;;; ai/gptel.el -*- lexical-binding: t; -*-

;;; ============================================================================
;;; gptel Configuration
;;; ============================================================================

;; Core gptel setup
(use-package! gptel
  :defer t
  :config
  ;; Default backend: OpenRouter
  (setq gptel-model 'google/gemini-3-flash-preview
        gptel-backend
        (gptel-make-openai "OpenRouter"
          :host "openrouter.ai"
          :endpoint "/api/v1/chat/completions"
          :stream t
          :key "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"
          :models '(google/gemini-3-flash-preview
                    x-ai/grok-4.1-fast
                    x-ai/grok-code-fast-1
                    google/gemini-3-pro-preview
                    anthropic/claude-sonnet-4.5)))

  ;; Use org-mode by default for better note-taking
  (setq gptel-default-mode 'org-mode)

  ;; Move cursor to end of response automatically
  (add-hook 'gptel-post-response-functions 'gptel-end-of-response)

  ;; Keybindings - using SPC A for AI (uppercase to avoid conflicts)
  (map! :leader
        (:prefix ("A" . "AI/gptel")
         :desc "gptel chat" "g" #'gptel
         :desc "gptel send" "s" #'gptel-send
         :desc "gptel menu" "m" #'gptel-menu
         :desc "gptel rewrite" "r" #'gptel-rewrite
         :desc "Add context" "c" #'gptel-add
         :desc "Add file to context" "f" #'gptel-add-file))

  ;; Additional keybindings in gptel buffer
  (map! :map gptel-mode-map
        "C-c RET" #'gptel-send
        "C-c C-k" #'gptel-abort
        "C-c C-c" #'gptel-menu))

;; gptel presets for different tasks
(after! gptel
  ;; Coding assistant preset
  (gptel-make-preset 'coder
    :description "Expert coding assistant"
    :backend "OpenRouter"
    :model 'anthropic/claude-sonnet-4.5
    :system "You are an expert coding assistant. Provide high-quality code solutions, refactorings, and explanations. Be concise but thorough. Include error handling and follow best practices.")

  ;; Code explainer preset
  (gptel-make-preset 'explain
    :description "Explain code to beginners"
    :system "Explain this code to a novice programmer. Use simple language and break down complex concepts.")

  ;; Refactoring preset
  (gptel-make-preset 'refactor
    :description "Code refactoring expert"
    :model 'anthropic/claude-sonnet-4.5
    :system "You are a code refactoring expert. Improve code quality, readability, and performance while maintaining functionality. Explain your changes.")

  ;; Quick answers preset
  (gptel-make-preset 'quick
    :description "Quick, concise answers"
    :model 'google/gemini-3-flash-preview
    :system "Provide quick, concise answers. Be direct and to the point.")

  ;; Documentation writer preset
  (gptel-make-preset 'docs
    :description "Documentation writer"
    :system "Write clear, comprehensive documentation. Include examples and explain edge cases."))

;;; ============================================================================
;;; gptel-quick - Quick lookups and explanations
;;; ============================================================================

(use-package! gptel-quick
  :after gptel
  :defer t
  :config
  ;; Include context from gptel-add if available
  (setq gptel-quick-use-context t)

  (map! :leader
        (:prefix "A"
         :desc "Quick lookup" "q" #'gptel-quick)))

;;; ============================================================================
;;; gptel-extensions - Extra utility functions
;;; ============================================================================

(use-package! gptel-extensions
  :after gptel
  :defer t
  :config
  (map! :leader
        (:prefix "A"
         :desc "Load buffer into session" "l" #'gptel-extensions-load-buffer
         :desc "Send whole buffer" "b" #'gptel-extensions-send-whole-buffer
         :desc "Refactor region" "R" #'gptel-extensions-refactor)))

;;; ============================================================================
;;; gptel-autocomplete - Inline code completion
;;; ============================================================================

(use-package! gptel-autocomplete
  :after gptel
  :defer t
  :commands (gptel-complete gptel-accept-completion)
  :config
  ;; Configure context size
  (setq gptel-autocomplete-before-context-lines 100
        gptel-autocomplete-after-context-lines 20
        gptel-autocomplete-temperature 0.1)

  ;; Keybindings for autocomplete
  (map! :leader
        (:prefix "A"
         :desc "Complete at point" "C" #'gptel-complete
         :desc "Accept completion" "a" #'gptel-accept-completion))

  ;; Also add convenient keybindings in prog-mode
  (map! :map prog-mode-map
        "M-TAB" #'gptel-complete
        "C-c TAB" #'gptel-complete
        "C-c C-a" #'gptel-accept-completion))

(defun my/gptel-quick-explain-region ()
  "Quickly explain selected code region in the gptel buffer."
  (interactive)
  (when (use-region-p)
    (let* ((code (buffer-substring-no-properties (region-beginning) (region-end)))
           (buf (get-buffer-create "*gptel*")))
      ;; Prepare the buffer and insert the query immediately
      (with-current-buffer buf
        (goto-char (point-max))
        (unless (derived-mode-p 'gptel-mode)
          (funcall gptel-default-mode)
          (gptel-mode 1))
        (insert "\n\n--- Code to Explain ---\n\n" code "\n\n### Explanation Request Sent...\n"))
      (display-buffer buf)
      ;; Send the request
      (gptel-request
          (format "Explain this code concisely in 2-3 sentences:\n\n%s" code)
        :system "You are an expert programmer explaining code."
        :callback (lambda (response info)
                    (with-current-buffer (get-buffer "*gptel*")
                      (goto-char (point-max))
                      (insert "\n### Code Explanation\n\n" response "\n\n"))
                    (message "Explanation received in *gptel* buffer."))))))

(defun my/gptel-proofread-region ()
  "Proofread and improve selected text."
  (interactive)
  (when (use-region-p)
    (gptel-rewrite-region (region-beginning) (region-end)
                          "Fix spelling, grammar, and improve clarity. Keep the same tone and style.")))

(defun my--get-region-as-path-tag (path-fn)
  "Helper to get path tag using PATH-FN to determine the file path."
  (let* ((filename (funcall path-fn))
         (start-line (line-number-at-pos (if (use-region-p) (region-beginning) (point))))
         (tag (if (use-region-p)
                  (let* ((end-pos (1- (region-end)))
                         (end-line (line-number-at-pos (max (region-beginning) end-pos))))
                    (format "@%s:%d-%d" filename start-line end-line))
                (format "@%s:%d" filename start-line))))
    tag))

(defun my/copy-region-as-path-tag ()
  "Copy the current region as a relative path tag: @path/to/file.ext:start-end"
  (interactive)
  (let ((tag (my--get-region-as-path-tag
              (lambda () (file-relative-name (buffer-file-name) (doom-project-root))))))
    (kill-new tag)
    (message "Copied: %s" tag)))

(defun my/copy-region-as-path-tag-absolute ()
  "Copy the current region as an absolute path tag: @/abs/path/to/file.ext:start-end"
  (interactive)
  (let ((tag (my--get-region-as-path-tag #'buffer-file-name)))
    (kill-new tag)
    (message "Copied: %s" tag)))

;; Add keybindings for helper functions
(defvar my-ai-helper-map (make-sparse-keymap)
  "Keymap for my AI helper functions.")

(global-set-key (kbd "C-c a") my-ai-helper-map)
(define-key my-ai-helper-map (kbd "e") #'my/gptel-quick-explain-region)
(define-key my-ai-helper-map (kbd "p") #'my/gptel-proofread-region)
(define-key my-ai-helper-map (kbd "t") #'my/copy-region-as-path-tag)
(define-key my-ai-helper-map (kbd "T") #'my/copy-region-as-path-tag-absolute)

(map! :leader
      (:prefix "A"
       :desc "Quick explain" "e" #'my/gptel-quick-explain-region
       :desc "Proofread text" "p" #'my/gptel-proofread-region
       :desc "Copy path tag (relative)" "t" #'my/copy-region-as-path-tag
       :desc "Copy path tag (absolute)" "T" #'my/copy-region-as-path-tag-absolute))