1use crate::{Anchor, Point, TextBuffer, ToOffset as _, ToPoint as _};
 2use std::{cmp::Ordering, mem, ops::Range};
 3
 4pub type SelectionSetId = clock::Lamport;
 5pub type SelectionsVersion = usize;
 6
 7#[derive(Copy, Clone, Debug, Eq, PartialEq)]
 8pub enum SelectionGoal {
 9    None,
10    Column(u32),
11    ColumnRange { start: u32, end: u32 },
12}
13
14#[derive(Clone, Debug, Eq, PartialEq)]
15pub struct Selection {
16    pub id: usize,
17    pub start: Anchor,
18    pub end: Anchor,
19    pub reversed: bool,
20    pub goal: SelectionGoal,
21}
22
23impl Selection {
24    pub fn head(&self) -> &Anchor {
25        if self.reversed {
26            &self.start
27        } else {
28            &self.end
29        }
30    }
31
32    pub fn set_head(&mut self, buffer: &TextBuffer, cursor: Anchor) {
33        if cursor.cmp(self.tail(), buffer).unwrap() < Ordering::Equal {
34            if !self.reversed {
35                mem::swap(&mut self.start, &mut self.end);
36                self.reversed = true;
37            }
38            self.start = cursor;
39        } else {
40            if self.reversed {
41                mem::swap(&mut self.start, &mut self.end);
42                self.reversed = false;
43            }
44            self.end = cursor;
45        }
46    }
47
48    pub fn tail(&self) -> &Anchor {
49        if self.reversed {
50            &self.end
51        } else {
52            &self.start
53        }
54    }
55
56    pub fn point_range(&self, buffer: &TextBuffer) -> Range<Point> {
57        let start = self.start.to_point(buffer);
58        let end = self.end.to_point(buffer);
59        if self.reversed {
60            end..start
61        } else {
62            start..end
63        }
64    }
65
66    pub fn offset_range(&self, buffer: &TextBuffer) -> Range<usize> {
67        let start = self.start.to_offset(buffer);
68        let end = self.end.to_offset(buffer);
69        if self.reversed {
70            end..start
71        } else {
72            start..end
73        }
74    }
75}