diff --git a/codex-rs/tui/src/bottom_pane/chat_composer.rs b/codex-rs/tui/src/bottom_pane/chat_composer.rs index 59d6e457..cd8e9fa1 100644 --- a/codex-rs/tui/src/bottom_pane/chat_composer.rs +++ b/codex-rs/tui/src/bottom_pane/chat_composer.rs @@ -290,26 +290,28 @@ impl ChatComposer<'_> { // Guard against out-of-bounds rows. let line = textarea.lines().get(row)?.as_str(); - // Clamp the cursor column to the line length to avoid slicing panics - // when the cursor is at the end of the line. - let col = col.min(line.len()); + // Calculate byte offset for cursor position + let cursor_byte_offset = line.chars().take(col).map(|c| c.len_utf8()).sum::(); // Split the line at the cursor position so we can search for word // boundaries on both sides. - let before_cursor = &line[..col]; - let after_cursor = &line[col..]; + let before_cursor = &line[..cursor_byte_offset]; + let after_cursor = &line[cursor_byte_offset..]; - // Find start index (first character **after** the previous whitespace). + // Find start index (first character **after** the previous multi-byte whitespace). let start_idx = before_cursor - .rfind(|c: char| c.is_whitespace()) - .map(|idx| idx + 1) + .char_indices() + .rfind(|(_, c)| c.is_whitespace()) + .map(|(idx, c)| idx + c.len_utf8()) .unwrap_or(0); - // Find end index (first whitespace **after** the cursor position). + // Find end index (first multi-byte whitespace **after** the cursor position). let end_rel_idx = after_cursor - .find(|c: char| c.is_whitespace()) + .char_indices() + .find(|(_, c)| c.is_whitespace()) + .map(|(idx, _)| idx) .unwrap_or(after_cursor.len()); - let end_idx = col + end_rel_idx; + let end_idx = cursor_byte_offset + end_rel_idx; if start_idx >= end_idx { return None; @@ -336,21 +338,25 @@ impl ChatComposer<'_> { let mut lines: Vec = self.textarea.lines().to_vec(); if let Some(line) = lines.get_mut(row) { - let col = col.min(line.len()); + // Calculate byte offset for cursor position + let cursor_byte_offset = line.chars().take(col).map(|c| c.len_utf8()).sum::(); - let before_cursor = &line[..col]; - let after_cursor = &line[col..]; + let before_cursor = &line[..cursor_byte_offset]; + let after_cursor = &line[cursor_byte_offset..]; // Determine token boundaries. let start_idx = before_cursor - .rfind(|c: char| c.is_whitespace()) - .map(|idx| idx + 1) + .char_indices() + .rfind(|(_, c)| c.is_whitespace()) + .map(|(idx, c)| idx + c.len_utf8()) .unwrap_or(0); let end_rel_idx = after_cursor - .find(|c: char| c.is_whitespace()) + .char_indices() + .find(|(_, c)| c.is_whitespace()) + .map(|(idx, _)| idx) .unwrap_or(after_cursor.len()); - let end_idx = col + end_rel_idx; + let end_idx = cursor_byte_offset + end_rel_idx; // Replace the slice `[start_idx, end_idx)` with the chosen path and a trailing space. let mut new_line = @@ -618,3 +624,154 @@ impl WidgetRef for &ChatComposer<'_> { } } } + +#[cfg(test)] +mod tests { + use crate::bottom_pane::ChatComposer; + use tui_textarea::TextArea; + + #[test] + fn test_current_at_token_basic_cases() { + let test_cases = vec![ + // Valid @ tokens + ("@hello", 3, Some("hello".to_string()), "Basic ASCII token"), + ( + "@file.txt", + 4, + Some("file.txt".to_string()), + "ASCII with extension", + ), + ( + "hello @world test", + 8, + Some("world".to_string()), + "ASCII token in middle", + ), + ( + "@test123", + 5, + Some("test123".to_string()), + "ASCII with numbers", + ), + // Unicode examples + ("@İstanbul", 3, Some("İstanbul".to_string()), "Turkish text"), + ( + "@testЙЦУ.rs", + 8, + Some("testЙЦУ.rs".to_string()), + "Mixed ASCII and Cyrillic", + ), + ("@诶", 2, Some("诶".to_string()), "Chinese character"), + ("@👍", 2, Some("👍".to_string()), "Emoji token"), + // Invalid cases (should return None) + ("hello", 2, None, "No @ symbol"), + ("@", 1, None, "Only @ symbol"), + ("@ hello", 2, None, "@ followed by space"), + ("test @ world", 6, None, "@ with spaces around"), + ]; + + for (input, cursor_pos, expected, description) in test_cases { + let mut textarea = TextArea::default(); + textarea.insert_str(input); + textarea.move_cursor(tui_textarea::CursorMove::Jump(0, cursor_pos)); + + let result = ChatComposer::current_at_token(&textarea); + assert_eq!( + result, expected, + "Failed for case: {} - input: '{}', cursor: {}", + description, input, cursor_pos + ); + } + } + + #[test] + fn test_current_at_token_cursor_positions() { + let test_cases = vec![ + // Different cursor positions within a token + ("@test", 0, Some("test".to_string()), "Cursor at @"), + ("@test", 1, Some("test".to_string()), "Cursor after @"), + ("@test", 5, Some("test".to_string()), "Cursor at end"), + // Multiple tokens - cursor determines which token + ("@file1 @file2", 0, Some("file1".to_string()), "First token"), + ( + "@file1 @file2", + 8, + Some("file2".to_string()), + "Second token", + ), + // Edge cases + ("@", 0, None, "Only @ symbol"), + ("@a", 2, Some("a".to_string()), "Single character after @"), + ("", 0, None, "Empty input"), + ]; + + for (input, cursor_pos, expected, description) in test_cases { + let mut textarea = TextArea::default(); + textarea.insert_str(input); + textarea.move_cursor(tui_textarea::CursorMove::Jump(0, cursor_pos)); + + let result = ChatComposer::current_at_token(&textarea); + assert_eq!( + result, expected, + "Failed for cursor position case: {description} - input: '{input}', cursor: {cursor_pos}", + ); + } + } + + #[test] + fn test_current_at_token_whitespace_boundaries() { + let test_cases = vec![ + // Space boundaries + ( + "aaa@aaa", + 4, + None, + "Connected @ token - no completion by design", + ), + ( + "aaa @aaa", + 5, + Some("aaa".to_string()), + "@ token after space", + ), + ( + "test @file.txt", + 7, + Some("file.txt".to_string()), + "@ token after space", + ), + // Full-width space boundaries + ( + "test　@İstanbul", + 6, + Some("İstanbul".to_string()), + "@ token after full-width space", + ), + ( + "@ЙЦУ　@诶", + 6, + Some("诶".to_string()), + "Full-width space between Unicode tokens", + ), + // Tab and newline boundaries + ( + "test\t@file", + 6, + Some("file".to_string()), + "@ token after tab", + ), + ]; + + for (input, cursor_pos, expected, description) in test_cases { + let mut textarea = TextArea::default(); + textarea.insert_str(input); + textarea.move_cursor(tui_textarea::CursorMove::Jump(0, cursor_pos)); + + let result = ChatComposer::current_at_token(&textarea); + assert_eq!( + result, expected, + "Failed for whitespace boundary case: {description} - input: '{input}', cursor: {cursor_pos}", + ); + } + } +}