(require 'which-func)

(require 'cl-lib)

(require 'magit)

(require 'flycheck nil t)

(require 'ai-code-input)

(require 'ai-code-prompt-mode)

(declare-function ai-code-read-string "ai-code-input")

(declare-function ai-code--insert-prompt "ai-code-prompt-mode")

(declare-function ai-code--get-clipboard-text "ai-code")

(declare-function ai-code--git-root "ai-code-file" (&optional dir))

(declare-function ai-code--get-git-relative-paths "ai-code-discussion")

(declare-function ai-code--get-region-location-info "ai-code-discussion")

(declare-function ai-code--format-repo-context-info "ai-code-file")

(declare-function flycheck-error-pos "flycheck")

(declare-function flycheck-error-line "flycheck")

(declare-function flycheck-error-column "flycheck")

(declare-function flycheck-error-message "flycheck")

(defvar flycheck-current-errors)

(defconst ai-code-change--selected-region-note

"Note: Please apply the code change to the selected region specified above."

"Prompt note for code changes scoped to the selected region.")

(defconst ai-code-change--generic-note

"Note: Please make the code change described above."

"Prompt note for generic code-change requests.")

(defconst ai-code-change--selected-files-note

"Note: Please make the code change described above for the selected files/directories."

"Prompt note for code changes scoped to selected files or directories.")

(defconst ai-code-change--ask-question-note

"Note: Please only answer the question about the code above, do not make any code changes."

"Prompt note for question-only requests without code changes.")

(defun ai-code--is-comment-line (line)

"Check if LINE is a comment line based on current buffer's comment syntax.

(when comment-start

(let* ((comment-str (string-trim-right comment-start))

(trimmed-line (string-trim-left line))

(comment-re (concat "^[ ]*"

(regexp-quote comment-str)

"+[ ]*")))

(when (string-match comment-re trimmed-line)

(let ((content (string-trim-left (substring trimmed-line (match-end 0)))))

(unless (string-prefix-p "DONE:" content)

t))))))

(defun ai-code--is-comment-block (text)

"Check if TEXT is a block of comments (ignoring blank lines)."

(let ((lines (split-string text "\n")))

(cl-every (lambda (line)

(or (string-blank-p line)

(ai-code--is-comment-line line)))

lines)))

(defun ai-code--get-function-name-for-comment ()

"Get the appropriate function name when cursor is on a comment line.

(interactive)

(let* ((current-func (which-function))

(resolved-func

(save-excursion

(cl-labels ((line-text ()

(buffer-substring-no-properties

(line-beginning-position)

(line-end-position))))

(forward-line 1)

(cl-block resolve

(let ((text (line-text)))

;; Stop immediately if the next line is blank or buffer ended.

(when (or (eobp) (string-blank-p text))

(cl-return-from resolve nil))

;; Skip leading comment lines, aborting on blank lines.

(while (ai-code--is-comment-line text)

(forward-line 1)

(setq text (line-text))

(when (or (eobp) (string-blank-p text))

(cl-return-from resolve nil)))

;; Resolve with a short lookahead; stop on blank lines.

(let ((next-func (which-function)))

(cl-loop with lookahead = 5

while (and (> lookahead 0)

(or (null next-func)

(string= next-func current-func)))

do (forward-line 1)

(setq lookahead (1- lookahead))

(setq text (line-text))

(when (string-blank-p text)

(cl-return-from resolve nil))

(unless (ai-code--is-comment-line text)

(setq next-func (which-function)))

finally return (cond

((not current-func) next-func)

((not next-func) current-func)

((not (string= next-func current-func)) next-func)

(t current-func))))))))))

;; (when resolved-func

;; (message "Identified function: %s" resolved-func))

resolved-func))

(defun ai-code--detect-todo-info (region-active)

"Detect TODO comment information at cursor or in selected region.

(let ((text (if region-active

(buffer-substring-no-properties (region-beginning) (region-end))

(thing-at-point 'line t))))

(when (and text comment-start)

(let* ((first-line (car (split-string text "\n")))

(comment-prefix-re (concat "^[ \t]*" (regexp-quote (string-trim-right comment-start)) "+[ \t]*")))

(when (string-match comment-prefix-re first-line)

(let ((rest (string-trim-left (substring first-line (match-end 0)))))

(when (string-prefix-p "TODO" rest)

(list text

(if region-active (region-beginning) (line-beginning-position))

(if region-active (region-end) (line-end-position))))))))))

(defun ai-code--generate-prompt-label (clipboard-context region-active function-name)

"Generate appropriate prompt label based on context.

(cond

((and clipboard-context

(string-match-p "\\S-" clipboard-context))

(cond

(region-active

(if function-name

(format "Change code in function %s (clipboard context): " function-name)

"Change selected code (clipboard context): "))

(function-name

(format "Change function %s (clipboard context): " function-name))

(t "Change code (clipboard context): ")))

(region-active

(if function-name

(format "Change code in function %s: " function-name)

"Change selected code: "))

(function-name

(format "Change function %s: " function-name))

(t "Change code: ")))

(defun ai-code--handle-regular-code-change (arg region-active)

"Handle regular code change operation.

(let* ((clipboard-context (when arg (ai-code--get-clipboard-text)))

(function-name (which-function))

(region-text (when region-active

(buffer-substring-no-properties (region-beginning) (region-end))))

(region-start-line (when region-active

(line-number-at-pos (region-beginning))))

(region-location-info (when region-active

(ai-code--get-region-location-info (region-beginning) (region-end))))

(prompt-label (ai-code--generate-prompt-label clipboard-context region-active function-name))

(initial-prompt (ai-code-read-string prompt-label ""))

(files-context-string (ai-code--get-context-files-string))

(repo-context-string (ai-code--format-repo-context-info))

(final-prompt

(concat initial-prompt

(when region-text

(concat "\nSelected region:\n"

(cond

(region-location-info

(concat region-location-info "\n"))

(region-start-line

(format "Start line: %d\n" region-start-line)))

region-text))

(when function-name (format "\nFunction: %s" function-name))

files-context-string

repo-context-string

(when (and clipboard-context

(string-match-p "\\S-" clipboard-context))

(concat "\n\nClipboard context:\n" clipboard-context))

(if region-text

(concat "\n" ai-code-change--selected-region-note)

(concat "\n" ai-code-change--generic-note)))))

(ai-code--insert-prompt final-prompt)))

(defun ai-code--handle-dired-code-change (arg)

"Handle code change operation in Dired mode.

(let* ((clipboard-context (when arg (ai-code--get-clipboard-text)))

(files (dired-get-marked-files))

(files-str (mapconcat #'identity files "\n"))

(single-file (when (= (length files) 1) (car files)))

(prompt-prefix (if single-file

(format "Change code in %s" (file-name-nondirectory single-file))

"Change code in files"))

(prompt-label (if (and clipboard-context (string-match-p "\\S-" clipboard-context))

(format "%s (clipboard context): " prompt-prefix)

(format "%s: " prompt-prefix)))

(initial-prompt (ai-code-read-string prompt-label ""))

(repo-context-string (ai-code--format-repo-context-info))

(final-prompt

(concat initial-prompt

"\nSelected files/directories:\n" files-str

repo-context-string

(when (and clipboard-context

(string-match-p "\\S-" clipboard-context))

(concat "\n\nClipboard context:\n" clipboard-context))

(concat "\n" ai-code-change--selected-files-note))))

(ai-code--insert-prompt final-prompt)))

(defun ai-code-code-change (arg)

"Generate prompt to change code under cursor or in selected region.

(interactive "P")

;; DONE: when current file is dired buffer: 1. when there is marked

;; file / dir, use them as context; 2. otherwise, use file / dir

;; under cursor as context. After that, build up full prompt using

;; above context and other context such as repository context, and

;; send the full prompt to LLM. Otherwise, using current code path.

(cond

((derived-mode-p 'dired-mode)

(ai-code--handle-dired-code-change arg))

(t

(unless buffer-file-name

(user-error "Error: buffer-file-name must be available"))

(let* ((region-active (region-active-p))

(todo-info (ai-code--detect-todo-info region-active)))

(if todo-info

(ai-code-implement-todo arg)

(ai-code--handle-regular-code-change arg region-active))))))

(defun ai-code-implement-todo (arg)

"Generate prompt to implement TODO comments in current context.

(interactive "P")

(if (not buffer-file-name)

(user-error "Error: buffer-file-name must be available")

(cl-block finalize

(when (ai-code--implement-todo--handle-done-line)

(cl-return-from finalize nil))

(when (ai-code--implement-todo--handle-blank-line)

(cl-return-from finalize nil))

(ai-code--implement-todo--build-and-send-prompt arg))))

(defun ai-code--implement-todo--handle-done-line ()

"Handle actions when current line is a DONE comment.

(let* ((line-str (buffer-substring-no-properties (line-beginning-position) (line-end-position)))

(comment-prefix (and comment-start (string-trim-right comment-start)))

(done-re (when comment-prefix

(concat "^\\([ \t]*" (regexp-quote comment-prefix) "+[ \t]*\\)DONE:"))))

(when (and line-str done-re (string-match done-re line-str) (not (region-active-p)))

(let* ((action (completing-read

"Current line starts with DONE:. Action: "

'("Toggle to TODO" "Delete comment line" "Keep as DONE")

nil t nil nil "Toggle to TODO"))

(line-beg (line-beginning-position))

(line-end (line-end-position)))

(pcase action

("Toggle to TODO"

(save-excursion

(goto-char line-beg)

(when (search-forward "DONE:" line-end t)

(replace-match "TODO:" nil nil)))

(message "Toggled DONE to TODO on current comment line"))

("Delete comment line"

(let ((line-next

(save-excursion

(goto-char line-beg)

(forward-line 1)

(min (point) (point-max)))))

(delete-region line-beg line-next))

(message "Deleted DONE comment line"))

(_ (message "Keeping DONE comment line as is")))

t))))

(defun ai-code--implement-todo--handle-blank-line ()

"Handle insertion of a TODO comment when on a blank line.

;; (interactive)

(when (and (not (region-active-p))

(or (not (thing-at-point 'line t)) (string-blank-p (thing-at-point 'line t)))

comment-start)

(let ((todo-text (ai-code-read-string "Enter TODO comment: "))

(comment-prefix (if (derived-mode-p 'emacs-lisp-mode)

(let* ((trimmed (string-trim-right comment-start)))

(if (= (length trimmed) 1)

(make-string 2 (string-to-char trimmed))

trimmed))

(string-trim-right comment-start))))

(unless (string-blank-p todo-text)

(delete-region (line-beginning-position) (line-end-position))

(indent-according-to-mode)

(insert comment-prefix

" TODO: "

todo-text

(if (and comment-end (not (string-blank-p comment-end)))

(concat " " (string-trim-left comment-end))

""))

(indent-according-to-mode)))

t))

(defun ai-code--implement-todo--build-and-send-prompt (arg)

"Build the TODO implementation prompt and insert it.

;; DONE: ask user with completing-read before build up prompt, candidate should be 1. Code change; 2. Ask question. Given selection, add suffix to them respectively to indicate AI to make code change, or do not make any code change

(let* ((clipboard-context (when arg (ai-code--get-clipboard-text)))

(current-line (string-trim (thing-at-point 'line t)))

(current-line-number (line-number-at-pos (point)))

(is-comment (ai-code--is-comment-line current-line))

(function-name (if is-comment

(ai-code--get-function-name-for-comment)

(which-function)))

(function-context (if function-name

(format "\nFunction: %s" function-name)

""))

(region-active (region-active-p))

(region-text (when region-active

(buffer-substring-no-properties

(region-beginning)

(region-end))))

(region-start-line (when region-active

(line-number-at-pos (region-beginning))))

(region-location-info (when region-active

(ai-code--get-region-location-info

(region-beginning)

(region-end))))

(region-location-line (when region-text

(or (and region-location-info

(format "Selected region: %s"

region-location-info))

(when region-start-line

(format "Selected region starting on line %d"

region-start-line)))))

(files-context-string (ai-code--get-context-files-string))

(region-comment-block-p (or (not region-text)

(ai-code--is-comment-block region-text)))

;; Validate scenario before prompting user

(_ (unless (or region-text is-comment)

(user-error "Current line is not a TODO comment and cannot proceed with `ai-code-implement-todo'. Please select a TODO comment (not DONE), a region of comments, or activate on a blank line")))

(_ (unless region-comment-block-p

(user-error "Selected region must be a comment block")))

(action-intent (completing-read "Select action: "

'("Code change" "Ask question")

nil t))

(ask-question-p (string= action-intent "Ask question"))

(prompt-label

(cond

(ask-question-p

(if (and clipboard-context (string-match-p "\\S-" clipboard-context))

"Question about TODO comment (clipboard context): "

"Question about TODO comment: "))

((and clipboard-context

(string-match-p "\\S-" clipboard-context))

(cond

(region-text "TODO implementation instruction (clipboard context): ")

(is-comment "TODO implementation instruction (clipboard context): ")

(function-name (format "TODO implementation instruction for function %s (clipboard context): " function-name))

(t "TODO implementation instruction (clipboard context): ")))

(region-text "TODO implementation instruction: ")

(is-comment "TODO implementation instruction: ")

(function-name (format "TODO implementation instruction for function %s: " function-name))

(t "TODO implementation instruction: ")))

(initial-input

(cond

((and ask-question-p region-text)

(format "Regarding this TODO comment block in the selected region:\n%s\n%s%s%s"

region-location-line region-text function-context files-context-string))

((and ask-question-p is-comment)

(format "Regarding this TODO comment on line %d: '%s'%s%s"

current-line-number current-line function-context files-context-string))

(region-text

(format

"Please implement code for this requirement comment block in the selected region first. After implementing, keep the comment in place and ensure it begins with a DONE prefix (change TODO to DONE or prepend DONE if no prefix). If this is a pure new code block, place it after the comment; otherwise keep the existing structure and make corresponding change for the context.\n%s\n%s%s%s"

region-location-line region-text function-context

files-context-string))

(is-comment

(format "Please implement code for this requirement comment on line %d: '%s' first. After implementing, keep the comment in place and ensure it begins with a DONE prefix (change TODO to DONE or prepend DONE if needed). If this is a pure new code block, place it after the comment; otherwise keep the existing structure and make corresponding change for the context.%s%s"

current-line-number current-line function-context files-context-string))

(t "")))

(repo-context-string (ai-code--format-repo-context-info))

(prompt (ai-code-read-string prompt-label initial-input))

(final-prompt

(concat prompt

(when (and clipboard-context

(string-match-p "\\S-" clipboard-context))

(concat "\n\nClipboard context:\n" clipboard-context))

repo-context-string

(when (string= action-intent "Ask question")

(concat "\n" ai-code-change--ask-question-note)))))

(ai-code--insert-prompt final-prompt)))

(defun ai-code-flycheck--get-errors-in-scope (start end)

"Return Flycheck errors within given START and END buffer positions."

(when (and (bound-and-true-p flycheck-mode) flycheck-current-errors)

(cl-remove-if-not

(lambda (err)

(let ((pos (flycheck-error-pos err)))

(and (integerp pos) (>= pos start) (< pos end))))

flycheck-current-errors)))

(defun ai-code-flycheck--format-error-list (errors file-path-for-error-reporting)

"Formats a list string for multiple Flycheck ERRORS.

(let ((error-reports '()))

(dolist (err errors)

(let* ((line (flycheck-error-line err))

(col (flycheck-error-column err))

(msg (flycheck-error-message err)))

(if (and (integerp line) (integerp col))

(let* ((error-line-text

(save-excursion

(goto-char (point-min))

(forward-line (1- line))

(buffer-substring-no-properties (line-beginning-position) (line-end-position)))))

(push (format "File: %s:%d:%d\nError: %s\nContext line:\n%s"

file-path-for-error-reporting line col msg error-line-text)

error-reports))

(progn

(message "AI-Code: Flycheck error for %s. Line: %S, Col: %S. Full location/context not available. Sending general error info."

file-path-for-error-reporting line col)

(push (format "File: %s (Location: Line %s, Column %s)\nError: %s"

file-path-for-error-reporting

(if (integerp line) (format "%d" line) "N/A")

(if (integerp col) (format "%d" col) "N/A")

msg)

error-reports)))))

(mapconcat #'identity (nreverse error-reports) "\n\n")))

(defun ai-code--choose-flycheck-scope ()

"Return a list (START END DESCRIPTION) for Flycheck fixing scope."

(let* ((scope (if (region-active-p) 'region

(intern

(completing-read

"Select Flycheck fixing scope: "

(delq nil

`("current-line"

,(when (which-function) "current-function")

"whole-file"))

nil t))))

start end description)

(pcase scope

('region

(setq start (region-beginning)

end (region-end)

description

(format "the selected region (lines %d–%d)"

(line-number-at-pos start)

(line-number-at-pos end))))

('current-line

(setq start (line-beginning-position)

end (line-end-position)

description (format "current line (%d)"

(line-number-at-pos (point)))))

('current-function

(let ((bounds (bounds-of-thing-at-point 'defun)))

(unless bounds

(user-error "Not inside a function; cannot select current function"))

(setq start (car bounds)

end (cdr bounds)

description (format "function '%s' (lines %d–%d)"

(which-function)

(line-number-at-pos (car bounds))

(line-number-at-pos (cdr bounds))))))

('whole-file

(setq start (point-min)

end (point-max)

description "the entire file"))

(_

(user-error "Unknown Flycheck scope %s" scope)))

(list start end description)))

(defun ai-code-flycheck-fix-errors-in-scope ()

"Ask AI to generate a patch fixing Flycheck errors.

(interactive)

(unless (featurep 'flycheck)

(user-error "Flycheck package not found. This feature is unavailable"))

(unless buffer-file-name

(user-error "Error: buffer-file-name must be available"))

(when (bound-and-true-p flycheck-mode)

(if (null flycheck-current-errors)

(message "No Flycheck errors found in the current buffer.")

(let* ((git-root (or (ai-code--git-root) default-directory))

(rel-file (file-relative-name buffer-file-name git-root))

;; determine start/end/scope-description via helper

(scope-data (ai-code--choose-flycheck-scope))

(start (nth 0 scope-data))

(end (nth 1 scope-data))

(scope-description (nth 2 scope-data)))

;; collect errors and bail if none in that scope

(let ((errors-in-scope

(ai-code-flycheck--get-errors-in-scope start end)))

(if (null errors-in-scope)

(message "No Flycheck errors found in %s." scope-description)

(let* ((files-context-string (ai-code--get-context-files-string))

(error-list-string

(ai-code-flycheck--format-error-list errors-in-scope

rel-file))

(prompt

(if (string-equal "the entire file" scope-description)

(format "Please fix the following Flycheck errors in file %s:\n\n%s\n%s\n%s"

rel-file error-list-string

files-context-string

ai-code-change--generic-note)

(format "Please fix the following Flycheck errors in %s of file %s:\n\n%s\n%s\n%s"

scope-description

rel-file

error-list-string

files-context-string

ai-code-change--generic-note)))

(edited-prompt (ai-code-read-string "Edit prompt for AI: "

prompt)))

(when (and edited-prompt (not (string-blank-p edited-prompt)))

(ai-code--insert-prompt edited-prompt)

(message "Generated prompt to fix %d Flycheck error(s) in %s."

(length errors-in-scope)

scope-description)))))))))

(provide 'ai-code-change)