(baba-yaga-font-lock-keywords))
  (setq font-lock-syntactic-keywords baba-yaga-font-lock-syntactic-keywords)
  
  ;; Indentation
  (setq-local indent-line-function 'baba-yaga-indent-line)
  (setq-local tab-width baba-yaga-indent-width)
  
  ;; Comments
  (setq-local comment-start "// ")
  (setq-local comment-end "")
  (setq-local comment-start-skip "//+\\s-*")
  
  ;; Keymap
  (use-local-map baba-yaga-mode-map))

;;;###autoload
(add-to-list 'auto-mode-alist '("\\.baba\\'" . baba-yaga-mode))

(provide 'baba-yaga-mode)

;;; baba-yaga-mode.el ends here