chore: refactor the input component (#165)

* refactor the input component

* fix clippy

* clean up

crates/ui/src/input/rope_ext.rs

@@ -0,0 +1,207 @@
+use std::ops::Range;
+
+use rope::{Point, Rope};
+
+use super::cursor::Position;
+
+/// An extension trait for `Rope` to provide additional utility methods.
+pub trait RopeExt {
+    /// Get the line at the given row (0-based) index, including the `\r` at the end, but not `\n`.
+    ///
+    /// Return empty rope if the row (0-based) is out of bounds.
+    fn line(&self, row: usize) -> Rope;
+
+    /// Start offset of the line at the given row (0-based) index.
+    fn line_start_offset(&self, row: usize) -> usize;
+
+    /// Line the end offset (including `\n`) of the line at the given row (0-based) index.
+    ///
+    /// Return the end of the rope if the row is out of bounds.
+    fn line_end_offset(&self, row: usize) -> usize;
+
+    /// Return the number of lines in the rope.
+    fn lines_len(&self) -> usize;
+
+    /// Return the lines iterator.
+    ///
+    /// Each line is including the `\r` at the end, but not `\n`.
+    fn lines(&self) -> RopeLines;
+
+    /// Check is equal to another rope.
+    fn eq(&self, other: &Rope) -> bool;
+
+    /// Total number of characters in the rope.
+    fn chars_count(&self) -> usize;
+
+    /// Get char at the given offset (byte).
+    ///
+    /// If the offset is in the middle of a multi-byte character will panic.
+    ///
+    /// If the offset is out of bounds, return None.
+    fn char_at(&self, offset: usize) -> Option<char>;
+
+    /// Get the byte offset from the given line, column [`Position`] (0-based).
+    fn position_to_offset(&self, line_col: &Position) -> usize;
+
+    /// Get the line, column [`Position`] (0-based) from the given byte offset.
+    fn offset_to_position(&self, offset: usize) -> Position;
+
+    /// Get the word byte range at the given offset (byte).
+    fn word_range(&self, offset: usize) -> Option<Range<usize>>;
+
+    /// Get word at the given offset (byte).
+    #[allow(dead_code)]
+    fn word_at(&self, offset: usize) -> String;
+}
+
+/// An iterator over the lines of a `Rope`.
+pub struct RopeLines {
+    row: usize,
+    end_row: usize,
+    rope: Rope,
+}
+
+impl RopeLines {
+    /// Create a new `RopeLines` iterator.
+    pub fn new(rope: Rope) -> Self {
+        let end_row = rope.lines_len();
+        Self {
+            row: 0,
+            end_row,
+            rope,
+        }
+    }
+}
+
+impl Iterator for RopeLines {
+    type Item = Rope;
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.row >= self.end_row {
+            return None;
+        }
+
+        let line = self.rope.line(self.row);
+        self.row += 1;
+        Some(line)
+    }
+
+    #[inline]
+    fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        self.row = self.row.saturating_add(n);
+        self.next()
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let len = self.end_row - self.row;
+        (len, Some(len))
+    }
+}
+
+impl std::iter::ExactSizeIterator for RopeLines {}
+impl std::iter::FusedIterator for RopeLines {}
+
+impl RopeExt for Rope {
+    fn line(&self, row: usize) -> Rope {
+        let start = self.line_start_offset(row);
+        let end = start + self.line_len(row as u32) as usize;
+        self.slice(start..end)
+    }
+
+    fn line_start_offset(&self, row: usize) -> usize {
+        let row = row as u32;
+        self.point_to_offset(Point::new(row, 0))
+    }
+
+    fn position_to_offset(&self, pos: &Position) -> usize {
+        let line = self.line(pos.line as usize);
+        self.line_start_offset(pos.line as usize)
+            + line
+                .chars()
+                .take(pos.character as usize)
+                .map(|c| c.len_utf8())
+                .sum::<usize>()
+    }
+
+    fn offset_to_position(&self, offset: usize) -> Position {
+        let point = self.offset_to_point(offset);
+        let line = self.line(point.row as usize);
+        let column = line.clip_offset(point.column as usize, sum_tree::Bias::Left);
+        let character = line.slice(0..column).chars().count();
+        Position::new(point.row, character as u32)
+    }
+
+    fn line_end_offset(&self, row: usize) -> usize {
+        if row > self.max_point().row as usize {
+            return self.len();
+        }
+
+        self.line_start_offset(row) + self.line_len(row as u32) as usize
+    }
+
+    fn lines_len(&self) -> usize {
+        self.max_point().row as usize + 1
+    }
+
+    fn lines(&self) -> RopeLines {
+        RopeLines::new(self.clone())
+    }
+
+    fn eq(&self, other: &Rope) -> bool {
+        self.summary() == other.summary()
+    }
+
+    fn chars_count(&self) -> usize {
+        self.chars().count()
+    }
+
+    fn char_at(&self, offset: usize) -> Option<char> {
+        if offset > self.len() {
+            return None;
+        }
+
+        let offset = self.clip_offset(offset, sum_tree::Bias::Left);
+        self.slice(offset..self.len()).chars().next()
+    }
+
+    fn word_range(&self, offset: usize) -> Option<Range<usize>> {
+        if offset >= self.len() {
+            return None;
+        }
+
+        let offset = self.clip_offset(offset, sum_tree::Bias::Left);
+
+        let mut left = String::new();
+        for c in self.reversed_chars_at(offset) {
+            if c.is_alphanumeric() || c == '_' {
+                left.insert(0, c);
+            } else {
+                break;
+            }
+        }
+        let start = offset.saturating_sub(left.len());
+
+        let right = self
+            .chars_at(offset)
+            .take_while(|c| c.is_alphanumeric() || *c == '_')
+            .collect::<String>();
+
+        let end = offset + right.len();
+
+        if start == end {
+            None
+        } else {
+            Some(start..end)
+        }
+    }
+
+    fn word_at(&self, offset: usize) -> String {
+        if let Some(range) = self.word_range(offset) {
+            self.slice(range).to_string()
+        } else {
+            String::new()
+        }
+    }
+}